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.     

Priorities in children's expectations about object label reference: form over color

Young children show considerable interest in color similarity; thus we might expect them to use color as a basis for generalizing object labels. However, natural language observations suggest they do not: children tend to overextend labels based on form similarity and rarely, if ever, overextend labels to objects that share only color. Perhaps, then, children give form priority over color in their expectations about object-label reference. This hypothesis was investigated in 2 studies. In a first study, 40 2- and 3-year-olds sorted 10 sets of 3 pictures that contrasted form with color. Children participated in 1 of 2 conditions: half of the children were shown a target object and asked to "find another one" from among the two choice objects, while the other children heard a novel label for the target (e.g., "See this zom?") and were asked to extend the label (e.g., "Can you find another zom?"). 3-year-olds sorted almost exclusively on the basis of form in both conditions, while 2-year-olds performed differently in the 2 conditions: they frequently chose the color match when labels were absent, but selected by form rather than color when asked to extend a novel label. A second study replicated these findings with novel objects that were real rather than pictured. This study also suggested that 3-year-olds grant color some role in their decisions about object-label reference as long as form differences are reduced to a tolerable level. In sum, young children expect form to be more important than color for guiding object-label reference, even though they may find color interesting when not asked to extend labels. This expectation helps explain the speed and relative ease with which children acquire object labels.     

Learning words from knowledgeable versus ignorant speakers: links between preschoolers' theory of mind and semantic development

Two studies addressed whether children consider speakers' knowledge states when establishing initial word-referent links. In Study 1, forty-eight 3- and 4-year-olds were taught two novel words by a speaker who expressed either knowledge or ignorance about the words' referents. Children showed better word learning when the speaker was knowledgeable. In Study 2, forty-eight 3- and 4-year-olds were taught two novel words by a speaker who expressed uncertainty about their referents. Whether the uncertainty truly reflected ignorance, however, differed across conditions. In one condition, the speaker said he made the object himself and thus, he was knowledgeable. In the other condition, the speaker stated that the object was made by a friend and thus, expressed ignorance about it. Four-year-olds learned better in the speaker-made than in the friend-made condition; 3-year-olds, however, showed relatively poor learning in both conditions. These findings suggest that theory-of-mind developments impact word learning.     

Preschoolers modulate contrastive inferences during online language comprehension

This study examined 4- and 5-year-olds' incremental interpretation of size adjectives, focusing on whether contrastive inferences are modulated by speaker behavior. Children (N = 120, 59 females, mostly White, tested between July, 2018 and August, 2019) encountered either a conventional or unconventional speaker who labeled objects in a correspondingly typical or atypical way. Critical utterances contained size adjectives (e.g., “Look at the big duck”). With conventional speakers, gaze measures indicated that children rapidly used the adjective to differentiate members of a contrasting pair, indicating that even 4-year-olds derive contrastive inferences. With unconventional speakers, contrastive inferences were delayed in processing. The findings demonstrate that preschoolers adjust their use of pragmatic cues when presented with evidence disconfirming their default assumptions about a speaker.     

Young children's beliefs about the relationship between gender and aggressive behavior

Young children's beliefs about the relationship between gender and aggression were examined across 3 studies (N=121). In Study 1, preschoolers (ages 3 to 5) described relational aggression as the most common form of aggression among girls and physical aggression as the most common form among boys. In Study 2, preschoolers and a comparison group of 7- to 8-year-olds were likely to infer that relationally aggressive characters are female and physically aggressive characters are male. Study 3 revealed that preschoolers show systematic memory distortions when recalling stories that conflict with these gender schemas. These findings suggest that even before children reach school age, they have organized patterns of beliefs about gender that affect the way they process social information.     

The nominal passover effect depends on addressee age, speaker goal, and object similarity

If after teaching a label for 1 object, a speaker does not name a nearby object, 3-year-olds tend to reject the label for the nearby object (W.E. Merriman, J.M. Marazita, L.H. Jarvis, J.A. Evey-Burkey, and M. Biggins, 1995a). In Studies 1 (5-year-olds) and 3 (3-year-olds), this effect depended on object similarity. In Study 2, when a speaker used a label without teaching it, 5-year-olds showed no passover effect. 3-year-olds showed none for inanimate objects, but one for animate objects. When extraneous factors that may have promoted animate object individuation were eliminated (Study 3), 3-year-olds showed the effect when a label was taught, but not when it was merely used. Children honor rational restrictions on when the unacceptability of a name can be inferred from its nonoccurrence.     

Learning words through overhearing

Recent research indicates that toddlers can monitor others' conversations, raising the possibility that they can acquire vocabulary in this way. Three studies examined 2-year-olds' (N = 88) ability to learn novel words when overhearing these words used by others. Children aged 2,6 were equally good at learning novel words-both object labels and action verbs-when they were overhearers as when they were directly addressed. For younger 2-year-olds (2,1), this was true for object labels, but the results were less clear for verbs. The findings demonstrate that 2-year-olds can acquire novel words from overheard speech, and highlight the active role played by toddlers in vocabulary acquisition.     

