Psychophysiological correlates of conflict solving and cigarette smoking

Twenty-eight subjects participated in three sessions which involved three successive rows of STROOP stimuli presented in a spaced trial technique. The first session was a training session, and in the second and third sessions the subjects had to smoke in balanced sequence a 0.2 mg and a 1.2 mg nicotine cigarette between the second and third rows of STROOP stimuli. For these two smoking sessions these experimental subjects were compared with a yoked-control group which attended the task passively without responding to the stimuli but also had to smoke a 1.2 mg nicotine cigarette. Continuous psychophysiological recording showed: (a) Before smoking the heart rates were lower in the yoked than in the experimental subjects. (b) A gradual but modest habituation of intrasession heart rate and EEG measures developed in all experimental groups. (c) Pronounced skin conductance and vasoconstrictive responses to the STROOP stimuli persisted in the experimental groups without any tendency to habituate and without modification by smoking. (d) Significant smoking-induced tachycardia and cutaneous vasoconstriction were seen in the yoked subjects only. Behaviorally, puffing style of smoking was intensified in the experimental group as opposed to the yoked group, and smoking neither impaired nor improved STROOP performance.