Domain differences in absolute judgments of category membership: evidence for an essentialist account of categorization

There has been some debate about the correspondence between typicality gradients and category membership. The present study investigates the relationship between these two measures in the domains of animals and artifacts. Forty-two adults judged the degree of typicality or category membership of 293 animals and artifacts. The subjects’ tendency for animals, but not for artifacts, was to make more absolute ratings on category membership (i.e., judging exemplars as definitely members or definitely not members of their respective category) than on typicality. More importantly, at almost every level of typicality, subjects were more likely to make absolute judgments of category membership for animals than for artifacts. These results indicate that people treat category membership of animals as relatively absolute (which best fits an essentialist model of categorization) and treat category membership of artifacts as relatively graded (which best fits a prototype model of categorization). These domain differences add crucial supporting evidence for claims about the domain-specificity of essentialism.     

Preverbal and verbal counting and computation.

We describe the preverbal system of counting and arithmetic reasoning revealed by experiments on numerical representations in animals. In this system, numerosities are represented by magnitudes, which are rapidly but inaccurately generated by the Meck and Church (1983) preverbal counting mechanism. We suggest the following. (1) The preverbal counting mechanism is the source of the implicit principles that guide the acquisition of verbal counting. (2) The preverbal system of arithmetic computation provides the framework for the assimilation of the verbal system. (3) Learning to count involves, in part, learning a mapping from the preverbal numerical magnitudes to the verbal and written number symbols and the inverse mappings from these symbols to the preverbal magnitudes. (4) Subitizing is the use of the preverbal counting process and the mapping from the resulting magnitudes to number words in order to generate rapidly the number words for small numerosities. (5) The retrieval of the number facts, which plays a central role in verbal computation, is mediated via the inverse mappings from verbal and written numbers to the preverbal magnitudes and the use of these magnitudes to find the appropriate cells in tabular arrangements of the answers. (6) This model of the fact retrieval process accounts for the salient features of the reaction time differences and error patterns revealed by experiments on mental arithmetic. (7) The application of verbal and written computational algorithms goes on in parallel with, and is to some extent guided by, preverbal computations, both in the child and in the adult.     

Nonverbal arithmetic in humans: light from noise

Animal and human data suggest the existence of a cross-species system of analog number representation (e.g., Cordes, Gelman, Gallistel, & Whalen, 2001; Meeck & Church, 1983), which may mediate the computation of statistical regularities in the environment (Gallistel, Gelman, & Cordes, 2006). However, evidence of arithmetic manipulation of these nonverbal magnitude representations is sparse and lacking in depth. This study uses the analysis of variability as a tool for understanding properties of these combinatorial processes. Human subjects participated in tasks requiring responses dependent upon the addition, subtraction, or reproduction of nonverbal counts. Variance analyses revealed that the magnitude of both inputs and answer contributed to the variability in the arithmetic responses, with operand variability dominating. Other contributing factors to the observed variability and implications for logarithmic versus scalar models of magnitude representation are discussed in light of these results.     

Differences in the Evaluation of Generic Statements About Human and Non‐Human Categories

Generic statements (e.g., “Birds lay eggs”) express generalizations about categories. Current theories suggest that people should be especially inclined to accept generics that involve threatening information. However, previous tests of this claim have focused on generics about non‐human categories, which raises the question of whether this effect applies as readily to human categories. In Experiment 1, adults were more likely to accept generics involving a threatening (vs. a non‐threatening) property for artifacts, but this negativity bias did not also apply to human categories. Experiment 2 examined an alternative hypothesis for this result, and Experiments 3 and 4 served as conceptual replications of the first experiment. Experiment 5 found that even preschoolers apply generics differently for humans and artifacts. Finally, Experiment 6 showed that these effects reflect differences between human and non‐human categories more generally, as adults showed a negativity bias for categories of non‐human animals, but not for categories of humans. These findings suggest the presence of important, early‐emerging domain differences in people's judgments about generics.     

Children’s and Adults’ Predictions of Black,White, and Multiracial Friendship Patterns

Cross-race friendships can promote the development of positive racial attitudes, yet they are relatively uncommon and decline with age. In an effort to further our understanding of the extent to which children expect cross-race friendships to occur, we examined 4- to 6-year-olds’ (and adults’) use of race when predicting other children’s friendship patterns. In contrast to previous research, we included White (Studies 1 and 2), Black (Study 3), and Multiracial (Study 4) participants and examined how they predicted the friendship patterns of White, Black, and Multiracial targets. Distinct response patterns were found as a function of target race, participant age group, and participant race. Participants in all groups predicted that White children would have mostly White friends and Black children would have mostly Black friends. Moreover, most participant groups predicted that Multiracial children would have Black and White friends. However, White adults predicted that Multiracial children would have mostly Black friends, whereas Multiracial children predicted that Multiracial children would have mostly White friends. These data are important for understanding beliefs about cross-race friendships, social group variation in race-based reasoning, and the experiences of Multiracial individuals more broadly.     

Multiracial Children’s and Adults’ Categorizations of Multiracial Individuals

Research has explored how multiracial individuals are categorized by monoracial individuals, but it has not yet explored how they are categorized by multiracial individuals themselves. We examined how multiracial children (aged 4–9 years old) and adults categorized multiracial targets (presented with and without parentage information). When parentage information was provided, multiracial targets were more likely to be categorized as neither wholly Black nor wholly White. However, both multiracial adults and children more often categorized multiracial targets as Black than as White regardless of the absence or presence of parentage information. For multiracial children, increased contact with White people predicted the tendency to categorize multiracial targets as Black. These data suggest that multiracial children’s categorizations are more flexible than those of monoracial children in previous research and that the tendency to categorize multiracial targets as Black emerges early in development within multiracial samples and is especially likely in predominantly White contexts.