Young children's attribution of action to beliefs and desires

When and how children understand beliefs and desires is central to whether they are ever childhood realists and when they evidence a theory of mind. Adults typically construe human action as resulting from an actor's beliefs and desires, a mentalistic interpretation that represents a common and fundamental form of psychological explanation. We investigated children's ability to do likewise. In Experiment 1, 60 subjects were asked to explain why story characters performed simple actions, such as looking under a piano for a kitten. Both preschoolers and adults gave predominantly psychological explanations, attributing the actions to the actor's beliefs and desires. Even 3-year-olds attributed actions to beliefs and false beliefs, demonstrating an understanding of belief not evident in previous research. In Experiment 2, 24 3-year-olds were tested further on their understanding of false belief. They were given both false belief prediction and explanation tasks. Children performed well on explanation taks, attributing an anomalous action to the actor's false belief, even when they failed to predict correctly what action would follow from a false belief. We concluded that 3-year-olds and adults share a fundamentally similar construal of human action in terms of beliefs and desires, even false beliefs.     

There's More to the Picture Than Meets the Eye: Young Children's Difficulty Understanding Biased Interpretation

5 experiments investigated children's understanding that expectations based on prior experience may influence a person's interpretation of ambiguous visual information. In Experiment 1, 4- and 5-year-olds were asked to infer a puppet's interpretation of a small, ambiguous portion of a line drawing after the puppet had been led to have an erroneous expectation about the drawing's identity. Children of both ages failed to ascribe to the puppet an interpretation consistent with the puppet's expectation. Instead, children attributed complete knowledge of the drawing to the puppet. In Experiment 2, the task was modified to reduce memory demands, but 4- and 5-year-olds continued to overlook the puppet's prior expectations when asked to infer the puppet's interpretation of an ambiguous scene. 6-year-olds responded correctly. In Experiment 3, 4- and 5-year-olds correctly reported that an observer who saw a restricted view would not know what was in the drawing, but children did not realize that the observer's interpretation might be mistaken. Experiments 4 and 5 explored the possibility that children's errors reflect difficulty inhibiting their own knowledge when responding. The results are taken as evidence that understanding of interpretation begins at approximately age 6 years.     

Children's ability to impute inferentially based knowledge

Do young children appreciate the importance of access to premises when judging what another person knows? In Experiment 1, 5-year-olds (N=31) were sensitive to another person's access to premises when predicting that person's ability to point to a target after eliminating alternatives in a set of 3 cartoon characters. Experiment 2 replicated the finding when 5- to 6-year-olds (N=102) judged who the other person thought the target was, and whether the other person knew who the target was. Experiment 3 demonstrated that children aged 5-7 years (N=107) more successfully imputed inference by elimination than syllogistical inferential knowledge. Findings suggest that an early understanding of inference by elimination offers a route into understanding that people can sometimes gain knowledge without direct perceptual access.     

Children's developing awareness of diversity in people's trains of thought

This research explored the development of one insight about the mind, namely, the belief that people's trains of thought differ even when they see the same stimulus. In Study 1, 5-year-olds, 9-year-olds, and adults heard stories about characters who saw the same object. Although the older groups predicted the object would trigger different trains of thought, most 5-year-olds did not. In Study 2, 5-year-olds (preschoolers and kindergartners) and 7-year-olds heard similar stories, plus stories with additional individuating information about each character. With age, children increasingly recognized that thoughts would differ and could explain why. The development of this insight during the school years likely provides children with a more complete understanding of what it means to be a unique individual.     

Young children's reasoning about many-to-one correspondences

Young children's understanding of many-to-one correspondence problems was studied to illuminate the developmental transition from additive to multiplicative numerical knowledge. A many-to-one correspondence exists when a fixed number of target objects (greater than 1) is associated with each of a set of referents, as in putting 3 flowers in each of several vases. Two experiments examined effects of a brief training procedure that highlighted the iterative nature of many-to-one mappings. In Experiment 1, 5- and 6-year-old children did not benefit from the training, but a subset of 7-year-olds did. In Experiment 2, 7-year-olds showed training effects that extended to generalization problems. Patterns of performance across experimental and generalization problems suggested that some children had difficulty applying what they learned from training to the experimental problems.     

