Abstract

Pigeons were rewarded alternately for pecking when a red bulb was lit but not when a blue bulb was lit and then for pecking when a blue bulb was lit but not when a red bulb was lit. It has been shown that repeated rewards when the red bulb was lit led to greater frequency of pecking in the presence of the red light compared to that in the presence of the blue light, even when rewards were not given temporarily in the presence of either light. Conversely, repeated rewards in the presence of the blue key led to greater frequency of pecking the blue key as compared to the frequency of pecking the red key.

No effect of scopolamine was found on either the development ("learning") of the discrimination or its retention ("memory") although the scopolamine was given in sufficient dosage to interfere with learned performance. The suggestion is made that effects of drugs on behavior may be due predominantly to effects on learned patterns of behavior rather than to effects on "processes of learning".