The cat's response to stimulus difference as attention focus and cue.

The cat's response to visual difference targets in figure-ground and figure-figure arrays (a unique target figure in a field of contrasting identical figures) was studied. Subjects approached the targets of the figure-ground arrays readily when they were presented in a training series, learning to use them as cues to the location of a food reward, and showing no disturbance when stimulus aspects of the arrays were reversed. Response to the figure-figure targets during training was more variable. Some were approached promptly, but others, especially those involving interchanging of target and background elements, required considerable training before consistent approach was achieved. Subjects selected the target with significant frequency in test series with novel figure-ground arrays, even after only brief training; they did not, however, select the target in novel figure-figure arrays until they had extended experience with training stimuli.