Aversive functions of response effort: Fact or artifact?

Abstract

Historically, effort has been viewed as aversive. Most supporting evidence comes from studies demonstrating increased force/effort requirements reduce operant responding. Changes in force/effort requirements, however, are often accompanied by changes in response definition when mechanical devices are used to define the response. As a consequence, responses measured at one point in a study may go unmeasured at other points. In an alternative approach, we used a continuous measurement strategy that provided a means to fix the threshold force defining the response class and simultaneously allowed independent manipulation of the force criteria required to produce reinforcement. Rats pressed a force transducer according to a fixed-ratio 5 schedule of food delivery. The criterion force was systematically increased and decreased; the threshold for response detection was constant. When response rates included only criterion responses, overall rate decreased when force requirements increased. By contrast, when all responses, both those meeting force criteria and those that did not (above the threshold but below the criteria for reinforcement) were included in the rate calculation, increases in force increased response rate. Increases in force criteria also increased the maximum force (g) and time-integral of force (g-s) of operant behavior. Control conditions showed increases in responding could be explained by the emergence of subcriterion responses, irrespective of force. We conclude that prior results showing effort decreases response rates are due to an artifact arising from inadvertent changes in response definitions. Increases in effort may better be understood as changes in the response:reinforcer payoff owing to the emergence of a subcriterion response class.

Toward accurate inferences of response class membership

“…However, we also observed unreinforced responses that produced longer latencies to the target behavior (see bottom panel of Figure ). Responses that fall above the threshold but below criterion have been referred to as subcriterion responses (Pinkston & Libman, ). The implication for applied work is that rates of target behaviors may often be an artifact of the criterion.…”

The role of response force on the persistence and structure of behavior during extinction

“…Bands limits were informed by our previous work on force. We have found that responding can be maintained within the range of 5 – 80 g. Increasing the force beyond that range results in unreliable responding and forces in excess of 100 g has eliminated responding in every rat we have studied (e.g., Pinkston & Libman, ). Thus, the span of the bands cover the range of forces where responding can be sustained reliably.…”

“…Recently, our lab examined force distributions maintained by fixed‐ratio schedules (Pinkston & Libman, ). An analysis of the distributions showed relatively consistent coefficients of variation as force requirements increased, indicating force production obeys Weber's Law.…”

A Review of Recent Research on the Manipulation of Response Effort in Applied Behavior Analysis

“…Although basic research has suggested that participants generally prefer low effort to high effort conditions (Perone & Baron, 1980), and that increased effort requirements generally reduce responding (Chung, 1965), more recent data suggest that increased effort may not be as aversive as previously thought. Pinkston and Libman (2017) note that most basic research on effort has employed levers with minimum response forces. For example, a lever with a minimum force of 20 g can only be depressed when at least 20 g of force is applied.…”