Young Children's Understanding of the Mind-Body Distinction

4 experiments investigated children's understanding of the mind-body distinction. Children of ages 4 and 5 recognized not only the differential modifiability of changeable versus unchangeable human properties and bodily versus mental properties, but also the independence of activities of bodily organs from a person's intention (Experiment 1). When presented 3 types of causal explanations (i.e., intentional, vitalistic, mechanical), 6-year-olds chose most often as most plausible for bodily functions vitalistic explanations (i.e., those ascribing the phenomena to a relevant bodily organ's initiative and effortful engagement in activity); 8-year-olds chose the vitalistic explanations second most often, following mechanical ones (Experiment 2). However, 6-year-olds, as well as 8-year-olds and adults, did not always choose vitalistic explanations over intentional explanations (Experiment 3); whereas they tended to prefer vitalistic explanations for biological phenomena, they predominantly accepted intentional ones for psychological phenomena (Experiment 3A). These results suggest that children as young as 6 years of age have acquired a form of biology as an autonomous domain which is separate from that of psychology.     

Children's Understanding of Knowledge Acquisition: The Tendency for Children to Report That They Have Always Known What They Have Just Learned

Children's attention to knowledge-acquisition events was examined in 4 experiments in which children were taught novel facts and subsequently asked how long they had known the new information. In Experiment 1, 4- and 5-year-olds tended to claim they had known novel animal facts for a long time and also reported that other children would know the novel facts. This finding was replicated in Experiment 2, using facts associated with chemistry demonstrations. In Experiments 3 and 4, children were taught new color words. 5-year-olds, but not 4-year-olds, distinguished between novel and familiar color words, reporting they had not known the novel words before the test session, but they had always known the familiar words. 4-year-olds in Experiment 4 were better able to distinguish novel and familiar color words when the teaching of the novel words was an explicit and salient part of the procedure.     

Confusions between memories for performed and imagined actions: a developmental comparison

Children are often assumed to be more confused than adults are about the origin of self-generated memories (e.g., what they did or thought). The present experiments showed evidence in support of this assumption but only under some circumstances. In Experiment 1, 6- and 9-year-olds were as good as adults in distinguishing what they did from what they saw someone else do. However, children had particular trouble distinguishing what they did from what they imagined doing. Confusion between performed and imagined actions was evident across a range of actions. Clustering data also showed that information about origin is part of the memory for an event; all subjects recalled actions according to who performed what action (Experiment 1). Further, the presence of person categories as a basis for organization reduced clustering based on action class more for children than for adults (Experiment 1 vs. 2). Collectively, these findings indicate that children become sensitive to some distinctions in memories sooner than they do to others.     

Children''s Understanding of the Modal Expression of Speaker Certainty and Uncertainty and Its Relation to the Development of a Representational Theory of Mind

2 experiments examined children's understanding of the expression of speaker certainty and uncertainty and its relation to their developing theory of mind. In the first experiment, 80 children between 3 and 6 years of age were presented with a task in which they had to guess the location of an object hidden in 1 of 2 boxes. As clues to location, the children were presented with contrasting pairs of statements by 2 puppets. Different trials contained all of the possible pairwise combinations of either the modal verbs must, might, and could or the modal adjuncts probably, possibly, and maybe. Results showed that while 3-year-olds did not differentiate between any of the modal contrasts presented, 4-year-olds and older children were able to find the hidden object on the basis of what they heard. Performance was best for contrasts involving a highly certain term (either must or probably) paired with a less certain term (might, could, possibly, and maybe). Experiment 2 was designed to determine whether competence with modal terms was related to competence with mental terms in the same task, and whether performance on the certainty task was related to other aspects of the child's understanding of the nature of beliefs. 26 4-year-olds were presented with the certainty task, involving both modal and mental terms, and with tasks assessing their understanding of false beliefs, representational change, and the appearance-reality distinction. Results showed that all of these tasks were intercorrelated, implying that what may develop at 4 years of age may be a general understanding of the representational nature of belief.     

