@article {5065, title = { AGENT: A Benchmark for Core Psychological Reasoning}, year = {2021}, month = {07/2021}, author = {Tianmin Shu and Abhishek Bhandwaldar and Chuang Gan and Kevin A Smith and Shari Liu and Dan Gutfreund and Elizabeth S Spelke and Joshua B. Tenenbaum and Tomer D. Ullman} } @mastersthesis {4451, title = {Nature and origins of intuitive psychology in human infants}, year = {2020}, author = {Shari Liu} } @conference {4449, title = {Hard choices: Children{\textquoteright}s understanding of the cost of action selection. }, booktitle = {Cognitive Science Society}, year = {2019}, author = {Shari Liu and Fiery A Cushman and Samuel J Gershman and Kool, Wouter and Elizabeth S Spelke} } @article {4452, title = {Origins of the concepts cause, cost, and goal in prereaching infants.}, year = {2019}, author = {Shari Liu and Neon B. Brooks and Elizabeth S Spelke} } @article {4282, title = {Origins of the concepts cause, cost, and goal in prereaching infants}, journal = {PNAS}, year = {2019}, month = {08/2019}, abstract = {

We investigated the origins and interrelations of causal knowledge and knowledge of agency in 3-month-old infants, who cannot yet effect changes in the world by reaching for, grasping, and picking up objects. Across 5 experiments, n = 152 prereaching infants viewed object-directed reaches that varied in efficiency (following the shortest physically possible path vs. a longer path), goal (lifting an object vs. causing a change in its state), and causal structure (action on contact vs. action at a distance and after a delay). Prereaching infants showed no strong looking preference between a person{\textquoteright}s efficient and inefficient reaches when the person grasped and displaced an object. When the person reached for and caused a change in the state of the object on contact, however, infants looked longer when this action was inefficient than when it was efficient. Three-month-old infants also showed a key signature of adults{\textquoteright} and older infants{\textquoteright} causal inferences: This looking preference was abolished if a short spatial and temporal gap separated the action from its effect. The basic intuition that people are causal agents, who navigate around physical constraints to change the state of the world, may be one important foundation for infants{\textquoteright} ability to plan their own actions and learn from the acts of others.

}, issn = {1091-6490}, doi = {https://doi.org/10.1073/pnas.1904410116}, url = {https://www.pnas.org/content/early/2019/08/19/1904410116/tab-article-info}, author = {Shari Liu and Neon B. Brooks and Elizabeth S Spelke} } @conference {4450, title = {People{\textquoteright}s perceptions of others{\textquoteright} risk preferences.}, booktitle = {Cognitive Science Society}, year = {2019}, author = {Shari Liu and John P. McCoy and Ullman, Tomer D.} } @article {2358, title = {Six-month-old infants expect agents to minimize the cost of their actions}, journal = {Cognition}, volume = {160}, year = {2017}, month = {03/2017}, pages = {35-42}, abstract = {

Substantial evidence indicates that infants expect agents to move directly to their goals when no obstacles block their paths, but the representations that articulate this expectation and its robustness have not been characterized. Across three experiments (total N = 60), 6-month-old infants responded to a novel, curvilinear action trajectory on the basis of its efficiency, in accord with the expectation that an agent will move to its goal on the least costly path that the environment affords. Infants expected minimally costly action when presented with a novel constraint, and extended this expectation to agents who had previously acted inefficiently. Infants{\textquoteright} understanding of goal-directed action cannot be explained alone by sen- sitivity to specific features of agent{\textquoteright}s actions (e.g. agents tend to move on straight paths, along supporting surfaces, when facing their goals directly) or extrapolations of agents{\textquoteright} past actions to their future ones (e.g. if an agent took the shortest path to an object in the past, it will continue to do so in the future). Instead, infants{\textquoteright} reasoning about efficiency accords with the overhypothesis that agents minimize the cost of their actions.

