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.     

The relationship between category typicality and concept familiarity: Evidence from Spanish- and English-speaking monolinguals

We examined the relationship between an item’s familiarity and its category typicality, employing ratings obtained from Spanish- and English-speaking monolinguals living in southern Florida. In the first experiment, Spanish- and English-speaking monolinguals were asked to rate the prototypicality of instances of 12 common language categories. The correlations between the Spanish and English speakers’ rated item typicality indicated that the prototypicality gradients of the Spanish and English monolinguals were fairly discrepant for a number of categories. In the second experiment, we examined the degree to which these differences in cultural typicality could be accounted for by differences in rated cultural familiarity. It was predicted that, if familiarity plays a role in determining cultural differences in prototypicality, statistically controlling for the effects of cultural familiarity should result in higher interlingual typicality correlations. This should be true particularly for those categories for which there is a wide discrepancy in the typicality gradients for the two language groups. These predictions were confirmed. Consequently, we conclude that item familiarity is at least one variable influencing cultural differences in category typicality gradients.     

Judgments relative to patterns: how temporal sequence patterns affect judgments and memory

Six experiments studied relative frequency judgment and recall of sequentially presented items drawn from 2 distinct categories (i.e., city and animal). The experiments show that judged frequencies of categories of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We found (a) a first-run effect whereby people overestimated the frequency of a given category when that category was the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge 1 event more likely than the other and yet recall more instances of the latter. Specifically, the distribution of recalled items does not correspond to the frequency estimates for the event categories, indicating that participants do not make frequency judgments by sampling their memory for individual items as implied by other accounts such as the availability heuristic (Tversky & Kahneman, 1973) and the availability process model (Hastie & Park, 1986). We interpret these findings as reflecting the operation of a judgment heuristic sensitive to sequential patterns and offer an account for the relationship between memory and judged frequencies of sequentially encountered stimuli.     

The effect of category focus at encoding on category frequency estimation strategies

We investigated whether category focus at encoding affects how people estimate category frequencies. Participants in three experiments viewed items of various categories. They estimated category frequencies after categorizing them into relevant versus irrelevant categories (Experiments 1-2) or after categorizing versus memorizing them (Experiment 3). Verbal protocols (Experiments 2A and 2B), response latencies (Experiments 2A and 2B), frequency estimate changes (Experiment 2B), and the relationships between objective and estimated category frequencies and instance recall (Experiments 1-3) showed that the participants mainly used availability to estimate category frequencies after memorizing instances (Experiment 3) or after categorizing them into irrelevant categories (Experiments 1-2). After categorizing items into relevant categories, the participants relied more often on stored category frequency information (Experiments 1-3).     

Proximity to central tendency and usefulness in attaining goals as predictors of prototypicality for behaviour-descriptive categories

This study investigated determinants of the internal structure of categories of directed behaviours. For the categories Sport, Gardening, Craft, Making music, and Housekeeping, proximity to the category's central tendency and usefulness in accomplishing category-specific goals were compared as predictors of prototypicality ratings. In a preliminary study, subjects suggested activities and goals for the five categories. In the main study, subjects estimated the prototypicality of these activities for the categories, their usefulness in attaining the category-specific goals, and the similarity of the activities among each other. Family resemblance scores were derived from the latter ratings. It was found that family resemblance and usefulness in attaining category-specific goals were about equally useful in predicting the actual prototypicality ratings.     

Free recall and retrieval speed of categorized items by kindergarten children

Kindergarten Ss were presented with 16 pictorial items in four category sets or a partially random ordem with one item from each category composing the four presentation sets. The pictures were presented either on conceptually related background pictures or on white backgrounds. The categorically grouped presentation facilitated free recall performance, both in terms of number of items recalled and the speed with which the items were recalled, and increased the amount of clustering in recall. Categorical clustering in recall was associated with shorter within- than between-category intervals and for those Ss who recalled items from each of four categories successively, the over-all temporal pattern in recall closely approximated that found with adults. No background effects were found.     

