Dopamine Modulation of Individual Differences in Openness to Experience

Abstract

Individual differences in openness to experience have been theoretically linked to functions of the neuromodulator dopamine. Although a few trait characteristics have been connected to dopamine activity, causal connections with the broad domain still lack empirical evidence. In preparation for the first study, I developed a novel perceptual paradigm to examine the hypothesized association between openness and anticipation- related states with frontal EEG alpha asymmetry. The results yielded a main effect of state curiosity on left-lateralized activation and an interaction between openness and self- reported confidence, indicating that openness might explain individual differences in the responsiveness to perceptual uncertainty. The second study was conducted to directly assess the influence of dopamine on divergent thinking, a behavioral correlate of openness to experience. For this purpose, the dopamine receptor blocker sulpiride was administered in a placebo-controlled between-subjects design. The data yielded an interaction between openness to experience and substance group, indicating that the dopamine manipulation selectively affected divergent thinking as a function of openness to experience. The results provide novel empirical evidence for an association between dopamine activity and both openness to experience and divergent thinking. Performed in the same pharmacological design, the third study was conducted to assess the influence of dopamine activity on the relationship between openness and implicit learning. The hypothesized interaction between implicit learning and substance group, however, failed to reach statistical significance. In summary, evidence for the initial hypotheses was found in two of three studies. Implications of the present findings are discussed along with methodological considerations and future directions.