}, keywords = {cognitive development, goal inference, open data, open materials, social cognition}, issn = {00100277}, doi = {10.1016/j.cognition.2016.12.007}, url = {http://www.sciencedirect.com/science/article/pii/S001002771630302X}, author = {Shari Liu and Elizabeth S Spelke} } @article {3485, title = {Ten-month-old infants infer the value of goals from the costs of actions}, journal = {Science}, volume = {358}, year = {2017}, month = {11/2017}, pages = {1038-1041}, chapter = {1038}, abstract = {

Infants understand that people pursue goals, but how do they learn which goals people prefer? We tested whether infants solve this problem by inverting a mental model of action planning, trading off the costs of acting against the rewards actions bring. After seeing an agent attain two goals equally often at varying costs, infants expected the agent to prefer the goal it attained through costlier actions. These expectations held across three experiments that conveyed cost through different physical path features (height, width, and incline angle), suggesting that an abstract variable{\textemdash}such as {\textquotedblleft}force,{\textquotedblright} {\textquotedblleft}work,{\textquotedblright} or {\textquotedblleft}effort{\textquotedblright}{\textemdash}supported infants{\textquoteright} inferences. We modeled infants{\textquoteright} expectations as Bayesian inferences over utility-theoretic calculations, providing a bridge to recent quantitative accounts of action understanding in older children and adults.

}, author = {Shari Liu and Ullman, Tomer D. and Joshua B. Tenenbaum and Elizabeth S Spelke} } @article {2604, title = {Ten-month-old infants infer value from effort}, year = {2017}, address = {Austin, TX}, author = {Shari Liu and Tomer Ullman and Joshua B. Tenenbaum and Elizabeth S Spelke} } @article {2636, title = {Ten-month-old infants infer value from effort}, year = {2017}, author = {Shari Liu and Tomer Ullman and Joshua B. Tenenbaum and Elizabeth S Spelke} } @article {1808, title = {Continuous representations of action efficiency in infancy}, year = {2016}, month = {01/2016}, abstract = {

In reasoning about action, infants apply the principle of efficiency, recovering attention when agents pursue goals using curvilinear paths if a straight path was available (Csibra et al., 1999). What representations support these capacities? The present research explores the hypothesis that infants represent cost as a continuous function within a naive utility calculus (Jara-Ettinger et al., 2015) by testing 6-month-old infants{\textquoteright} expectations for efficiency using action trajectories differing in curvature. In Study 1, we habituated infants to a rational agent, whose goal-directed actions were constrained by tall barriers, and then measured how long infants attended when the same agent navigated over a novel, low barrier efficiently or inefficiently. In Study 2, we asked whether infants recover attention to inefficient actions solely on the basis of low-level perceptual properties by repeating Study 1 but moving the barrier beyond the agent{\textquoteright}s goal, causing all actions to be unconstrained. In Study 3, we used the unconstrained habituation events from Study 2 and the constrained test events from Study 1 to test whether infants expect an irrational agent to act efficiently given a novel constraint. Across these studies, we demonstrate that 6-month-olds (1) analyze trajectories of goal-directed action differing in curvature on the basis of their efficiency, (2) expect minimally costly action given novel constraints, even for previously irrational agents, and (3) differentiate between these actions on the basis of efficiency, not low-level perceptual differences in height or motion. Our findings indicate that continuous cost representations support an early, robust expectation for rational action.\ 

}, author = {Shari Liu and Elizabeth S Spelke} } @article {1810, title = {Pre-reaching infants expect causal agents to act efficiently without motor training}, year = {2016}, month = {05/2016}, author = {Shari Liu and Neon B. Brooks and Elizabeth S Spelke} } @article {1809, title = {Six-month-old infants represent action efficiency on a continuous scale.}, year = {2015}, month = {10/2015}, address = {Columbus, Ohio}, author = {Shari Liu and Elizabeth S Spelke} }