The dimensionality of judgments of heaviness

Two groups of Ss judged differences in heaviness between all pairs of stimuli in three series of five weights each. One group judged differences in the 100-300 g range, the other group judged differences in the 700–900 g range. The three series of weights in the two ranges consisted of one series of constant size varying in both weight and density, one series varying only in weight, and one series varying only in density. Multidimensional scaling analysis revealed at least two dimensions, and indicated that where both weight and density are allowed to vary, both will affect judgment of the magnitude of differences in heaviness. With heavier weights, density appears to exert an increasingly important influence on judgments of heaviness. Predictions from Ross and Di Lollo’s vector theory were confirmed.