Publication Date


Document Type


First Advisor

Pielstick, Norval L.||Woodruff, Arnold Bond, 1920-

Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Psychology


Mentally handicapped; Motivation (Psychology); Rewards and punishments in education


A wealth of information is available supporting the Hullian principle which states that "reaction potential" is a function of the quantity of an incentive. That is, as more of an incentive becomes available, the increase in the magnitude of the reward will bring a corresponding increase in the amount of effort the subject will expend to obtain it. This has been reliably demonstrated in lower animals and also in normal human subjects. Several attempts have been made to demonstrate this phenomenon in retardates, but have met with little success. The purpose of the present research was to investigate this principle as well as that of reward value in retardates (reward value as used here included quantitative differences). This was accomplished in three phases; Phase I, mental age testing; Phase II, pair comparisons testing; and Phase III, maze testing. In Phase I, a sufficient number of subjects were tested with the Peabody Picture Vocabularly Test so that two groups of 60 subjects each, differing in mental age by two years, but having comparable chronological ages, could be formed. In Phase II, ten items or quantities of items were presented in all possible pairs. This data was then scaled using Guilford’s Case V solution for pair comparisons. It was found that retardates were able to reliably indicate differences in magnitude among the items used and that mental age, chronological age and length of institutionalization had no significant affect on the preferences reflected by the scaled items. From the scales constructed in Phase II, the most preferred item (billfold) and the least preferred item (one M & M candy) were used as incentives in the learning situation of Phase III. It was found that the difference in reward value between these two items was sufficient to produce a change in performance such that the subjects worked significantly harder for the most preferred item. It was also found that this effect was magnified over trials. Mental age, chronological age and length of institutionalization had little influence on performance.


Includes bibliographical references.||Includes illustrations.


ii, 55 pages




Northern Illinois University

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