Fig. 1.
A conceptual replication of Premack's apple study. Row 1 shows the possible control in which a glass of water is lowered and causes no change to the whole apple. Row 2 shows a possible transformation in which a knife is lowered and causes a transformation of the apple into two half apples. Row 3 shows an impossible transformation in which a glass is lowered and appears to cause a transformation of the apple into two half apples. Row 4 shows an impossible transformation in which two half apples appear to be transformed into a whole apple by a knife.