Interresponse-time analysis of stimulus control in multiple schedules

Interresponse times and the structure of choice

This paper presents some analyses of available data on interresponse-time emission on concurrent variable-interval schedules arranged either continuously or as discrete components, and in which either reinforcer rates or magnitudes were varied. Ratios of frequencies of interresponse times in a series of temporal bins varied in their sensitivity to reinforcement: Sensitivity values were least for interresponse times around 0.2-0.4s, were higher in the region 0-0.2s, and were highest at values greater than 0.4s. Relative frequencies of interresponse times were greatest around 0.2-1.6s. As a result, time allocation to alternatives were mainly determined by IRTs between 0.8 and 6.4s, and least by IRTs less than 0.8s. If inter-bout times reflect time allocation to unmeasured responses, then time spent emitting unmeasured behavior may be the main constituent of time allocation on concurrent schedules. An analysis of log survivor plots supported this suggestion, and further suggested that a full understanding of time allocation in choice requires accepting that unmeasured responses do not result from a unitary process, but from many disparate contributing processes. These other behaviors can be revealed through Gaussian log-normal analyses of interresponse-time distributions.

From molecular to molar: a paradigm shift in behavior analysis

A paradigm clash is occurring within behavior analysis. In the older paradigm, the molecular view, behavior consists of momentary or discrete responses that constitute instances of classes. Variation in response rate reflects variation in the strength or probability of the response class. The newer paradigm, the molar view, sees behavior as composed of activities that take up varying amounts of time. Whereas the molecular view takes response rate and choice to be "derived" measures and hence abstractions, the molar view takes response rate and choice to be concrete temporally extended behavioral allocations and regards momentary "responses" as abstractions. Research findings that point to variation in tempo, asymmetry in concurrent performance, and paradoxical resistance to change are readily interpretable when seen in the light of reinforcement and stimulus control of extended behavioral allocations or activities. Seen in the light of the ontological distinction between classes and individuals, extended behavioral allocations, like species in evolutionary taxonomy, constitute individuals, entities that change without changing their identity. Seeing allocations as individuals implies that less extended activities constitute parts of larger wholes rather than instances of classes. Both laboratory research and everyday behavior are explained plausibly in the light of concrete extended activities and their nesting. The molecular- view, because it requires discrete responses and contiguous events, relies on hypothetical stimuli and consequences to account for the same phenomena. One may prefer the molar view on grounds of elegance, integrative power, and plausibility.

Action at a temporal distance: Component transition as the relational basis for successive discrimination

In a successive discrimination, red and green hues signaled component variable-interval schedules. The exponent of the power function relating ratios of responses in the red and green components to ratios of reinforcers provided a reinforcement-free measure of discrimination or stimulus control. Responses were recorded in successive 10-s subintervals of the 50-s components. The power-function exponent decreased systematically with increasing time since component transition in most conditions of five experiments. This reduction was not influenced by the absolute rate of reinforcement, consistent with the interpretation of the exponent as a measure of stimulus control. A reduction in the overall level of stimulus control by increasing the duration of response-produced keylight offset did not influence the decrease in discrimination with increasing time since component transition. The results support the conclusion that discriminative responding in successive discriminations is governed by several sources of stimulus control including delayed control by component transition.

Delayed and current stimulus control in successive discriminations

In a successive discrimination in which successively alternating red and green hues signaled component variable-interval schedules, sensitivity of the ratio of responses in the two components to variation in the component reinforcer ratio decreased systematically during the course of the component. This decrease in stimulus control or discrimination over the course of the component was shown to be the result of delayed control of responding during the component by the stimulus transition between components. When the red-green stimulus transition was altered by interpolating a white stimulus at the end of each 60-s component, discrimination at the beginning of the component (measured by the power-function exponent for sensitivity to reinforcement) was reduced. Conditions with the white stimulus inserted in other quarters of the component indicated that the current discriminative stimulus exerts control over responding throughout the component, whereas during about the first half of the component, response differentials are influenced by the transition between discriminative stimuli.