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

Abstract

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.

A Two‐Stage Model of Category Construction

“…The generality of our findings may be constrained by conflicting results obtained by Smith (1981) with different stimulus materials. The general consensus from developmental studies is that children's sorting is based on overall similarity, whereas adults' sorting is based on a single feature (Imai & Garner, 1968;Smith & Kemler, 1977).…”

“…The general consensus from developmental studies is that children's sorting is based on overall similarity, whereas adults' sorting is based on a single feature (Imai & Garner, 1968;Smith & Kemler, 1977). Smith (1981), however, attributed these findings to the use of only a small number of dimensions {e.g., two or three) in the stimuli.…”

A psychophysical approach to dimensional separability

“…This pattern of results argues against Lockhead and King's hypothesis that overall similiarity can account for differences in interference, and supports our interpretation in terms of psychophysical correspondence. Smith (1981) found that adults as well as children structured their free classifications of complex objects (i.e., objects that varied simultaneously on relatively many dimensions) on the basis of overall-similarity relations, rather than identity on compelling psychological dimensions such as shape and color. As Smith herself pointed out, however, this finding does not imply that separable dimensions become more integral as more dimensions vary.…”

Multimodal similarity and categorization of novel, three-dimensional objects

“…Thus, the memory requirements of our task may have been another factor which encouraged the use of unidimensional rules. A final factor could be that our stimuli only varied along two dimensions; it has been shown that subjects tend to classify using similarity when objects vary simultaneously along many dimensions, but prefer unidimensional rules when objects vary along fewer dimensions (Smith, 1981). Further studies are needed to disentangle the effects of stimulus dimensions and task design on category construction and to determine whether, under certain circumstances, categorization can be predicted from similarity in a multimodal setting.…”