ABSTRACT
Considerable data on perception are available to demonstrate that a particular object shown repeatedly to a subject induces cognitive effects that are not identical. This is manifested in the fact that the object is reproduced by the subject in different ways, or that the manner in which it governs his acts varies. These differences cannot be explained in terms of properties of stimulation, and they are not directly explainable by the morphophysiological mechanisms of perception: both may be relatively invariable. Nor can we be fully satisifed with the very general explanation of these facts by the assertion that repeated presentations of an object cause ever newer aspects to be discovered.
