Effects of intertrial interval and Trial 1 reward during acquisition of an object-discrimination learning set in monkeys.

Abstract

Gave 10 female rhesus monkeys a series of 720 2-trial object-discrimination problems. Each problem involved presentation of 1 object on Trial 1, which was either rewarded or not rewarded, an ITI of 5, 10, or 20 sec., and presentation of the Trial 1 object along with a 2nd object on Trial 2. The ITI duration had no effect upon performance during the initial stages of training for object-discrimination learning set (ODLS), but an effect was apparent during the later stages of training, when Trial 2 performance decreased as a function of increased ITI. Better Trial 2 performance followed a nonrewarded Trial 1 response at all stages of ODLS acquisition, but the difference decreased during the later stages of training. The ITI duration and Trial 1 reward and nonreward did not interact to affect performance at any stage of ODLS acquisition. Findings are discussed in terms of D. W. Bessemer's short-term memory analysis of learning sets. (15 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)