Category boundaries and category labels: When does a category name influence the perceived similarity of category members?

Three experiments examined the effect of verbal labels on the perception of category members. Participants were presented with silhouette drawings of female body types, ordered on a continuum from very thin to very heavy, and asked to judge the degree of similarity between pairs, as well as absolute weight of each silhouette. The presence/absence of category boundaries and labels were experimentally manipulated (Exp. 1–3), as was the “strength” of the labels (Exp. 2 and 3), their source (Exp. 1 and 2), and their implications (Exp. 3). The presence of a label, even when self-generated, showed clear effects on judgment: labels consistently increased within-category similarity (assimilation), and reduced across-category similarity (contrast). The judged strength of the verbal labels was correlated with the strength of categorization effects.