Conceptually Rich, Perceptually Sparse: Object Representations in 6-Month-Old Infants' Working Memory.

Six-month-old infants can store representations of multiple objects in working memory but do not always remember the objects' features (e.g., shape). Here, we asked whether infants' object representations (a) may contain conceptual content and (b) may contain this content even if perceptual features are forgotten. We hid two conceptually distinct objects (a humanlike doll and a nonhuman ball) one at a time in two separate locations and then tested infants' memory for the first-hidden object by revealing either the original hidden object or an unexpected other object. Using looking time, we found that infants remembered the categorical identity of the hidden object but failed to remember its perceptual identity. Our results suggest that young infants may encode conceptual category in a representation of an occluded object, even when perceptual features are lost.

The interplay between moral actions and moral judgments in children and adults.

Do choices about which moral actions to take cohere with subsequent judgments of their outcomes? The first set of experiments (N = 60 preschoolers and 30 adults) directly compared whether moral choices and judgments reflect distinct considerations, and whether coherence varies based on the valence of the moral scenario. Participants' responses suggested that moral principles may be applied differently for moral choices and judgments, and that harm-based situations are particularly demanding for children. To determine whether children's difficulty with harm-based situations reflects demand characteristics, a second set of experiments presented forty-three preschoolers and thirty-nine adults with a moral dilemma wherein they could choose to omit an action and maximize harm or act to minimize harm. Both age groups acted to minimize harm when caused indirectly. These results suggest that making choices about harm are not unilaterally demanding for preschoolers, but they struggle to make choices that minimize harm in a forced-choice scenario.

Bayesian change-point analysis reveals developmental change in a classic theory of mind task.

Although learning and development reflect changes situated in an individual brain, most discussions of behavioral change are based on the evidence of group averages. Our reliance on group-averaged data creates a dilemma. On the one hand, we need to use traditional inferential statistics. On the other hand, group averages are highly ambiguous when we need to understand change in the individual; the average pattern of change may characterize all, some, or none of the individuals in the group. Here we present a new method for statistically characterizing developmental change in each individual child we study. Using false-belief tasks, fifty-two children in two cohorts were repeatedly tested for varying lengths of time between 3 and 5 years of age. Using a novel Bayesian change point analysis, we determined both the presence and-just as importantly-the absence of change in individual longitudinal cumulative records. Whenever the analysis supports a change conclusion, it identifies in that child's record the most likely point at which change occurred. Results show striking variability in patterns of change and stability across individual children. We then group the individuals by their various patterns of change or no change. The resulting patterns provide scarce support for sudden changes in competence and shed new light on the concepts of "passing" and "failing" in developmental studies.

Children's Sharing Behavior in Mini-Dictator Games: The Role of In-Group Favoritism and Theory of Mind.

This study investigated the motivational and social-cognitive foundations (i.e., inequality aversion, in-group bias, and theory of mind) that underlie the development of sharing behavior among 3- to 9-year-old Chinese children (N = 122). Each child played two mini-dictator games against an in-group member (friend) and an out-group member (stranger) to divide four stickers. Results indicated that there was a small to moderate age-related increase in children's egalitarian sharing with strangers, whereas the age effect was moderate to large in interactions with friends. Moreover, 3- to 4-year-olds did not treat strangers and friends differently, but 5- to 6-year-old and older children showed strong in-group favoritism. Finally, theory of mind was an essential prerequisite for children's sharing behavior toward strangers, but not a unique predictor of their sharing with friends.

What's the object of object working memory in infancy? Unraveling 'what' and 'how many'.

Infants have a bandwidth-limited object working memory (WM) that can both individuate and identify objects in a scene, (answering 'how many?' or 'what?', respectively). Studies of infants' WM for objects have typically looked for limits on either 'how many' or 'what', yielding different estimates of infant capacity. Infants can keep track of about three individuals (regardless of identity), but appear to be much more limited in the number of specific identities they can recall. Why are the limits on 'how many' and 'what' different? Are the limits entirely separate, do they interact, or are they simply two different aspects of the same underlying limit? We sought to unravel these limits in a series of experiments which tested 9- and 12-month-olds' WM for object identities under varying degrees of difficulty. In a violation-of-expectation looking-time task, we hid objects one at a time behind separate screens, and then probed infants' WM for the shape identity of the penultimate object in the sequence. We manipulated the difficulty of the task by varying both the number of objects in hiding locations and the number of means by which infants could detect a shape change to the probed object. We found that 9-month-olds' WM for identities was limited by the number of hiding locations: when the probed object was one of two objects hidden (one in each of two locations), 9-month-olds succeeded, and they did so even though they were given only one means to detect the change. However, when the probed object was one of three objects hidden (one in each of three locations), they failed, even when they were given two means to detect the shape change. Twelve-month-olds, by contrast, succeeded at the most difficult task level. Results show that WM for 'how many' and for 'what' are not entirely separate. Individuated objects are tracked relatively cheaply. Maintaining bindings between indexed objects and identifying featural information incurs a greater attentional/memory cost. This cost reduces with development. We conclude that infant WM supports a small number of featureless object representations that index the current locations of objects. These can have featural information bound to them, but only at substantial cost.

