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People construct simplified mental representations to plan |
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Mark K. Ho1,2,*, David Abel3,+, Carlos G. Correa4, Michael L. Littman3, Jonathan D. Cohen1,4, |
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and Thomas L. Griffiths1,2 |
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1Princeton University, Department of Psychology, Princeton, NJ, USA;2Princeton University, Department |
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of Computer Science, Princeton, NJ, USA;3Brown University, Department of Computer Science, |
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Providence, RI, USA;+Now at DeepMind, London, United Kingdom;4Princeton University, Princeton |
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Neuroscience Institute, Princeton, NJ, USA;*Corresponding author: Mark K Ho, |
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[email protected] |
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One of the most striking features of human cognition is the capacity to plan. Two aspects |
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of human planning stand out: its efficiency and flexibility. Efficiency is especially impres- |
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sive because plans must often be made in complex environments, and yet people successfully |
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plan solutions to myriad everyday problems despite having limited cognitive resources1–3. |
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Standard accounts in psychology, economics, and artificial intelligence have suggested hu- |
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man planning succeeds because people have a complete representation of a task and then use |
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heuristics to plan future actions in that representation4–11. However, this approach gener- |
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ally assumes that task representations are fixed . Here, we propose that task representations |
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can be controlled and that such control provides opportunities to quickly simplify problems |
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and more easily reason about them. We propose a computational account of this simplifica- |
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tion process and, in a series of pre-registered behavioral experiments, show that it is subject |
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to online cognitive control12–14and that people optimally balance the complexity of a task |
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representation and its utility for planning and acting. These results demonstrate how strate- |
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gically perceiving and conceiving problems facilitates the effective use of limited cognitive |
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resources. |
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1arXiv:2105.06948v2 [cs.AI] 26 Nov 2022In the short story “On Exactitude in Science,” Jorge Luis Borges describes cartographers who |
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seek to create the perfect map, one that includes every possible detail of the country it represents. |
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However, this innocent premise leads to an absurd conclusion: The fully detailed map of the |
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country must be the size of the country itself, which makes it impractical for anyone to use. Borges’ |
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allegory illustrates an important computational principle. Namely, useful representations do not |
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simply mirror every aspect of the world, but rather pick out a manageable subset of details that |
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are relevant to some purpose (Figure 1a). Here, we examine the consequences of this principle for |
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how humans flexibly construct simplified task representations to plan. |
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Classic theories of problem solving distinguish between representing a task andcomputing a |
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plan4,15,16. For instance, Newell and Simon17introduced heuristic search , in which a decision- |
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maker has a full representation of a task (e.g., a chess board, chess pieces, and the rules of chess), |
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and then computes a plan by simulating and evaluating possible action sequences (e.g., sequences |
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of chess moves) to find one that is likely to achieve a goal (e.g., checkmate the king). In artificial |
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intelligence, the main approach to making heuristic search tractable involves limiting the com- |
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putation of action sequences (e.g., only thinking a few moves into the future, or only examining |
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moves that seem promising)5. Similarly, psychological research on planning largely focuses on |
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how limiting, prioritizing, pruning, or chunking action sequences can reduce computation6–11,18–20. |
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However, people are not necessarily restricted to a single, full, or fixed representation for a |
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task. This matters since simpler representations can make better use of limited cognitive resources |
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when they are tailored to specific parts or versions of a task. For example, in chess, considering the |
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interaction of a few pieces, or focusing on part of the board, is easier than reasoning about every |
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piece and part of the board. Furthermore, it affords the opportunity to adapt the representation, |
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tailoring it to the specific needs of the circumstance—a process that we refer to as controlling a |
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task construal . Although studies show that people can flexibly form representations to guide action |
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(e.g., forming the ad hoc category of “things to buy for a party” when organizing a social gath- |
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ering21), a long-standing challenge for cognitive science and artificial intelligence is explaining, |
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predicting, and deriving such representations from general computational principles22,23. |
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2a |
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Task Action PlanDecision-Maker |
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Decision-Maker |
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Plan ConstrualTask |
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Task Actionb |
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cFigure 1. Construal and planning. a, A satellite photo of Princeton, NJ (top) and maps of |
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Princeton for bicycling versus automotive use cases (bottom). Like maps and unlike photographs, |
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a decision-maker’s construal picks out a manageable subset of details from the world relevant to |
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their current goals. Imagery ©2022 Google, Map data ©2022. b,Standard models assume that a |
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decision-maker computes a plan, , with respect to a fixed task representation, T, and then uses |
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it to guide their actions, a.c,According to our model of value-guided construal , the decision- |
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maker forms a simplified task construal, Tc, that is used to compute a plan, c. This process can |
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be understood as two nested optimizations: an “outer loop” of construal and an “inner loop” of |
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planning. |
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Our approach to studying how people control task construals starts with the premise that ef- |
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fective decision-making depends on making rational use of limited cognitive resources1–3. Specif- |
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ically, we derive how an ideal, cognitively-limited decision-maker should form value-guided con- |
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3struals that balance the complexity of a representation and its utility for planning and acting. We |
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then show that pre-registered predictions of this account explain how people attend to task elements |
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in several planning experiments (see Data Availability Statement). Our analysis and findings sug- |
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gest that controlled, moment-to-moment task construals play a key role in efficient and flexible |
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planning. |
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Task construals from first principles |
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We build on models of sequential decision-making expressed as Markov Decision Processes24. |
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Formally, a taskTconsists of a state space, S; an initial state, s02S; an action space, A; a |
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transition function P:SAS ! [0;1]; and a utility function U:S ! R. In standard |
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formulations of planning, the value of a plan:SA! [0;1]from a state sis determined |
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by the expected, cumulative utility of using that plan25:V(s) =U(s) +P |
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a(ajs)P |
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s0P(s0j |
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s;a)V(s0). Standard planning algorithms5(e.g., heuristic search methods) attempt to efficiently |
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compute plans that optimize value by directly planning over a fixed task representation, T, that |
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is not subject to the decision-maker’s control (Figure 1b). Our aim is to relax this constraint and |
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consider the process of adaptively selecting simplified task representations for planning, which we |
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call the construal process (Figure 1c). |
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Intuitively, a construal “picks out” details in a task to consider. Here, we examine construals |
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that pick out cause-effect relationships in a task. This focus is motivated by the intuition that a key |
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source of task complexity is the interaction of different causes and their effects with one another. |
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For instance, consider interacting with various objects in someone’s living room. Walking towards |
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the couch and hitting it is a cause-effect relationship, while pulling on the coffee table and moving |
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itmight be another such relationship. These individual effects can interact and may or may not be |
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integrated into a single representation of moving around the living room. For example, imagine |
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pulling on the coffee table and causing it to move, but in doing so, backing into the couch and |
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hitting it. Whether or not a decision-maker anticipates and represents the interaction of multiple |
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4effects depends on what causes and effects are incorporated into their construal; this, in turn, can |
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impact the outcome of behavior. |
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Related work has studied how attention guides learning about how different state features pre- |
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dict rewards26. By contrast, to model construals, we require a way to express how attention flexibly |
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combines different causes and their effects into an integrated model to use for planning. For this, |
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we use a product of experts27, a technique from the machine learning literature for combining dis- |
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tributions that is similar to factored approximations used in models of perception28. Specifically, |
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we assume that the agent has Nprimitive cause-effect relationships that each assign probabili- |
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ties to state, action, and next-state transitions, i:SAS ! [0;1],i= 1;:::;N . Each |
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i(s0js;a)is a potential function representing, say, the local effect of colliding with the couch or |
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pulling on the coffee table. Then a construal is a subset of these primitive cause-effect relation- |
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ships,cf1;:::;Ng, that produces a task construal, Tc, with the following construed transition |
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function: |
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Pc(s0js;a)/Y |
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i2ci(s0js;a): (1) |
