Children expect generic knowledge to be widely shared

The ability to acquire and store generic information (that is, information about entire categories) is at the core of human cognition. Remarkably, even young children place special value on generic information, often inferring that it holds important insights about the world. Here, we tested whether children's assumptions about the nature of generic information guide their expectations about how widely known this information is. Across four experiments, 4- to 7-year-old children (N=192) were presented with novel facts in either generic (e.g., "Hedgehogs eat hexapods") or non-generic (e.g., "This hedgehog eats hexapods") format and were asked whether other people (e.g., their moms, grown-ups in general) knew these facts. Overall, children were more likely to say that others knew the generic than the non-generic facts. In addition to highlighting the centrality of generic knowledge in early cognitive life, children's assumption that generic facts are widely known has implications for their social cognition and academic achievement, as well as for the process of language acquisition.     

Why are dunkels sticky? Preschoolers infer functionality and intentional creation for artifact properties learned from generic language

Artifacts pose a potential learning problem for children because the mapping between their features and their functions is often not transparent. In solving this problem, children are likely to rely on a number of information sources (e.g., others’ actions, affordances). We argue that children’s sensitivity to nuances in the language used to describe artifacts is an important, but so far unacknowledged, piece of this puzzle. Specifically, we hypothesize that children are sensitive to whether an unfamiliar artifact’s features are highlighted using generic (e.g., “Dunkels are sticky”) or non-generic (e.g., “This dunkel is sticky”) language. Across two studies, older—but not younger—preschoolers who heard such features introduced via generic statements inferred that they are a functional part of the artifact’s design more often than children who heard the same features introduced via non-generic statements. The ability to pick up on this linguistic cue may expand considerably the amount of conceptual information about artifacts that children derive from conversations with adults.     

This cat has nine lives? Children's memory for genericity in language

Generic noun phrases ("Birds lay eggs") are important for expressing knowledge about abstract kinds. The authors hypothesized that genericity would be part of gist memory, such that young children would appropriately recall whether sentences were presented as generic or specific. In 4 experiments, preschoolers and college students (N = 280) heard a series of sentences in either generic form (e.g., "Bears climb trees") or specific form (e.g., "This bear climbs trees") and were asked to recall the sentences following a 4-min distractor task. Participants in all age groups correctly distinguished between generic and specific noun phrases (NPs) in their recall, even when forgetting the details of the NP form. Memory for predicate content (e.g., "climb trees") was largely unaffected by genericity, although memory for category labels (e.g., "bear") was at times better for those who heard sentences with generic wording. Overall, these results suggest that generic form is maintained in long-term memory even for young children and thus may serve as the foundation for constructing knowledge about kinds.     

Information learned from generic language becomes central to children’s biological concepts: Evidence from their open-ended explanations

Generic sentences (e.g., “Snakes have holes in their teeth”) convey that a property (e.g., having holes in one’s teeth) is true of a category (e.g., snakes). We test the hypothesis that, in addition to this basic aspect of their meaning, generic sentences also imply that the information they express is more conceptually central than the information conveyed in similar non-generic sentences (e.g., “This snake has holes in his teeth”). To test this hypothesis, we elicited 4- and 5-year-old children’s open-ended explanations for generic and non-generic versions of the same novel properties. Based on arguments in the categorization literature, we assumed that, relative to more peripheral properties, properties that are understood as conceptually central would be explained more often as causes and less often as effects of other features, behaviors, or processes. Two experiments confirmed the prediction that preschool-age children construe novel information learned from generics as more conceptually central than the same information learned from non-generics. Additionally, Experiment 2 suggested that the conceptual status of novel properties learned from generic sentences becomes similar to that of familiar properties that are already at the category core. These findings illustrate the power of generic language to shape children’s concepts.     

