Explicit knowledge of stimulus-outcome contingencies and stimulus control of selective attention and instrumental action in human smoking behaviour

Rationale: External stimuli (S+) that reliably signal that addictive drugs are available command the focus of selective attention and control instrumental action that procures the drug. According to incentive salience theory, as the contingency between the S+ and the drug is learned the magnitude of attentional orienting towards the S+ increases. By contrast, alternative theories propose that processing of the S+ becomes more efficient with training such that the measured attentional orienting response elicited by the S+ decreases. Objectives: The aim of the present study was to prompt half of participants to acquire explicit knowledge of the stimulus-reinforcer contingencies arranged in training, to examine the impact of this manipulation on the magnitude of attentional orienting towards the S+. Methods: Smokers (n=32) completed an instrumental discrimination training procedure in which a set of stimuli were established as differential predictors that an instrumental response would yield tobacco-smoke reinforcement. During training, attention for the stimuli and performance of the instrumental tobacco-seeking response were measured in parallel. One group (n=16) was prompted to develop explicit knowledge of the discriminative contingencies in training whereas another group (n=16) underwent discrimination training without prompting. Results: The prompted group reported accurate knowledge of the contingencies and showed no attentional orienting response towards the S+. By contrast, the unprompted group reported inaccurate knowledge of the contingencies and showed an attentional orienting response towards the S+. The S+ appeared to control the instrumental tobacco-seeking response in both groups equally. Conclusions: The results suggest that attention for drug paired S+ is associated with the process of learning about the relationship between those cues and the drug.