Two-year-olds use the generic/nongeneric distinction to guide their inferences about novel kinds

Testimony and observation of statistical evidence interact in adults' and children's category-based induction

Hearing generic or other kind-relevant claims can influence the use of information from direct observations in category learning. In the current study, we ask how both adults and children integrate their observations with testimony when learning about the causal property of a novel category. Participants were randomly assigned to hear one of four types of testimony: generic, quantified "all", specific, or only labels. In Study 1, adults (N = 1249) then observed that some proportion of objects (10%-100%) possessed a causal property. In Study 2, children (N = 123, Mage = 5.06 years, SD = 0.61 years, range 4.01-5.99 years) observed a sample where 30% of the objects had the causal property. Generic and quantified "all" claims led both adults and children to generalize the causal property beyond what was observed. Adults and children diverged, however, in their overall trust in testimony that could be verified by observations: adults were more skeptical of inaccurate quantified claims, whereas children were more accepting. Additional memory probes suggest that children's trust in unverified claims may have been due to misremembering what they saw in favor of what they heard. The current findings demonstrate that both child and adult learners integrate information from both sources, offering insights into the mechanisms by which language frames first-hand experience.

Parents' talk about conceptual categories with infants: stability, variability, and implications for expressive language development

Children's exposure to talk about conceptual categories plays a powerful role in shaping their conceptual development. However, it remains unclear when parents begin to talk about categories with young children and whether such talk relates to children's language skills. This study examines relations between parents' talk about conceptual categories and infants' expressive language development. Forty-seven parent-infant dyads were videotaped playing together at child age 10, 12, 14, and 16 months. Transcripts of interactions were analyzed to identify parents' talk about conceptual categories. Children's expressive language development was assessed at 18 months. Findings indicate that parents indeed talked about conceptual categories with infants and that talk was stable across time, with college-educated parents producing more than non-college-educated parents. Further, parents' talk about conceptual categories between 10 and 16 months predicted children's 18-month expressive language. This study sheds new light on mechanisms through which early experiences may support children's language development.

Learning the rules of the game: The role of generic "you" and "we" in shaping children's interpretations of norms

A critical skill of childhood is learning social norms. We examine whether the generic pronouns "you" and "we," which frame information as applying to people in general rather than to a specific individual, facilitate this process. In one pre-registered experiment conducted online between 2020 and 2021, children 4- to 9-year-old primarily living in the midwestern U.S. (N = 146, 75 girls, 71 boys, M_age  = 7.14, SD = 1.69, 82% White) interpreted actions described with generic pronouns (vs. "I") as normatively correct and selected the speaker who used generic pronouns as the rule-follower, particularly when generic pronouns were presented first. There were no significant effects of age. These results illustrate how generic pronouns influence how children discern unfamiliar norms and form interpersonal judgments.

The influence of linguistic form and causal explanations on the development of social essentialism

Generic descriptions of social categories (e.g., boys play baseball; girls have long hair) lead children and adults to think of the referenced categories (i.e., boys and girls) in essentialist terms-as natural ways of dividing up the world. Yet, key questions remain unanswered about how, why, and when generic language shapes the development of essentialist beliefs. The present experiment examined the scope of these effects by testing the extent to which generics elicit essentialist beliefs because of their linguistic form or because of the causal information they convey. Generic language led children (N = 199, M_age = 6.07 years, range = 4.5-7.95) to essentialize a novel social category, regardless of the causal information used to describe category-property relations (either biological or cultural). In contrast, both linguistic form and causal information influenced adults' (N = 234) beliefs. These findings reveal a unique role of linguistic form in the development and communication of essentialist beliefs in young children.

