When similarity and causality compete in category-based property generalization

Five experiments were performed to investigate the category-based generalization of nonblank properties, properties that were novel but that were attributed to existing category features with causal explanations. Experiments 1-3 tested how such explanations interact with the well-known effects of similarity on such generalizations. The results showed that when the causal explanations were used, standard effects of typicality (Experiment 1), diversity (Experiment 2), or similarity itself (Experiment 3) were almost completely eliminated. Experiments 4 and 5 demonstrated that category-based generalizations exhibit some of the standard properties of causal reasoning; for example, an effect (i.e., a novel category property) is judged to be more prevalent when its cause (i.e., an existing category feature) is also prevalent. These findings suggest that category-based property generalization is often an instance of causal inference.     

Categorization by schema relations and perceptual similarity in 5-year-olds and adults: A study in vision and in audition

This research explores the way in which young children (5 years of age) and adults use perceptual and conceptual cues for categorizing objects processed by vision or by audition. Three experiments were carried out using forced-choice categorization tasks that allowed responses based on taxonomic relations (e.g., vehicles) or on schema category relations (e.g., vehicles that can be seen on the road). In Experiment 1 (visual modality), prominent responses based on conceptually close objects (e.g., objects included in a schema category) were observed. These responses were also favored when within-category objects were perceptually similar. In Experiment 2 (auditory modality), schema category responses depended on age and were influenced by both within- and between-category perceptual similarity relations. Experiment 3 examined whether these results could be explained in terms of sensory modality specializations or rather in terms of information processing constraints (sequential vs. simultaneous processing).     

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.     

The time for doing is not the time for change: effects of general action and inaction goals on attitude retrieval and attitude change

Implicit in many informal and formal principles of psychological change is the understudied assumption that change requires either an active approach or an inactive approach. This issue was systematically investigated by comparing the effects of general action goals and general inaction goals on attitude change. As prior attitudes facilitate preparation for an upcoming persuasive message, general action goals were hypothesized to facilitate conscious retrieval of prior attitudes and therefore hinder attitude change to a greater extent than general inaction goals. Experiment 1 demonstrated that action primes (e.g., "go," "energy") yielded faster attitude report than inaction primes (e.g., "rest," "still") among participants who were forewarned of an upcoming persuasive message. Experiment 2 showed that the faster attitude report identified in Experiment 1 was localized on attitudes toward a message topic participants were prepared to receive. Experiments 3, 4, and 5 showed that, compared with inaction primes, action primes produced less attitude change and less argument scrutiny in response to a counterattitudinal message on a previously forewarned topic. Experiment 6 confirmed that the effects of the primes on attitude change were due to differential attitude retrieval. That is, when attitude expression was induced immediately after the primes, action and inaction goals produced similar amounts of attitude change. In contrast, when no attitude expression was induced after the prime, action goals produced less attitude change than inaction goals. Finally, Experiment 7 validated the assumption that these goal effects can be reduced or reversed when the goals have already been satisfied by an intervening task.     

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.     

Clarifying the role of shape in children's taxonomic assumption.

When asked to find a new referent of a novel label children tend to ignore thematic relations (e.g., the relation between a spider and its web) and focus instead on taxonomic relations (e.g., the relation between a spider and a snake). The precise nature of children's taxonomic assumption has not been clear, however. One possibility is that the taxonomic assumption reduces to a "similar-shape rule": perhaps children tend to select objects of the same taxonomic kind when asked to extend new labels simply because these objects are more similar in shape than objects which are only thematically related. Sixty children between 3 and 5 years of age participated in three studies which examined children's attention to thematic relations, similarity of shape, and taxonomic relations when extending novel object labels. The findings indicated that shape has some primacy in children's expectations about object label reference, yet when shape is not available as a guide, children also take taxonomic kind into consideration when searching for new referents of novel labels. Thus children make use of a relatively rich and somewhat varied set of expectations to guide their inferences about object label reference.     

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.     

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.     

Differences in preschool children's conceptual strategies when thinking about animate entities and artifacts.

Two-, 3-, and 4-year-old children viewed 10 stimulus sets. Each set contained a sample picture (e.g., a dog), a basic-level taxonomic match (e.g., another dog), a thematic match (e.g., a bone), and an irrelevant match (e.g., a pen). The children were asked to choose a match that "goes with" each sample. Sample pictures were either animate entities or artifacts. The children's choice behavior indicated that a shift occurs between 3 and 4 years of age from a taxonomic bias to a thematic bias and that, at both ages, animate sample stimuli enhance the children's tendency to adopt thematic conceptual strategies. These data are consistent with recent suggestions that thematic thinking presupposes basic-level taxonomic thinking during early conceptual development and that this developmental progression occurs more rapidly in some domains of knowledge than in others.     