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Here, we assume that task construals ( Tc) and the original task ( T) share the same state space, |
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action space, and utility function. But, crucially, the construed transition function can be simpler |
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than that of the actual task. |
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What task construal should a decision-maker select? Ideally, it would be one that only includes |
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those elements (cause-effect relationships) that lead to successful planning, excluding any others |
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so as to make the planning problem as simple as possible. To make this intuition precise, it is |
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essential to first distinguish between computing a plan with a construal and using the plan induced |
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by a construal. In our example, suppose the decision-maker forms a construal of their living |
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room that includes the effect of pulling on the coffee table but ignores the effect of colliding with |
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the couch. They might then compute a plan in which they pull on the coffee table without any |
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complications, but when they usethat plan in the actual living room, they inadvertently stumble |
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over their couch. This particular construal is less than optimal. |
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Thus, we formalize the distinction between the computed plan associated with a construal and |
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5its resulting behavioral utility : If the decision-maker has a task construal Tc, denote the plan that |
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optimizes it as c. Then, the utility of the computed plan when starting at state s0is given by its |
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performance when interacting with the actual transition dynamics, P: |
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U(c) =U(s0) +X |
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ac(ajs0)X |
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s0P(s0js0;a)Vc(s0): (2) |
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Put simply, the behavioral utility of a construal is determined by the consequences of using it to |
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plan and act in the actual task. |
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Having established the relationship between a construal and its utility, we can define the value |
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of representation (VOR) associated with a construal. Our formulation resembles previous models |
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of resource-rationality2and the expected value of control13by discounting utilities with a cognitive |
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cost,C. This cost could be further enriched by specifying algorithm-specific costs29or hard con- |
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straints30. However, our aim is to understand value-guided construal with respect to the complexity |
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of the construal itself and with minimal algorithmic assumptions. To this end, we use a cost that |
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penalizes the number of effects considered: C(c) =jcj, wherejcjis the cardinality of c. Intuitively, |
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this cost reflects the description length of a program that expresses the construed transition func- |
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tion in terms of primitive effects31. It also generalizes recent economic models of sparsity-based |
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behavioral inattention32. The value of representation for construal cis then its behavioral utility |
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minus its cognitive cost: |
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VOR (c) =U(c) C(c): (3) |
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In short, we introduce the notion of a task construal (Equation 1) that relaxes the assumption |
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of planning over a fixed task representation. We then define an optimality criterion for a construal |
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based on its complexity and its utility for planning and acting (Equations 2-3). This optimality |
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criterion provides a normative standard we can use to ask whether people form optimal value- |
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guided construals33,34. We note that the question of precisely how people identify or learn optimal |
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construals is beyond the scope of our current aims. Rather, here our goal is to simply determine |
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whether their planning is consistent with optimal construal. If so, then understanding how people |
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6achieve (or approximate) this ability will be a key direction for future research (see Supplementary |
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Discussion of Construal Optimization Algorithms). |
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A paradigm for examining construals |
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Do people form construals that optimally balance complexity and utility? To answer this question, |
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we designed a paradigm analogous to the example in Figure 1a, in which participants were shown |
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a two-dimensional map of a maze and had to move a blue dot to reach a goal location. On each |
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trial, participants were shown a new maze composed of a starting location, a goal location, center |
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black walls in the shape of a +, and an arrangement of blue obstacles. The goal, starting state, |
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and the blue obstacles (but not the center black walls) changed on every trial, which required |
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participants to examine the layout of the maze and plan an efficient route to the goal (Figure 2a). |
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In our framework, each obstacle corresponds to a cause-effect relationship, i—i.e., attempting to |
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move into the space occupied by the obstacle and then being blocked. This is analogous to the |
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effect of being blocked by a piece of furniture in our earlier example. |
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Two key features make our maze-navigation paradigm useful for isolating and studying the |
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construal process. First, the mazes are fully observable : Complete information about the task |
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is immediately accessible from the visual stimulus. Second, each instance of a maze emerges |
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from a particular composition of individual elements (e.g., the obstacles). This means that while |
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all the components of a particular maze are immediately accessible, participants need to choose |
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which ones to integrate into an effective representation for planning (i.e., select a construal). Fully |
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observable but compositionally-structured problems occur routinely in everyday life—e.g., using |
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a map to navigate through exhibits in a museum—as well as in popular games—e.g., in chess, |
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figuring out how to move one’s knight across a board occupied by an opponent’s pieces. By |
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providing people with immediate access to all the components of a task while planning, we can |
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examine which ones they attend to versus ignore and whether these patterns of awareness reflect |
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a process of value-guided construal (Methods, Model Implementations, Value-guided Construal |
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7Implementation; Code Availability Statement). Furthermore, this general paradigm can be used in |
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concert with several different experimental measures to assess attention (Extended Data Figures |
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1-3; Supplementary Experimental Materials; Data Availability Statement). |
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b |
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An obstacle was either in the yellow or |
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green location (not both), which one was it? |
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How confident are you?Goal, agent, and |
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obstacles appearObstacles are invisible |
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during navigationRecall probe |
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Confidence probea |
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Trial BeginsGoal, agent, and |
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obstacles appearParticipant navigatesAwareness probe |
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How aware of the highlighted |
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obstacle were you at any point? |
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Figure 2. Maze-navigation paradigm and design of memory probes, Value-guided con- |
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strual predicts how people will form representations that are simple but useful for planning |
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and acting. These predictions were tested in a new paradigm in which participants controlled |
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a blue circle and navigated mazes composed of center black walls in the shape of a cross, blue |
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tetronimo-shaped obstacles, and a yellow goal state with a shrinking green square. We assume |
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that attention to obstacles as a result of construal is reflected in memory of obstacles and used |
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two types of probes to assess memory. a,In our initial experiment, participants were shown the |
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maze and navigated to the goal (dashed line indicates an example path). After navigating, partic- |
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ipants were given awareness probes in which they were asked to report their awareness of each |
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obstacle on an 8-point scale (for analyses, responses were scaled to range from 0 to 1). b,In a |
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subsequent experiment, obstacles were only visible prior to moving in order to encourage plan- |
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ning up-front, and participants were given recall probes in which they were shown a pair of ob- |
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stacles in green and yellow, only one of which had been present in the maze they had just com- |
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pleted. They were then asked which one had been in the maze as well as their confidence. |
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8Traces of construals in people’s memory |
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We assume that the obstacles included in a construal will be associated with greater awareness |
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and thereby memory; accordingly, we began by probing memory for obstacles after participants |
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completed each maze to test whether they formed value-guided construals of the mazes. In our ini- |
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tial experiment, participants received awareness probes in which, following navigation, they were |
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shown a picture of the maze they had just completed with one of the obstacles highlighted. Then, |
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they were asked, “How aware of the highlighted obstacle were you at any point?” and responded |
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on an 8-point scale that was later scaled to range from 0 to 1 for analyses (Figure 2a). If participants |
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formed representations of the mazes that balance utility and complexity, their responses should be |
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positively predicted by value-guided construal. This is precisely what we found: Value-guided con- |
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strual predicted awareness judgments (likelihood ratio test comparing hierarchical linear models |
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with and without z-score normalized value-guided construal probabilities: 2(1) = 2297:21;p < |
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1:010 16;= 0:133, S.E. = 0:003; Methods, Experiment Analyses; Figure 3). Furthermore, |
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we also observed the same results when participants could not see the obstacles while moving and |
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so needed to plan their route entirely up front ( 2(1) = 726:95;p < 1:010 16;= 0:115, |
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S.E.= 0:004). This was also the case when we probed awareness judgments immediately after |