The influence of language input on 3-year-olds' learning about novel social categories

There is considerable variability in the social categories that children essentialize and the types of expectations children form about these categories, suggesting children's essentialist beliefs are shaped by environmental input. Prior studies have shown that exposure to generic statements about a social category promotes essentialist beliefs in 4.5- to 8-year-old children. However, by this age children form essentialist beliefs quite robustly, and thus it is unclear whether generic statements impact children's expectations about social categories at younger ages when essentialist beliefs first begin to emerge. Moreover, in prior studies the generic statements were delivered by an experimenter and carefully controlled, and thus it is unclear whether these statements would have the same impact if they occurred in a somewhat less constrained setting, such as parents reading a picture book to their child. The current study addressed these open questions by investigating whether generic statements delivered during a picture-book interaction with their parents influenced 3-year-olds' expectations about members of a novel social category. Our results showed that children who heard generic statements during the picture-book interaction used social-group membership to make inferences about the likely behavior of a novel category member, whereas children who were not exposed to generic statements did not. These findings suggest that as early as 3 years of age, children's expectations about social categories are influenced by generic statements that occur during brief parent-child interactions.

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.

The Unintended Consequences of the Things We Say: What Generic Statements Communicate to Children About Unmentioned Categories

Adults frequently use generic language (e.g., "Boys play sports") to communicate information about social groups to children. Whereas previous research speaks to how children often interpret information about the groups described by generic statements, less is known about what generic claims may implicitly communicate about unmentioned groups (e.g., the possibility that "Boys play sports" implies that girls do not). Study 1 (287 four- to six-year-olds, 56 adults) and Study 2 (84 four- to six-year-olds) found that children as young as 4.5 years draw inferences about unmentioned categories from generic claims (but not matched specific statements)-and that the tendency to make these inferences strengthens with age. Study 3 (181 four- to seven-year-olds, 65 adults) provides evidence that pragmatic reasoning serves as a mechanism underlying these inferences. We conclude by discussing the role that generic language may play in inadvertently communicating social stereotypes to young children.

Generic language in scientific communication

Scientific communication poses a challenge: To clearly highlight key conclusions and implications while fully acknowledging the limitations of the evidence. Although these goals are in principle compatible, the goal of conveying complex and variable data may compete with reporting results in a digestible form that fits (increasingly) limited publication formats. As a result, authors' choices may favor clarity over complexity. For example, generic language (e.g., "Introverts and extraverts require different learning environments") may mislead by implying general, timeless conclusions while glossing over exceptions and variability. Using generic language is especially problematic if authors overgeneralize from small or unrepresentative samples (e.g., exclusively Western, middle-class). We present 4 studies examining the use and implications of generic language in psychology research articles. Study 1, a text analysis of 1,149 psychology articles published in 11 journals in 2015 and 2016, examined the use of generics in titles, research highlights, and abstracts. We found that generics were ubiquitously used to convey results (89% of articles included at least 1 generic), despite that most articles made no mention of sample demographics. Generics appeared more frequently in shorter units of the paper (i.e., highlights more than abstracts), and generics were not associated with sample size. Studies 2 to 4 (n = 1,578) found that readers judged results expressed with generic language to be more important and generalizable than findings expressed with nongeneric language. We highlight potential unintended consequences of language choice in scientific communication, as well as what these choices reveal about how scientists think about their data.

Generalizing About Striking Properties: Do Glippets Love to Play With Fire?

Two experiments investigated whether 4- and 5-year-old children are sensitive to whether the content of a generalization is about a salient or noteworthy property (henceforth "striking") and whether varying the number of exceptions has any effect on children's willingness to extend a property after having heard a generalization. Moreover, they investigated how the content of a generalization interacts with exception tolerance. Adult data were collected for comparison. We used generalizations to describe novel kinds (e.g., "glippets") that had either a neutral (e.g., "play with toys") or a striking property (e.g., "play with fire") and measured how willing participants were to extend the property to a new instance of the novel kind. Experiment 1 demonstrated that both adults and children show sensitivity to strikingness in that striking properties were extended less than neutral ones, although children extended less than adults overall. The responses of both age groups were significantly different from chance. Experiment 2 introduced varying numbers of exceptions to the generalization made (minimal: 1 exception; maximal: 3 exceptions). Both adults and children extended both types of properties even in the face of exceptions, but to a lower degree than in Experiment 1. Striking properties were extended less than neutral ones, as in Experiment 1. We observed that the greater the number of exceptions, the lower the rates of extension we obtained, for both types of properties in adults, but only with striking properties in children. Children seemed to keep track of varying numbers of exceptions for striking properties, but their performance did not differ from chance. The findings underscore that 4- and 5-year-old children are sensitive to strikingness and to exception tolerance for generalizations and are developing toward an adult-like behavior with respect to the interplay between strikingness and exception tolerance when they learn about novel kinds. We discuss the implications of these results with regards to how children make generalizations.

