Gaining knowledge via other minds: Children's flexible trust in others as sources of information

In five experiments, we examined 3‐ to 6‐year‐olds’ understanding that they could gain knowledge indirectly from someone who had seen something they had not. Consistent with previous research, children judged that an informant, who had seen inside a box, knew its contents. Similarly, when an informant marked a picture to indicate her suggestion as to the content of the box, 3‐ to 4‐year‐olds trusted this more frequently when the informant had seen inside the box than when she had not. Going beyond previous research, 3‐ to 4‐year‐olds were also sensitive to informants’ relevant experience when they had to look over a barrier to see the marked picture, or ask for the barrier to be raised. Yet when children had to elicit the informant's suggestion, rather than just consult a suggestion already present, even 4‐ to 5‐year‐olds were no more likely to do so when the informant had seen the box's content than when she had not, and no more likely to trust the well‐informed suggestion than the uninformed one. We conclude that young children who can ask questions may not yet fully understand the process by which they can gain accurate information from someone who has the experience they lack.     

Two rooms,two representations? Episodic‐like memory in toddlers and preschoolers

Episodic memory involves binding together what‐where‐when associations. In three experiments, we tested the development of memory for such contextual associations in a naturalistic setting. Children searched for toys in two rooms with two different experimenters; each room contained two identical sets of four containers, but arranged differently. A distinct toy was hidden in a distinct container in each room. In Experiment 1, which involved children between 15 and 26 months who were prompted with a very explicit cue (a part of the hidden toy), we found a marked shift in performance with age: while 15‐ to 20‐month‐olds concentrated their searches on the two containers that sometimes contained toys, they did not distinguish between them according to context, but 21–26‐month‐olds did. However, surprisingly, without toy cues, even the youngest children showed a fragile ability to disambiguate the two containers by room context. In Experiment 2, we tested 34‐ to 40‐month‐olds and 64‐ to 72‐month‐olds without toy cues. The 5‐year‐olds were nearly perfect, and the 3‐year‐olds showed a significant preference for the correct container given only the context. In Experiment 3, we filled in the age range, and also investigated the effects of the use of labels (i.e. names of experimenters and rooms) and of familiarization time, in groups of 34‐ to 40‐month‐olds, 42‐ to 48‐month‐olds, and 50‐ to 56‐month‐olds. Neither labels nor familiarization time had an effect. Across experiments, there was regular age‐related improvement in context‐based memory. Overall, the results suggest that children's episodic memory may undergo an early qualitative change, yet to be precisely characterized, and that continuing increments in the use of contextual cues occur throughout the preschool period. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=DkwEFw0UEz4&list=PLwxXcOKHPC0llAPVcJyW4EtzlA934A2Rz&index=1     

Older (but not younger) preschoolers understand that knowledge differs between people and across time

We examined 3‐ to 5‐year‐olds' understanding of general knowledge (e.g., knowing that clocks tell time) by investigating whether (1) they recognize that their own general knowledge has changed over time (i.e., they knew less as babies than they know now), and (2) such intraindividual knowledge differences are easier/harder to understand than interindividual differences (i.e., Do preschoolers understand that a baby knows less than they do?). Forty‐eight 3‐ to 5‐year‐olds answered questions about their current general knowledge (‘self‐now’), the general knowledge of a 6‐month‐old (‘baby‐now’), and their own general knowledge at 6 months (‘self‐past’). All age groups were significantly above chance on the self‐now questions, but only 5‐year‐olds were significantly above chance on the self‐past and baby‐now questions. Moreover, children's performance on the baby‐now and self‐past questions did not differ. Our findings suggest that younger preschoolers do not fully appreciate that their past knowledge differs from their current knowledge, and that others may have less knowledge than they do. We situate these findings within the research on knowledge understanding, more specifically, and cognitive development, more broadly.     

Opening the cuebox: The information children and young adults generate and rely on when making inferences from memory

We used a cue‐generation and a cue‐selection paradigm to investigate the cues children (9‐ to 12‐year‐olds) and young adults (17‐year‐olds) generate and select for a range of inferences from memory. We found that children generated more cues than young adults, who, when asked why they did not generate some particular cues, responded that they did not consider them relevant for the task at hand. On average, the cues generated by children were more perceptual but as informative as the cues generated by young adults. When asked to select the most informative of two cues, both children and young adults tended to choose a hidden (i.e., not perceptual) cue. Our results suggest a developmental change in the cuebox (i.e., the set of cues used to make inferences from memory): New cues are added to the cuebox as more cues are learned, and some old, perceptual cues, although informative, are replaced with hidden cues, which, by both children and young adults, are generally assumed to be more informative than perceptual cues.     