Preschoolers use the means principle in their moral judgments.

We ask whether moral judgment in preschool children observes a "means principle." It is well established that young children consider both the consequences and the goals of actions when making moral judgments; much less studied is the question of whether the means used to attain a given goal also matter. By obtaining preschoolers' judgments regarding when, if ever, it is permissible for 1 person to harm another as a means, we show, across 2 experiments, that children (N = 200 across 2 studies; Mage = 5.1 yrs.) use the means principle in their moral judgments. Subjects recognized not only when a harm was being used as a means but also situated that means appropriately with respect to the correct superordinate goal. In this respect, the preschoolers in this sample are like adults across a wide range of cultures. These findings have important implications for the understanding of moral development: young children can use an agent's means, and not just her goal, to make a moral judgment. We discuss the broader issue of whether, in light of emerging evidence for the means principle, there really are any moral universals. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

What do infants remember when they forget? Location and identity in 6-month-olds' memory for objects.

What does an infant remember about a forgotten object? Although at age 6 months, infants can keep track of up to three hidden objects, they can remember the featural identity of only one. When infants forget the identity of an object, do they forget the object entirely, or do they retain an inkling of it? In a looking-time study, we familiarized 6-month-olds with a disk and a triangle placed on opposite sides of a stage. During test trials, we hid the objects one at a time behind different screens, and after hiding the second object, we removed the screen where the first object had been hidden. Infants then saw the expected object, the unexpected other object, or the empty stage. Bayes factor analysis showed that although the infants did not notice when the object changed shape, they were surprised when it vanished. This finding indicates that infants can represent an object without its features.

Inhibitory control interacts with core knowledge in toddlers' manual search for an occluded object.

Core knowledge theories advocate the primacy of fundamental principles that constrain cognitive development from early infancy. However, there is concern that core knowledge of object properties does not constrain older preschoolers' reasoning during manual search. Here we address in detail both failure and success on two well-established search measures that require reasoning about solidity. We show that poor performance arises from an inability to engage the appropriate search strategy rather than a simple failure of core knowledge. Moreover, we demonstrate that successful search is positively correlated with inhibitory control. We believe that toddlers' manual search for an occluded object reflects a general capacity to deploy inhibition so that search behaviour can be guided by core knowledge.

Attributing false beliefs about non-obvious properties at 18 months.

Reports that infants in the second year of life can attribute false beliefs to others have all used a search paradigm in which an agent with a false belief about an object's location searches for the object. The present research asked whether 18-month-olds would still demonstrate false-belief understanding when tested with a novel non-search paradigm. An experimenter shook an object, demonstrating that it rattled, and then asked an agent, "Can you do it?" In response to this prompt, the agent selected one of two test objects. Infants realized that the agent could be led through inference (Experiment 1) or memory (Experiment 2) to hold a false belief about which of the two test objects rattled. These results suggest that 18-month-olds can attribute false beliefs about non-obvious properties to others, and can do so in a non-search paradigm. These and additional results (Experiment 3) help address several alternative interpretations of false-belief findings with infants.

The generative basis of natural number concepts.

Number concepts must support arithmetic inference. Using this principle, it can be argued that the integer concept of exactly ONE is a necessary part of the psychological foundations of number, as is the notion of the exact equality - that is, perfect substitutability. The inability to support reasoning involving exact equality is a shortcoming in current theories about the development of numerical reasoning. A simple innate basis for the natural number concepts can be proposed that embodies the arithmetic principle, supports exact equality and also enables computational compatibility with real- or rational-valued mental magnitudes.

A Bayesian framework for the development of belief-desire reasoning: Estimating inhibitory power.

