Feeling the parts: a developmental study of separable perception with tactile dimensions.

A tetrad classification task was used to determine perceptual sensitivity to the tactile dimensions of texture, hardness, and shape in 5- and 11-year-old children who classified objects by touch, unaided by vision. Both age groups reliably used separate dimensions to group the objects. Both age-related and individual differences in dimensional salience were observed. Five-year-olds predominantly grouped objects that were identical in hardness; 11-year-olds most often grouped objects identical in hardness or shape. Overall (integral) similarity was not used reliably by any participant. Results support the differential-sensitivity view of cognitive development and are consistent with Garner's (1970) distinction between integral and separable stimulus structure, but they do not support the hypothesized developmental trend from integral to separable perception.