Personality and temperament in the event-related potentials during stimulus recognition tasks

Abstract

Visual event-related potentials (ERPs) were recorded from 60 women during a stressless (No-stress) and a stressful (Stress) stimulus recognition task. The task employed differed from simple reaction time (RT) tasks especially with regard to processing and attention demands. In the No-stress condition the subject was required to determine as quickly and accurately as possible whether a ‘complex’ probe, presented for 120 msec, was identical or not to one of two distinct memory items, presented at the onset of each trial. In the Stress condition the subject was advised that in some trials she might receive one unforeseeable electric shock. The following electrocortical and behavioural measures were obtained: (1) N1, P2, N2, P3 and N4 peak amplitudes in the ERP response; (2) RT scores, orthogonal personality dimensions of Anxiety, Venturesomeness, and Strength of Inhibition were derived from a joint analysis of the following questionnaires: (1) Eysenck Personality Questionnaire; (2) Strelau Temperament Inventory; and (3) Sensation Seeking Scale. Principal component analyses of ERP peak amplitudes evidenced four reproducible factors between the two experimental conditions. The reduction of ERP peak amplitudes to 4 factors enabled the relationships with personality variables to be re-analysed. A 3-factor solution revealed some relationships with personality and temperamental variables. In parallel with results from direct correlations, factor 1 loaded with positive Strength of Excitation (SE) and with positive ‘Anterior-Posterior N4’ and ‘Posterior-Occipital N4’ peaks for both the No-stress and Stress conditrions. Factor 2 loaded with negative Extroversion, negative Thrill and Adventure Seeking, positive ‘Anterior P2 and N2’ peaks amplitude and with ‘Left Posterior-Occipital P2’ peak. Factor 3 loaded with positive Disinhibition (Dis), Boredom Susceptibility, Experience Seeking, ‘Left Posterior-Occipital P2’ both in No-stress and in stress conditions. Separate analyses of variance evidenced greater ‘Left Posterior-Occipital P2’ peak amplitudes as compared to extraverts in No-stress condition. High Dis subjects displayed greater ‘Left Posterior-Occipital P2’ peaks than low Dis subjects in both experimental conditions. High SE subjects showed shorter reaction times than low SE subjects.