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planning but before execution (2(1) = 679:20;p< 1:010 16;= 0:106, S.E. = 0:004; Meth- |
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ods, Experimental Design, Up-front Planning Experiment; Supplementary Memory Experiment |
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Analyses). |
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9Value-Guided Construal |
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Expected Obstacle Probability |
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≤ 0.5 > 0.5ab |
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c |
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0.00.51.0 |
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Participant mean awareness response (experiment) |
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Value-guided construal probability (predicted) |
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0.00 0.25 0.50 0.75 1.00 |
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Initial Experiment Mean Awareness051015Count |
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Figure 3. Initial experiment results, In our initial planning experiment (out of four), each |
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person (n= 161 independent participants) navigated twelve 2D mazes, each of which had seven |
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blue tetronimo-shaped obstacles. To assess whether attention to obstacles reflects a process of |
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value-guided construal, participants were given an awareness probe (see Figure 2a) for each ob- |
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stacle in each maze. a,For our first analysis, we split the set of 84 obstacles across mazes based |
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on whether value-guided construal assigned a probability less than or equal to 0:5or greater than |
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0:5. Here, we plot two histograms of participants’ mean awareness responses corresponding to |
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the two sets of obstacles ( 0:5in grey,>0:5in blue; individual by-obstacle mean awareness un- |
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derlying the histograms are represented underneath). We then similarly split the obstacles based |
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on whether mean awareness responses were less than or equal to 0:5or greater than 0:5and, us- |
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ing a chi-squared test for independence, found that this split was predicted by value-guided con- |
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strual (2(1;N= 84) = 23:03,p= 1:610 6, effect size w= 0:52).b,Value-guided construal |
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predictions for three of the twelve mazes used in the experiment (blue circle indicates the starting |
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location, green and yellow square indicates the goal; obstacle colors represent model probabilities |
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according to the colorbar). c,Participant mean awareness judgments for the same three mazes |
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(obstacle colors represent mean judgments according to the colorbar). Responses in this initial |
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experiment generally reflect value-guided construal of mazes. Participants were recruited through |
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the Prolific online experiment platform. |
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While the awareness probes provide useful insight into people’s task construals, it is a step |
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removed from their memory (which is already a step removed from the construal process itself) |
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since it requires participants to reflect on their earlier awareness during planning. To address this |
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limitation, we developed a second set of critical mazes with two properties. First, the mazes were |
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10designed to test the distinctive predictions of value-guided construal (e.g., Figure 4a). Second, |
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these new mazes allowed us to use a more stringent measure of memory for task elements. Specif- |
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ically, we used obstacle recall probes , in which, following navigation, participants were shown a |
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grid with the black center walls, a green obstacle, a yellow obstacle, and no other obstacles. Either |
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the green or yellow obstacle had actually been present in the maze, whereas the other obstacle did |
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not overlap with any of those that had been present. Participants were then asked, “An obstacle |
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was either in the yellow or green location (not both), which one was it?” and could select either op- |
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tion, followed by a confidence judgment on an 8-point scale (Figure 2b; Extended Data Figure 4a). |
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The recall probes thus provided two measures, accuracy and confidence, and using hierarchical |
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generalized linear models (HGLMs) we found that value-guided construal predicted both types of |
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responses (likelihood ratio tests comparing models on accuracy: 2(1) = 249:34;p< 1:010 16; |
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= 0:648, S.E. = 0:042; and confidence: 2(1) = 432:76;p < 1:010 16;= 0:104, |
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S.E.= 0:005. Methods, Experiment Analyses). Additionally, when we gave a separate group |
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of participants the awareness probes on these mazes, value-guided construal was again predictive |
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(Awareness: 2(1) = 837:47;p < 1:010 16;= 0:175, S.E. = 0:006). Thus, using three |
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different measures of memory (recall accuracy, recall confidence, and awareness judgments), we |
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found further evidence that when planning, people form task representations that optimally balance |
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complexity and utility. |
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11a b |
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c |
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0.0 0.4 0.5 0.6 0.7 0.8 0.9 1.0 |
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Accuracy0.00.30.40.50.60.70.80.9ConfidencePlanning |
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0.0 0.4 0.5 0.6 0.7 0.8 0.9 1.0 |
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Accuracy0.00.30.40.50.60.70.80.9Perception Control |
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Obstacle Type |
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Relevant/Near |
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Relevant/Far (Critical) |
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Irrelevant |
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0.0 0.4 0.5 0.6 0.7 0.8 0.9 1.0 |
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Accuracy0.00.30.40.50.60.70.80.9Execution Control |
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Optimal PathIrrelevantIrrelevant |
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Relevant/Far |
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(Critical)Relevant/Near |
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0 20 40 60 80 100 120 |
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Change in AICVGC |
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Traj HS |
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Graph HS |
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Bottleneck |
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SR Overlap |
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Nav Dist |
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Nav Dist Step |
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Goal Dist |
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Start Dist |
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Wall Dist |
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Center DistLesioned |
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Predictor |
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Figure 4. Critical mazes recall experiment, model comparisons, and control studies. a, |
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The critical mazes recall experiment ( n= 78 independent participants; one version of one of the |
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four planning experiments) used critical mazes that included critical obstacles that were highly |
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relevant to planning but far from an optimal path (dashed line). Value-guided construal predicts |
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critical obstacles will be included in a construal while irrelevant obstacles will not, indepen- |
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dent of distance to the optimal path. b,We fit a global model to recall responses that included |
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the fixed parameter value-guided construal modification model (VGC) along with ten alternative |
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predictors based on heuristic search models, successor representation-based predictors, and low- |
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level perceptual cues (see Methods, Experiment Analyses). Then, each predictor was removed |
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from this global model, and we calculated the resulting change in fit (in AIC). Removing value- |
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guided construal led to the largest degradation of fit (greatest increase in AIC), underscoring its |
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unique explanatory value. c,In a pair of non-planning control experiments, new participants ei- |
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ther viewed patterns that looked exactly like the mazes (perceptual control; n= 88 independent |
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participants) or followed “breadcrumbs” through the maze along a path taken by a participant |
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from the original experiment (execution control; n= 80 independent participants). They then an- |
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swered the exact same recall questions. Value-guided construal remains a significant factor when |
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explaining recall in the original critical mazes experiment (planning) while including mean re- |
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call from the perceptual and execution controls as covariates (likelihood ratio test for accuracy: |
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2(1) = 106:36;p= 6:210 25; confidence: 2(1) = 18:56;p= 1:610 5;p-values |
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are unmodified). This confirms that responses consistent with value-guided construal are not a |
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simple function of perception and execution. Participants were recruited through the Prolific on- |
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line experiment platform. Plotted are the mean values for each obstacle, with relevant/near, rele- |
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vant/far (critical), and irrelevant obstacle types distinguished. Error bars are standard errors about |
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the mean. |
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12Controlling for perception and execution |
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The memory studies provide preliminary confirmation of our hypothesis, but they have several |
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limitations. One is that, although participants were engaged in planning , they were also necessarily |
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engaged in other forms of cognitive processing, and these unrelated processes may have influenced |
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memory of the obstacles. In particular, participants’ perception of a maze or their execution of a |
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particular plan through a maze may have influenced their responses to the memory probes. This |
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potentially confounds the interpretation of our results, since a key part of our hypothesis is that |
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task construals arise from planning , rather than simply perceiving or executing. |
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Thus, to test that responses to the memory probes cannot be fully explained by perception |
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and/or execution, we administered two sets of yoked controls that did not require planning (Meth- |
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ods, Experimental Design, Control Experiments). In the perceptual controls , new participants were |
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shown patterns that looked exactly like the mazes, but they performed an unrelated, non-planning |
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task. Each pattern was presented to a new participant for the same amount of time that a partic- |
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ipant in the original experiments had examined the corresponding maze before moving—i.e., the |
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amount of time the original participant spent examining the maze to plan. The new participant then |
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responded to the same probes, in the same order, as the original participant. For the execution con- |
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trols, we recruited another group of participants and gave them instructions similar to those in the |
