Reported are two studies which describe the early development in children of the ability to consider every one of an array of instances. Taken together with other recent studies, the data reveal early development in preschool children of a fundamental, general problem solving skill. (PCB)

Examined effects of cognitive focusing training in early and late concrete operational children. Focusing was manifested by the late concrete operational children regardless of whether or not they had been trained. The amount of negative feedback and the nature of the probe techniques affected the manifestation of focusing. (Author/DB)

Pairs of elementary school children at different concept development levels were given problems to discuss, in order to examine the prediction, derived from the equilibration model, that when two children holding different beliefs must arrive at a consenus, the child possessing the higher level of cognitive development will prevail over the child…