Eye movements of monkeys during performance of ambiguous cue problems

Abstract

Eye movements of four stumptailed monkeys were measured during performance of simple and ambiguous form discriminations. Duration of fixations increased during learning of the simple discrimination, whereas the number of shifts in fixation from one stimulus to the other (scanning) increased and subsequently decreased. The asymptotic levels of scanning in both simple and ambiguous discriminations were consistent with predictions generated by a minimum frequency of observing hypothesis. Duration of fixations other than the last fixation preceding the choice response did not change significantly during performance of an ambiguous cue problem in comparison with the simple discrimination, but duration of the last fixation increased significantly. This result was discussed in terms of altered information processing requirements.