Monkeys' Solution of an Ambiguous-Cue Problem

Abstract

In a WGTA situation 12 monkeys were trained on a 2-choice discrimination task involving 3 stimuli: P, the consistently rewarded stimulus; N, the consistently nonrewarded stimulus; and A, the stimulus ambiguously rewarded depending upon whether it was paired with either P or N on a particular trial. Trials were either of the PA or NA type, and 6 Ss received a random schedule of such trials throughout 12 sessions while 6 Ss received a schedule designed to gradually introduce the two types of trials. The results unambiguously demonstrated that regardless of training method Ss were correct more often on the PA trial. Confirming and extending previous research, these data were interpreted in terms of parallel development of excitatory and inhibitory processes.