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planning experiments. However, unlike the original experiments, the task did not require planning. |
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Rather, these mazes included “breadcrumbs” that needed to be collected and that appeared every |
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two steps. Breadcrumbs appeared along the exact path taken by one of the original participants, |
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meaning that the new participant executed the same actions but without having planned . After |
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completing each maze, the participant then received the same probes, in the same order, as the |
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original participant. |
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We assessed whether responses in the planning experiments can be explained by a simple |
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combination of perception and/or execution by testing whether value-guided construal remained |
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a significant factor after accounting for control responses. Specifically, we used the mean by- |
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obstacle responses from the perceptual and execution controls as predictors in HGLMs fit to |
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13the corresponding planning responses. We then tested whether adding value-guided construal |
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as a predictor improved fits. For the awareness, accuracy, and confidence responses in the re- |
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call experiment, we found that including value-guided construal significantly improved fits (like- |
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lihood ratio tests comparing models on accuracy: 2(1) = 106:36;p= 6:210 25; confi- |
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dence:2(1) = 18:56;p= 1:610 5; and awareness: 2(1) = 55:34;p= 1:010 13) |
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and that value-guided construal predictions were positively associated with responses (coefficients |
|
for accuracy: = 0:58;S.E. = 0:058; confidence: = 0:039;S.E. = 0:009; and awareness: |
|
= 0:054;S.E. = 0:007). Thus, responses following planning are not reducible to a simple |
|
combination of perception andexecution , and they can be further explained by the formation of |
|
value-guided construals (Figure 4c; Supplementary Control Experiment Analyses). |
|
Externalizing the planning process |
|
Another limitation of the previous planning experiments is that they assess construal after planning |
|
is complete (i.e., by probing memory). To obtain a measure of the planning process as it unfolds , |
|
we developed a novel process-tracing paradigm . In this version of the task, participants never |
|
saw all of the obstacles at once. Instead, at the beginning of the trial, after being shown the start |
|
and goal locations, they could use their mouse to reveal individual obstacles by hovering over them |
|
(Methods, Experimental Design, Process-tracing Experiments; Extended Data Figure 4b). This led |
|
participants to externalize the planning process, and so their behavior on this task provides insight |
|
into how planning computations unfolded internally. We tested whether value-guided construal |
|
accounted for behavior by analyzing two measures: whether an obstacle was hovered over and, if |
|
it was hovered over, the duration of hovering. Value-guided construal was a significant predictor |
|
for both these measures on both the initial mazes (likelihood ratio tests comparing HGLMs for |
|
hovering:2(1) = 1221:76;p < 1:010 16;= 0:704, S.E. = 0:021; and hover duration [log |
|
milliseconds]: 2(1) = 169:90;p < 1:010 16;= 0:161, S.E. = 0:012) and on the critical |
|
mazes (hovering: 2(1) = 1361:92;p < 1:010 16;= 0:802, S.E. = 0:023; hover duration |
|
14[log milliseconds]: 2(1) = 540:63;p < 1:010 16;= 0:369, S.E. = 0:016). These results |
|
thus complement our original memory-based measurements of people’s task representations and |
|
strengthen the interpretation of them in terms of value-guided construal during planning. |
|
Value-guided construal modification |
|
Thus far, our account of value-guided construal has assumed that an obstacle is either always |
|
or never included in a construal. This simplification is useful since it enables us to derive clear |
|
qualitative predictions based on whether a plan is influenced by an obstacle, but it overlooks graded |
|
factors such as how much of a plan is influenced by an obstacle. For example, an obstacle may only |
|
be relevant for planning a few movements around a participant’s initial location in a maze and, as |
|
a result, could receive less total attention than one that is relevant for deciding how to act across |
|
a larger area of the maze. To characterize these more fine-grained attentional processes, we first |
|
generalized the original construal selection problem to a one in which the decision-maker revisits |
|
and potentially modifies their construal during planning. Then, we derived obstacle awareness |
|
predictions based on a theoretically optimal construal modification policy that balances complexity |
|
and utility (Methods, Model Implementation, Value-Guided Construal). |
|
To assess value-guided construal modification, we re-analyzed our data using three versions of |
|
the model with increasing ability to capture variability in responses. First, we used an idealized |
|
fixed parameter model to derive a single set of obstacle attention predictions and confirmed that |
|
they also predict participant responses on the planning tasks (Supplementary Construal Modifica- |
|
tion Analyses). Second, for each planning measure and experiment, we calculated fitted parameter |
|
models in which noise parameters for the computed plan and construal modification policy were |
|
fit (Methods, Model Implementation, Value-Guided Construal). Scatter plots comparing mean by- |
|
obstacle responses and model outputs for parameters with the highest R2are shown in Figure 5. |
|
Finally, we fit a set of models that allowed for biases in computed plans (e.g., a bias to stay along |
|
the edge of a maze or an explicit penalty for bumping into walls) and found that this additional ex- |
|
15pressiveness led to obstacle attention predictions with an improved correspondence to participant |
|
responses (Supplementary Construal Modification Analyses). Together, these analyses provide |
|
additional insight into the fine-grained dynamic structure of value-guided construal modification. |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.20.40.60.8Initial Exp |
|
Awareness Judgment |
|
R2=0.53 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.20.40.60.8Up-Front Planning Exp |
|
Awareness Judgment |
|
R2=0.44 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.40.50.60.70.80.91.0Critical Maze Exp |
|
Recall Accuracy |
|
R2=0.87 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.40.50.60.70.80.9Critical Maze Exp |
|
Recall Confidence |
|
R2=0.81 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.20.40.60.8Critical Maze Exp |
|
Awareness Judgment |
|
R2=0.74 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.00.20.40.60.81.0Process-Tracing |
|
(Initial Mazes) |
|
Hovering |
|
R2=0.42 |
|
0.0 0.5 1.0 |
|
Fitted Value-Guided |
|
Construal Modification Prob5.05.56.06.57.07.5Process-Tracing |
|
(Initial Mazes) |
|
Log-Hover Duration |
|
R2=0.30 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob0.00.20.40.60.81.0Process-Tracing |
|
(Critical Mazes) |
|
Hovering |
|
R2=0.61 |
|
0.00 0.25 0.50 0.75 1.00 |
|
Fitted Value-Guided |
|
Construal Modification Prob5.56.06.57.0Process-Tracing |
|
(Critical Mazes) |
|
Log-Hover Duration |
|
R2=0.48 |
|
Figure 5. Fitted value-guided construal modification. Our initial model of value-guided |
|
construal focuses on whether an obstacle should or should not be included in a construal. We de- |
|
veloped a generalization that additionally accounts for how much an obstacle influences a plan if |
|
a decision-maker is optimally modifying their construal during planning (Methods, Model Im- |
|
plementations, Value-Guided Construal). We used an "-softmax noise model [35] for computed |
|
action plans and construal modification policies and, for each experiment and measure, searched |
|
for parameters that maximize the R2between model predictions and mean by-obstacle responses. |
|
Shown here are plots comparing scores that the fitted construal modification model assigns to |
|
each obstacle with participants’ mean by-obstacle responses for the nine measures. |
|
Accounting for alternative mechanisms |
|
While the analyses so far confirm the predictive power of value-guided construal, it is also im- |
|
portant to consider alternative planning processes. For instance, differential awareness could have |
|
been a passive side-effect of planning computations , rather than an active facilitator of planning |
|
computations as posited by value-guided construal. In particular, participants could have been |
|
planning by performing heuristic search over action sequences without actively construing the task, |
|
which would have led to differential awareness of obstacles as a byproduct of planning. Differ- |
|
ential awareness could also have arisen from alternative representational processes, such as those |
|
16based on the successor representation36or related subgoaling mechanisms37. Similarly, perceptual |
|
factors, such as the distance to the start, goal, walls, center, optimal path, or path taken, could have |
|
influenced responses. |
|
Based on these considerations, we identified ten alternative predictors (Methods, Model Imple- |
|
mentations; Extended Data Figures 5, 6, and 7; Code Availability Statement). All ten predictors |
|
plus the fixed value-guided construal modification predictions were included in global models that |
|
were fit to each of the nine planning experiment measures, and, in all cases, value-guided construal |
|
was a significant predictor (Extended Data Table 1; see Supplementary Alternative Mechanisms |
|
Analyses for the same analyses with the single-construal model). |
|
Furthermore, to assess the relative importance of each predictor, we calculated the change in |
|
fit (in terms of AIC) that resulted from removing each predictor from a global model (Methods, |
|
Experiment Analyses). Across all planning experiment measures, removing value-guided con- |
|
strual led to the first or second largest reduction in fit (Figure 4b; Extended Data Table 1). These |
|
“knock-out” analyses demonstrate the explanatory necessity of value-guided construal. To assess |
|
explanatory sufficiency , we fit a new set of single-predictor and two-predictor models using all pre- |
|
dictors and then calculated their AICs (Methods, Experiment Analyses; Extended Data Figure 8). |
|
For all nine experimental measures, value-guided construal was one of the top two single-predictor |
|
models and was one of the two factors included in the best two-predictor model. Together, these |
|
analyses confirm the explanatory necessity and sufficiency of value-guided construal. |
|
Discussion |
|
We tested the idea that when people plan, they do so by constructing a simplified mental representa- |
|
tion of a problem that is sufficient to solve it—a process that we refer to as value-guided construal. |
|
We began by formally articulating how an ideal, cognitively-limited decision-maker should con- |
|
strue a task so as to balance complexity and utility. Then, we showed that pre-registered predictions |
|
of this model explain people’s awareness, ability to recall problem elements (obstacles in a maze), |
|
17confidence in recall ability, and behavior in a process-tracing paradigm, even after controlling for |
|
the baseline influence of perception and execution as well as ten alternative mechanisms. These |
|
findings support the hypothesis that people make use of a controlled process of value-guided con- |
|
strual, and that it can help explain the efficiency of human planning. More generally, our account |
|
provides a framework for further investigating the cognitive mechanisms involved in construal. For |
|
instance, how are construal strategies acquired? How is construal selection shaped by computation |
|
costs, time, or constraints? From a broader perspective, our analysis suggests a deep connection |
|
between the control of construals and the acquisition of structured representations like objects and |
|
their parts that can be cognitively manipulated38,39, which can inform the development of intelli- |
|
gent machines. Future investigation into these and other mechanisms that interface with the control |
|
of representations will be crucial for developing a comprehensive theory of flexible and efficient |
|
intelligence. |
|
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21Methods |
|
Model Implementations |
|
Value-guided Construal |
|
Our model assumes the decision-maker has a set of cause-effect relationships that can be combined |
|
into a task construal that is then used for planning. To derive empirical predictions for the maze |
|
tasks, we assume a set of primitive cause-effect relationships, each of which is analogous to the |
|
example of interacting with furniture in a living room (see main text). For each maze, we modeled |
|
the following: The default effect of movement (i.e., pressing an arrow key causes the circle to |
|
move in that direction with probability 1 "and stay in place with probability ","= 10 5),Move; |
|
the effect of being blocked by the center, plus-shaped ( +) walls (i.e., the wall causes the circle to |
|
notmove when the arrow key is pressed), Walls; and effects of being blocked by each of the N |
|
obstacles,Obstacle i;i= 1;:::;N . Since every maze includes the same movements and walls, the |
|
model only selected which obstacle effects to include. The utility function for all mazes was given |
|
by a step cost of 1until the goal state was reached. |
|
Value-guided construal posits a bilevel optimization procedure involving an “outer loop” of |
|
construal and an “inner loop” of planning. Here, we exhaustively calculate potential solutions to |
|
this nested optimization problem by enumerating and planning with all possible construals (i.e., |
|
subsets of obstacle effects). We exactly solved the inner loop of planning for each construal us- |
|
ing dynamic programming40and then evaluated the optimal stochastic computed plan under the |
|
actual task dynamics (i.e., Equation 2). For planning and evaluation, transition probabilities were |
|