The Development of Verb Concepts: Children''s Use of Verbs to Label Familiar and Novel Events

The importance of actions, results, and instruments in verb concepts was examined in four studies. Study 1 investigated how children label familiar events for which instrument, action, and result verbs were appropriate labels. In Study 2, subjects were taught novel verbs and were asked to use these verbs to label events in which the instrument, action, or result had been changed. Study 1 showed that 3-year-olds used action verbs more frequently than older children and adults, and that they preferred to use an action verb over a result verb when both verbs were appropriate labels. Instrument verbs were used most frequently as first responses to the events, and were most frequently used by older children and adults. In Study 2, subjects were least likely to use the novel verbs to label events in which the result had changed. This effect increased with age. Action changes had a moderate effect for all age groups, while instrument changes had the weakest effect. Studies 3 and 4 ruled out stimulus salience and a familiar word strategy as interpretations of these findings. The studies are discussed in terms of current theory and research on conceptual development, word-learning strategies, and the semantic organization of nouns and verbs.     

The development of uncertainty monitoring in early childhood

This study examined the development of uncertainty monitoring in early childhood. Specifically, this study tested the prediction that preschoolers can reflect on their sense of certainty about the likely accuracy of their decisions, and it examined whether this ability differs across domains. Three-, 4-, and 5-year-olds (N = 74) completed a perceptual identification and a lexical identification task in which they reported whether they were certain or uncertain about their answers. Results showed that even 3-year-olds provided confidence judgments that discriminated accurate from inaccurate responses, but this discrimination increased with age. Furthermore, results suggest that 3-year-olds primarily rely on response latency to assess certainty, whereas older preschoolers do not. Overall, these findings suggest that uncertainty monitoring emerges and develops during the preschool years.     

Understanding Categorical Hierarchies: The Earliest Levels of Skill

2 categorization skills necessary for understanding hierarchies are the ability to form categories at different levels of generality and the ability to include the same objects into multiple categories. 2-year-olds appear to have the first skill, but some theoretical and empirical work suggests that the second may be a later acquisition. Yet, in 3 studies, 2- and 3-year-olds applied familiar basic level and superordinate labels to the same objects, even when reminded of basic labels before being tested with superordinates. They did not reserve superordinates for objects with unfamiliar basic level names (Study 2), and they were willing to apply superordinates to objects presented singly rather than in groups (Study 3). Thus, contrary to the implications of some previous work, 2- and 3-year-olds appear to have both of the categorization skills necessary for forming categorical hierarchies.     

Lessons from television: children's word learning when viewing

The study investigated if preschoolers can learn novel words when viewing television and if the learning is influenced by age or type of word. 61 preschoolers, ages 3 and 5, were assigned to either an experimental or control group. They viewed a 15-min television program, featuring 20 different novel words, 5 each in the 4 categories of object, action, attribute, and affective-state words. Comprehension was tested before and after viewing. The experimental group performed better than the controls for object, action, and attribute words. 5-year-olds were more accurate than 3-year-olds and gained relatively more from the experimental condition. The easiest words to learn were object and attribute words. The results are relevant for studies of media effects and accounts of preschoolers' "fast mapping" of new words.     

Acquiring Color Names via Linguistic Contrast: The Influence of Contrasting Terms

Linguistic contrast of the form "It's not X; it's Y" is often used by adults to correct children's naming errors. The present studies examined whether such linguistic contrast could help preschoolers learn a novel color name. In Experiment 1, a novel color term was contrasted only once with 1 or 2 familiar color names. Contrasting a new color term with children's own label for the stimulus color helped 5-year-olds learn the new term, but contrasting the new term with randomly chosen familiar color terms did not. For 4-year-olds, neither kind of contrast helped much. Experiments 2 and 3 showed that when the contrastive information was presented more than once, even 3- and 4-year-olds performed much like the 5-year-olds in Experiment 1. Together, these findings suggest that contrasting a new term with a child's own term facilitates the acquisition of the new term, perhaps because it gives the child specific information about how two terms are related in meaning.     

Characterizing Children’s Expectations About Expertise and Incompetence: Halo or Pitchfork Effects?

Do children expect an expert in one domain to also be an expert in an unrelated domain? In Study 1, 32 three‐ and four‐year‐olds learned that one informant was an expert about dogs relative to another informant. When presented with pictures of new dogs or of artifacts, children who could remember which informant was the dog expert preferred her over the novice as an informant about the names of dogs, but they had no preference when the informants presented artifact labels. In Study 2, 32 children learned that one informant was incompetent about dogs whereas another was neutral. In this case, children preferred the neutral speaker over the incompetent one about both dogs and artifacts. Taken together, these results suggest that for children, expertise is not subject to a “halo effect,” but incompetence may be subject to a “pitchfork effect.”     

