Biopsychological foundations of extraversion: Differential effort reactivity and state control

• Published in: Personality and individual differences 1997, Vol.22 (4), p.447-458
• Main Authors: Brocke, B., Tasche, K.G., Beauducel, A.
• Format: Article
• Language: English
• Subjects: Behavioral psychophysiology; Biological and medical sciences; Biopsychological aspects; Electrophysiology; Extraversion; Fundamental and applied biological sciences. Psychology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology
• ISSN: 0191-8869; 1873-3549
• DOI: 10.1016/S0191-8869(96)00226-7

The differential P300 effect, the larger P300 amplitude of introverts in vigilance and odd-ball tasks, is one of the limited number of replicable psychophysiological correlates of psychometric traits. We have demonstrated that this effect can be explained on the basis of the cognitive-energetical control theory of arousal, as a result of differential reactivity of the effort system in introverts and extraverts. However in most previous studies, the differential P300 effect has been shown for only one level of stimulation. A single level of stimulation can hardly be classified as ‘high’, ‘low’ or ‘medium’. At present, it seems more appropriate to compare different levels of stimulation and to classify one level as lower or higher than the other one. Therefore, studies with more than one level of stimulation in order to test comparative state hypotheses are lacking. In the present study we induced differential effort levels for introverts and extraverts via three levels of stimulation. Eighteen subjects who scored high or low on the extraversion scale of the Eysenck Personality Inventory (EPI) performed a 32-minute visual vigilance task under three different experimental conditions: without acoustic stimulation (baseline), with 40 db SPL and with 60 db SPL white noise. Besides a significant vigilance decrement for the performance measures, a theoretically predicted group × treatment interaction emerged for the P300 amplitude. Introverts showed larger P300 amplitudes in the baseline and 40 db condition, whereas extraverts have a larger P300 amplitude in the 60 db condition. The replication of the differential P300 effect and the predictable reversal of this effect under conditions with high stimulation, demonstrate the usefulness of the effort concept within the larger frame of the cognitive-energetical control theory of arousal.