Young children's understanding of pretend crying: The effect of context

Reasoning about another's pretend and real crying is related to ma'ny important social cognitive abilities (e.g., emotional understanding, appearance–reality, and theory of mind). This study investigated whether children aged 6 years and younger could distinguish between instances of pretend crying and real crying as presented in stories. Sixty‐five Japanese children aged 4–6 years were given stories within two contexts (Play and Non‐play). In the Play context, the protagonist of the story was pretending to cry or really crying during a pretend play activity. In the Non‐play context, the protagonist was also pretending to cry or really crying after his/her toy had been hidden by another child. The children answered questions about these crying events. The results showed that the 4‐ and 5‐year‐olds showed significantly better understanding of pretend crying in the Play context compared to the Non‐play context. In the Non‐play context, they were significantly less likely to understand the cause of pretend crying compared to the 6‐year‐olds. The results suggest that the context of pretend play facilitates the children's understanding of pretend crying.     

To be or not to be a galaprock: Preschoolers' intuitions about the importance of knowledge and action for pretending

Can someone pretend to be a galaprock without knowing what a galaprock is? Do children recognize that such knowledge is required for pretending? Three studies focusing on the relations among action, knowledge and pretending suggest that children have this understanding by age 4 years. In Study 1, 4‐year‐olds and adults willingly pretended to be moving and unmoving objects but had trouble pretending to be objects that were difficult to represent physically. In Study 2, 3‐ and 4‐year‐olds claimed they could not pretend to be an unknown thing, justifying their refusals with mentalistic language indicating their ignorance of the object or its typical actions. In Study 3, 3‐ to 5‐year‐olds predicted that other children who have knowledge of an object unfamiliar to the subjects themselves can nevertheless pretend to be it, whereas those lacking that knowledge cannot. The results add support to the growing literature showing that preschoolers conceptualize pretense as involving mental activity.     

Developmental changes in children's inductive inferences for biological concepts: implications for the development of essentialist beliefs

We examined developmental changes in children's inductive inferences about biological concepts as a function of knowledge of properties and concepts. Specifically, 4‐ to 5‐year‐olds and 9‐ to 10‐year‐olds were taught either familiar or unfamiliar internal, external, or functional properties about known and unknown target animals. Children were asked to infer whether each of four probes, varying in categorical and perceptual similarity to the target, also shared that property. Overall, children made more inferences for known concepts and familiar properties. Older children were more likely to use categorical than perceptual information when making inferences about internal and functional properties of known concepts; however, younger children, in general, made no distinction for property type, and they weighted categorical and perceptual information similarly. Both age groups utilized appearance when making inferences about external properties. Results are discussed in terms of developmental changes in children's appreciation of essentialism. Copyright © 2010 John Wiley & Sons, Ltd.     

Enculturation to musical pitch structure in young children: evidence from behavioral and electrophysiological methods

Children learn the structure of the music of their culture similarly to how they learn the language to which they are exposed in their daily environment. Furthermore, as with language, children acquire this musical knowledge without formal instruction. Two critical aspects of musical pitch structure in Western tonal music are key membership (understanding which notes belong in a key and which do not) and harmony (understanding which notes combine to form chords and which notes and chords tend to follow others). The early developmental trajectory of the acquisition of this knowledge remains unclear, in part because of the difficulty of testing young children. In two experiments, we investigated 4‐ and 5‐year‐olds' enculturation to Western musical pitch using a novel age‐appropriate and engaging behavioral task (Experiment 1) and electroencephalography (EEG; Experiment 2). In Experiment 1 we found behavioral evidence that 5‐year‐olds were sensitive to key membership but not to harmony, and no evidence that 4‐year‐olds were sensitive to either. However, in Experiment 2 we found neurophysiological evidence that 4‐year‐olds were sensitive to both key membership and harmony. Our results suggest that musical enculturation has a long developmental trajectory, and that children may have some knowledge of key membership and harmony before that knowledge can be expressed through explicit behavioral judgments.     

The role of the physical context in supporting young children's use of spatiotemporal organization in recall

Four experiments were conducted to investigate the role of the physical context in supporting 3‐ to 5‐year‐olds' use of spatiotemporal organization in recall. Children were familiarized with several target items and their corresponding landmarks arranged along a path in a model park. After familiarization, an experimenter removed the target items from the park. In Experiment 1, 3‐ and 4‐year‐olds recalled the missing items with the park either in view or out of view. When the park model was in view, 4‐ year‐olds used the order of the items along the path to structure their recall. In Experiment 2, 4‐ and 5‐year‐olds recalled the missing items with the landmarks arranged either in the same order as in familiarization or in a new order. Children used the order of landmarks along the path at test to structure their recall, even though the order of landmarks changed from familiarization to test. Experiment 3 was identical to Experiment 2, except that the path was removed from the park. Five‐year‐olds used the order of landmarks along the path at test to structure their recall when the order of landmarks remained the same from familiarization to test, but had much more difficulty doing so when the order of landmarks changed from familiarization to test. Using a more difficult task, Experiment 4 revealed that spatiotemporal organization was positively related to amount recalled. Together, these findings suggest that the structure of the physical environment plays an important role in supporting young children's use of spatiotemporal organization in recall.     

