Importance of the overall similarity of objects of adults' and children's classifications

Previous work has shown that adults and older children tend to classify multi-dimensional objects by identity on one dimension, whereas children under 8 years of age tend to classify these same objects by a relation of overall similarity. The present study investigated the hypothesis that this developmental trend is restricted to the classification of simple objects that differ only by limited amounts on a few dimensions. The specific hypothesis was that overall-similarity relations structure both adults' and children's classifications of heterogenous objects (objects that differ in a variety of ways). This hypothesis was suggested by the correspondence between the structure of young children's classifications and the structure of natural categories. The result of two experiments supported the hypothesis. When the to-be-classified objects varied simultaneously on relatively many dimensions, adults as well as children constructed classifications that maximized within-category similarity on all varying dimensions. The implications of these results for accounts of the perception of multidimensional relations and classificatory behavior are discussed.     

Perceptual sensitivity to dimensional and similarity relations in free and rule-governed classifications

Two experiments were conducted to investigate the perceptual primacy of dimensional and similarity relations in the stimulus classifications of younger and older subjects. In Experiment 1, 4- and 10-year-olds were given free classifications in which they could group stimuli according to overall similarity or identities in size, color, or orientation. Both age groups classified stimuli most frequently according to identities on separate dimensions. In Experiment 2, 4-year-olds and adults were given free classifications followed by rule-governed classifications which required them to group stimuli according to specific relations. In the free classifications, a majority of subjects in both age groups classified the stimuli most frequently according to identities on separate dimensions. In the rule-governed classifications, both age groups were more accurate when a single separate relation was required for solution than when overall similarity was required. These results support a differential-sensitivity view of perceptual development, which asserts that individuals at all ages primarily perceive and use separate relations.     

Processes of overall similarity sorting in free classification

The processes of overall similarity sorting were investigated in 5 free classification experiments. Experiments 1 and 2 demonstrated that increasing time pressure can reduce the likelihood of overall similarity categorization. Experiment 3 showed that a concurrent load also reduced overall similarity sorting. These findings suggest that overall similarity sorting can be a time-consuming analytic process. Such results appear contrary to the idea that overall similarity is a nonanalytic process (e.g., T. B. Ward, 1983) but are in line with F. N. Milton and A. J. Wills's (2004) dimensional summation hypothesis and with the stochastic sampling assumptions of the extended generalized context model (K. Lamberts, 2000). Experiments 4 and 5 demonstrated that the relationship between stimulus presentation time and overall similarity sorting is nonmonotonic, and the shape of the function is consistent with the idea that the three aforementioned processes operate over different parts of the time course.     

Functional equivalence between same-different classifications and judged similarity of Markov patterns

This experiment represented an initial at tempt at comparing same-different classifications and similarity judgments of Markov histoforms sampled from three different schema families. A measure of individual stimulus variability was more strongfy related to classification responses than to judged similarity. Dichotomous responses, derived from the similarity data by imposing threshold criteria, were found to be highly similor to real classification responses when the threshold values were estimated directly from the latter; little correspondence, however, was obtained using optimal classification criteria. The results support the notion that somewhat different features are used in making classification responses and similarity judgments, and indicate the need for developing more sensitive tasks involving controlled scanning of pattem information.     

A developmental and cross-cultural study of the influences of rule structure and problem composition on the learning of conceptual classifications

Five experiments were conducted permitting direct comparisons in the way Ss of different ages and cultures solved conceptual problems. One group of problems (Traditional) could be solved using a reference rule of conjunction or disjunction. Another group of problems (Intradimensional) could be solved either by one of the reference rules, or by a structurally simpler rule. Analysis of American performance confirmed that older Ss not only solved using the simpler rule more often than younger Ss, but when they did so they solved faster. For both American age groups, solution using the simpler rule led to no difference in performance between conjunctive and disjunctive Intradimensional problems. Conjunction proved easier than disjunction only for the Traditional problems. Unlike Americans, the Kpelle of Liberia did not solve using the simpler rule, and found conjunction easier than disjunction for both Traditional and Intradimensional problems. When a memory aid was provided the Kpelle showed a pattern of performance exactly like Americans.     

