KOHLBERG'S THEORY OF MORAL DEVELOPMENT: CRITICAL ANALYSIS OF VALIDATION STUDIES WITH THE DEFINING ISSUES TEST

This paper evaluates studies that have used the Defining Issues Test for validating Kohlberg's theory of moral stage development. Although this test was introduced to overcome inadequacies with Kohlberg's procedure, it too encounters serious methodological and conceptual difficulties. Its limitations include truncation of the stages and age range assessed. The validation studies, both cross-sectional and longitudinal, have used a correlational design and confounded age with other variables. Threats to internal and external validity obviate support claimed for Kohlberg; moral reasoning thus measured seems a function of education, IQ, direct moral training, and cultural values rather than maturation. Nor is the stage model upheld by longitudinal data, which fail to reveal sequential stepwise change and belie occasional regression. Attempted redefinition of the stage concept to salvage these data has not rescued Kohlberg's proposal, which remains to be validated empirically.     

Rate-change effects with equal potential reinforcements during the “warning” stimulus

Two pre-schedule-change stimuli were superimposed on the same VI baseline and were thereby equated with respect to reinforcement potential. One such stimulus preceded a transition to an extinction schedule or a VI schedule of lower reinforcement frequency while the other preceded a transition to a VI schedule of higher reinforcement frequency. It was found that response rate during the warning stimulus was greater preceding the transition to the lower reinforcement frequency than it was preceding the transition to the higher reinforcement frequency. That difference was often evidenced by an absolute increase and decrease in rate, in conformity with previous findings on the topic. The present experiment extends previous findings in several ways, including the presentation of quantitative estimates of the effects.     

Free-operant compounding of variable-interval and low-rate discriminative stimuli

Four rats were trained on a schedule containing stimuli associated with variable-interval 30-sec and differential-reinforcement-of-low-rate 20-sec schedules of reinforcement. Subsequently, a stimulus compounding test was administered that included individual presentations of two intensities of each stimulus plus compounds of these stimuli. In training, extremely high rates were emitted to the variable-interval stimulus, and very low rates to the differential-reinforcement-of-low-rate stimulus. Compounding the two training stimuli always produced an overall response rate intermediate between the rates controlled by the two stimuli separately presented. Essentially the same relationship held with different stimulus intensities. These results resolve the confounding of response and reinforcement variables present in previous conditioning studies reporting response averaging. They are discussed in terms of the incompatibility of the response chains associated with the individual stimuli compounded.     

Magnitude estimates of distance based on object-size

At a fixed distance of 1.5 ft., varying sizes of vertical lines or circles were presented to S.Subjects estimated either apparent size or distance based on relative size. Estimates of line height and circle diameter yielded power functions with exponents of 0.97 and 0.98, respectively. Distance estimates were curvilinearly related to distance predicted from the size/distance ratio. This result is discussed in terms of non-Euclidean space and in relation to the nature of the judgmental task.