A cross-cultural comparison using the act frequency approach (AFA) in West Germany and the United States

Two studies were conducted in West Germany and the United States to investigate cultural similarities and differences on features of personality assessed through act frequency methods. The first study analysed the acts considered to be central and peripheral to each of six dispositional categories: dominance, quarrelsomeness, gregariousness, submissiveness, agreeableness, and aloofness. The results indicated moderate to strong similarity between the cultures in the prototypicality structure for all categories except agreeableness, which showed little concordance. The second study examined the manifested structure of act performance as assessed through retrospective act reports. The results indicated greater similarity of act endorsements between the two sexes within each culture than between cultures within each sex. Generally, the Americans showed higher base rates than the Germans. Furthermore, over all samples, females showed lower base rates than males. The correlations between relative base rates within each of the six different categories were moderately strong between the cultures (0.56, p < 0.001). Analyses of the relations between the prototypicality structure and the manifested structure yielded a complex picture that was highly dependent on dispositional category. For quarrelsome acts, for example, the more central acts were reported to be performed less frequently in both cultures, while other categories showed positive correlations between base rates and prototypicality. The limitations of these studies are described, and future research directions regarding expanding the range of act frequency methods and the number of nations in the search for personality functioning across cultures are suggested.     

Availability and category-frequency estimation

Individuals judged how often examples of taxonomic categories had occurred in a study list. An availability hypothesis was tested--that frequency estimates are based on the retrieval of instances. Cued (by category names) recall of the examples served as an index of availability. The hypothesis was confirmed--there were strong positive correlations between frequency judgments and recall (with the influence of actual frequency removed)--given one or more of the following conditions: List instances were not categorized aloud as they were presented; frequency estimation was preceded by cued recall; frequency estimation was delayed by a week. Limitations on availability occurred under other conditions--notably, when individuals, during list presentation, named the categories to which items belonged and received feedback about their categorizations. Under these circumstances, correlations of frequency estimation and recall were often not significantly different from zero, and frequency judgments and recall sometimes reacted differently to changes in independent variables (e.g., frequency judgments of young and elderly subjects did not differ reliably, even though cued recall of young persons markedly exceeded that of elderly subjects).     

The role of categorical information in processing relational attributes

In two experiments, the effect of knowledge about relevant common taxonomic categories on judgments of relative magnitude was investigated. In Experiment 1, subjects judged the relative size of objects that belonged to the categoriesbuilding andanimal. The symbolic distance effect was smaller for between-category pairs (e.g.,horse-cabin) whose members could be classified more quickly into the two categories. This result strongly suggests that subjects used category membership to determine relative size on at least some portion of the trials. In Experiment 2, a similar attenuation of symbolic distance was obtained when subjects judged the relative height of furniture and vehicles. A simple explanation of the reduced symbolic distance effect for between-category pairs is that subjects occasionally fail to categorize the items into different categories and have to compute relative magnitude from the magnitudes of the two items. Fits to the data using the bootstrap technique suggest that more involved assumptions are required.     

Kindergarten children's use of category membership

Kindergarten children (N = 70) learned to order 12 photographically presented objects. The objects were well known and either unrelated or categorizable into two, three, four, or six well-known categories. Free recall was assessed. Results indicated that the children used category membership both to learn and to recall the items. However, they processed the list composed of six pairs of items at least as efficiently as lists composed of fewer but larger groups of items (including a list indexed as easiest through previous adult performance).     

