An investigation of Piaget's theory of object concept development through a series of six tasks administered in a combined longitudinal/cross-sectional design (which incorporated a number of methodological controls). Subjects were 36 infants who received the six tasks during each of three testing sessions over a 6-month period. (Author/ED)

Three longitudinal studies examined means-ends behavior of 6- to 8-month olds. Found that intentional means-end behavior increased between 6 and 7 months, with 7-month olds' performance influenced by the presence of a toy on the cloth. Performance was the same when cloth was attached to or separate from the toy. By 8 months, infants adjusted…

Reports a series of studies conducted to investigate possible differences in the exploratory manipulation and play behavior of human infants 7-1/2- 11-1/2 months of age as a function of the attributes of the stimulus, the familiarity of the subject with the stimuli, the age and sex of the infants, and individual differences. (Author/CS)