Learning-Set Formations by Naive Rhesus Monkeys

Effects of differential pretraining on learning-set formation in rhesus monkeys.

“…Trial 2 win-stay responses began at a higher than chance level and by the end of 120 extended problems constituted 80% of such responses. This contrasts markedly with the failure of naive macaques in the McDowell et al (1965) study to show other than chance Trial 2 performance during 1,344 2-trial win-stay problems. One can only speculate why those animals failed to improve, but it is likely that they developed strong position habits.…”

“…The most straightforward way to accomplish this would be to train the WS group on a series of 2-trial problems in which the Trial 1 response to either object would be rewarded and Trial 2 reward would be obtained by responding to the same object responded to on Trial 1. However, naive monkeys failed to show any improvement on this task after 1,344 problems (McDowell, Gaylord, & Brown, 1965). The corresponding training for a hypothetical LS group would consist of training on a series of 2-trial problems, in which the Trial 1 response to either object would be nonrewarded and on Trial 2 reward would be obtained by responding to the object not responded to on Trial 1.…”

“…In order to increase the likelihood of learning by the WS group, the McDowell et al (1965) procedure was modified in the present experiment in 2 ways. First, problem length was increased from 2 trials to a maximum of 8, each problem continuing until an error was made, at which time the problem was terminated.…”