Classification behavior and measures of intelligence: dimensional identity versus overall similarity

Individuals tend to adopt either analytic or holistic modes of categorizing objects. In two studies, we examined the relation between these categorization tendencies and cognitive abilities as measured by standard psychometric instruments. The participants in both studies were pretested with a restricted classification task in which it was possible for them to classify simple stimuli by dimensional identity or overall similarity. Those making a large number of either type of categorization were then tested with subtests of the WAIS-R and with the Raven's progressive matrices. Across both studies, the analytic individuals (many dimensional identity classifications) scored higher than the holistic individuals (many overall similarity classifications) on some but not all of the subtests. The results are consistent with the idea that holistic modes of categorization may be more "primitive" than analytic modes. The findings are discussed in terms of the association between categorization mode and either general or specific cognitive abilities.     

Olfactory categorization: A developmental study

This study examined the ability of children to classify fruit and flower odors. We asked four groups of children (4-11years of age) and a group of adults to identify, categorize, and evaluate the edibility, liking, and typicality of 12 fruit and flower odors. Results showed an increase in interindividual agreement with age for the taxonomic (fruit/flower) and function-based (edible/nonedible) categories but not for the hedonic component. So, it seems that this hedonic component is not the explicit basis for this increase in interindividual agreement when categorizing an odor as a fruit/flower odor or as being edible or nonedible. An age-related trend was also observed on the typicality scores: The youngest group of children did not show a typicality gradient, but all of the other groups did. Blackcurrant and lemon were rated as the most typical fruit odors, whereas raspberry and peach were rated as the least typical. For flower odorants, results were not as clear, yet it seems that for all groups lavender was considered as quite typical.     

Personality perception: A developmental study

We investigated the ability of adults and children to perceive the Big Five personality traits in others from “thin slices” of the behavioral stream. Targets were videotaped in five carefully crafted situations, each designed to maximally reveal a different trait domain. In addition, each target’s personality was assessed by close friends or parents, serving as the personality criterion. Judges’ agreement with the criterion improved generally with age, but different developmental trends were observed across traits.     

Orthographic-morphemic factors in reading: A developmental study

Children from grades 3, 5 and 7, and adults were given a lexical decision task to investigate the development of the use of a lexical access and storage code: the Basic Orthographic Syllabic Structure (BOSS; Taft, 1979). This structure approximates the base morpheme of a word and comprises the initial vowel-plus-consonant unit of a word (e.g., RUD is the BOSS of RUDE, MAD the BOSS of MADE). Stimuli were letter-strings, equally divided into three word and three nonword conditions. BOSS was manipulated in word and nonword conditions and compared to words of same or higher frequency or nonwords. All nonword decisions took longer than word decisions, suggesting an age-invariant exhaustive lexical search. Relatively larger word/nonword differences for younger children were attributed to different bases of lexical distinctions. The availability of a BOSS-based lexical file was apparent at all ages although utilization of a BOSS-mediated code seems to emerge gradually.     

Feature selection and classification: A developmental study

Two hundred and thirteen children between the ages of 4 and 16 sorted 30 complex objects freely into groups. These were either schematic faces, schematic imaginary animals, or histoform patterns and were constructed from 9 independently and continuously varying features, each with 10 levels. The three sets were equivalent in terms of underlying numerical structure. A new method of analysis of the groups formed yielded the following direct measures of subjective organization in the sorting of each child: the number of features used in sorting, the accuracy of sorting, and the number of independent dimensions of classification. Both the material and the analysis of sorting were devised on the assumption that only some of the component features of complex objects are used for classification, while others are ignored. Sorting performance differed markedly both with age and with different types of material. The improvement in sorting ability with age, except for the youngest children, could be attributed to an increase in the number of features used rather than an improvement in the accuracy of use. In contrast, the poor sorting of histoform patterns as opposed to faces and animals was due to a low level of sorting accuracy. The basic results on the development of classification confirmed previous studies, and hence suggest that it is valid to consider feature selection as a basic component of classification.     

