Some effects of reward on the strength of position stereotypes in the white rat

Certain aspects of Maier's hypothesis that rigid behaviour stereotypes elicited in an insoluble problem situation are not explicable in terms of goal-motivated learning were tested thus: Forty-one white rats of Wistar stock were exposed to an insoluble problem in a water discrimination unit. Each of the twenty-four animals who formed position stereotypes was assigned to one of four groups. One of these groups served as a control and received no special treatment. Each of the remaining three experimental groups was given a different number of successively rewarded trials to the side of the stereotype. Finally, all groups were presented with a soluble problem, and the strengths of the stereotypes in each group observed in terms of the breaking of the stereotypes.

It was found that the strength of the stereotype behaviour was directly proportional to the number of rewarded trials. None of the stereotypes was sufficiently rigid to meet Maier's criterion of “fixated” response patterns. More stereotypes were formed by males than females. On the other hand no sex differences appeared in the subsequent behaviour of animals who did form stereotypes.

These results are interpreted as showing that stereotyped responses formed under conditions of the present experiment are not qualitatively different from learned responses.