Duck or rabbit? Reversing ambiguous figures and understanding ambiguous representations

In two studies we investigated 3‐ to 5‐year‐old children’s ability to reverse ambiguous figures and the relation between this ability and the ability to understand multiple representations. Children never reversed before they were informed of the two alternative interpretations of the figures. Even when they were informed of the alternatives and understood that both were possible, 3‐year‐olds and most 4‐year‐olds did not reverse. In contrast, a majority of 5‐year‐olds did reverse. In general, children only reversed if they also passed a standard false belief task. However, there was a closer correlation between reversals and a ‘droodle’ task that involved an understanding of the ambiguity of perceptual representations. These results suggest that the immediate experience of reversal may depend on a more abstract understanding of ambiguous representations.     

First‐hand sensory experience plays a limited role in children's early understanding of seeing and hearing as sources of knowledge: Evidence from typically hearing and deaf children

One early‐developing component of theory of mind is an understanding of the link between sensory perception and knowledge formation. We know little about the extent to which children's first‐hand sensory experiences drive the development of this understanding, as most tasks capturing this early understanding target vision, with less attention paid to the other senses. In this study, 64 typically hearing children (M_age = 4.0 years) and 21 orally educated deaf children (M_age = 5.44 years) were asked to identify which of two informants knew the identity of a toy animal when each had differing perceptual access to the animal. In the ‘seeing’ condition, one informant saw the animal and the other did not; in the ‘hearing’ condition, one informant heard the animal and the other did not. For both hearing and deaf children, there was no difference between performance on hearing and seeing trials, but deaf children were delayed in both conditions. Further, within both the hearing and deaf groups, older children outperformed younger children on these tasks, indicating that there is a developmental progression. Taken together, the pattern of results suggests that experiences other than first‐hand sensory experiences drive children's developing understanding that sensory perception is associated with knowledge.     

Children's working understanding of knowledge sources: Confidence in knowledge gained from testimony

In three experiments, children aged between 3 and 5 years (N = 38, 52, 94; mean ages 3–7 to 5–2) indicated their confidence in their knowledge of the identity of a hidden toy. With the exception of some 3-year-olds, children revealed working understanding of their knowledge source by showing high confidence when they had seen or felt the toy, and lower confidence when they had been told its identity by an apparently well-informed speaker. Correct explicit source reports were not necessary for children to show relative uncertainty when the speaker subsequently doubted the adequacy of his access to the toy. After a 2-min delay, 3–4-year-olds, unlike 4–5-year-olds, failed to see the implications of the speaker's doubt about his access.     

Children's recognition of time in the causes and cures of physical and emotional reactions to illnesses and injuries

The present set of studies examined children's and college students' recognition of the role of time in the manifestation of causes and cures for illnesses and injuries. In Study 1, participants ranging from 4‐year‐olds through college students were presented with biological, moral, psychological, and irrelevant causes for illness symptoms and were asked how much time elapsed between the cause and the symptom. They were also asked if medicine would make the person feel better and if so how much time elapsed between taking the medicine and feeling better. Study 2 replicated Study 1 with 4‐ and 5‐year‐olds. Study 3 examined whether 4‐ and 5‐year‐olds and college students could differentiate between physical and emotional reactions to illnesses and injuries, with regard to time course. Overall, young children underestimate how long it takes for illness symptoms to emerge (expecting them to result right away following exposure to contamination). Nonetheless, children generated longer timelines for biological cures than biological causes. Moreover, 4‐ and 5‐year‐olds expect physical and emotional reactions to follow different time courses. These results suggest that young children have a nascent expectation that biological events are distinct from non‐biological events, in how they unfold over time.     

Magical thinking in judgments of causation: Can anomalous phenomena affect ontological causal beliefs in children and adults?