Parallel and serial search in haptics

We propose a model that distinguishes between parallel and serial search in haptics. To test this model, participants performed three haptic search experiments in which a target and distractors were presented to their fingertips. The participants indicated a target's presence by lifting the corresponding finger, or its absence by lifting all fingers. In one experiment, the target was a cross and the distractors were circles. In another, the target was a vertical line and the distractors were horizontal lines. In both cases, we found a serial search pattern. In a final experiment, the target was a horizontal line and the distractors were surfaces without any contours. In this case, we found a parallel search pattern. We conclude that the model can describe our data very well.     

Conceptual implicit memory: A developmental study

The widely accepted standpoint that implicit memory emerges earlier in development than explicit memory, and is more stable from childhood to adult age, is based on experimental data essentially collected in perceptual tasks. The present study was aimed at investigating whether these findings still hold when a more conceptual task is used. We compared the performance of children at two age levels (2nd and 4th grades) on a category-exemplar generation task. Results showed that performances of the two groups were comparable when the target items were typical of their categories, as in Experiment 2, and for a subset of the items in Experiment 1. However, the older children outperformed the younger children in Experiment 1 when the items selected were atypical of their categories. Interpretations of these findings are discussed.Preparation of this article was supported by the Centre National de la Recherche Scientifique (URA CNRS 316 and 1838), the Université de Bourgogne, and the Université René-Descartes     

Cognitive competencies and aggressive behavior: A developmental study

A number of studies have demonstrated that increased socially related cognitive skills are associated with decreases in aggressive behavior. However, the link between aggression and intelligence or academic skills is less evident. While some research indicates that poor academic performance is related to aggression, it is unclear which components of intellectual ability and performance are critical to the management of aggressive behaviors. In two independent longitudinal studies of elementary school-age children, the relationship among several aspects of cognitive competence and several aspects of aggressive behavior were examined. The results of the first study showed that aggressive behavior observed in kindergarten children was more closely related to academic performance in the first and second grades than to general cognitive ability (IQ). The results of the second study, a comprehensive three-year investigation of upper elementary school-age children, indicated that teachers' assessments of aggression and parents' ratings of cruelty were consistent over time for boys, but not for girls. The intercorrelations among aggression measures within each of the three years also revealed stable sex differences. Boys identified as aggressive in the classroom were more likely to be perceived as aggressive, cruel, and/or delinquent at home, but for girls, there was little correlation between aggression at school and in the home. The analyses relating measures of cognitive functioning to indices of aggressive behavior made clear the importance of discriminating among various facets of these psychological constructs. IQ had a negligible relationship with aggression and a weak inverse relationship to delinquency. An overall index of cognitive functioning was a somewhat more consistent negative correlate of aggression, cruelty, and delinquency, especially for boys. A similar pattern was found for the correlates of academic performance. Academic disability was strongly related to delinquency in boys, and to a lesser degree to aggression in boys. Of the several cognitively related factors that were explored, Low Need Achievement manifested the strongest and most consistent relationships with the different facets of aggression and antisocial behavior, especially in boys. The implications of these results for psychological interventions in the school are discussed.     

Predicting aggressive patterns in girls and boys: A developmental study

The aim of this multimethod, longitudinal study was to examine similarities and differences in aggressive expression and prediction among school-aged boys and girls. The primary research sample involved 174 children (93 females, 81 males). They were in the fourth grade at the beginning of the study, and the fifth grade at its conclusion. Embedded in the primary sample was a subgroup of 20 children identified as being highly aggressive (ten males, ten females), and a subgroup of 20 matched control children. The research measures included teachers' ratings of aggressive behavior, peer-nominations/reports of prior conflicts, individual interviews/self-ratings, and extensive behavioral observations. Analyses of the concurrent relations among measures pointed to a “public” cluster of measures (including peer-nominations, behaviors, and teacher ratings) and relatively “private” measures (ie, subjects' self-evaluations). In the primary sample, significant developmental trends were detected in the teacher ratings with increasing gender differentiation as children grew older. Few gender differences were observed in the high-aggressive subgroup, but the aggressive and the matched control groups differed on virtually all comparisons. Gender differences in predictability were a function of risk status, with high-aggressive girls showing as much stability as high-aggressive boys.     