Associative and categorical processes in children's memory: The role of automaticity in the development of organization in free recall

Free recall performance was assessed in children in Grades 3, 5, 7, and 9 (Experiment 1) and adults (Experiment 2) on a list of categorically related words constructed so that some items within a category were highly associated with one another and interitem associations were low among other items (e.g., dog, cat, cow, lion, tiger). Associative relations were used frequently in recall by subjects of all ages, with analyses of interitem latencies and correlations between recall and clustering indicating that organization in recall was based only on associative relations for the third and fifth graders but based on both associative and nonassociative categorical relations for older subjects. Examination of the placement of high associates in recall indicated that seventh- and ninth-grade children were more apt to use associative relations to begin category clusters than were younger children or adults. These children were hypothesized to use the relatively automatic activation of associative relations to instigate categorical organization and to represent a stage in development between nonstrategic younger children and strategic adults. The results were discussed in terms of the role that the automatic activation of semantic memory relations may play in the development of strategic memory organization.     

Conceptual combination: Conjunction and negation of natural concepts

The operation of negation on combinations of natural categories was examined in two experiments. In the first, category membership ratings of lists of items were obtained for pairs of concepts considered individually and in two logical combinations: conjunctions (e.g., “Tools which are also Weapons”) and negated conjunctions—forms of those conjunctions in which the modifier noun category was negated (“Tools which arenot Weapons”). For conjunctions, results supported earlier findings of overextension and the geometric averaging of constituent membership values (Hampton, 1988b). Previous findings of concept dominance and noncommutativity within conjunctions were also replicated, both for typicality ratings and for probability of class membership. For negated conjunctions, the pattern of dominance was similar but interacted with order within the conjunction. Negated conjunctions were also overextended. The second experiment explored how the attributes of negated conjunctions were derived from those of the two component concepts. Frequency of generation of attributes expressed positively (has wheels) or negatively (has no wheels) followed rated frequency in the negated category. The distinctiveness of an attribute to distinguish the complement from the head-noun class was associated with the generation of attributes, particularly when there was relatively high overlap between the two categories.     

Category typicality effects in children's memory performance: Qualitative and quantitative differences in the processing of category information

Kindergarten, third, and sixth graders (6, 9, and 12 years of age, respectively) received a cue-at-input/cue-at-output recall task, using category typical and atypical items that were based on either (1) children's conceptions of item typicality, or (2) adults' conceptions of item typicality. At each grade level, recall was greater with the child-defined lists than with the adult-defined lists, and typical items were recalled to a greater extent than atypical items. Further analyses items were recalled to a greater extent than atypical items. Further analyses revealed that the recall of typical items varied as a function of children's typicality ratings of items, and that the “typicality effect” in the adult-norm condition was due primarily to the childrennot realizing that many of the atypical items were appropriate category exemplars. In contrast, typicality effects in the child-norm condition were attributed to qualitative differences in the judged “goodness of example” of the typical and atypical items. The results were discussed in terms of the appropriateness of typicality as a dimension of children's natural language concepts, the role of age differences in knowledge base in affecting performance on a cognitive task, and of the importance of using child-generated norms in studies of children's processing of category information.     

Children’s incidental learning of the colors of objects and clothing

Few researchers have examined adults’ and children’s incidental recall of color information. In Experiment 1, we examined how well children recalled the colors of items seen in a first aid demonstration. Color recall of objects was above chance levels after three different time delays. However, recall of clothing color was poor. In Experiment 2, we examined whether colors of items from the same category (e.g., items of clothing) were more difficult to remember than distinct items (i.e., belonging to a range of different categories). Children and adults saw 18 items from three different categories. Color recall was above chance levels. The colors of distinct items were recalled more often than the color of category items. The results suggest that color is encoded automatically to some extent. However, participants had difficulty in recalling the color of clothing worn by the experimenter.     

Developmental trends in children’s typicality judgments

Category typicality norms from 12 natural language categories are presented for kindergarten, third-grade, sixth-grade, and college students. Subjects first selected examples of familiar word concepts and rated them on a 3-point scale in terms of category typicality. Age differences in the percentage of items included as category members were found primarily for the less typical items, with inclusion rates varying as a function of both age and typicality level. The absolute level of typicality judgments increased with age, although correlations between the children’s and college students’ ratings were generally significant for all three children’s groups, with average correlations increasing somewhat with age. It was suggested that the rating data would be useful to developmental investigators interested in children’s processing of category information.     

