PATTERNS OF EXPERIENCE AND THE ACQUISITION OF CONSERVATION OF LENGTH

The effects of five procedures on the acquisition of conservation of length were studied. A Müller-Lyer illusion was used to induce apparent changes in length in the test- and practice-situations. Two procedures involved practice on addition-subtraction, one a progressive increase in the strength of the Müller-Lyer illusion, and one the anticipation of the outcome of displacements of the objects. A fifth procedure was a composite of the other four. The results showed some acquisitions in all groups, with highest frequency in the anticipation group, and lowest in the increase-in-illusion group.