The impact of category structure and training methodology on learning and generalizing within-category representations

When interacting with categories, representations focused on within-category relationships are often learned, but the conditions promoting within-category representations and their generalizability are unclear. We report the results of three experiments investigating the impact of category structure and training methodology on the learning and generalization of within-category representations (i.e., correlational structure). Participants were trained on either rule-based or information-integration structures using classification (Is the stimulus a member of Category A or Category B?), concept (e.g., Is the stimulus a member of Category A, Yes or No?), or inference (infer the missing component of the stimulus from a given category) and then tested on either an inference task (Experiments 1 and 2) or a classification task (Experiment 3). For the information-integration structure, within-category representations were consistently learned, could be generalized to novel stimuli, and could be generalized to support inference at test. For the rule-based structure, extended inference training resulted in generalization to novel stimuli (Experiment 2) and inference training resulted in generalization to classification (Experiment 3). These data help to clarify the conditions under which within-category representations can be learned. Moreover, these results make an important contribution in highlighting the impact of category structure and training methodology on the generalization of categorical knowledge.     

Korean deaf adolescents' recognition of written words for taxonomic categories of different levels

Deaf college students seem to have relatively stronger associations from words for taxonomic categories of basic (e.g., snake) to those of super-ordinate (e.g., reptiles) level than vice versa compared with hearing students in word association (Marschark, Convertino, McEvoy & Masteller, 2004). In deciding whether two sequentially presented words for taxonomic categories of different levels are conceptually related, deaf adolescents might therefore have a poorer performance when they see a category name before than when they see it after one of the corresponding exemplar words. Deaf Korean adolescents were found to recognize words for taxonomic categories of super-ordinate level with lower efficiencies than those of basic level. Their accuracy seemed to reflect a reversed typicality effect when they decided that first-presented words for taxonomic categories of basic level were conceptually related to second-presented words for those of super-ordinate level. It was argued that deaf Korean adolescents went through a temporary stage of having iconic representations of several exemplars of the category aroused in working memory before the abstract semantic representation was fully activated when they saw the word for a taxonomic category of super-ordinate level.     

Speeded induction under uncertainty: The influence of multiple categories and feature conjunctions

When people are uncertain about the category membership of an item (e.g., Is it a dog or a dingo?), research shows that they tend to rely only on the dominant or most likely category when making inductions (e.g., How likely is it to befriend me?). An exception has been reported using speeded induction judgments where participants appeared to use information from multiple categories to make inductions (Verde, Murphy, &; Ross, 2005). In two speeded induction studies, we found that participants tended to rely on the frequency with which features co-occurred when making feature predictions, independently of category membership. This pattern held whether categories were considered implicitly (Experiment 1) or explicitly (Experiment 2) prior to feature induction. The results converge with other recent work suggesting that people often rely on feature conjunction information, rather than category boundaries, when making inductions under uncertainty.     

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.     

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.     

Associations to unfamiliar words: Learning the meanings of new words

Five experiments were designed to examine whether subjects attend to different aspects of meaning for familiar and unfamiliar words. In Experiments 1–3, subjects gave free associations to high- and low-familiarity words from the same taxonomic category (e.g.,seltzer:sarsparilla; Experiment 1), from the same noun synonym set (e.g.,baby:neonate; Experiment 2), and from the same verb synonym set (e.g.,abscond:escape; Experiment 3). In Experiments 4 and 5, subjects first read a context sentence containing the stimulus word and then gave associations; stimuli were novel words or either high- or low-familiarity nouns. Low-familiarity and novel words elicited more nonsemantically based responses (e.g.,engram:graham) than did high-familiarity words. Of the responses semantically related to the stimulus, low-familiarity and novel words elicited a higher proportion of definitional responses [category (e.g.,sarsparilla:soda), synonym (e.g.,neonate:newborn), and coordinate (e.g.,armoire:dresser)], whereas high-familiarity stimuli elicited a higher proportion of event-based responses [thematic (e.g.,seltzer:glass) and noun:verb (e.g.,baby:cry)]. Unfamiliar words appear to elicit a shift of attentional resources from relations useful in understanding the message to relations useful in understanding the meaning of the unfamiliar word.     

Category label effects on Chinese children's inductive inferences: modulation by perceptual detail and category specificity

Inductive generalization of novel properties to same-category or similar-looking objects was studied in Chinese preschool children. The effects of category labels on generalizations were investigated by comparing basic-level labels, superordinate-level labels, and a control phrase applied to three kinds of stimulus materials: colored photographs (Experiment 1), realistic line drawings (Experiment 2), and cartoon-like line drawings (Experiment 3). No significant labeling effects were found for photos and realistic drawings, but there were significant effects for cartoon-like drawings. Children made mostly (>70%) category-based inferences about photographs whether or not labels were provided (Experiment 1). Children showed a bias toward category-based inferences about realistic drawings (Experiment 2) but did so only when labels were provided. Finally, children made mostly appearance-based generalizations for cartoon-like drawings (Experiment 3). However, labels (basic or superordinate level) reduced appearance-based responses. Labeling effects did not depend on having identical labels; however, identical superordinate labels were more effective than different basic-level labels for the least informative stimuli (i.e., cartoons). Thus, labels sometimes confirm the identity of ambiguous items. This evidence of labeling effects in Mandarin-speaking Chinese children extends previous findings beyond English-speaking children and shows that the effects are not narrowly culture and language specific.