Discriminative stimuli that control instrumental tobacco-seeking by human smokers also command selective attention

Rationale. Incentive salience theory states that acquired bias in selective attention for stimuli associated with tobacco-smoke reinforcement controls the selective performance of tobacco-seeking and tobacco-taking behaviour. Objectives. To support this theory, we assessed whether a stimulus that had acquired control of a tobacco-seeking response in a discrimination procedure would command the focus of visual attention in a subsequent test phase. Methods. Smokers received discrimination training in which an instrumental key-press response was followed by tobacco-smoke reinforcement when one visual discriminative stimulus (S+) was present, but not when another stimulus (S-) was present. The skin conductance response to the S+ and S- assessed whether Pavlovian conditioning to the S+ had taken place. In a subsequent test phase, the S+ and S- were presented in the dot-probe task and the allocation of the focus of visual attention to these stimuli was measured. Results. Participants learned to perform the instrumental tobacco-seeking response selectively in the presence of the S+ relative to the S-, and showed a greater skin conductance response to the S+ than the S-. In the subsequent test phase, participants allocated the focus of visual attention to the S+ in preference to the S-. Correlation analysis revealed that the visual attentional bias for the S+ was positively associated with the number of times the S+ had been paired with tobacco-smoke in training, the skin conductance response to the S+ and with subjective craving to smoke. Furthermore, increased exposure to tobacco-smoke in the natural environment was associated with reduced discrimination learning. Conclusions. These data demonstrate that discriminative stimuli that signal that tobacco-smoke reinforcement is available acquire the capacity to command selective attentional and elicit instrumental tobacco-seeking behaviour.