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.     

Mechanism-based causal reasoning in young children

The hypothesis that children develop an understanding of causal mechanisms was tested across 3 experiments. In Experiment 1 (N = 48), preschoolers had to choose as efficacious either a cause that had worked in the past, but was now disconnected from its effect, or a cause that had failed to work previously, but was now connected. Four-year-olds chose the now-connected cause more often than 3-year-olds. Experiment 2 (N = 16) showed 4-year-olds responded appropriately to an irrelevant modification in the same causal system. Experiment 3 (N = 24) demonstrated when the mechanism was batteries rather than connection, 3-year-olds could properly distinguish between relevant and irrelevant modifications. Together, these data suggest that understanding of specific causal mechanisms develops at different ages.     

Lexical form class information guides word-to-object mapping in preschoolers

We demonstrate that lexical form class information can play a powerful role in directing the establishment of word-to-object mappings in referentially ambiguous situations. A total of 144 3- and 4-year-olds heard a novel label, modeled syntactically as either a proper name or an adjective, for a stuffed animal of a familiar kind. We then added a second object of the same kind and asked children (1) to choose one of the two objects as the referent of a second novel label, also presented syntactically as either a proper name or an adjective, and (2) to decide whether this second label could also apply to the object they did not choose. In each of three experiments, preschoolers were most likely to reject two words for the same object if both words were proper names (as if one dog could not be both "Fido" and "Rover"). They were significantly less likely to do so if both were adjectives (as if one dog could be both "spotted" and "furry") or if one was a proper name and the other was an adjective (as if one dog could be both "Fido" and "furry"). Information about lexical form class thus contributed significantly to the formation of linkages between words and objects.     

Children''s Interpretation of Messages from a Speaker with a False Belief

In 5 investigations we examined a new procedure for assessing children's understanding that messages arise from speakers' internal representations. 3- and 4-year-olds watched the enactment of a message-desire discrepant story in which a speaker doll, who believed wrongly that bag A was in location 1 and that bag B was in location 2, gave a message referring to the bag in location 1. In a message-desire consistent control condition, the speaker had a correct belief about the bags' locations. Children frequently judged correctly in the discrepant story that the speaker (who specified location 1) wanted the bag in location 2, and judged correctly in the consistent story that the speaker wanted the bag in location 1. That is, young children attended to the speaker's internal representations, and not just the real-world referent of the message, when judging what the speaker wanted. In one of the investigations, children performed better on the message-desire discrepant task than on a false belief task. We discuss why they might find it particularly easy to take into account false belief when inferring desire on the basis of behavior.     

Developmental differences in part/whole identification

At issue in the present research was whether or not preschoolers are able to simultaneously perceive multiple aspects of an object. This issue was examined in 2 experiments in which 3-5-year-olds were asked to describe part/whole pictures (e.g., a "house made of crayons"). Prior developmental research has suggested that preschoolers typically fail to name both part and whole aspects of such pictures. In the present study, parts and wholes ranged from relatively "simple" to relatively "difficult" for preschoolers to identify and label. The results showed that even 3-year-olds frequently named both part and whole aspects of our "simple" pictures but were significantly less likely to name both aspects of more "difficult" pictures. Overall, the results suggest that multiple-aspect perception is available as early as 3 years of age, and that preschoolers' failure in previous studies to explicitly identify both part and whole aspects of the same object may reflect failure in verbal or metacognitive skills rather than in children's ability to perceive multiple aspects of an object.     

Preschool Children's Symbolic Representation of Objects through Gestures

To investigate the symbolic quality of preschoolers' gestural representations in the absence of real objects, 48 children (16 3-, 4-, and 5-year-olds) performed 2 tasks. In the first task, they were asked to pretend to use 8 common objects (e.g., "pretend to brush your teeth with a toothbrush"). There was an age-related progression in the symbolic quality of gestural representations. 3- and 4-year-olds used mostly body part gestures (e.g., using an extended finger as the toothbrush), whereas 5-year-olds used imaginary object gestures (e.g., pretending to hold an imaginary toothbrush). To determine if children's symbolic skill is sufficiently flexible to allow them to use gestures other than those spontaneously produced in the first task, in the second task children were asked to imitate, for each object, a gesture modeled by an experimenter. The modeled gesture was different from the one the child performed on the first task (e.g., if the child used a body part gesture to represent a particular object, the experimenter modeled an imaginary object gesture for that object). Ability to imitate modeled gestures was positively related to age but was also influenced by the symbolic mode of gesture. 3-year-olds could not imitate imaginary object gestures as well as body part gestures, suggesting that young preschoolers have difficulty performing symbolic acts that exceed their symbolic level even when the acts are modeled. Results from both tasks provide strong evidence for a developmental progression from concrete body part to more abstract imaginary object gestural representations during the preschool years.