Infant response to stimuli of similar hue and dissimilar shape: tracing the origins of the categorization of objects by hue.

This study confirms that infants, like older children, are capable of responding "categorically" to stimuli of different shape if these are similar in hue. 24 infants (mean age 20.0 weeks) were familiarized to a stimulus in 1 hue (dominant wavelength 515 nm) and in either of 2 different shapes (face of a bear or a rabbit) and then presented with 4 main test comparisons in which the familiar stimulus was paired with a novel stimulus in either the familiar or the alternate (novel) shape and in a novel hue from the same or a different category (dominant wavelengths being 548 and 482 nm, respectively, and equally different from the familiar hue). Infants displayed a preference for the novel stimuli only in the new-category hue. Control tasks with a further 40 infants (same mean age as experimental group) eliminated alternative explanations of this pattern of response in terms of differential brightness of the hues, hue preferences, or inability to discriminate the shapes.