multiplied by a discount rate of :99was used to ensure values were finite. The general procedure |
|
for calculating the value of construals is outlined in the algorithm in Extended Data Table 2. To |
|
be clear, our current research strategy is to derive theoretically optimal predictions for the inner |
|
loop of planning and outer loop of construal in the spirit of resource-rational analysis2. Thus, |
|
this specific procedure should not be interpreted as a process model of human construal. In the |
|
Supplemental Discussion of Algorithms for Construal Optimization, we discuss the feasibility of |
|
22optimizing construals and how an important direction for future research will involve investigating |
|
tractable algorithms for finding good construals. |
|
Given a value of representation function, VOR, that assigns a value to each construal, we model |
|
participants as selecting a construal according to a softmax decision-rule: |
|
P(c)/exp |
|
1VOR (c) |
|
; (4) |
|
where > 0is a temperature parameter (for our pre-registered predictions = 0:1). We then |
|
calculated a marginalized probability for each obstacle being included in the construal, from the |
|
initial state, s0, corresponding to the expected awareness of that obstacle: |
|
P(Obstacle i) =X |
|
c1[Obstacle i2c]P(c); (5) |
|
where, for a statement X, 1[X]evaluates to 1ifXis true and 0ifXis false. We implemented this |
|
model in Python 3.7 using the msdm library (see Code Availability Statement). |
|
The basic value-guided construal model makes the simplifying assumption that the decision- |
|
maker plans with a single static construal. We can extend this idea to consider a decision-maker |
|
who revisits and potentially modifies their construal at each stage of planning. In particular, we |
|
can conceptualize this process in terms of a sequential decision-making problem induced by the |
|
interaction between task dynamics (e.g., a maze) and the internal state of an agent (e.g., a con- |
|
strual) [41]. The solution to this problem is then a sequence of modified construals associated with |
|
planning over different parts of the task (e.g., planning movements for different areas of the maze). |
|
Formally, we denote the set of possible construals as C=P(f1;:::;Ng), the powerset of |
|
cause-effect relationships, and define a construal modification Markov Decision Process , which |
|
has a state space corresponding to the Cartesian product of task states and construals, (s;c)2SC , |
|
and an action space corresponding to possible next construals, c02 C. Having chosen a new |
|
construalc0, the probability of transitioning from task state stos0comes from first calculating |
|
a joint distribution using the actual transition function P(s0js;a)and planc0(ajs)and then |
|
23marginalizing over task actions a: |
|
P(s0js;c0) =X |
|
ac0(ajs)P(s0js;a): (6) |
|
In this construal modification setting, the analogue to the value of representation (VOR; Equa- |
|
tion 3) is the optimal construal modification value function , defined over all s;c: |
|
V(s;c) =U(s) + max |
|
c0"X |
|
s0P(s0js;c0)V(s0;c0) C(c0;c)# |
|
; (7) |
|
whereC(c0;c) =jc0 cjis the number of additional1cause-effect relationships in the new construal |
|
c0compared to c. Importantly, this cost on modifying the construal encourages consistency—i.e., |
|
withoutC(c0;c), a decision-maker would have no disincentive to completely change their construal |
|
for each state. Note that in the special case where c=?, we recover the original static construal |
|
cost for a single step. Finally, using the construal modification value function, we define a softmax |
|
policy over the task/construal state space, (c0js;c)/expf 1 |
|
c[P |
|
s0P(s0js;c0)V(s0;c0) C(c0;c)]g. |
|
For the fixed parameter model we set c= 0:1(as with the single-construal model). |
|
The construal modification formulation allows us to consider not just whether an obstacle ap- |
|
pears in a construal, but also how long it appears in a construal. In particular, we would like to |
|
compute a quantity that is analogous to Equation 5 that assigns model values for each obstacle. |
|
To do this, we use the normalized task/construal state occupancy induced by a construal policy |
|
from the initial task/construal state, (s;cjs0;c0)/M(s0;c0;s;c), wherec0=?andMis |
|
the successor representation under (for a self-contained review of M, see the section on Succes- |
|
sor Representation-based Predictors below). Given a policy and starting task state s0, for each |
|
obstacle, we calculate the probability of having a construal that includes that obstacle: |
|
P(Obstacle i) =X |
|
s;c1[Obstacle i2c](s;cjs0;c0): (8) |
|
1For sets AandB, the set difference A B=fa:a2Aanda =2Bg. |
|
24To calculate the optimal construal modification value function, V(s;c), for each maze, we con- |
|
structed construal modification Markov Decision Processes in Python (3.7) using scipy (1.5.2) |
|
sparse matrices [42]. We then exactly solved for V(s;c)using a custom implementation of policy |
|
iteration [43] designed to take advantage of the sparse matrix data structure (see Code Availability |
|
Statement). For the fitted parameter models, we used separate "-softmax noise models [35] for the |
|
computed plans, c(ajs), and construal modification policy, (c0js;c), and performed a grid |
|
search over the four parameters for each of the nine planning measures ( 1 |
|
a2f1;3;5;7g;"a2 |
|
f0:0;0:1;0:2g; 1 |
|
c2f1;3;5;7;9g;"c2f0;0:05;0:1;0:2;0:3g). Additionally, for parameter fit- |
|
ting, we limited the construals c02C to be of size three. This improves the speed of parameter |
|
evaluation and yields results comparable to the fixed parameter model, which uses the full con- |
|
strual set. Finally, to obtain obstacle value-guided construal probabilities we simulate 1000 rollouts |
|
of the construal modification policy to estimate (js0;c0). As with the initial model, we empha- |
|
size that these procedures are not intended as an algorithmic account of construal modification, but |
|
rather allow us to derive theoretically optimal predictions of the fine-grained dynamics of value- |
|
guided construals during planning. |
|
Heuristic Search Over Action Sequences |
|
Value-guided construal posits that people control their task representations to actively facilitate |
|
planning , which, in the maze navigation paradigm, leads to differential attention to obstacles. How- |
|
ever, differential attention could also occur as a passive side-effect of planning , even in the absence |
|
of active construal. In particular, heuristic search over action sequences is another mechanism for |
|
reducing the cost of planning, but it accomplishes this in a different way: by examining possible |
|
action sequences in order of how promising they seem, not by simplifying the task representation. |
|
If people are simulating candidate action sequences via heuristic search (and not engaged in an ac- |
|
tive construal process), differential attention to task elements could have simply been a side-effect |
|
of how those simulations unfolded. |
|
Thus, we wanted to derive predictions of differential awareness as a byproduct of search over |
|
25action sequences. To do so, we considered two general classes of heuristic search algorithms. |
|
The first, a variant of Real-Time Dynamic Programming (RTDP)44,45, is a trajectory-based search |
|
algorithm that simulates physically realizable trajectories (i.e., sequences of states and actions that |
|
could be generated by repeatedly calling a fixed transition function). The algorithm works by |
|
first initializing a heuristic value function (e.g., based on domain knowledge). Then, it simulates |
|
trajectories that greedily maximize the heuristic value function while also performing Bellman |
|
updates at simulated states44. This scheme then leads RTDP to simulate states in order of how |
|
promising they are (according to the continuously updated heuristic value function) until the value |
|
function converges. Importantly, RTDP can end up visiting a fraction of the total state space, |
|
depending on the heuristic. Our implementation was based on the Labeled RTDP algorithm of |
|
Bonet & Geffner45, which additionally includes a labeling scheme that marks states where the |
|
estimate of the value function has converged, leading to faster overall convergence. |
|
To derive obstacle awareness predictions, we ran RTDP (implemented in msdm ; see Code |
|
Availability Statement) on each maze and initialized it with a heuristic corresponding to the optimal |
|
value function assuming there are plus-shaped walls but no obstacles . This models the background |
|
knowledge participants have about distances, while also providing a fair comparison to the initial |
|
information provided to the value-guided construal implementation. Additionally, if at any point |
|
the algorithm had to choose actions based on estimated value, ties were resolved randomly, making |
|
the algorithm stochastic. For each maze, we ran 200 simulations of the algorithm to convergence |
|
and examined which states were visited by the algorithm over all simulations. We calculated the |
|
mean number of times each obstacle was hitby the algorithm, where a hit was defined as a visit |
|
to a state adjacent to an obstacle such that the obstacle was in between the state and the goal. |
|
Because the distribution of hit counts has a long tail, we used the natural log of hit counts +1as |
|
the obstacle hit scores. The reason why the raw hit counts have a long tail is due to the particular |
|
way in which RTDP calculates the value of regions where the heuristic value is much higher than |
|
the actual value (e.g., dead ends in a maze). Specifically, RTDP explores such regions until it has |
|
confirmed that it is no better than an alternative path, which can take many steps. More generally, |
|
26trajectory-based algorithms are limited in that they can only update states by simulating physically |
|
realizable trajectories starting from the initial state. |
|
The limitations of trajectory-based planning algorithms motivated our use of a second class |
|
ofgraph-based planning algorithms. We used LAO46, a version of the classic Aalgorithm47 |
|
generalized to be used on Markov Decision Processes (implemented in msdm ; see Code Availabil- |
|
ity Statement). Unlike trajectory-based algorithms, graph-based algorithms like LAOmaintain a |
|
graph of previously simulated states. LAOin particular builds a graph of the task rooted at the |
|
initial state and then continuously plans over the graph. If it computes a plan that leads it to a state |
|
at the edge of the graph, the graph is expanded according to the transition model to include that |
|
state and then the planning cycle is restarted. Otherwise, if it computes an optimal plan that only |
|
visits states in the simulated graph, the algorithm terminates. By continuously expanding the task |
|
graph and performing planning updates, the algorithm can intelligently explore the most promising |
|
(according to the heuristic) regions of the state space being constrained to physically realizable se- |
|
quences. In particular, graph-based algorithms can quickly “backtrack” when they encounter dead |
|
ends. |
|
Obstacle awareness predictions based on LAOwere derived by using the same initial heuristic |
|
as was used for RTDP and a similar scheme for handling ties. We then calculated the total number |
|
of times an obstacle was hit during graph expansion phases only, using the same definition of a hit |
|
as above. For each maze, we generated 200 planning simulations and used the raw hit counts as |
|
the hit score. |
|
Algorithms like RTDP and LAOplan by simulating realizable action sequences that begin at |
|
the start state. As a result, these models tend to predict greater awareness to obstacles that are near |
|
the start state and are consistent with the initial heuristic, regardless of whether those obstacles |
|
strongly affect or lie along the final optimal path. For instance, obstacles down initially promising |
|
dead ends have a high hit score. This contrasts with value-guided construal, which predicts greater |
|
attention to relevant obstacles, even if they are distant, and lower attention to irrelevant ones, even |
|
if they are nearby. For an example of these distinct model predictions, see maze #14 in Extended |
|
27Data Figure 6. |
|
To be clear, our goal was to obtain predictions for search over action sequences in the absence |
|
of an active construal process for comparison with value-guided construal. However, in general, |
|
heuristic search and value-guided construal are complementary mechanisms, since the former is a |
|
way to plan given a representation and the latter is a way to choose a representation for planning. |
|
For instance, one could perform heuristic search over a construed planning model, or a construal |
|
could help with selecting a heuristic to guide search over actions. These kinds of interactions |
|
between action-sequence search and construal are important directions for future research that can |
|
be built on the ideas developed here. |
|
Successor Representation-based Predictors |
|
We also considered two measures based on the successor representation , which has been proposed |
|
as a component in several computational theories of efficient sequential decision-making36,48. Im- |
|
portantly, the successor representation is not a specific model; rather it is a predictive coding of a |
|
task in which states are represented in terms of the future states likely to be visited from that state, |
|
given the decision-maker follows a certain policy. Formally, the value function of a policy (ajs) |
|
can be expressed in the following two equivalent ways: |
|
V(s) =U(s) +X |
|
a(ajs)X |
|
s0P(s0js;a)V(s0) (9) |
|
=X |
|
s+M(s;s+)U(s+); (10) |
|
whereM(s;s+)is expected occupancy of s+starting from s, when acting according to . The |
|
successor representation of a state sunderis then the vector M(s;). Algorithmically, Mcan |
|
be calculated by solving a set of recursive equations (implemented in Python with numpy49; see |
|
Code Availability Statement): |
|
M(s;s+) = 1[s=s+] +X |
|
a;s0(ajs)P(s0js;a)M(s0;s+): (11) |
|
28Again, the successor representation is not itself an algorithm, but rather a policy-conditioned re- |
|
coding of states that can be a component of a larger computational process (e.g, different kinds |
|
of learning or planning). Here, we focus on its use in the context of transfer learning48,50and |
|
bottleneck states37,51. |
|
Research on transfer learning posits that the successor representation supports transfer that is |
|
more flexible than pure model-free mechanisms but less flexible than model-based planning. For |
|
example, Russek et al.50model agents that learned a successor representation for the optimal pol- |
|
icy in an initial maze and then examined transfer when the maze was changed (e.g., adding in a |