Differences in preschoolers’ and adults’ use of generics about novel animals and artifacts: A window onto a conceptual divide

Children and adults commonly produce more generic noun phrases (e.g., birds fly) about animals than artifacts. This may reflect differences in participants’ generic knowledge about specific animals/artifacts (e.g., dogs/chairs), or it may reflect a more general distinction. To test this, the current experiments asked adults and preschoolers to generate properties about novel animals and artifacts (Experiment 1: real animals/artifacts; Experiments 2 and 3: matched pairs of maximally similar, novel animals/artifacts). Data demonstrate that even without prior knowledge about these items, the likelihood of producing a generic is significantly greater for animals than artifacts. These results leave open the question of whether this pattern is the product of experience and learned associations or instead a set of early-developing theories about animals and artifacts.     

Effects of generic language on category content and structure

We hypothesized that generic noun phrases (“Bears climb trees”) would provide important input to children’s developing concepts. In three experiments, four-year-olds and adults learned a series of facts about a novel animal category, in one of three wording conditions: generic (e.g., “Zarpies hate ice cream”), specific–label (e.g., “This zarpie hates ice cream”), or no-label (e.g., “This hates ice cream”). Participants completed a battery of tasks assessing the extent to which they linked the category to the properties expressed, and the extent to which they treated the category as constituting an essentialized kind. As predicted, for adults, generics training resulted in tighter category–property links and more category essentialism than both the specific-label and no-label training. Children also showed effects of generic wording, though the effects were weaker and required more extensive input. We discuss the implications for language-thought relations, and for the acquisition of essentialized categories.     

Generic statements require little evidence for acceptance but have powerful implications

Generic statements (e.g., "Birds lay eggs") express generalizations about categories. In this paper, we hypothesized that there is a paradoxical asymmetry at the core of generic meaning, such that these sentences have extremely strong implications but require little evidence to be judged true. Four experiments confirmed the hypothesized asymmetry: Participants interpreted novel generics such as "Lorches have purple feathers" as referring to nearly all lorches, but they judged the same novel generics to be true given a wide range of prevalence levels (e.g., even when only 10% or 30% of lorches had purple feathers). A second hypothesis, also confirmed by the results, was that novel generic sentences about dangerous or distinctive properties would be more acceptable than generic sentences that were similar but did not have these connotations. In addition to clarifying important aspects of generics' meaning, these findings are applicable to a range of real-world processes such as stereotyping and political discourse.     

Language Signaling High Proportions and Generics Lead to Generalizing,but Not Essentializing,for Novel Social Kinds

Generics (e.g., “Dogs bark”) are thought by many to lead to essentializing: to assuming that members of the same category share an internal property that causally grounds shared behaviors and traits, even without evidence of such a shared property. Similarly, generics are thought to increase generalizing, that is, attributing properties to other members of the same group given evidence that some members of the group have the property. However, it is not clear from past research what underlies the capacity of generic language to increase essentializing and generalizing. Is it specific to generics, or are there broader mechanisms at work, such as the fact that generics are terms that signal high proportions? Study 1 (100 5–6 year-olds, 140 adults) found that neither generics, nor high-proportion quantifiers (“most,” “many”) elicited essentializing about a novel social kind (Zarpies). However, both generics and high-proportion quantifiers led adults and, to a lesser extent, children, to generalize, with high-proportion quantifiers doing so more than generics for adults. Specifics (“this”) did not protect against either essentializing or generalizing when compared to the quantifier “some.” Study 2 (100 5–6 year-olds, 112 adults) found that neither generics nor visual imagery signaling high proportions led to essentializing. While generics increased generalizing compared to specifics and visual imagery signaling both low and high proportions for adults, there was no difference in generalizing for children. Our findings suggest high-proportion quantifiers, including generics, lead adults, and to some extent children, to generalize, but not essentialize, about novel social kinds.     

