Eye Movements of Monkeys During Learning-Set Formation

Abstract

Eye movements of stump-tailed monkeys were measured during learning of a long series of two-choice pattern discrimination problems. The amount of scanning per trial (shifts in visual fixation from one pattern to the other) and the duration of individual fixations on the patterns increased during the course of learning-set formation and (except for the amount of scanning by some animals) remained high during the prolonged training following learning-set formation. Some of the changes in eye movements were different from those seen during the learning of single discrimination problems, a difference that possibly reflects cognitive processes specific to the learning-set task.

Eye movements of stumptailed monkeys during discrimination learning: VTE revisited

“…None of the hypotheses mentioned so far appears to provide a very satisfactory explanation of the results and, hence, we are tempted to look further .2 In line with recent trends in interpretation of results of studies of eye movements of humans (Rayner, 1978;Senders, Fisher, & Monty, 1978) as weIl as of monkeys (Geary & Schrier, 1975;Schrier & Povar, 1978), a promising avenue of approach would seem to be to view the changes in ocular observing as a function of practice as representing, at least in part, changes in information processing strategies. For example, the changes seen in the present work could reflect processes similar to those hypothesized by Nodine and Simmons (1974) to account for differences in amount of scanning by children of different ages who were discriminating between letter-like visual patterns.…”

“…On the other hand, contrary to what might have been expected on the basis of results for VTE, there was no clear-cut relations hip between amount of scanning and speed or asymptotic level of learning. There has, in addition, been little indication of a relationship between the two in our previous work (Schrier & Povar, 1978). How might the obtained pattern of change in amount of scanning be explained?…”

“…One was closed vs. open square (squares problem), the sides of each of which were approximately 3 mm (visual angle approximately 34'). The other problem consisted of a pair of irregular patterns of seven dots selected from the set used by Schrier and Povar (1978).…”

“…The former is a much more accurate measure of VTE than were those in the earlier studies on the question. Duration of individual observing responses has been given almost no attention in the previous literature, although we have found it to be sensitive to a number of variables that either do not influence frequency of scanning or influence it in a different manner (Geary & Schrier, 1975;Schrier & Povar, 1978).…”

“…Duration of the last fixation on a discriminative stimulus during a trial showed similar, though not identical, changes with practice. The decrease in duration of the last fixation following learning contrasts with results of prior studies involving more complex tasks, and supports our conclusion that the duration of the last fixation is particularly sensitive to the cognitive processing requirements of the discriminative task.During the past several years, our laboratory has reported a variety of changes in the ocular observing behavior (that is, number and duration of eye fixations) of monkeys during brightness discrimination revers al learning (Schrier & Wing, 1973), du ring the learning of aseries of color and form discrimination problems involving reversal and nonreversal shifts (Schrier & Vaughan, 1973), during learning-set formation over the course of a long series of dot-pattern discrimination problems (Schrier & Povar, 1978), and as a function of problem complexity (Geary & Schrier, 1975). We have not yet explored systematically the changes in ocular observing behavior during the original learning of single, simple discrimination problems, although a number of questions have arisen about such changes in the course of our own prior work as weIl as related work by others.…”