A robust empirical finding in theory-of-mind (ToM) reasoning, as measured by standard false-belief tasks, is that children four years old or older succeed whereas three-year-olds typically fail in predicting a person's behavior based on an attributed false belief. Nevertheless, when the child's own belief is undermined by increasing their subjective uncertainty about the truth, as introduced in low-demand false-belief tasks, three-year-olds can better appreciate another person's false belief. Inhibition is believed to play a critical role in such developmental patterns. Within a Bayesian framework, using meta-data, we present the first computational implementation of inhibition, as specified by the Theory of Mind Mechanism (ToMM) model, to account for both the developmental shift from three to four years of age and the change in children's performances between high-demand and low-demand false-belief tasks. A Bayesian framework enables us to evaluate the predictive power of the model and infer the underlying psychological parameters. Together with behavioral evidence, we discuss the critical role of inhibitory control, as specified by ToMM, in children's theory-of-mind development.

The Mental Representation of Human Action.

Various theories of moral cognition posit that moral intuitions can be understood as the output of a computational process performed over structured mental representations of human action. We propose that action plan diagrams-"act trees"-can be a useful tool for theorists to succinctly and clearly present their hypotheses about the information contained in these representations. We then develop a methodology for using a series of linguistic probes to test the theories embodied in the act trees. In Study 1, we validate the method by testing a specific hypothesis (diagrammed by act trees) about how subjects are representing two classic moral dilemmas and finding that the data support the hypothesis. In Studies 2-4, we explore possible explanations for discrete and surprising findings that our hypothesis did not predict. In Study 5, we apply the method to a less well-studied case and show how new experiments generated by our method can be used to settle debates about how actions are mentally represented. In Study 6, we argue that our method captures the mental representation of human action better than an alternative approach. A brief conclusion suggests that act trees can be profitably used in various fields interested in complex representations of human action, including law, philosophy, psychology, linguistics, neuroscience, computer science, robotics, and artificial intelligence.

Presumed innocent? How tacit assumptions of intentional structure shape moral judgment.

The presumption of innocence is not only a bedrock principle of American law, but also a fundamental human right. The psychological underpinnings of this presumption, however, are not well understood. To make progress, one important task is to explain how adults and children infer the goals and intentional structure of complex actions, especially when a single action has more than one salient effect. Many theories of moral judgment have either ignored this intention inference problem or have simply assumed a particular solution without empirical support. We propose that this problem may be solved by appealing to domain-specific prior knowledge that is either built-up over the probability of prior intentions or built-in as part of core cognition. We further propose a specific solution to this problem in the moral domain: a good intention prior, which entails a rebuttable presumption that if an action has both good and bad effects, the actor intends the good effects and not the bad effects. Finally, in a series of novel experiments we provide the first empirical support - from both adults and preschool children - for the existence of this good intention prior. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The conceptual underpinnings of pretense: pretending is not 'behaving-as-if'.

The ability to engage in and recognize pretend play begins around 18 months. A major challenge for theories of pretense is explaining how children are able to engage in pretense, and how they are able to recognize pretense in others. According to one major account, the metarepresentational theory, young children possess both production and recognition abilities because they possess the mental state concept, pretend. According to a more recent rival account, the Behavioral theory, young children are behaviorists about pretense, and only produce and recognize pretense as a sort of behavior - namely, behaving 'as-if'. We review both the metarepresentational and Behavioral accounts and argue that the Behavioral theory fails to characterize very young children's abilities to produce and to recognize pretense. Among other problems, the Behavioral theory implies that children should frequently mis-recognize regular behavior as pretense, while certain regular forms of pretend play should neither be produced nor recognized. Like other mental states, pretense eludes purely behavioral description. The metarepresentational theory does not suffer these problems and provides a better account of children's pretense.

15-month-old infants detect violations in pretend scenarios.

Are 15-month-old infants able to detect a violation in the consistency of an event sequence that involves pretense? In Experiment 1, infants detected a violation when an actor pretended to pour liquid into one cup and then pretended to drink from another cup. In Experiment 2, infants no longer detected a violation when the cups were replaced with objects not typically used in the context of drinking actions, either shoes or tubes. Experiment 3 showed that infants' difficulty in Experiment 2 was not due to the use of atypical objects per se, but arose from the novelty of seeing an actor appearing to drink from these objects. After receiving a single familiarization trial in which they observed the actor pretend to drink from either a shoe or a tube, infants now detected a violation when the actor pretended to pour into and to drink from different shoes or tubes. Thus, at an age (or just before the age) when infants are beginning to engage in pretend play, they are able to show comprehension of at least one aspect of pretense in a violation-of-expectation task: specifically, they are able to detect violations in the consistency of pretend action sequences.

Developmental parallels in understanding minds and bodies.

A recent article by Onishi and Baillargeon presents evidence that 15-month-old infants attribute false beliefs (FBs) to other people. If correct, it lends dramatic new support to the idea that mental state concepts ("theory of mind") emerge from a specialized neurocognitive mechanism that matures during the second year of life. But it also raises new puzzles concerning the FB task--puzzles that have intriguing parallels in results from infants' reasoning about solid bodies.