When Your Kind Cannot Live Here: How Generic Language and Criminal Sanctions Shape Social Categorization

Using generic language to describe groups (applying characteristics to entire categories) is ubiquitous and affects how children and adults categorize other people. Five-year-olds, 8-year-olds, and adults ( N = 190) learned about a novel social group that separated into two factions (citizens and noncitizens). Noncitizens were described in either generic or specific language. Later, the children and adults categorized individuals in two contexts: criminal (individuals labeled as noncitizens faced jail and deportation) and noncriminal (labeling had no consequences). Language genericity influenced decision making. Participants in the specific-language condition, but not those in the generic-language condition, reduced the rate at which they identified potential noncitizens when their judgments resulted in criminal penalties compared with when their judgments had no consequences. In addition, learning about noncitizens in specific language (vs. generic language) increased the amount of matching evidence participants needed to identify potential noncitizens (preponderance standard) and decreased participants' certainty in their judgments. Thus, generic language encourages children and adults to categorize individuals using a lower evidentiary standard regardless of negative consequences for presumed social-group membership.

Once a frog-lover, always a frog-lover?: Infants' goal generalization is influenced by the nature of accompanying speech

The ability to interpret choices as enduring preferences that generalize beyond the immediate situation gives adults a powerful means of predicting and explaining others' behavior. How do infants come to recognize that current choices can be driven by generalizable preferences? Although infants can encode others' actions in terms of goals (Woodward, 1998), there is evidence that 10-month-olds still fail to generalize goal information presented in one environment to an event sequence occurring in a new environment (Sommerville & Crane, 2009). Are there some circumstances in which infants interpret others' goals as generalizable across environments? We investigate whether the vocalizations a person produces while selecting an object in one room influences infants' generalization of the goal to a new room. Ten-month-olds did not spontaneously generalize the actor's goal, but did generalize the actor's goal when the actor initially accompanied her object selection with a statement of preference. Infants' generalization was not driven by the attention-grabbing features of the statement or the mere use of language, as they did not generalize when the actor used matched nonspeech vocalizations or sung speech. Infants interpreted the goal as person-specific, as they did not generalize the choice to a new actor. We suggest that the referential specificity of accompanying speech vocalizations influences infants' tendency to interpret a choice as personal rather than situational. (PsycINFO Database Record

Preferences for Explanation Generality Develop Early in Biology But Not Physics

One of the core functions of explanation is to support prediction and generalization. However, some explanations license a broader range of predictions than others. For instance, an explanation about biology could be presented as applying to a specific case (e.g., "this bear") or more generally across "all animals." The current study investigated how 5- to 7-year-olds (N = 36), 11- to 13-year-olds (N = 34), and adults (N = 79) evaluate explanations at varying levels of generality in biology and physics. Findings revealed that even the youngest children preferred general explanations in biology. However, only older children and adults preferred explanation generality in physics. Findings are discussed in light of differences in our intuitions about biological and physical principles.

Fitting the Message to the Listener: Children Selectively Mention General and Specific Facts

In three experiments, two hundred and ninety-seven 4- to 6-year-olds were asked to describe objects to a listener, and their answers were coded for the presence of general and specific facts. In Experiments 1 and 2, the listener's knowledge of the kinds of objects was manipulated. This affected references to specific facts at all ages, but only affected references to general facts in children aged 5 and older. In Experiment 3, children's goal in communicating was either pedagogical or not. Pedagogy influenced references to general information from age 4, but not references to specific information. These findings are informative about how children vary general and specific information in conversation, and suggest that listeners' knowledge and children's pedagogical goals influenced children's responses via different mechanisms.