|
new barrier). While their work focuses on learning, rather than planning, we can borrow the ba- |
|
sic insight that the successor representation induced by the optimal policy for a source task can |
|
influence the encoding of a target task, which constitutes a form of construal. In our experiments, |
|
participants were not trained on any particular source task, but we can use the maze with all obsta- |
|
cles removed as a proxy (i.e., representing what all mazes had in common). Thus, we calculated |
|
the optimal policy for the maze without any obstacles (but with the start and goal), computed the |
|
successor representation M, and then calculated, for each obstacle iin the actual maze with the |
|
obstacles, a successor representation overlap (SR-Overlap) score: |
|
SR-Overlap (i) =X |
|
s2ObsiM(s0;s); (12) |
|
wheres0is the starting state and Obs iis the set of states occupied by the obstacle i. This quantity |
|
can be interpreted as the amount of overlap between an obstacle and the successor representation of |
|
the starting state. If the successor representation shapes how people represent tasks, this quantity |
|
would be associated with greater awareness of certain obstacles. |
|
The second predictor is related to the idea of bottleneck states . These emerge from how the |
|
successor representation encodes multi-scale task structure37, and they have been proposed as a |
|
basis for subgoal selection51. If bottlenecks guide subgoal selection, then distance to bottleneck |
|
states could give rise to differential awareness of obstacles via subgoaling processes. Thus, we |
|
29wanted to test that responses consistent with value-guided construal were not entirely attributable to |
|
the effect of bottleneck states calculated in the absence of an active construal process. Importantly, |
|
we note that as with alternative planning mechanisms like heuristic search, the identification of |
|
bottleneck states for subgoaling is compatible with value-guided construal (e.g., one could identify |
|
subgoals for a construed version of a task). |
|
When viewing the transition function of a task (e.g., a maze) as a graph over states, bottleneck |
|
states lie on either side of a partitioning of the state space into two regions such that there is high |
|
intra-region connectivity and low inter-region connectivity. This can be computed for any transition |
|
function using the normalized min-cuts algorithm52or derived from the second eigenvector of the |
|
successor representation under a random policy37. Here, we use a variant of the second approach |
|
as described in the appendix of37. Formally, given a transition function, P(s0js;a), we define an |
|
adjacency matrix, A(s;s0) = 1[9as.t.P(s0js;a)>0], and a diagonal degree matrix, D(s;s) = |
|
P |
|
s0A(s;s0). Then, the graph Laplacian, a representation often used to derive low-dimensional |
|
embeddings of graphs in spectral graph theory, is L=D A. We take the eigenvector with |
|
the second largest eigenvalue, which assigns a positive or negative value to each state in the task. |
|
This vector can be interpreted as projecting the state space onto a single dimension in a way that |
|
best preserves connectivity information, with a zero point that represents the mid-point of the |
|
projected graph. Bottleneck states correspond to those states nearest to 0. For each maze, we |
|
used this method to identify bottleneck states and further reduced these to the optimal bottleneck |
|
states , defined as bottleneck states with a non-zero probability of being visited under the optimal |
|
stochastic policy for the maze. Finally, for each obstacle, we calculated a bottleneck distance score, |
|
the minimum Manhattan distance from an obstacle to any of these bottleneck states. |
|
Notably, value-guided construal also predicts greater attention to obstacles that form bottle- |
|
necks because one often needs to carefully navigate through them to reach the goal. However, |
|
the predictions of our model differ for obstacles that are distant from the bottleneck. Specifically, |
|
value-guided construal predicts greater attention to relevant obstacles that affect the optimal plan, |
|
even if they are far from the bottleneck (e.g., see model predictions for maze #2 in Extended Data |
|
30Figure 5). |
|
Perceptual Landmarks |
|
Finally, we considered several predictors based on low-level perceptual landmarks and partici- |
|
pants’ behavior. These included the minimum Manhattan distance from an obstacle to the start |
|
location, the goal location, the center black walls, the center of the grid, and any of the locations |
|
visited by the participant in a trial (navigation distance). We also considered the timestep at which |
|
participants were closest to an object as a measure of how recently they were near an object. In |
|
cases where navigation distance was not an appropriate measure (e.g., if participants never nav- |
|
igated to the goal), we used the minimum Manhattan distance to trajectories sampled from the |
|
optimal policy averaged over 100 samples. |
|
Experimental Design |
|
All experiments were pre-registered (see Data Availability Statement) and approved by the Prince- |
|
ton Institutional Review Board (IRB). All participants were recruited from the Prolific online plat- |
|
form and provided informed consent. At the end of each experiment, participants provided free- |
|
response demographic information (age and gender, coded as male/female/neither). Experiments |
|
were implemented with psiTurk53and jsPsych54frameworks (see Code Availability Statement). |
|
Instructions and example trials are shown in the Supplementary Experimental Materials. |
|
Initial experiment |
|
Our initial experiment used a maze-navigation task in which participants moved a circle from |
|
a starting location on a grid to a goal location using the arrow keys. The set of initial mazes |
|
consisted of twelve 11 11 mazes with seven blue tetronimo-shaped obstacles and center walls |
|
arranged in a cross that blocked movement. On each trial, participants were first shown a screen |
|
displaying only the center walls. When they pressed the spacebar, the circle they controlled, the |
|
goal, and the obstacles appeared, and they could begin moving immediately. In addition, to ensure |
|
31that participants remained focused on moving, we placed a green square on the goal that shrank |
|
and would disappear after 1000ms but reset whenever an arrow key was pressed, except at the |
|
beginning of the trial when the green square took longer to shrink (5000ms). Participants received |
|
$0.10 for reaching the goal without the green square disappearing (in addition to the base pay |
|
of $0.98). The mazes were pseudo-randomly rotated or flipped, so the start and end state was |
|
constantly changing, and the order of mazes were pseudo-randomized. After completing each |
|
trial, participants received awareness probes, which showed a static image of the maze they had |
|
just navigated, with one of the obstacles shown in light blue. They were asked “How aware of the |
|
highlighted obstacle were you at any point?” and could respond using an 8-point scale (rescaled |
|
from 0 to 1 for analyses). Probes were presented for the seven obstacles in a maze. None of the |
|
probes were associated with a bonus. |
|
We requested 200 participants on Prolific and received 194 complete submissions. Following |
|
pre-registered exclusion criteria, a trial was excluded if, during navigation, >5000ms was spent at |
|
the initial state, >2000ms was spent at any non-initial state, >20000ms was spent on the entire |
|
trial, or>1500ms was spent in the last three steps in total. Participants with <80% of trials after |
|
exclusions or who failed 2 of 3 comprehension questions were excluded, which resulted in n= 161 |
|
participants’ data being analyzed (median age of 28;81male, 75female, 5neither). |
|
Up-front planning experiment |
|
The up-front planning version of the memory experiment was designed to dissociate planning |
|
and execution. The main change was that after participants took their first step, all of the blue |
|
obstacles (but not the walls or goal) were removed from the display (though they still blocked |
|
movement). This strongly encouraged planning prior to execution. To provide sufficient time to |
|
plan, the green square took 60000ms to shrink on the first step. Additionally, on a random half |
|
of the trials, after taking two steps, participants were immediately presented with the awareness |
|
probes ( early termination trials). The other half were fulltrials. We reasoned that responses |
|
following early termination trials would better reflect awareness after planning but before execution |
|
32(see Supplementary Memory Experiment Analyses for analyses comparing early versus full trials). |
|
We requested 200 participants on Prolific and received 188 complete submissions. The exclu- |
|
sion criteria were the same as in the initial experiment, except that the initial state and total trial |
|
time criteria were raised to 30000ms and 60000ms, respectively. After exclusions, we analyzed |
|
data fromn= 162 participants (median age of 28; 85 male, 72 female, 5 neither). |
|
Critical mazes experiment |
|
In the critical mazes experiment , participants again could not see the obstacles while executing |
|
and so needed to plan up front, but no trials ended early. There were two main differences with |
|
the previous experiments. First, we used a set of four critical mazes that included critical obsta- |
|
cles chosen to test predictions specific to value-guided construal. These were obstacles relevant |
|
to decision-making, but distant from the optimal path (see Supplementary Memory Experiment |
|
Analyses for analyses focusing on these critical obstacles). Second, half of the participants re- |
|
ceived recall probes in which they were shown a static image of the grid with only the walls, a |
|
green obstacle, and a yellow obstacle. They were then asked “An obstacle was either in the yellow |
|
or green location (not both), which one was it?” and could select either option, followed by a |
|
confidence judgment on an 8-point scale (rescaled from 0 to 1 for analyses). Pairs of obstacles |
|
and their contrasts in the critical mazes are shown in Extended Data Figure 4a. Participants each |
|
received two blocks of the four critical mazes, pseudo-randomly oriented and/or flipped. |
|
We requested 200 participants on Prolific and received 199 complete submissions. The trial |
|
and participant exclusion criteria were the same as in the up-front planning experiment. After |
|
exclusions, we analyzed data from n= 156 participants (median age of 26; 78 male, 75 female, 3 |
|
neither). |
|
Control Experiments |
|
The aim of the control experiments was to obtain yoked baselines for perception and execution for |
|
comparison with probe responses in the memory studies. The perceptual control used a variant of |
|
33the task in which participants were shown patterns that were perceptually identical to the mazes. |
|
Instead of solving a maze, they were told to “catch the red dot”: On each trial, a small red dot could |
|
appear anywhere on the grid, and participants were rewarded based on whether they pressed the |
|
spacebar after it appeared. Each participant was yoked to the responses of a participant from either |
|
theup-front planning orcritical mazes experiments. On yoked trials , participants were shown |
|
the exact same maze/pattern as their counterpart. Additionally, they were shown the pattern for |
|
the amount of time that their counterpart took before making their first move—since the obstacles |
|
were not visible during execution for the counterpart, this is roughly the time the counterpart spent |
|
looking at the maze to plan. A red dot never appeared on these trials, and they were followed by |
|
the exact same probes that the counterpart received. References to “obstacles” were changed to |
|
“tiles” (e.g., “highlighted tiles” as opposed to “highlighted obstacle” for the awareness probes). |
|
We also included dummy trials , which showed mazes in orientations not appearing in the yoked |
|
trials, for durations sampled from the yoked durations. Half of the dummy trials had red dots. We |
|
recruited enough participants such that at least one participant was matched to each participant |
|
from the original experiments and excluded people who said that they had participated in a similar |
|
experiment. This resulted in data from n= 164 participants being analyzed for the initial mazes |
|
perceptual control (median age of 30:5; 84 male, 79 female, 1 neither) and n= 172 for the critical |
|
mazes perceptual control (median age of 36.5; 86 male, 85 female, 1 neither). |
|
The execution control used a variant of the task in which participants followed a series of |
|
“breadcrumbs” through the maze to the goal and so did not need to plan a path to the goal. Each |
|
participant was yoked to a counterpart in either the initial experiment or the critical mazes experi- |
|
ment so that the breadcrumbs were generated based on the exact path taken by the counterpart. The |
|
ordering of the mazes and obstacle probes (i.e., awareness or location recall) were also the same. |
|
We recruited participants until at least one participant was matched to each participant from the |
|
original experiments. Additionally, we used the same exclusion criteria as in the initial experiment |
|
with the additional requirement that all black dots be collected on a trial. This resulted in data from |
|
n= 163 participants being analyzed for the initial mazes execution control (median age of 29; 86 |
|
34male, 77 female) and n= 161 for the critical mazes execution control (median age of 30; 94 male, |
|
63 female; 4 neither). |
|
Process-Tracing Experiments |
|
We ran process-tracing experiments using the initial mazes and the critical mazes. These experi- |
|
ments were similar to the memory experiments, except they used a novel process-tracing paradigm |
|
designed to externalize the planning process. Specifically, participants never saw all the obstacles |
|
in the maze at once. Rather, at the beginning of a trial, after clicking on a red X in the center |
|
of the maze, the goal and agent appeared, and participants could use their mouse to hover over |
|
the maze and reveal individual obstacles. An obstacle would become completely visible if the |
|
mouse hovered over any tile that was part of it for at least 25ms, until the mouse was moved to a |
|
tile that was not part of that obstacle. Once the participant started to move using the arrow keys, |
|
the cursor became temporarily invisible (to prevent using the cursor as a cue to guide execution), |
|
and the obstacles could no longer be revealed. We examined two dependent measures for each |
|