Preschoolers are sensitive to the speaker's knowledge when learning proper names

Unobservable properties that are specific to individuals, such as their proper names, can only be known by people who are familiar with those individuals. Do young children utilize this “familiarity principle” when learning language? Experiment 1 tested whether forty-eight 2- to 4-year-old children were able to determine the referent of a proper name such as “Jessie” based on the knowledge that the speaker was familiar with one individual but unfamiliar with the other. Even 2-year-olds successfully identified Jessie as the individual with whom the speaker was familiar. Experiment 2 examined whether children appreciate this principle at a general level, as do adults, or whether this knowledge may be specific to certain word-learning situations. To test this, forty-eight 3- to 5-year-old children were given the converse of the task in Experiment 1—they were asked to determine the individual with whom the speaker was familiar based on the speaker’s knowledge of an individual’s proper name. Only 5-year-olds reliably succeeded at this task, suggesting that a general understanding of the familiarity principle is a relatively late developmental accomplishment.     

Almost thinking counterfactually: children's understanding of close counterfactuals

Saying something "almost happened" indicates that one is considering a close counterfactual world. Previous evidence suggested that children start to consider these close counterfactuals at around 2 years of age (P. L. Harris, 1997), substantially earlier than they pass other tests of counterfactual thinking. However, this success appears to result from false positives. In Experiment 1 (N = 41), 3- and 4-year-olds could identify a character who almost completed an action when the comparison did not complete it. However, in Experiments 1 and 2 (N = 98), children performed poorly when the comparison character completed the action. In Experiment 3 (N = 28), 5- and 6-year-olds consistently passed the task, indicating that they made appropriate counterfactual interpretations of the "almost" statements. This understanding of close counterfactuals proved more difficult than standard counterfactuals.     

Children's suggestibility in relation to their understanding about sources of knowledge

In the experiments reported here, children chose either to maintain their initial belief about an object's identity or to accept the experimenter's contradicting suggestion. Both 3- to 4-year-olds and 4- to 5-year-olds were good at accepting the suggestion only when the experimenter was better informed than they were (implicit source monitoring). They were less accurate at recalling both their own and the experimenter's information access (explicit recall of experience), though they performed well above chance. Children were least accurate at reporting whether their final belief was based on what they were told or on what they experienced directly (explicit source monitoring). Contrasting results emerged when children decided between contradictory suggestions from two differentially informed adults: Three- to 4-year-olds were more accurate at reporting the knowledge source of the adult they believed than at deciding which suggestion was reliable. Decision making in this observation task may require reflective understanding akin to that required for explicit source judgments when the child participates in the task.     

Young children's knowledge about visual perception: projective size and shape

Although recent research indicates that an increased sensitivity to visual appearances develops around 4 or 5 years of age, evidence from perceptual studies suggests that certain types of appearances, that is, projective size and shape, are not noticed or understood until at least 7. 4 experiments investigated preschool children's knowledge of the projective size--distance and projective shape--orientation relationships. In Experiment 1, 3- and 4-year-olds were asked whether an object should be moved farther or nearer in order to increase or decrease its apparent size. 4-year-olds performed significantly better than chance, but 3-year-olds did not. Experiment 2 showed that 3-year-olds are able to perceive projective size changes, indicating that although they do not fully understand the projective size-distance relationship, the necessary perceptual information is potentially available to them. In Experiment 3, 3- and 4-year-olds were asked to indicate how a circular object should be rotated to make it appear either circular or elliptical. Again, 4-year-olds performed significantly better than chance, but 3-year-olds did not. Again also, the results of Experiment 4 indicate that although 3-year-olds are not aware of the projective shape-orientation relationship, they are capable of attending to changes in projective shape. Thus, the constraints on children's knowledge of the projective size-distance and projective shape-orientation relationships seem to be at least partly cognitive rather than wholly perceptual. These results are interpreted as further evidence for the acquisition of level 2 percept knowledge during early childhood.     

