Developmental and Social Determinants of Religious Social Categorization

The purpose of this study was to assess developmental and social determinants of the age at which children become aware that the social environment can be marked by categorization into religious groups and that those groups are associated with different religious beliefs. The results show that middle childhood is a critical period for this religious social categorization. Moreover, social factors play a role in the development. Religious categorization is likely to appear sooner in children attending heterogeneous schools than in those at homogeneous schools, and children from the minority religious group in the country understand religious categorization earlier than children from the majority group. However, no relation was found between the age at which religious categorization was understood and parents’ religious socialization practices. This study is of both theoretical and practical interest: It complements what is already known about gender, race, and ethnic categorization by integrating developmental and social frameworks, and it can serve as a guideline for educational programs.     

Learning in context: linguistic and attentional constraints on children's color term learning

Three experiments investigated whether linguistic and/or attentional constraints might account for preschoolers' difficulties when learning color terms. Task structure and demands were equated across experiments, and both speed and degree of learning were compared. In Experiment 1, 3-year-olds who were matched on vocabulary score were taught new secondary color terms by corrective, semantic, or referential linguistic contrast. Corrective contrast produced more rapid and more extensive learning than did either semantic or referential contrast, supporting the hypothesis that targeted linguistic feedback facilitates learning. Experiment 2 replicated and extended the first experiment with Italian children and found cross-cultural differences in the amount learned about colors named differently in the two languages. In Experiment 3, some of the children were introduced to the new terms within a context of enhanced perceptual salience. These children learned as fast and performed as accurately as those given corrective linguistic feedback in Experiment 1.     

A defense of the subordinate-level expertise account for the N170 component

A recent paper in this journal reports two event-related potential (ERP) experiments interpreted as supporting the domain specificity of the visual mechanisms implicated in processing faces (Cognition 83 (2002) 1). The authors argue that because a large neurophysiological response to faces (N170) is less influenced by the task than the response to objects, and because the response for human faces extends to ape faces (for which we are not expert), we should reject the hypothesis that the face-sensitivity reflected by the N170 can be accounted for by the subordinate-level expertise model of object recognition (Nature Neuroscience 3 (2000) 764). In this commentary, we question this conclusion based on some of our own ERP work on expert object recognition as well as the work of others.     

A bird's eye view: biological categorization and reasoning within and across cultures

Many psychological studies of categorization and reasoning use undergraduates to make claims about human conceptualization. Generalizability of findings to other populations is often assumed but rarely tested. Even when comparative studies are conducted, it may be challenging to interpret differences. As a partial remedy, in the present studies we adopt a 'triangulation strategy' to evaluate the ways expertise and culturally different belief systems can lead to different ways of conceptualizing the biological world. We use three groups (US bird experts, US undergraduates, and ordinary Itza' Maya) and two sets of birds (North American and Central American). Categorization tasks show considerable similarity among the three groups' taxonomic sorts, but also systematic differences. Notably, US expert categorization is more similar to Itza' than to US novice categorization. The differences are magnified on inductive reasoning tasks where only undergraduates show patterns of judgment that are largely consistent with current models of category-based taxonomic inference. The Maya commonly employ causal and ecological reasoning rather than taxonomic reasoning. Experts use a mixture of strategies (including causal and ecological reasoning), only some of which current models explain. US and Itza' informants differed markedly when reasoning about passerines (songbirds), reflecting the somewhat different role that songbirds play in the two cultures. The results call into question the importance of similarity-based notions of typicality and central tendency in natural categorization and reasoning. These findings also show that relative expertise leads to a convergence of thought that transcends cultural boundaries and shared experiences.     

Categorizing a moving target in terms of its speed,direction, or both

Pigeons categorized a moving target in terms of its speed and direction in an adaptation of the randomization procedure used to study human categorization behavior (Ashby & Maddox, 1998). The target moved according to vectors that were sampled with equal probabilities from two slightly overlapping bivariate normal distributions with the dimensions of speed and direction. On the average, pigeons categorized optimally in that they attended to either speed or direction alone, or divided attention between them, as was required by different reinforcement contingencies. Decision bounds were estimated for individual pigeons for each attentional task. Average slopes and y intercepts of these individually estimated decision bounds closely approximated the corresponding values for optimal decision bounds. There is therefore at least one task in which pigeons, on the average, display flexibility and quantitative precision in allocating attention to speed and direction when they categorize moving targets.     

Discrimination and categorization of photographs of natural objects by chimpanzees (Pan troglodytes)

Two experiments assessed the ability of four adult female chimpanzees to categorize natural objects. Chimpanzees were initially trained to match different color photographs of familiar objects from four possible categories. In training, all the comparison stimuli were from the same category in one condition, and from different categories in another condition. For all subjects, training performance was consistently better for the "different category" than for the "same category" trials. Probe trials were shown after training. In probe trials, the sample and positive comparison stimuli were different items from the same category, and the foils were selected from among the three other test categories. Individual performance was above chance in probe trials, suggesting that categorization by chimpanzees may transcend perceptual resemblance. These results were later replicated with novel stimulus items from the same four categories (experiment 2). Altogether, this research demonstrates that chimpanzees grouped perceptually different exemplars within the same category, and further suggests that these animals formed conceptual representations of the categories. Accepted after revision: 10 August 2001 Electronic Publication     

Default categorization of outgroup faces and the other race effect: Commentary on the special issue

This commentary addresses how studies examining the neurophysiological correlates of racial categorization can provide insight into the neurocognitive mechanisms of the other-race effect in recognition memory. Several articles in the special issue describe how event-related potentials (ERPs) have been used to examine processing of faces that vary according to race, some of which have concluded that larger ERP amplitudes elicited by other-race (relative to own-race) faces indicates less efficient visual processing of other-race faces. I describe findings from ERP studies of race categorization that suggest an alternative interpretation–that other-race faces elicit stronger categorization, which impedes individuation of other-race faces. Suggestions for future research are offered.     

On the existence of prelinguistic categories: A case study

The purpose of this study was to investigate whether infants spontaneously form categories during the prelinguistic period and whether these categories are based on the same principles as adult basic-level categories. A new methodology, using a functional use measure as the determinant of category composition, was employed in a case study of one infant's horn category. Results indicated that this category met Schlesinger's (1982) criteria for a prelinguistic category and that the category was based on similarity relationships, as adult categories are.     

Detection of gender-related categories by 10-month-old infants

Thirty-two 10-month-olds completed an habituation procedure where a male or female face was paired with a specific object. Results reveal 10-month-olds can form categories based on correlations among attributes of social information. Basic processes involved in gender role formation are present in 10-month-olds.     

The recognition and categorization of upright and inverted emotional expressions by 7-month-old infants

Upright and inverted faces were used to determine whether 7-month-old infants discriminate emotional expressions on the basis of affectively relevant information. In Experiment 1, infants recognized the similarity of happy faces over changing identities and discriminated this expression from fear and anger when the stimuli were presented upright, but not when they were inverted. In Experiment 2, infants were able to discriminate happiness from fear and anger posed by a single model, regardless of the orientation of the stimuli. From these studies it was suggested that categorizing emotional expressions depends upon attending to affectively relevant, orientation-specific information, whereas the discrimination of emotional expressions can be done on a featural basis, something that remains invariant regardless of the orientation of the stimuli. In Experiment 3, infants discriminated toothy happiness posed by several models from nontoothy happiness and nontoothy anger when the stimuli were presented upright and inverted. Thus, when salient features were available, the infants based their discriminations on perceptual aspects rather than on conceptual aspects such as categories of emotions.