obstacle: whether participants hovered over an obstacle, and if so, the duration of hovering in log |
|
milliseconds. |
|
For each experiment with each set of mazes, we requested 200 participants on Prolific. Partic- |
|
ipants who completed the task had their data excluded if they did not hover over any obstacles on |
|
more than half of the trials. For the experiment with the initial set, we received completed submis- |
|
sions from 174 people and, after exclusions, analyzed data from n= 167 participants (median age |
|
of 30; 82 male, 82 female, 3 neither). For the experiment with the critical set, we received com- |
|
pleted submissions from 188 people and, after exclusions, analyzed data from n= 179 participants |
|
(median age of 32; 89 male, 86 female, 4 neither). |
|
Experiment Analyses |
|
Hierarchical generalized linear models (HGLMs) were implemented in Python and R using the |
|
lme455andrpy256packages (see Code Availability Statement). For all models, we included by- |
|
35participant and by-maze random intercepts, unless the resulting model was singular, in which case |
|
we removed by-maze random intercepts. For the memory experiment analyses testing whether |
|
value-guided construal predicted responses, we fit models with and without z-score normalized |
|
value-guided construal probabilities as a fixed effect and performed likelihood ratio tests to assess |
|
significance. For the control experiment analyses reported in the main text, we calculated mean |
|
by-obstacle responses from the perceptual and execution controls, and then included these values |
|
as fixed effects in models fit to the responses in the planning experiments. We then contrasted |
|
models with and without value-guided construal and performed likelihood ratio tests (additional |
|
analyses are reported in the Supplementary Memory Experiment Analyses and Supplementary |
|
Control Experiment Analyses). |
|
For our comparison with alternative models, we considered 11 different predictors that assign |
|
scores to obstacles in each maze: fixed-parameter value-guided construal modification probabil- |
|
ity (VGC), trajectory-based heuristic search score (Traj HS), graph-based heuristic search score |
|
(Graph HS), bottleneck state distance (Bottleneck), successor representation overlap (SR Over- |
|
lap), minimum navigation distance (Nav Dist), timestep of minimum navigation distance (Nav |
|
Dist Step), minimum optimal policy distance (Opt Dist), distance to goal (Goal Dist), distance to |
|
start (Start Dist), distance to center walls (Wall Dist), and distance to the center of the maze (Cen- |
|
ter Dist). We included predictors in the analysis of each experiment’s data where appropriate. For |
|
example, in the up-front planning experiment, participants did not navigate on early termination |
|
trials, and so we used the optimal policy distance rather than navigation distance. All predictors |
|
were z-score normalized before being included as fixed effects in HGLMs in order to facilitate |
|
comparison of estimated coefficients. |
|
We performed three types of analyses using the 11 predictors. First, we wanted determine |
|
whether value-guided construal captured variability in responses from the planning experiments |
|
even when accounting for the other predictors. For these analyses, we compared HGLMs that |
|
included all predictors to HGLMs with all predictors except value-guided construal and tested |
|
whether there was a significant difference in fit using likelihood ratio tests (Extended Data Table 1). |
|
36Second, we wanted to evaluate the relative necessity of each mechanism for explaining attention to |
|
obstacles when planning. For these analyses, we compared global HGLMs to HGLMs with each |
|
of the predictors removed and calculated the resulting change in AIC (see Extended Data Table |
|
1 for estimated coefficients and resulting AIC values). Finally, we wanted to assess the relative |
|
sufficiency of predictors in accounting for responses on the planning tasks. For these analyses, we |
|
fit HGLMs to each set of responses that included only individual predictors or pairs of predictors, |
|
and for each model we calculated the AIC relative to the best-fitting model (Extended Data |
|
Figure 8). Note that for all of these models, AIC values are summed over participants. |
|
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38Acknowledgements : The authors would like to thank Jessica Hamrick, Louis Gularte, Ceyda |
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Sayalı, Qiong Zhang, Rachit Dubey, and William Thompson for valuable feedback on this work. |
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This work was funded by NSF grant #1545126, John Templeton Foundation grant #61454, and |
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AFOSR grant # FA 9550-18-1-0077. |
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Author Contributions : All authors contributed to conceptualizing the project and editing the |
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manuscript. MKH, DA, MLL, and TLG developed the value-guided construal model. MKH im- |
|
plemented it. MKH and CGC implemented the heuristic search models and msdm library. MKH, |
|
JDC, and TLG designed the experiments. MKH implemented the experiments, analyzed the re- |
|
sults, and drafted the manuscript. |
|
Competing Interest Declaration : The authors declare no competing interests. |
|
Supplementary Information is available for this paper. |
|
Data Availability Statement : Data for the current study are available through the Open Science |
|
Foundation repository http://doi.org/10.17605/OSF.IO/ZPQ69. |
|
Code Availability Statement : Code for the current study are available through the Open Science |
|
Foundation repository http://doi.org/10.17605/OSF.IO/ZPQ69, which links to a GitHub repository |
|
and contains an archived version of the repository. The value-guided construal model and alterna- |
|
tive models were implemented in Python (3.7) using the msdm (0.6) library, numpy (1.19.2), and |
|
scipy (1.5.2). Experiments were implemented using psiTurk (3.2.0) and jsPsych (6.0.1). |
|
Hierarchical generalized linear regressions were implemented using rpy2 (3.3.6), lme4 (1.1.21), |
|
and R (3.6.1). |
|
39Maze 0.68 |
|
.42 .74.26 |
|
.83 |
|
.60.19Initial Exp |
|
Awareness |
|
.53 |
|
.38 .69.25 |
|
.73 |
|
.57.20Up-front planning |
|
Awareness |
|
.72 |
|
.69 .75.31 |
|
.93 |
|
.90.35Process-tracing |
|
Hovering |
|
6.6 |
|
6.1 6.85.8 |
|
7.2 |
|
7.05.9Process-tracing |
|
DurationMaze 1 |
|
.66 .63.29.76.28 |
|
.26.22 |
|
.57 .69.28.70.23 |
|
.27.21 |
|
.81 .85.26.75.31 |
|
.56.24 |
|
6.6 7.05.76.76.1 |
|
6.06.0Maze 2.70 |
|
.50 |
|
.59.50.79 |
|
.31 |
|
.44.56 |
|
.41 |
|
.65.50.71 |
|
.35 |
|
.47.94 |
|
.67 |
|
.75.64.88 |
|
.27 |
|
.796.6 |
|
5.7 |
|
6.56.36.6 |
|
6.0 |
|
6.6Maze 3.36.28 |
|
.33 |
|
.75.81 |
|
.66.51.36.25 |
|
.29 |
|
.71.75 |
|
.64.44.63.57 |
|
.45 |
|
.93.77 |
|
.87.686.66.5 |
|
6.4 |
|
7.06.5 |
|
6.86.0Maze 4.47 |
|
.72.76 |
|
.56.73 |
|
.72.33 |
|
.36 |
|
.71.69 |
|
.52.59 |
|
.59.32 |
|
.93 |
|
.86.83 |
|
.79.60 |
|
.81.56 |
|
6.5 |
|
6.96.8 |
|
5.96.0 |
|
6.66.5Maze 5.71 |
|
.37 |
|
.41 |
|
.76.54.83.24 |
|
.61 |
|
.29 |
|
.31 |
|
.71.53.73.23 |
|
.77 |
|
.52 |
|
.71 |
|
.84.85.89.52 |
|
6.7 |
|
6.1 |
|
6.4 |
|
7.47.17.36.4Extended Data Fig. 1 jExperimental measures on mazes 0 to 5, Average responses as- |
|
sociated with each obstacle in mazes 0 to 5 in the initial experiment (awareness judgment), the |
|
40up-front planning experiment (awareness judgment), and the process-tracing experiment (whether |
|
an obstacle was hovered over and, if so, the duration of hovering in log milliseconds). Obstacle |
|
colors are normalized by the minimum and maximum values for each measure/maze, except for |
|
awareness judgments, which are scaled from 0 to 1. |
|
41Maze 6.39 |
|
.48.40 |
|
.44.71.51 |
|
.38Initial Exp |
|
Awareness |
|
.33 |
|
.46.33 |
|
.61.74.49 |
|
.41Up-front planning |
|
Awareness |
|
.90 |
|
.68.39 |
|
.72.50.55 |
|
.60Process-tracing |
|
Hovering |
|
6.5 |
|
5.66.4 |
|
6.76.46.4 |
|
5.8Process-tracing |
|
DurationMaze 7.36.19 |
|
.74 |
|
.20.43 .18 |
|
.69 |
|
.31.27 |
|
.76 |
|
.25.47 .26 |
|
.69 |
|
.71.16 |
|
.67 |
|
.25.27 .13 |
|
.67 |
|
6.25.4 |
|
6.3 |
|
6.15.8 5.8 |
|
6.6Maze 8.18 |
|
.61.29 |
|
.41.25.35 |
|
.70.20 |
|
.72.28 |
|
.35.24.40 |
|
.79.09 |
|
.51.49 |
|
.70.18.14 |
|
.885.0 |
|
6.36.0 |
|
6.25.75.5 |
|
6.5Maze 9 |
|
.30 |
|
.20.79.81.39 |
|
.34 |
|
.78.27 |
|
.23.73.80.42 |
|
.30 |
|
.78.50 |
|
.66.82.88.79 |
|
.82 |
|
.915.8 |
|
6.86.97.56.9 |
|
6.6 |
|
6.9Maze 10.66 |
|
.77 .27 |
|
.23 |
|
.39.56 .43.74 |
|
.73 .24 |
|
.30 |
|
.36.51 .39.92 |
|
.65 .41 |
|
.29 |
|
.50.72 .416.8 |
|
6.2 6.4 |
|
5.9 |
|
6.26.3 6.0Maze 11.71 |
|
.47.23.80.83 |
|
.19.41 |
|
.65 |
|
.32.22.77.79 |
|
.23.38 |
|
.59 |
|
.57.21.77.93 |
|
.15.63 |
|
6.3 |
|
6.45.97.17.5 |
|
6.06.5Extended Data Fig. 2 jExperimental measures on mazes 6 to 11, Average responses as- |
|
sociated with each obstacle in mazes 6 to 11 in the initial experiment (awareness judgment), the |
|
42up-front planning experiment (awareness judgment), and the process-tracing experiment (whether |
|
an obstacle was hovered over and, if so, the duration of hovering in log milliseconds). Obstacle |
|
colors are normalized by the minimum and maximum values for each measure/maze, except for |
|
awareness judgments, which are scaled from 0 to 1. |
|
43Maze 12 |
|
.67.51.57.92 |
|
.78Critical Mazes Exp |
|
Accuracy |
|
.59.43.44.84 |
|
.61Critical Mazes Exp |
|
Confidence |
|
.35.23.32.81 |
|
.71Critical Mazes Exp |
|
Awareness |
|
.62.18.39.90 |
|
.62Process-tracing |
|
Hovering |
|
6.45.35.36.8 |
|
6.5Process-tracing |
|
DurationMaze 13 |
|
.70.60.51.76.92 |
|
.58.46.47.66.78 |
|
.34.35.26.69.84 |
|
.65.44.18.52.89 |
|
6.25.45.46.26.9Maze 14.65.49 |
|
.54.79.94 |
|
.54.53 |
|
.40.68.81 |
|
.41.35 |
|
.23.81.79 |
|
.78.69 |
|
.28.88.85 |
|
6.36.5 |
|
5.37.26.8Maze 15.66 |
|
.58.45 |
|
.85.87 |
|
.56 |
|
.42.62 |
|
.74.79 |
|
.39 |
|
.23.32 |
|
.81.76 |
|
.75 |
|
.56.67 |
|
.85.88 |
|
6.5 |
|
6.56.6 |
|
6.96.8Extended Data Fig. 3 jExperimental measures on mazes 12 to 15, Average responses as- |
|
sociated with each obstacle in mazes 12 to 15 in the critical mazes experiment (recall accuracy, |
|
recall confidence, and awareness judgment) and the process-tracing experiment (whether an ob- |
|
stacle was hovered over and, if so, the duration of hovering in log milliseconds). Obstacle colors |
|
are scaled to range from 0.5 to 1.0 for accuracy, 0 to 1 for hovering, confidence, and awareness |
|
judgments, and the minimum to maximum values across obstacles in a maze for hovering duration |
|
in log milliseconds. |
|
44Extended Data Fig. 4 jAdditional Experimental Details, a, Items from critical mazes exper- |
|
iment. Blue obstacles are the location of obstacles during the navigation part of the trial. Orange |
|
obstacles with corresponding number are copies that were shown during location recall probes. |
|
During recall probes, participants only saw an obstacle paired with its copy. b,Example trial from |
|
process-tracing experiment. Participants could never see all the obstacles at once, but, before nav- |
|
igating, could use their mouse to reveal obstacles. We analyzed whether value-guided construal |
|
predicted which obstacles people tended to hover over and, if so, the duration of hovering. |
|
45Maze 0.15 |
|
.05 .430.0 |
|
.73 |
|
0.00.0VGC |
|
2.7 |
|
3.6 3.82.9 |
|
3.1 |
|
2.0.04Traj HS |
|
1.4 |
|
3.0 4.0.82 |
|
5.0 |
|
2.00.0Graph HS |
|
7.0 |
|
5.0 1.011.0 |
|
7.0 |
|
1.09.0Bottleneck |
|
.76 |
|
1.3 1.4.32 |
|
.62 |
|
.01.12SR Overlap |
|
1.0 |
|
1.1 1.04.0 |
|
1.0 |
|
1.03.6Opt DistMaze 1 |
|
.25 .040.0.400.0 |
|
0.00.0 |
|
1.7 .360.01.20.0 |
|
0.00.0 |
|
4.0 .530.01.30.0 |
|
0.00.0 |
|
11.0 3.07.01.07.0 |
|
11.012.0 |
|
1.6 .051.5.421.4 |
|
.81.01 |
|
1.0 1.64.01.03.0 |
|
2.08.0Maze 2.42 |
|
0.0 |
|
.170.0.85 |
|
0.0 |
|
0.03.1 |
|
4.5 |
|
1.83.13.1 |
|
0.0 |
|
.311.0 |
|
5.0 |
|
1.25.05.0 |
|
0.0 |
|
.096.0 |
|
5.0 |
|
1.05.09.0 |
|
3.0 |
|
5.01.0 |
|
0.0 |
|
0.00.00.0 |
|
0.0 |
|
0.01.0 |
|
1.2 |
|
1.01.41.0 |
|
2.0 |
|
1.8Maze 3.160.0 |
|
.02 |
|
.70.80 |
|
.23.363.33.6 |
|
3.0 |
|
1.71.1 |
|
1.72.40.01.1 |
|
2.4 |
|
2.52.0 |
|
1.72.38.07.0 |
|
5.0 |
|
8.09.0 |
|
5.01.0.61.46 |
|
.62 |
|
.84.20 |
|
.25.833.07.0 |
|
4.1 |
|
1.01.0 |
|
1.21.0Maze 4.45 |
|
.03.47 |
|
.17.20 |
|
.31.01 |
|
4.3 |
|
1.93.2 |
|
4.5.86 |
|
1.6.13 |
|
3.0 |
|
1.04.5 |
|
5.01.0 |
|
2.1.14 |
|
9.0 |
|
5.01.0 |
|
7.010.0 |
|
3.05.0 |
|
1.0 |
|
0.00.0 |
|
0.00.0 |
|
0.00.0 |
|
4.0 |
|
1.01.0 |
|
1.01.0 |
|
1.02.3Maze 5.14 |
|
.02 |
|
0.0 |
|
.450.0.730.0 |
|
3.8 |
|
3.4 |
|
2.6 |
|
3.53.53.14.1 |
|
0.0 |
|
2.4 |
|
2.0 |
|
5.04.05.00.0 |
|
6.0 |
|
6.0 |
|
5.0 |
|
1.03.08.09.0 |
|
.78 |
|
.75 |
|
.47 |
|
.57.64.67.37 |
|
1.0 |
|
4.0 |
|
1.6 |
|
1.01.01.03.0Maze 6.38 |
|
.230.0 |
|
0.00.0.01 |
|
.32 |
|
3.9 |
|
3.80.0 |
|
0.00.0.10 |
|
.52 |
|
4.0 |
|
5.00.0 |
|
0.00.0.15 |
|
.63 |
|
6.0 |
|
7.08.0 |
|
5.01.04.0 |
|
4.0 |
|
2.0 |
|
1.1.84 |
|
0.00.00.0 |
|
1.7 |
|
4.1 |
|
1.01.0 |
|
3.01.02.1 |
|
1.2Maze 7.170.0 |
|
.29 |
|
0.00.0 0.0 |
|
.63 |
|
2.60.0 |
|
.86 |
|
0.00.0 0.0 |
|
.69 |
|
.750.0 |
|
.57 |
|
0.00.0 0.0 |
|
1.0 |
|
6.08.0 |
|
2.0 |
|
11.04.0 10.0 |
|
1.0 |
|
.50.13 |
|
.38 |
|
0.0.03 .03 |
|
.25 |
|
5.53.6 |
|
1.0 |
|
4.02.6 3.0 |
|
1.0Extended Data Fig. 5 jModel predictions on mazes 0 through 7, Shown are the predictions |
|
for six of the eleven predictors we tested: fixed parameter value-guided construal modification |
|
46obstacle probability (VGC, our model); trajectory-based heuristic search obstacle hit score (Traj |
|
HS); graph-based heuristic search obstacle hit score (Graph HS); distance to optimal bottleneck |
|
(Bottleneck); successor representation overlap score (SR Overlap); and distance to optimal paths |
|
(Opt Dist) (see Methods, Model Implementations). Mazes 0 to 7 were all in the initial set of mazes. |
|
Darker obstacles correspond to greater predicted attention according to the model. Obstacle colors |
|
normalized by the minimum and maximum values for each model/maze. |
|
47Maze 80.0 |
|
0.0.05 |
|
.120.00.0 |
|
.33VGC |
|
0.0 |
|
0.01.5 |
|
.970.00.0 |
|
.98Traj HS |
|
0.0 |
|
0.0.26 |
|
1.60.00.0 |
|
1.0Graph HS |
|
10.0 |
|
2.06.0 |
|
8.07.05.0 |
|
1.0Bottleneck |
|
0.0 |
|
0.0.97 |
|
.810.00.0 |
|
.26SR Overlap |
|
7.0 |
|
1.03.5 |
|
1.14.02.0 |
|
1.0Opt DistMaze 9 |
|
0.0 |
|
0.0.46.58.45 |
|
.28 |
|
.143.3 |
|
2.80.02.91.9 |
|
4.0 |
|
3.13.0 |
|
2.0.675.01.0 |
|
4.0 |
|
4.07.0 |
|
13.01.01.02.0 |
|
8.0 |
|
5.01.1 |
|
.01.19.63.58 |
|
.90 |
|
1.34.0 |
|
6.01.01.02.0 |
|
5.0 |
|
1.0Maze 10.19 |
|
.43 .20 |
|
0.0 |
|
0.0.04 0.0.84 |
|
2.6 4.1 |
|
3.9 |
|
1.9.28 .011.0 |
|
4.4 1.1 |
|
1.1 |
|
1.3.36 .015.0 |
|
1.0 8.0 |
|
8.0 |
|
6.08.0 11.0.06 |
|
1.4 .90 |
|
.58 |
|
.59.29 1.51.2 |
|
1.0 5.0 |
|
6.9 |
|
2.01.5 1.0Maze 11.32 |
|
.220.0.54.68 |
