Laboratory measurement of adaptive behavior change in humans with a history of substance dependence

Individuals vary in their ability to adapt to changes in environmental conditions. In the present study, two laboratory experiments investigated components of adaptation in subjects with and without a history of substance dependence. In each of two experiments, the subjects were exposed to conditions that required changing response patterns between experimental days. On day 1, subjects earned monetary rewards under conditions that produced high rate responding, but on day 2 were required to wait 10 s between each response. Collectively, the two experiments demonstrated that the subjects meeting criteria for past substance dependence, and having extensive histories of substance use (> 10 years), adjusted poorly to the transition. In both studies, these subjects tended to persevere on the previously established high-rate response pattern. These data suggest a deficiency in adaptive behavior change, particularly when that change requires an abrupt slowing of response rates following a brief history of high-rate responding.