RESUMO
AIMS: Many forms of human conditioned behaviour depend upon explicit knowledge of the predictive contingency between stimuli, responses and the reinforcer. However, it remains uncertain whether the conditioning of three key behaviours in drug addiction-selective attention, instrumental drug-seeking behaviour and emotional state--are dependent upon contingency knowledge. To test this possibility, we employed an avoidance procedure to generate rapidly these three forms of conditioned behaviour without incurring the methodological problems of drug conditioning. DESIGN: In two experiments, participants (16 students) were trained on a schedule in which one stimulus (S +) predicted the occurrence of a startling noise, which could be cancelled by performing an instrumental avoidance response. MEASUREMENTS: The allocation of attention to the S + and the rate and probability of the avoidance response in the presence of S + were measured. Following training, participants were tested for their knowledge of the stimulus-noise contingencies arranged in the study and rated the emotional qualities of the stimuli. FINDINGS: Both experiments showed that S + gained control of selective attention, instrumental avoidance behaviour and subjective anxiety, but only in participants who reported explicit knowledge of the Pavlovian contingency between the S + and the startling noise. CONCLUSIONS: The implication of the present findings is that the control of selective attention, instrumental drug-seeking behaviour and emotional state by drug-paired stimuli is mediated by cognitive knowledge of the predictive contingency between the stimulus and the drug.