|
0.0.01 |
|
3.7 |
|
3.10.03.22.8 |
|
0.0.22 |
|
5.0 |
|
3.00.05.05.0 |
|
0.0.29 |
|
4.0 |
|
8.09.01.01.0 |
|
12.07.0 |
|
1.2 |
|
.581.2.86.60 |
|
.071.5 |
|
1.0 |
|
5.04.01.01.0 |
|
7.91.0Maze 12 |
|
.210.00.0.79 |
|
.36 |
|
3.50.03.73.4 |
|
4.6 |
|
3.00.05.05.0 |
|
5.0 |
|
8.08.06.04.0 |
|
5.0 |
|
.54.68.31.54 |
|
.57 |
|
6.04.02.01.0 |
|
1.0Maze 13 |
|
.190.00.0.38.84 |
|
3.43.50.03.93.1 |
|
4.05.00.04.05.0 |
|
9.05.09.01.05.0 |
|
.56.31.74.75.56 |
|
6.02.05.01.01.0Maze 14.280.0 |
|
0.0.29.82 |
|
4.31.2 |
|
3.83.63.1 |
|
4.01.9 |
|
4.03.05.0 |
|
8.06.0 |
|
6.01.010.0 |
|
.93.02 |
|
.73.64.58 |
|
3.03.8 |
|
4.01.01.0Maze 15.34 |
|
0.00.0 |
|
.30.87 |
|
4.5 |
|
3.51.5 |
|
4.13.1 |
|
5.0 |
|
3.01.9 |
|
4.05.0 |
|
6.0 |
|
10.07.0 |
|
1.011.0 |
|
1.0 |
|
.02.02 |
|
.61.56 |
|
4.0 |
|
6.53.7 |
|
1.01.0Extended Data Fig. 6 jModel predictions on mazes 8 through 15, Shown are the predictions |
|
for six of the eleven predictors we tested (see Methods, Model Implementations). Mazes 8 to 11 |
|
48were part of the initial set of mazes, while mazes 12 to 15 constituted the set of critical mazes. |
|
Darker obstacles correspond to greater predicted attention according to the model. Obstacle colors |
|
normalized by the minimum and maximum values for each model/maze. |
|
49R² = 0.50 |
|
0.0 0.50.00.51.0Initial Exp. |
|
Awareness JudgmentVGC |
|
R² = 0.05 |
|
0.0 2.5Traj HS |
|
R² = 0.28 |
|
0 5Graph HS |
|
R² = 0.32 |
|
5 10Bottleneck |
|
R² = 0.00 |
|
0 2SR Overlap |
|
R² = 0.55 |
|
2.5 5.0 7.5Opt Dist |
|
R² = 0.00 |
|
5 10 15Goal Dist |
|
R² = 0.00 |
|
5 10 15Start Dist |
|
R² = 0.06 |
|
2.5 5.0Wall Dist |
|
R² = 0.05 |
|
2.5 5.0 7.5Center Dist |
|
R² = 0.40 |
|
0.0 0.50.00.51.0Up-front Planning Exp. |
|
Awareness JudgmentR² = 0.01 |
|
0.0 2.5R² = 0.18 |
|
0 5R² = 0.39 |
|
5 10R² = 0.01 |
|
0 2R² = 0.53 |
|
2.5 5.0 7.5R² = 0.00 |
|
5 10 15R² = 0.00 |
|
5 10 15R² = 0.01 |
|
2.5 5.0R² = 0.01 |
|
2.5 5.0 7.5 |
|
R² = 0.83 |
|
0.0 0.50.00.51.0Critical Maze Exp. |
|
Recall Accuracy |
|
R² = 0.25 |
|
0.0 2.5R² = 0.42 |
|
0 5R² = 0.06 |
|
5 10R² = 0.11 |
|
0 1R² = 0.44 |
|
2.5 5.0R² = 0.15 |
|
5 10 15R² = 0.12 |
|
10 20R² = 0.04 |
|
2.5 5.0R² = 0.01 |
|
5 10 |
|
R² = 0.80 |
|
0.0 0.50.00.51.0Critical Mazes Exp. |
|
Recall ConfidenceR² = 0.05 |
|
0.0 2.5R² = 0.19 |
|
0 5R² = 0.05 |
|
5 10R² = 0.02 |
|
0 1R² = 0.42 |
|
2.5 5.0R² = 0.27 |
|
5 10 15R² = 0.21 |
|
10 20R² = 0.02 |
|
2.5 5.0R² = 0.07 |
|
5 10 |
|
R² = 0.71 |
|
0.0 0.50.00.51.0Cricical Mazes Exp. |
|
Awareness JudgmentR² = 0.15 |
|
0.0 2.5R² = 0.27 |
|
0 5R² = 0.20 |
|
5 10R² = 0.05 |
|
0 1R² = 0.69 |
|
2.5 5.0R² = 0.11 |
|
5 10 15R² = 0.07 |
|
10 20R² = 0.00 |
|
2.5 5.0R² = 0.01 |
|
5 10 |
|
R² = 0.38 |
|
0.0 0.50.00.51.0Process-Tracing |
|
(Initial Mazes 0-11) |
|
Hovering |
|
R² = 0.23 |
|
0.0 2.5R² = 0.33 |
|
0 5R² = 0.17 |
|
5 10R² = 0.02 |
|
0 2R² = 0.32 |
|
2.5 5.0 7.5R² = 0.01 |
|
5 10 15R² = 0.03 |
|
5 10 15R² = 0.07 |
|
2.5 5.0R² = 0.07 |
|
2.5 5.0 7.5 |
|
R² = 0.29 |
|
0.0 0.5567Process-Tracing |
|
(Initial Mazes 0-11) |
|
Log-Hover Duration R² = 0.09 |
|
0.0 2.5R² = 0.17 |
|
0 5R² = 0.17 |
|
5 10R² = 0.00 |
|
0 2R² = 0.16 |
|
2.5 5.0 7.5R² = 0.00 |
|
5 10 15R² = 0.01 |
|
5 10 15R² = 0.00 |
|
2.5 5.0R² = 0.00 |
|
2.5 5.0 7.5 |
|
R² = 0.52 |
|
0.0 0.50.00.51.0Process-Tracing |
|
(Critical Mazes 12-15) |
|
Hovering |
|
R² = 0.22 |
|
0.0 2.5R² = 0.30 |
|
0 5R² = 0.03 |
|
5 10R² = 0.00 |
|
0 1R² = 0.21 |
|
2.5 5.0R² = 0.18 |
|
5 10 15R² = 0.13 |
|
10 20R² = 0.07 |
|
2.5 5.0R² = 0.17 |
|
5 10 |
|
R² = 0.42 |
|
0.0 0.55.56.06.57.0Process-Tracing |
|
(Critical Mazes 12-15) |
|
Log-Hover Duration R² = 0.12 |
|
0.0 2.5R² = 0.11 |
|
0 5R² = 0.04 |
|
5 10R² = 0.00 |
|
0 1R² = 0.13 |
|
2.5 5.0R² = 0.11 |
|
5 10 15R² = 0.08 |
|
10 20R² = 0.12 |
|
2.5 5.0R² = 0.24 |
|
5 10Extended Data Fig. 7 jSummaries of candidate models and data from planning experi- |
|
ments, Each row corresponds to a measurement of attention to obstacles from a planning exper- |
|
iment: Awareness judgments from the initial memory experiment, the up-front planning experi- |
|
ment, and the critical mazes experiment; recall accuracy and confidence from the critical mazes |
|
50experiment; and the binary hovering measure and hovering duration measure (in log milliseconds) |
|
from the two process-tracing experiments. Each column corresponds to candidate processes that |
|
could predict attention to obstacles: fixed parameter value-guided construal modification obsta- |
|
cle probability (VGC, our model), trajectory-based heuristic search hit score (Traj HS), graph- |
|
based heuristic search hit score (Graph HS), distance to bottleneck states (Bottleneck), successor- |
|
representation overlap (SR Overlap), expected distance to optimal paths (Opt Dist), distance to the |
|
goal location (Goal Dist), distance to the start location (Start Dist), distance to the invariant black |
|
walls (Wall Dist), and distance to the center of the maze (Center Dist). Note that for distance-based |
|
predictors, the x-axis is flipped. For each predictor, we quartile-binned the predictions across ob- |
|
stacles, and for each bin we plot (bright red lines) the mean and standard deviation of the predictor |
|
and mean by-obstacle response (overlapping bins were collapsed into a single bin). Black circles |
|
correspond to the mean response and prediction for each obstacle in each maze. Dashed dark red |
|
lines are simple linear regressions on the black circles, with R2values shown in the lower right |
|
of each plot. Across the nine measures, value-guided construal tracks attention to obstacles, while |
|
other candidate processes are less consistently associated with obstacle attention (data are based |
|
onn= 84215 observations taken from 825independent participants). |
|
51a |
|
b |
|
cExtended Data Table 1 jNecessity of different mechanisms for explaining attention to ob- |
|
stacles when planning, For each measure in each planning experiment, we fit hierarchical gener- |
|
alized linear models (HGLMs) that included the following predictors as fixed-effects: fixed param- |
|
eter value-guided construal modification obstacle probability (VGC, our model); trajectory-based |
|
heuristic search obstacle hit score (Traj HS); graph-based heuristic search obstacle hit score (Graph |
|
HS); distance to optimal bottleneck (Bottleneck); successor representation overlap score (SR Over- |
|
52lap); distance to path taken (Nav Dist); timestep of point closest along path taken (Nav Dist Step); |
|
distance to optimal paths (Opt Dist); distance to the goal state (Goal Dist); distance to the start |
|
state (Start Dist); distance to any part of the center walls (Wall Dist); and distance to the center of |
|
the maze (Center Dist) (Methods, Model Implementations). If the measure was taken before par- |
|
ticipants navigated, distance to the optimal paths was used, otherwise, distance to the path taken |
|
and its timestep were used. a, b, Estimated coefficients and standard errors for z-score normalized |
|
predictors in HGLMs fit to responses from the initial experiment, up-front planning experiment (F |
|
= full trials, E = early termination trials), the critical mazes experiment, and the process-tracing ex- |
|
periments. We found that value-guided construal was a significant predictor even when accounting |
|
for alternatives (likelihood ratio tests between full global models and models without value-guided |
|
construal: Initial Exp, Awareness: 2(1) = 501:11;p< 1:010 16; Up-front Exp, Awareness (F): |
|
2(1) = 282:17;p< 1:010 16; Up-front Exp, Awareness (E): 2(1) = 206:14;p< 1:010 16; |
|
Critical Mazes Exp, Accuracy: 2(1) = 114:87;p < 1:010 16; Critical Mazes Exp, Confi- |
|
dence:2(1) = 181:28;p < 1:010 16; Critical Mazes Exp, Awareness: 2(1) = 486:99;p < |
|
1:010 16; Process-Tracing Exp (Initial Mazes), Hovering: 2(1) = 294:40;p < 1:010 16; |
|
Process-Tracing Exp (Initial Mazes), Duration: 2(1) = 177:58;p< 1:010 16; Process-Tracing |
|
Exp (Critical Mazes), Hovering: 2(1) = 183:52;p< 1:010 16; Process-Tracing Exp (Critical |
|
Mazes), Duration: 2(1) = 251:16;p < 1:010 16).c,To assess the relative necessity of each |
|
predictor for the fit of a HGLM, we conducted lesioning analyses in which, for each predictor in a |
|
given global HGLM, we fit a new lesioned HGLM with only that predictor removed. Each entry of |
|
the table shows the change in AIC when comparing global and lesioned HGLMs, where larger pos- |
|
itive values indicate a greater reduction in fit as a result of removing a predictor. According to this |
|
criterion, across all experiments and measures, value-guided construal is either the first or second |
|
most important predictor.Largest increase in AIC after lesioning;ySecond-largest increase. |
|
53VGCTraj HSGraph HS Bottleneck SR OverlapNav Dist |
|
Nav Dist StepGoal Dist Start Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Nav Dist |
|
Nav Dist Step |
|
Goal Dist |
|
Start Dist |
|
Wall Dist |
|
Center Dist2110 |
|
20704937 |
|
204732463750 |
|
1096309223573127 |
|
20064938367231204993 |
|
0990684113213041306 |
|
2089486735363036494312744945 |
|
20244926370929814986129249374988 |
|
211149183602312949901305492849894995 |
|
2105481537343122478511584761480647954815 |
|
20994843374231274822119347924838482946954847Initial Exp. |
|
Awareness |
|
VGCTraj HSGraph HS Bottleneck SR OverlapGoal Dist Start Dist Opt Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Goal Dist |
|
Start Dist |
|
Opt Dist |
|
Wall Dist |
|
Center Dist1405 |
|
13003312 |
|
138720112557 |
|
279144610721444 |
|
11493267235014203287 |
|
130833142551137332893317 |
|
1403329124131441328332883303 |
|
0673496326500731725731 |
|
13113298254713923214329832747323296 |
|
129833062541137332313306328573032123304Up-front Planning Exp. |
|
Awareness |
|
VGCTraj HSGraph HS Bottleneck SR OverlapNav Dist |
|
Nav Dist StepGoal Dist Start Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Nav Dist |
|
Nav Dist Step |
|
Goal Dist |
|
Start Dist |
|
Wall Dist |
|
Center Dist28 |
|
24285 |
|
26221225 |
|
19285223350 |
|
30271207321332 |
|
22203180243223243 |
|
16272220340334244364 |
|
0209197252289222309313 |
|
2219201261301224325276326 |
|
27286227344330227352278297358 |
|
28284227351308239364300317246368Critical Mazes Exp. |
|
Accuracy |
|
VGCTraj HSGraph HS Bottleneck SR OverlapNav Dist |
|
Nav Dist StepGoal Dist Start Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Nav Dist |
|
Nav Dist Step |
|
Goal Dist |
|
Start Dist |
|
Wall Dist |
|
Center Dist39 |
|
38638 |
|
32481536 |
|
0622522639 |
|
21636535634662 |
|
26438408440440440 |
|
33591497584637429638 |
|
17414394325475328471475 |
|
8459424366523348524320523 |
|
16577477614538430628477524657 |
|
8543450579429406598468510413624Critical Mazes Exp. |
|
Confidence |
|
VGCTraj HSGraph HS Bottleneck SR OverlapNav Dist |
|
Nav Dist StepGoal Dist Start Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Nav Dist |
|
Nav Dist Step |
|
Goal Dist |
|
Start Dist |
|
Wall Dist |
|
Center Dist394 |
|
3671314 |
|
39211091129 |
|
011489321234 |
|
3921297110212031453 |
|
151687652715720740 |
|
28013011126120414557331511 |
|
13010971049782132070113241356 |
|
99115210758351373712139710451411 |
|
39512571096122613467421513134414061514 |
|
393122510721196120673714981358141211221498Critical Mazes Exp. |
|
Awareness |
|
VGCTraj HSGraph HS Bottleneck SR OverlapGoal Dist Start Dist Opt Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Goal Dist |
|
Start Dist |
|
Opt Dist |
|
Wall Dist |
|
Center Dist274 |
|
2271153 |
|
197743743 |
|
124674443902 |
|
27611497448241360 |
|
209115374490213531427 |
|
1761136740782129812831337 |
|
0127204493551550441563 |
|
26111547438961337135312935271357 |
|
256115574490013461366130453713051370Process-Tracing (Initial Mazes) |
|
Hovering |
|
VGCTraj HSGraph HS Bottleneck SR OverlapGoal Dist Start Dist Opt Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Goal Dist |
|
Start Dist |
|
Opt Dist |
|
Wall Dist |
|
Center Dist171 |
|
142455 |
|
167341414 |
|
35246223246 |
|
77421343229419 |
|
169446402201409447 |
|
144401323197383390399 |
|
125298281206255286243297 |
|
23406335150399394364247407 |
|
0388315124386378350229306390Process-Tracing (Initial Mazes) |
|
Duration |
|
VGCTraj HSGraph HS Bottleneck SR OverlapGoal Dist Start Dist Opt Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Goal Dist |
|
Start Dist |
|
Opt Dist |
|
Wall Dist |
|
Center Dist157 |
|
1141176 |
|
119875897 |
|
10811568611452 |
|
26117089914521588 |
|
3173172995512941292 |
|
0824771103013887911386 |
|
158857775103510409069301038 |
|
95748699141114241294138510181566 |
|
315605471253936121212849132401409Process-Tracing (Critical Mazes) |
|
Hovering |
|
VGCTraj HSGraph HS Bottleneck SR OverlapGoal Dist Start Dist Opt Dist Wall DistCenter DistVGC |
|
Traj HS |
|
Graph HS |
|
Bottleneck |
|
SR Overlap |
|
Goal Dist |
|
Start Dist |
|
Opt Dist |
|
Wall Dist |
|
Center Dist139 |
|
140580 |
|
72554552 |
|
7524476530 |
|
114582554529597 |
|
0484511337526526 |
|
5500521340540459541 |
|
141414419412419393393417 |
|
103367464481362513526384569 |
|
682643934211724734843357513Process-Tracing (Critical Mazes) |
|
Duration |
|
01000200030004000 |
|
050010001500200025003000 |
|
050100150200250300350 |
|
0100200300400500600 |
|
0200400600800100012001400 |
|
0200400600800100012001400 |
|
0100200300400 |
|
0200400600800100012001400 |
|
0100200300400500Extended Data Figure 8 jSufficiency of individual and pairs of mechanisms for explaining |
|
attention to obstacles when planning, To assess the individual and pairwise sufficiency of each |
|
54predictor for explaining responses in the planning experiments, we fit hierarchical generalized |
|
linear models (HGLMs) that included pairs of predictors as fixed effects. Each lower-triangle plot |
|
corresponds to one of the experimental measures, where pairs of predictors included in a HGLM |
|
as fixed-effects are indicated on the x- and y-axes. Values are the AIC for each model relative |
|
to the best fitting model associated with an experimental measure (lower values indicate better |
|
fit). Values along the diagonals correspond to models fit with a single predictor. According to this |
|
criterion, across all experimental measures, value-guided construal is the first, second, or third best |
|
single-predictor HGLM, and is always in the best two-predictor HGLM. |
|
55Extended Data Table 2 jAlgorithm for Computing the Value of Representation Function |
|
To obtain predictions for our our ideal model of value-guided construal, we calculated the value of |
|
representation of all construals in a maze. This was done by enumerating all construals (subsets of |
|
obstacle effects) and then, for each construal, calculating its behavioral utility and cognitive cost. |
|
This allows us to obtain theoretically optimal value-guided construals. For a discussion of alterna- |
|
tive ways of calculating construals, see the Supplementary Discussion of Construal Optimization |
|
Algorithms. |
|
56 |