Progressive reinforcement schedules (i.e. progressive ratio or interval schedules) have had limited use. What studies have been done show them to be valuable in testing perseverative hypotheses. Using these schedules the effects of variables that may affect perseveration, or persistence, of behaviour, can be assessed. Such variables are reinforcement magnitude, motivation conditions, and physiological manipulation using drugs, brain lesions and so on. Perseveration has been measured by the total number of responses or the size of the last completed ratio before responding becomes infrequent at the “break‐point”. Other dependent variables, such as the session time or the rate of responding may be used also to measure perseveration. The question of the criterion of the “break‐point” is discussed. The relationship between the different progressive schedules, the property of their aversiveness, the effects of various variables on them and the potential use of these schedules are discussed.

There is little empirical evidence for the prevention and treatment of PDM and the majority of published guidelines and studies focus on prescription opioids. Important limitations include the lack of information about appropriately identifying and managing persons at risk for PDM. More research is needed to identify and recommend effective mechanisms for the prevention and treatment of PDM.

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The frequency of the responses, i.e., squares entered (ambulation), rearing and grooming, were recorded over 30 min for saline, and 0.25, 1.0, 2.0 and 4.0 mg/kg scopolamine treated groups. Scopolamine produced an inverted U dose-response curve for ambulation, an increase in rearing but no effect on grooming. All three responses decreased over time; scopolamine did not attenuate this rate of habituation. There did appear a dose-related time effect. It was concluded that scopolamine may have different effects on various responses recorded simultaneously over a range of doses. The results when compared to other experiments emphasized the importance of environmental factors in determining drug effects on behaviour.

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