Family resemblances: Studies in the internal structure of categories

Six experiments explored the hypothesis that the members of categories which are considered most prototypical are those with most attributes in common with other members of the category and least attributes in common with other categories. In probabilistic terms, the hypothesis is that prototypicality is a function of the total cue validity of the attributes of items. In Experiments 1 and 3, subjects listed attributes for members of semantic categories which had been previously rated for degree of prototypicality. High positive correlations were obtained between those ratings and the extent of distribution of an item's attributes among the other items of the category. In Experiments 2 and 4, subjects listed superordinates of category members and listed attributes of members of contrasting categories. Negative correlations were obtained between prototypicality and superordinates other than the category in question and between prototypicality and an item's possession of attributes possessed by members of contrasting categories. Experiments 5 and 6 used artificial categories and showed that family resemblance within categories and lack of overlap of elements with contrasting categories were correlated with ease of learning, reaction time in identifying an item after learning, and rating of prototypicality of an item. It is argued that family resemblance offers an alternative to criterial features in defining categories.     

Tutor Attributions and Attitude As a Function of Tutee Performance1

In a single-session tutoring situation, a sixth-grade tutor taught a concept-formation task to a third-grade tutee. Over the series of trials, performance of the tutee was controlled to create differential patterns of success and failure on the task: success-success, failure-failure, success-failure, and failure-success. Results showed that sequence of performance exerted a strong impact on the tutor's attributions of ability and affective responses concerning the tutee. The tutee's initial performance had greater impact on the tutor's reactions than later performance, indicating a strong primacy effect. Differential performance by the tutee did not affect the tutor's evaluation of his own teaching ability.     

Basic objects in natural categories

Categorizations which humans make of the concrete world are not arbitrary but highly determined. In taxonomies of concrete objects, there is one level of abstraction at which the most basic category cuts are made. Basic categories are those which carry the most information, possess the highest category cue validity, and are, thus, the most differentiated from one another. The four experiments of Part I define basic objects by demonstrating that in taxonomies of common concrete nouns in English based on class inclusion, basic objects are the most inclusive categories whose members: (a) possess significant numbers of attributes in common, (b) have motor programs which are similar to one another, (c) have similar shapes, and (d) can be identified from averaged shapes of members of the class. The eight experiments of Part II explore implications of the structure of categories. Basic objects are shown to be the most inclusive categories for which a concrete image of the category as a whole can be formed, to be the first categorizations made during perception of the environment, to be the earliest categories sorted and earliest named by children, and to be the categories most codable, most coded, and most necessary in language.     

Responsiveness to babies: Life-situation specific sex differences in adulthood

Responsivity to babies was observed in 96 mature adults representative of three junctures of parenthood: parents of infants, parents of 8-to-9-year-olds, and parents of adolescents. Among the measures used were reactions to an unfamiliar infant in a waiting room, interest in pictures of babies versus other objects, and sex-role concept and attitudinal questionnaires. Stage of family life cycle affected women's responsivity, but not men's. New mothers displayed a heightened generalized interest in babies which is optimally timed and functional in terms of sex-differentiated role requirements. A possible confounding between cohort effects and stage in the family life cycle was examined and rejected. Traditionally sex-typed behaviors were reinterpreted as life-situation specific rather than general traits.This study was supported by grants from NIMH (1 R03 MH28264-01) and from Boys Town Center for the Study of Youth Development, Stanford University. The authors thank Barbara Aschenbrenner for her invaluable assistance in all phases of the research.