We studied the transition of stimuli from novel to familiar in visual search
and in the guidance of attention to a particular object. Ability to identify
an object improved dramatically over several days of training. The learning
was specific for the object's position in the visual field, orientation and
configuration. Improvement was initially localized to one or two positions
near the fixation spot and then expanded radially to include the full area
of the stimulus array. Characteristics of this learning process may reflect
a shift in the cortical representation of complex features toward earlier
stages in the visual pathway.
