Comments on method and theory in drug discrimination: A potpourri of problems, perplexities, and possibilities

Abstract

AbstractThis paper focuses on how selected training variables may affect the nature of drug discrimination (DD) during generalization tests, specifically addressing the following issues: (1) the production and interpretation of intermediate drug‐lever responding in drug‐saline tasks, (2) how the complexity of the interoceptive stimulus and the nature of the reinforcing event may interact to influence generalization functions, and (3) the ways in which DD history can influence the pattern of generalization results. The analysis of these issues suggests that knowledge of the behavioral factors that are operative in DD tasks may be as critical as knowledge of the pharmacological action of the drugs themselves. First, the issue of quantal vs. continuous response distribution in DD experiments may be partially resolved by attending to how the response class alternates are defined and to whether the reinforcement schedule biases the animal toward an “all‐or‐none”, or maximization, strategy or toward a response mixing or matching strategy. Both strategies appear equivalently to map the drug stimulus dimension. Second, the baseline motivational state defined by the nature of the reinforcing event (e.g., appetitive or aversive) may influence the pattern or profile of drug‐stimuli generalization tests by altering the saliency of one set of effects produced by a given drug over other effects produced by that same drug. In essence, basal conditions can exert selective influence over which stimulus features acquire stimulus control. Finally, the applicability of the paradigms of latent inhibition, overshadowing, and blocking to DD may provide some useful insights into how drug stimuli provide information to the organism.