Group presence, category labels, and generic statements influence children to treat descriptive group regularities as prescriptive

Children use descriptive regularities of social groups (what is) to generate prescriptive judgments (what should be). We examined whether this tendency held when the regularities were introduced through group presence, category labels, or generic statements. Children (ages 4-9years, N=203) were randomly assigned to one of four conditions that manipulated how descriptive group regularities were presented: group presence (e.g., "These ones [a group of three individuals] eat this kind of berry"), category labels (e.g., "This [individual] Hibble eats this kind of berry"), generic statements (e.g., [showing an individual] "Hibbles eat this kind of berry"), or control (e.g., "This one [individual] eats this kind of berry"). Then, children saw conforming and non-conforming individuals and were asked to evaluate their behavior. As predicted, children evaluated non-conformity negatively in all conditions except the control condition. Together, these results suggest that minimal perceptual and linguistic cues provoke children to treat social groups as having normative force.

Generics license 30-month-olds' inferences about the atypical properties of novel kinds

We examined whether the distinction between generic and nongeneric language provides toddlers with a rapid and efficient means to learn about kinds. In Experiment 1, we examined 30-month-olds' willingness to extend atypical properties to members of an unfamiliar category when the properties were introduced in 1 of 3 ways: (a) using a generic noun phrase ("Blicks drink ketchup"); (b) using a nongeneric noun phrase ("These blicks drink ketchup"); and (c) using an attentional phrase ("Look at this"). Hearing a generic noun phrase boosted toddlers' extension of properties to both the model exemplars and to novel members of the same category, relative to when a property had been introduced with a nongeneric noun phrase or an attentional phrase. In Experiment 2, properties were introduced with a generic noun phrase, and toddlers extended novel properties to members of the same-category, but not to an out-of-category object. Taken together, these findings demonstrate that generics highlight the stability of a feature and foster generalization of the property to novel within-category exemplars. (PsycINFO Database Record

Children's generic interpretation of pretense

We report two experiments investigating how 3- to 5-year-olds learn general knowledge from pretend play-how they learn about kinds of things (e.g., information about dogs) from information about particular individuals in pretend play (a certain dog in a pretend scenario). Children watched pretend-play enactments in which animals showed certain behaviors or heard utterances conveying the same information. When children were subsequently asked about who shows the behavior, children who watched pretend play were more likely to give generic responses than were children who heard the utterances. These findings show that children generalize information from pretend play to kinds even without being prompted to think about kinds, that pretend play can be informative about familiar kinds, and also that pretend play is a more potent source for general knowledge than are utterances about individuals.

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.

Children's Recall of Generic and Specific Labels Regarding Animals and People

Although children tend to categorize objects at the basic level, we hypothesized that generic sentences would direct children's attention to different levels of categorization. We tested children's and adults' short-term recall (Study 1) and longer-term recall (Study 2) for labels presented in generic sentences (e.g., Kids like to play jimjam) versus specific sentences (e.g., This kid likes to play jimjam). Label content was either basic level (e.g., cat, boy) or superordinate (e.g., animal, kid). As predicted, participants showed better memory for label content in generic than specific sentences (short-term recall for children; both short and longer-term recall for adults). Errors typically involved recalling specific noun phrases as generic, and recalling superordinate labels as basic. These results demonstrate that language influences children's representations of new factual information, but that cognitive biases also lead to distortions in recall.

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.

Children's Developing Intuitions About the Truth Conditions and Implications of Novel Generics Versus Quantified Statements

Generic statements express generalizations about categories and present a unique semantic profile that is distinct from quantified statements. This paper reports two studies examining the development of children's intuitions about the semantics of generics and how they differ from statements quantified by all, most, and some. Results reveal that, like adults, preschoolers (a) recognize that generics have flexible truth conditions and are capable of representing a wide range of prevalence levels; and (b) interpret novel generics as having near-universal prevalence implications. Results further show that by age 4, children are beginning to differentiate the meaning of generics and quantified statements; however, even 7- to 11-year-olds are not adultlike in their intuitions about the meaning of most-quantified statements. Overall, these studies suggest that by preschool, children interpret generics in much the same way that adults do; however, mastery of the semantics of quantified statements follows a more protracted course.