Memory Errors Reveal a Bias to Spontaneously Generalize to Categories

Much evidence suggests that, from a young age, humans are able to generalize information learned about a subset of a category to the category itself. Here, we propose that—beyond simply being able to perform such generalizations—people are biased to generalize to categories, such that they routinely make spontaneous, implicit category generalizations from information that licenses such generalizations. To demonstrate the existence of this bias, we asked participants to perform a task in which category generalizations would distract from the main goal of the task, leading to a characteristic pattern of errors. Specifically, participants were asked to memorize two types of novel facts: quantified facts about sets of kind members (e.g., facts about all or many stups) and generic facts about entire kinds (e.g., facts about zorbs as a kind). Moreover, half of the facts concerned properties that are typically generalizable to an animal kind (e.g., eating fruits and vegetables), and half concerned properties that are typically more idiosyncratic (e.g., getting mud in their hair). We predicted that—because of the hypothesized bias—participants would spontaneously generalize the quantified facts to the corresponding kinds, and would do so more frequently for the facts about generalizable (rather than idiosyncratic) properties. In turn, these generalizations would lead to a higher rate of quantified‐to‐generic memory errors for the generalizable properties. The results of four experiments (N = 449) supported this prediction. Moreover, the same generalizable‐versus‐idiosyncratic difference in memory errors occurred even under cognitive load, which suggests that the hypothesized bias operates unnoticed in the background, requiring few cognitive resources. In sum, this evidence suggests the presence of a powerful bias to draw generalizations about kinds.     

Preschool children's use of cues to generic meaning

Sentences that refer to categories - generic sentences (e.g., "Dogs are friendly") - are frequent in speech addressed to young children and constitute an important means of knowledge transmission. However, detecting generic meaning may be challenging for young children, since it requires attention to a multitude of morphosyntactic, semantic, and pragmatic cues. The first three experiments tested whether 3- and 4-year-olds use (a) the immediate linguistic context, (b) their previous knowledge, and (c) the social context to determine whether an utterance with ambiguous scope (e.g., "They are afraid of mice", spoken while pointing to 2 birds) is generic. Four-year-olds were able to take advantage of all the cues provided, but 3-year-olds were sensitive only to the first two. In Experiment 4, we tested the relative strength of linguistic-context cues and previous-knowledge cues by putting them in conflict; in this task, 4-year-olds, but not 3-year-olds, preferred to base their interpretations on the explicit noun phrase cues from the linguistic context. These studies indicate that, from early on, children can use contextual and semantic information to construe sentences as generic, thus taking advantage of the category knowledge conveyed in these sentences.     

Children's interpretation of generic noun phrases

Generic utterances (e.g., "Cows say 'moo'") have 2 distinctive semantic properties: (a) Generics are generally true, unlike indefinites (e.g., "Bears live in caves" is generic; "I saw some bears in the cave" is indefinite), and (b) generics need not be true of all category members, unlike universal quantifiers (e.g., all, every, each). This article examined whether preschool children and adults appreciate both these features, using a comprehension task (Study 1) and an elicited production task (Study 2). In both tasks, 4-year-old children--like adults--treated generics as distinct from both indefinites ("some") and universal quantifiers ("all"). In contrast, 3-year-olds did not differentiate among generics, "all," and "some." By 4 years of age, generics emerge as a distinct semantic device.     

The effect of generic statements on children's causal attributions: questions of mechanism

Generic statements, or generics, express generalizations about entire kinds (e.g., "Girls are good at a game called 'tooki'"). In contrast, nongeneric statements express facts about specific (sets of) individuals (e.g., "Jane is good at tooki"). Aside from simply conveying information, generics and nongenerics also instill different causal perspectives on the facts expressed, implying that these facts stem from deep, inherent causes (e.g., talent) or from external, mechanistic causes (e.g., instruction), respectively. In the present research (with samples of 4- to 7-year-olds and undergraduates, N = 220), we proposed that children's causal attributions for the facts learned through these statements are determined not by the generic/nongeneric format of the statements themselves but rather by the generic/nongeneric format of the beliefs relevant to these statements. This proposal led to two specific predictions. First, the influence of the generic belief induced by a novel generic statement should be detected in any subsequent context that falls under its scope--even in circumstances that involve particular individuals. Confirming this prediction, participants often attributed a fact conveyed in a nongeneric statement (e.g., a particular girl's tooki ability) to deep, inherent causes if they had previously formed a relevant generic belief (e.g., by hearing that girls are good at tooki). Second, we predicted that nongeneric statements such as "Most girls are good at tooki" should also promote attributions to deep causes because they often ultimately give rise to generic beliefs, as suggested by recent evidence. This prediction was confirmed as well. These results clarify and expand our knowledge of the influence of language on children's understanding of the world.     