Core mechanisms in "theory of mind".

Our ability to understand the thoughts and feelings of other people does not initially develop as a theory but as a mechanism. The "theory of mind" mechanism (ToMM) is part of the core architecture of the human brain, and is specialized for learning about mental states. Impaired development of this mechanism can have drastic effects on social learning, seen most strikingly in the autistic spectrum disorders. ToMM kick-starts belief-desire attribution but effective reasoning about belief contents depends on a process of selection by inhibition. This selection process (SP) develops slowly through the preschool period and well beyond. By modeling the ToMM-SP as mechanisms of selective attention, we have uncovered new empirical phenomena. We propose that early "theory of mind" is a modular-heuristic process of domain-specific learning.

A memory span of one? Object identification in 6.5-month-old infants.

Infants' abilities to identify objects based on their perceptual features develop gradually during the first year and possibly beyond. Earlier we reported [Káldy, Z., & Leslie, A. M. (2003). Identification of objects in 9-month-old infants: Integrating 'what' and 'where' information. Developmental Science, 6, 360-373] that infants at 9 months of age are able to use shape information to identify two objects and follow their spatiotemporal trajectories behind occlusion. On the other hand, another recent study suggests that infants at 4-5 months of age cannot identify objects by features and bind them to locations [Mareschal, D., & Johnson, M. H. (2003). The "what" and "where" of object representations in infancy. Cognition, 88, 259-276]. In the current study, we investigated the developmental steps between these two benchmark ages by testing 6.5-month-old infants. Experiment 1 and 2 adapted the paradigm used in our previous studies with 9-month-olds that involves two objects hidden sequentially behind separate occluders. This technique allows us to address object identification and to examine whether only one or both object identities are being tracked. Results of experiment 1 showed that 6.5-month-old infants could identify at least one of two objects based on shape and experiment 2 found that this ability holds for only one, the last object hidden. We propose that at this age, infants' working memory capacity is limited to one occluded object if there is a second intervening hiding. If their attention is distracted by an intervening object during the memory maintenance period, the memory of the first object identity appears to be lost. Results of experiment 3 supported this hypothesis with a simpler one-screen setup. Finally, results of experiment 4 show that temporal decay of the memory trace (without an intervening hiding) by itself cannot explain the observed pattern of results. Taken together, our findings suggest that at six months of age infants can store but a single object representation with bound shape information, most likely in the ventral stream. The memory span of one may be due to immaturity of the neural structures underlying working memory such that intervening items overwrite the existing storage.

Outcome producing potential influences twelve-month-olds' interpretation of a novel action as goal-directed.

Learning about a novel, goal-directed action is a complex process. It requires identifying the outcome of the action and linking the action to its outcome for later use in new situations to predict the action or to anticipate its outcome. We investigated the hypothesis that linking a novel action to a salient change in the environment is critical for infants to assign a goal to the novel action. We report a study in which we show that 12-month-old infants, who were provided with prior experience with a novel action accompanied with a salient visible outcome in one context, can interpret the same action as goal-directed even in the absence of the outcome in another context. Our control condition shows that prior experience with the action, but without the salient effect, does not lead to goal-directed interpretation of the novel action. We also found that, for the case of 9-month-olds infants, prior experience with the outcome producing potential of the novel action does not facilitate a goal-directed interpretation of the action. However, this failure was possibly due to difficulties with generalizing the learnt association to another context rather than with linking the action to its outcome.

Is young children's recognition of pretense metarepresentational or merely behavioral? Evidence from 2- and 3-year-olds' understanding of pretend sounds and speech.

When young children observe pretend-play, do they interpret it simply as a type of behavior, or do they infer the underlying mental state that gives the behavior meaning? This is a long-standing question with deep implications for how "theory on mind" develops. The two leading accounts of shared pretense give opposing answers. The behavioral theory proposes that children represent pretense as a form of behavior (behaving in a way that would be appropriate if P); the metarepresentational theory argues that children instead represent pretense via the early concept PRETEND. A test between these accounts is provided by children's understanding of pretend sounds and speech. We report the first experiments directly investigating this understanding. In three experiments, 2- and 3-year-olds' listened to requests that were either spoken normally, or with the pretense that a teddy bear was uttering them. To correctly fulfill the requests, children had to represent the normal utterance as the experimenter's, and the pretend utterances as the bear's. Children succeeded at both ages, suggesting that they can represent pretend speech (the requests) as coming from counterfactual sources (the bear rather than the experimenter). We argue that this is readily explained by the metarepresentational theory, but harder to explain if children are behaviorists about pretense.