Building theory-based concepts: four-year-olds preferentially seek explanations for features of kinds

Is the structure of human concepts continuous across development, or does it undergo qualitative transformations? Extensive evidence with adults has demonstrated that they are motivated to understand why categories have the features they do. To investigate whether young children display a similar motivation-an issue that bears on the question of continuity vs. transformation in conceptual structure-we conducted three studies involving 4-year-olds (N=90) and adults (N=124). Experiments 1 and 2 suggested that 4-year-olds indeed display a strong motivation to explain why categories have the features they do. Specifically, when provided with the option of asking "why?" about features of novel categories vs. features of individuals from other novel categories, children preferred to ask "why?" about the category features. Moreover, children's explanatory preference was specific to facts about categories per se and did not extend to facts that were merely presented in the context of multiple category instances. Experiment 3 also ruled out the possibility that the category facts were preferred because these facts were more surprising. In sum, these three studies reveal an early-emerging motivation to make sense of the categories encountered in the world and, more generally, speak to the richness of children's conceptual representations.

Individual differences in children's and parents' generic language

Generics ("Dogs bark") convey important information about categories and facilitate children's learning. Two studies with parents and their 2- or 4-year-old children (N = 104 dyads) examined whether individual differences in generic language use are as follows: (a) stable over time, contexts, and domains, and (b) linked to conceptual factors. For both children and parents, individual differences in rate of generic production were stable across time, contexts, and domains, and parents' generic usage significantly correlated with that of their own children. Furthermore, parents' essentialist beliefs correlated with their own and their children's rates of generic frequency. These results indicate that generic language use exhibits substantial stability and may reflect individual differences in speakers' conceptual attitudes toward categories.

Learning to Use an Alphabetic Writing System

Gaining facility with spelling is an important part of becoming a good writer. Here we review recent work on how children learn to spell in alphabetic writing systems. Statistical learning plays an important role in this process. Thus, young children learn about some of the salient graphic characteristics of written texts and attempt to reproduce these characteristics in their own productions even before they use letters to represent phonemes. Later, children apply their statistical learning skills to links between phonemes and spellings, including those that are conditioned by context and morphology. Children use what they know about language and about letter names when learning about spelling, and learning to spell in turn influences their ideas about language. Although children learn about some aspects of spelling implicitly, explicit instruction has an important role to play. We discuss some implications of the research for the design of that instruction.

Quantified statements are recalled as generics: evidence from preschool children and adults

Generics are sentences such as "ravens are black" and "tigers are striped", which express generalizations concerning kinds. Quantified statements such as "all tigers are striped" or "most ravens are black" also express generalizations, but unlike generics, they specify how many members of the kind have the property in question. Recently, some theorists have proposed that generics express cognitively fundamental/default generalizations, and that quantified statements in contrast express cognitively more sophisticated generalizations (Gelman, 2010; Leslie, 2008). If this hypothesis is correct, then quantified statements may be remembered as generics. This paper presents four studies with 136 preschool children and 118 adults, demonstrating that adults and preschoolers alike tend to recall quantified statements as generics, thus supporting the hypothesis that generics express cognitively default generalizations.

Remembering kinds: new evidence that categories are privileged in children's thinking

What are the representations and learning mechanisms that underlie conceptual development? The present research provides evidence in favor of the claim that this process is guided by an early-emerging predisposition to think and learn about abstract kinds. Specifically, three studies (N=192) demonstrated that 4- to 7-year-old children have better recall for novel information about kinds (e.g., that dogs catch a bug called "fep") than for similar information about individuals (e.g., that a particular dog catches a bug called "fep"). By showing that children are particularly likely to retain information about kinds, this work not only provides a first empirical demonstration of a phenomenon that may be key to conceptual development but also makes it apparent that young children's thinking is suffused with abstractions rather than being perceptually-based and concrete.