SOCIABILITY IMPULSIVITY AND ATTENUATED DOPAMINERGIC AROUSAL - CRITICAL FLICKER/FUSION FREQUENCY AND PROCEDURAL LEARNING/

Two experiments examined the interaction of sociability (Sec) and impu lsivity (Imp) components of extraversion and reduced dopamine activity (by haloperidol) on critical flicker/fusion frequency change scores ( Delta CFFT) and procedural learning. In double-blind designs, subjects received either haloperidol (5 mg) or placebo; Soc and Imp were rando mly sampled. In Experiment 1, Drug x Imp, and Drug x Imp x Soc interac tions were found on Delta CFFT; in Experiment 2, a drug x Soc interact ion was found on procedural learning. In both experiments, introverts seemed over-aroused under placebo (putatively due to the medical conte xt), more optimally aroused under haloperidol; for procedural learning , extraverts seemed more optimally aroused under placebo, less optimal ly aroused under haloperidol. These data indicate that both Soc and Im p mediate the effects of arousal; Drug x Imp effects my conceal joint effects of Soc x Imp; and that Soc shows more consistent effects than Imp. These data complement a previous study of Soc/Imp and caffeine-in duced arousal (Corr, Pickering & Gray, 1995), and lend support to H. J . Eysenck's (1967) arousal model of Extraversion. (C) 1997 Elsevier Sc ience Ltd.