Abstract:
The effectiveness of a reinforcer's control over an individual's behavior typically depends upon the contextual features of stimulus provision. The manipulation of these features may enhance or attenuate the effectiveness of the reinforcer being presented. The reinforcer which is being
studied as a function of the manipulation of contextual features is referred to as the focal stimulus (Gewirtz,1972). Contextual qualifiers may operate concurrently or
prior to the presentation of such a focal stimulus. Some contextual qualifiers of reinforcer efficacy may readily be interpretable as outcomes of learning, while others may have nothing to do with learning. Both sources of qualifiers may exist simultaneously and interact, the effect of the interaction possibly depending upon some other contextual condition. In general, stimulus functioning may also be affected by the presentation of contextual stimuli during a preliminary condition whether or not the stimuli presented and the focal stimulus are the same. Examples of preceding qualifiers include the conditioned value of a particular focal stimulus source, stimulus deprivation-satiation operations, and the delay between the preliminary condition and the criterion task. This dissertation sought to add relevant data about the effect of two contextual conditions on the effectiveness of an adult's approval in maintaining marble dropping behavior by preschoolers: (a) the frequency of preceding disapproving statements and (b) the delay-interval between the preliminary condition and the criterion task.