Children's understanding of the distinction between real and apparent emotion

2 experiments examined children's understanding of the distinction between real and apparent emotion. In Experiment 1, 6- and 10-year-old children listened to stories in which it would be appropriate for the story protagonist to feel either a positive or negative emotion but to hide that emotion. Subjects were asked to say both how the protagonist would look and how the protagonist would really feel, and to justify their claims. The results indicated that 6- and 10-year-olds alike could distinguish quite accurately between real and apparent emotion, although 10-year-olds were somewhat better at justifying this distinction. In Experiment 2, a slightly modified procedure was used to test 4- and 6-year-olds. Again, 6-year-olds demonstrated their grasp of the difference between real and apparent emotion, and even 4-year-olds showed a limited grasp of the distinction. The findings are discussed in relation to recent research concerning children's concept of mind, their grasp of the appearance-reality distinction, their ability to produce complex, embedded justifications, and their ideas about emotion.     

Epistemic states and traits: preschoolers appreciate the differential informativeness of situation-specific and person-specific cues to knowledge

Previous research has demonstrated that preschoolers can use situation-specific (e.g., visual access) and person-specific (e.g., prior accuracy) cues to infer what others know. The present studies investigated whether 4- and 5-year-olds appreciate the differential informativeness of these types of cues. In Experiment 1 (N = 50), children used others' prior labeling accuracy as a cue when learning labels for, but not the visual identity of, hidden objects. In Experiment 2 (N = 64), with both cues present, children attended more to visual access than prior accuracy when learning the visual identity of, but not labels for, hidden objects. These findings demonstrate that children appreciate the difference between situation- and person-specific cues and flexibly evaluate these cues depending on what information they are seeking.     

Early Deception and the Child's Theory of Mind: False Trails and Genuine Markers

The ability to understand false beliefs is critical to a concept of mind. Chandler, Fritz, and Hala challenge recent claims that this ability emerges only at around 4 years of age. They report that 2- and 3-year-olds remove true trails and lay false ones to mislead someone about the location of a hidden object. Experiment 1 confirmed that 2- and 3-year-olds produce apparently deceptive ploys, but they produce them less often than 4-year-olds, require prompting, and rarely anticipate their impact on the victim's beliefs or search. In addition, Experiment 2 showed that 3-year-olds produce deceptive and informative ploys indiscriminately, whether asked to mislead a competitor or inform a collaborator. By contrast, 4-year-olds act selectively. The results support earlier claims that an understanding of false beliefs and deceptive ploys emerges at around 4 years of age. 2- and 3-year-olds can be led to produce such ploys but show no clear understanding of their effect.     

Young children category learning: a training study

From an integrative approach, this work focuses on the role of conceptual mechanisms, such as comparison and conceptual-based inference, and sociopragmatic support in young children's taxonomic categorization. “Experiment 1” assessed whether 3-, 4-, and 6-year-old children succeed in detecting taxonomic relations on their own. A clear developmental trend was found: 6-year-olds succeeded, whereas 4- and 3-year-olds relied primarily on perceptually based categories. “Experiment 2” assessed if 3-year-olds are able to change their perceptual response into a taxonomic categorization as a function of the co-occurrence of contingent category information and feedback in an interactive process with an adult (experimenter). A pretest–posttest training study compared 3-year-olds' performance in four conditions: comparison, conceptual-based, information-only, and feedback-only. A perceptual–totaxonomic shift was found only in the comparison and conceptual-based training groups. Children who only received either category information or corrective feedback did not make such a shift. The results show that social interaction with supportive adults is a mechanism that drives conceptual understanding in early childhood.