In other words, most 
investigators today believe that 
innately determined, bottom-
up processing leads to some 
degree of organized pattern 
vision. Thus, the earlier belief 
that perception in its entirety 
is learned is disavowed. 
However, many investigators 
also believe that past 
experience plays some role in 
perception. Such experience 
might take many forms, from 
mere exposure to a normal 
environment very early in life 
to ensure the proper 
maturation of the visual 
nervous system, to learning to 
make fine discriminations 
among members of the same 
category, to enrichment 
effects. Many students of 
perception also accept the 
claim of stimulus theory that 
there is information in higher-
order dimensions of the 
stimulus, such as texture 
density or motion-perspective 
gradients.

    The conclusions drawn by 
students of perception about 
almost any topic discussed in 
the earlier chapters illustrate 
this eclecticism. Much depends 
upon the particular 
phenomenon under study. 
Nowadays there is a tendency to 
consider each type of 
perception separately and to 
sift out the evidence 
concerning it in arriving at a 
theoretical conclusion.