Age-related differences in clustering: A new approach

The present study attempted to determine why children under 8 years of age show categorical clustering in free recall above chance expectations, but such organization does not correlate with recall. Six-year-old children and adults were tested for their memory for 24 pictures of categorizable items. Several new measures of organization such as the proportion of items recalled in category strings and number of strings of each length were evaluated. It was found that children's output is characterized by strings of only two intracategory items and many isolates which does not contribute to recall. Adults produced longer strings from more categories which enhanced recall. In addition, different characteristics of output organization predicted recall for adults and children.     

The evaluation of architectural interior colour as a function of style of furnishings: Categorization effects

The purpose of this experiment was to investigate whether evaluative responses to a single attribute, colour, reflected categorization and prototypicality as did responses in a furniture selection study (Whitfield & Slatter, 1978). Subjects ranked colours in order of appropriateness for the walls of a simulated domestic interior furnished in one of three styles: Modern, Georgian or Art Nouveau. Style was designated by simulated items of furniture. The hypothesis that judged appropriateness would vary as a function of style was borne out by the results. Support was also provided for the prediction that two rather than three categories would be refernced by subjects–Georgian and Art Nouveau comparising a unitary category. Finally, evidence of effects due to prototypicality was descernible from inspection of the date.     

The nature and structure of infant form categories

The nature of form categories in 3 to 4-month infants was studied using the visual preference for novelty in the familiarization-novelty paradigm. Novelty preference indicates habituation to and recognition of the familiar. In a series of experiments employing three form categories composed of dot patterns, generalized habituation to new category members was used to assess categorization behavior in the recognition of visual forms. At 3 to 4 months of age, infants did not initially show any systematic preferences for “good” or symmetrical examples of a category relative to “distorted” examples (Experiment 1) and this was true for all three form categories used (i.e., square, triangle, and diamond). Evidence for categorization was seen in the recognition performance of 3- to 4-month infants (Experiment 2). Infants showed generalized habituation to the previously unseen category prototypes following exposure to six exemplars within each of the three form categories. Given evidence that infants could discriminate between the prototype and other category members (Experiment 3), “inability to discriminate” was ruled out as an explanation for this form categorization or generalized habituation effect. Four subsequent experiments were conducted to determine whether infants exhibit a prototypicality structure for their remembered categories and whether certain conditions which have been shown to enhance prototypicality effects with adults have similar effects with infants. No evidence of a prototypicality structure was found for the form categories of infants when the number of exemplars during familiarization was limited to 6 and the test for form recognition followed immediately (Experiment 4). However, a prototypicality structure for the remembered form categories was found when a 3-min delay was introduced between familiarization and tests for form recognition (Experiment 5), when 12 exemplars were presented during familiarization (Experiment 7), or when the prototype was included as one of the six exemplars during the familiarization period (Experiment 6).     

Inclusion in a superordinate category, in-group prototypicality, and attitudes towards out-groups

We hypothesized that group members’ attitudes towards an out-group are negatively related to the in-group’s perceived relative prototypicality for a superordinate category, but only if both the in-group and out-group are included in this superordinate category. In Experiment 1 (N=40), Germans’ attitudes towards Poles were negatively correlated with the relative prototypicality of Germans when “Europe” (including Poles), but not when “West-Europe” (excluding Poles), was the superordinate category. In Experiment 2 (N=63), female single parents’ attitudes about the competence of single parents to raise children depended on the in-group’s relative prototypicality for “single parents” (including fathers), but not on their relative similarity to “mothers” (excluding fathers). Both experiments showed that inclusion in a superordinate category had a more negative influence on attitudes towards the out-group when relative in-group prototypicality is high rather than low.