Children's (and Adults') Production Adjustments to Generic and Particular Listener Needs

Adults design utterances to match listeners' informational needs by making both “generic” adjustments (e.g., mentioning atypical more often than typical information) and “particular” adjustments tailored to their specific interlocutor (e.g., including things that their addressee cannot see). For children, however, relevant evidence is mixed. Three experiments investigated how generic and particular factors affect children's production. In Experiment 1, 4‐ to 5‐year‐old children and adults described typical and atypical instrument events to a silent listener who could either see or not see the events. In later extensions, participants described the same events to either a silent (Experiment 2) or an interactive (Experiment 3) addressee with a specific goal. Both adults and 4‐ to 5‐year‐olds performed generic adjustments but, unlike adults, children made listener‐particular adjustments inconsistently. These and prior findings can be explained by assuming that particular adjustments can be costlier for children to implement compared to generic adjustments.     

Development of Children's Awareness of Their Own Thoughts

Adults attach special value to objects that link to notable people or events—authentic objects. We examined children's monetary evaluation of authentic objects, focusing on four kinds: celebrity possessions (e.g., Harry Potter's glasses), original creations (e.g., the very first teddy bear), personal possessions (e.g., your grandfather's baseball glove), and merely old items (e.g., an old chair). Children ages 4 to 12 years old and adults (N = 151) were asked how much people would pay for authentic and control objects. Young children consistently placed greater monetary value on celebrity possessions than on original creations, even when adults judged the two kinds of items to be equivalent. These results suggest that contact with a special individual may be the foundation for the value placed on authentic objects.     

Reasoning about knowledge: Children’s evaluations of generality and verifiability

In a series of experiments, we examined 3- to 8-year-old children’s (N = 223) and adults’ (N = 32) use of two properties of testimony to estimate a speaker’s knowledge: generality and verifiability. Participants were presented with a “Generic speaker” who made a series of 4 general claims about “pangolins” (a novel animal kind), and a “Specific speaker” who made a series of 4 specific claims about “this pangolin” as an individual. To investigate the role of verifiability, we systematically varied whether the claim referred to a perceptually-obvious feature visible in a picture (e.g., “has a pointy nose”) or a non-evident feature that was not visible (e.g., “sleeps in a hollow tree”). Three main findings emerged: (1) young children showed a pronounced reliance on verifiability that decreased with age. Three-year-old children were especially prone to credit knowledge to speakers who made verifiable claims, whereas 7- to 8-year-olds and adults credited knowledge to generic speakers regardless of whether the claims were verifiable; (2) children’s attributions of knowledge to generic speakers was not detectable until age 5, and only when those claims were also verifiable; (3) children often generalized speakers’ knowledge outside of the pangolin domain, indicating a belief that a person’s knowledge about pangolins likely extends to new facts. Findings indicate that young children may be inclined to doubt speakers who make claims they cannot verify themselves, as well as a developmentally increasing appreciation for speakers who make general claims.     

Segmentation of spoken words into syllables by English-speaking children as compared to adults

Given the importance of syllables in the development of reading, spelling, and phonological awareness, information is needed about how children syllabify spoken words. To what extent is syllabification affected by knowledge of spelling, to what extent by phonology, and which phonological factors are influential? In Experiment 1, six- and seven-year-old children did not show effects of spelling on oral syllabification, performing similarly on words such as habit and rabbit. Spelling influenced the syllabification of older children and adults, with the results suggesting that knowledge of spelling must be well entrenched before it begins to affect oral syllabification. Experiment 2 revealed influences of phonological factors on syllabification that were similar across age groups. Young children, like older children and adults, showed differences between words with "short" and "long" vowels (e.g., lemon vs. demon) and words with sonorant and obstruent intervocalic consonants (e.g., melon vs. wagon).     