Children's beliefs about adoption: A developmental study

Attributions about adoption were examined in adopted and nonadopted children between the ages of 6 and 13 years. Results indicated that nonadopted children had a more negative view of adoption than their adopted age-mates, at least during the early to middle childhood years. By 10–11 years, however, no group difference was noted in adoption beliefs. In addition, with increasing age nonadopted children became less negative about adoption whereas adopted children became more negative about adoption. These results are discussed in the context of differential socialization for adopted and nonadopted children. Implications of adoption beliefs for children's adoption adjustment also are raised.     

Critical processes in serial short-term memory: A developmental study

Two experiments are described which were designed to test the possible involvement of two operations in developmental auditory serial short-term memory (SSTM), namely rehearsal proficiency and item identification. The experiments provided mainly negative support for the notion that these operations are critical in developmental SSTM. As an alternative, the possibility that developmental differences in SSTM might have their origins in the processing of speech sound patterns was discussed.     

Memory span and short-term memory capacity: A developmental study

A memory span task involving series conditions comprised of several different types of material was administered to children from three grade levels (7–12 years of age). As expected, age differences were strongly affected by type of material, with two conditions (consonant letters, words) intended to restrict opportunities for chunking yielding age differences that were negligible, and one condition (consonant-vowel letters) constructed to maximize sequential probability yielding age differences that were large. This finding renders less plausible the popular notion that capacity increases with age, and suggests that age differences in memory span reflect chunking processes. Additional findings, which indicate that age differences in memory span are affected by method of presentation and stage of practice, suggest that these variables should be considered in studies aimed at estimating children's memory capacity.     

Understanding strategic interactions in television commercials: A developmental study

The purpose of this study was to introduce an assessment procedure designed to explain developmental differences in understanding television advertising messages. Goffman's sociological concept of the “strategic interaction” and “recursive thinking,” the social analogue of Inhelder and Piaget's analysis of formal operational reasoning, provided the conceptual framework for our experimental paradigm. Four commercials for children's food products containing strategic interactions between two siblings were shown to 84 children, adolescents, and young adults. Participants were assessed for their understanding of the actors' behaviors and thoughts and for their understanding of the intent and persuasive strategy of the advertiser. Results indicated effects for both grade and commercial structure. The implications of these findings for social-cognitive development and for policy affecting children and television advertising are discussed.     

Common phoneme and overall similarity relations among spoken syllables: Their use by children and adults

This paper contrasts two kinds of relations among spoken syllables. One relation is based on a single common phoneme; the second is based on overall similarity of whole syllables. On the basis of recent studies with multidimensional visual stimuli, we hypothesized that preliterate children respond primarily to overall similarity relations among syllables, whereas literate adults respond primarily to common phoneme relations. These hypotheses were tested in two experiments using spoken syllables. Experiment 1 investigated the classification of syllables by preliterate children (mean age: 4 years 4 months) and college students. Experiment 2 studied the memory confusions among syllables by children (mean age: 4 years 8 months) and college students. The results of both experiments suggest that overall similarity relations are primary for preliterate children, while common phoneme relations are primary for adults. Moreover, children's limited use of common phoneme relations is not confined to tasks that require explicit judgments about language. Implications for the learning of reading are discussed.The work reported here formed a portion of the first author's doctoral dissertation submitted to the University of Pennsylvania. It was supported by Grant MH29453 to J. Baron and a Biomedical support grant through Indiana University to R. Treiman. We thank the children and teachers of the University of Pennsylvania Children's Center for their cooperation. Jonathan Baron, David Pisoni, Francis Ganong, Lila Gleitman, Kathy Hirsh-Pasek, Burton Rosner, Linda Smith, and Amanda Walley gave valuable comments on earlier versions of this paper.