Effect of amount of incentive on discrimination learning by monkeys.

Abstract

Eight Java monkeys (Macaca cynamolgus) were trained on a long series of ten-trial, planometric discrimination problems, with the amount of food incentive and problem difficulty (in terms of the percentage of differentially colored area of the stimulus cards) varied from problem to problem. Both incentive amount and problem difficulty were found to be positively related to learning efficiency and their effects on performance persisted over a period of six months. Over-all performance was also analyzed in terms of error-producing factors and the relationship between these factors and incentive amount is discussed.