In four experiments, 4‐, 5‐, 6‐ and 9‐year‐old children and adults were tested on the entrenchment of their magical beliefs and their beliefs in the universal power of physical causality. In Experiment 1, even 4‐year‐olds showed some understanding of the difference between ordinary and anomalous (magical) causal events, but only 6‐year‐olds and older participants denied that magic could occur in real life. When shown an anomalous causal event (a transformation of a physical object in an apparently empty box after a magic spell was cast on the box), 4‐ and 6‐year‐olds accepted magical explanations of the event, whereas 9‐year‐olds and adults did not. In Experiment 2, the same patterns of behaviour as above were shown by 6‐ and 9‐year‐olds who demonstrated an understanding of the difference between genuine magical events and similarly looking tricks. Testing the entrenchment of magical beliefs in this experiment showed that 5‐year‐olds tended to retain their magical explanations of the anomalous event, even after the mechanism of the trick had been explained to them, whereas 6‐ and 9‐year‐olds did not. In Experiment 3, adult participants refused to accept magical explanations of the anomalous event and interpreted it as a trick or an illusion, even after this event was repeated 4 times. Yet, when in Experiment 4 similar anomalous causal events were demonstrated without reference to magic, most adults acknowledged, both in their verbal judgments and in their actions, that the anomalous effects were not a fiction but had really occurred. The data of this study suggest that in the modern industrialized world, magical beliefs persist but are disguised to fit the dominant scientific paradigm.     

Cultural influences on children's understanding of the human body and the concept of life

This study aimed to identify the age by which children begin to demonstrate a biological understanding of the human body and the idea that the purpose of body functioning is to maintain life. The study also explored the influence of education, culturally specific experiences and religion on knowledge acquisition in this domain. Children aged between 4 and 7 years from three different cultural backgrounds (White British, British Muslim, and Pakistani Muslim) were interviewed about the human body and its functioning. At least half of the 4‐ to 5‐year‐olds in each cultural group, and almost all 6‐ to 7‐year‐olds, referred to the maintenance of life when explaining organs' functions and so were classified as ‘life theorizers’. Pakistani Muslim children gave fewer biological responses to questions about organs' functions and the purpose of eating and breathing, but referred to life more than their British counterparts. Irrespective of cultural group, older children understood organ location and function better than younger children. These findings support Jaakkola and Slaughter's (2002, Br. J. Dev. Psychol., 20, 325) view that children's understanding of the body as a ‘life machine’ emerges around the ages of 4–5 years. They also suggest that, despite many similarities in children's ideas cross‐culturally, different educational input and culturally specific experiences influence aspects of their biological understanding.     

Awareness of the origin of knowledge predicts child witnesses' recall of alleged sexual and physical abuse

Children who understand that knowledge may have different origins produce more information in their free‐recall accounts than children who are less aware of source. We examined whether the tendency to make knowledge attributions was related to the number and proportion of details elicited from child witnesses using open‐ended invitations and whether this relationship varied depending on the number of incidents of abuse reported. The tendency to make knowledge attributions was measured in the presubstantive portion of protocol‐guided interviews with 3‐ to 11‐year‐old alleged victims of abuse. Hierarchical regression analyses revealed that the production of knowledge attribution details was positively related to the proportion of substantive episodic details produced by 3‐ to 6‐year‐olds recalling a single incident and by 3‐ to 11‐year‐olds recalling multiple incidents of abuse. Presubstantive source details were also positively correlated with the amount of source information recalled about incidents of abuse. These findings remained significant after controlling for the children's verbosity, the relative prominence of open‐ended invitations, and the children's ages. © 2003 US Government work.     

Identifying unreliable informants: do children excuse past inaccuracy?

In three experiments (N = 123; 148; 28), children observed a video in which two speakers offered alternative labels for unfamiliar objects. In Experiment 1, 3‐ to 5‐year‐olds endorsed the label given by a speaker who had previously labeled familiar objects accurately, rather than that given by a speaker with a history of inaccurate labeling, even when the inaccurate speaker erred only while blindfolded. In Experiments 2 and 3, 3‐ to 7‐year‐olds showed no preference for the label given by a previously inaccurate but blindfolded speaker, over that given by a second inaccurate speaker with no obvious excuse for erring. Children based their endorsements on speakers’ history of accuracy or inaccuracy irrespective of the speakers’ information access at the time, raising doubts that children made mentalistic interpretations of speakers’ inaccuracy.     

Early humour production

The current studies explored early humour as a complex socio‐cognitive phenomenon by examining 2‐ and 3‐year‐olds’ humour production with their parents. We examined whether children produced novel humour, whether they cued their humour, and the types of humour produced. Forty‐seven parents were interviewed, and videotaped joking with their children. Other parents (N= 113) completed a survey. Parents reported children copy jokes during the first year of life, and produce novel jokes from 2 years. In play sessions, 3‐year‐olds produced mostly novel humorous acts; 2‐year‐olds produced novel and copied humorous acts equally frequently. Parents reported children smile, laugh, and look for a reaction when joking. In play sessions, 2‐ and 3‐year‐olds produced these behaviours more when producing humorous versus non‐humorous acts. In both parent reports and play sessions, they produced novel object‐based (e.g., underwear on head) and conceptual humour (e.g., ‘pig says moo’) and used wrong labels humorously (e.g., calling a cat a dog). Thus, parent report and child behaviour both confirm that young children produce novel humorous acts, and share their humour by smiling, laughing, and looking for a reaction.