Naming solids and nonsolids: Children's default construals

Four experiments used a free-naming task to examine children's and adults' default construals of solids and nonsolids. In Experiment 1,4-year-old children viewed entities presented in familiar geometric shapes (e.g., square, triangle), without touching them. One half saw solids (e.g., a square made of wood); the other half saw nonsol ids matched carefully in shape (e.g., a square with the same dimensions but made of peanut butter). To tap their default construals, children were simply asked, “What is that?” Answers varied sharply with the type of stimulus. If the entity was solid, children tended to provide an individual-related word (e.g., “a square”), even if they also knew a substance-related word (e.g., “wood”). But if the stimulus was nonsolid, children tended to give a substance-related word (e.g., “peanut butter”), even if they also knew an individual-related word (e.g., “a square”). These words were usually common nouns produced in appropriate sentential contexts, suggesting that 4-year-olds represented the words as naming kinds. The same pattern of results obtained in Experiments 2 and 3, which were modified replications of Experiment 1. The results of Experiment 4 replicated the main findings of Experiment 1 using adults as participants. The studies suggest that, as a default, 4-year-olds conceptualize solids and nonsolids in (a) fundamentally distinct, (b) kind-based (rather than perceptual property-based), and (c) adult-like ways.     

Generic language use reveals domain differences in young children's expectations about animal and artifact categories

The goal of the present study was to explore domain differences in young children's expectations about the structure of animal and artifact categories. We examined 5-year-olds’ and adults’ use of category-referring generic noun phrases (e.g., “Birds fly”) about novel animals and artifacts. The same stimuli served as both animals and artifacts; thus, stimuli were perceptually identical across domains, and domain was indicated exclusively by language. Results revealed systematic domain differences: children and adults produced more generic utterances when items were described as animals than artifacts. Because the stimuli were novel and lacking perceptual cues to domain, these findings must be attributed to higher-order expectations about animal and artifact categories. Overall, results indicate that by age 5, children are able to make knowledge-based domain distinctions between animals and artifacts that may be rooted in beliefs about the coherence and homogeneity of categories within these domains.     

You'll change more than I will: Adults’ predictions about their own and others’ future preferences

It has been argued that adults underestimate the extent to which their preferences will change over time. We sought to determine whether such mispredictions are the result of a difficulty imagining that one's own current and future preferences may differ or whether it also characterizes our predictions about the future preferences of others. We used a perspective-taking task in which we asked young people how much they liked stereotypically young-person items (e.g., Top 40 music, adventure vacations) and stereotypically old-person items (e.g., jazz, playing bridge) now, and how much they would like them in the distant future (i.e., when they are 70 years old). Participants also made these same predictions for a generic same-age, same-sex peer. In a third condition, participants predicted how much a generic older (i.e., age 70) same-sex adult would like items from both categories today. Participants predicted less change between their own current and future preferences than between the current and future preferences of a peer. However, participants estimated that, compared to a current older adult today, their peer would like stereotypically young items more in the future and stereotypically old items less. The fact that peers’ distant-future estimated preferences were different from the ones they made for “current” older adults suggests that even though underestimation of change of preferences over time is attenuated when thinking about others, a bias still exists.     

What does Batman think about SpongeBob? children's understanding of the fantasy/fantasy distinction

Young children reliably distinguish reality from fantasy; they know that their friends are real and that Batman is not. But it is an open question whether they appreciate, as adults do, that there are multiple fantasy worlds. We test this by asking children and adults about fictional characters' beliefs about other characters who exist either within the same world (e.g., Batman and Robin) or in different worlds (e.g., Batman and SpongeBob). Study 1 found that although both adults and young children distinguish between within-world and across-world types of character relationships, the children make an unexpected mistake: they often claim that Batman thinks that Robin is make believe. Study 2 used a less explicit task, exploring intuitions about the actions of characters-whom they could see, touch, and talk to--and found that children show a mature appreciation of the ontology of fictional worlds.