Differences in the transmission of sensory input into motor output between introverts and extraverts: Behavioral and psychophysiological analyses.
The present study was designed to investigate extraversion-related individual differences in the speed of transmission of sensory input into motor output. In a sample of 16 introverted and 16 extraverted female volunteers, event-related potentials, lateralized readiness potentials (LRPs), and electromyogram (EMG) were recorded as participants performed a visual choice reaction time task. As additional behavioral indicators of performance, measures of reaction time (RT) and response dynamics were obtained. Although extraversion-related differences were found neither for behavioral measures nor for the N1 and P3 components of the evoked potential, introverts showed a reliably shorter latency in stimulus-locked LRP than extraverts. This latter finding supports the notion of faster stimulus analysis in introverts compared to extraverts. Furthermore, there was no indication of extraversion-related individual differences in speed of response organization and response execution as indicated by response-locked LRP and EMG latencies, respectively. However, a significantly higher EMG amplitude observed with introverts pointed to a less accurately adjusted motor output system of introverts compared to extraverts.
Stahl
Jutta
J
Georg Elias Müller Institute for Psychology, University of Göttingen, Göttingen, Germany. jstahl@uni-goettingen.de
Rammsayer
Thomas
T
D000328:Adult; D003265:Contingent Negative Variation / Q000502:physiology; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005120:Extraversion, Psychological; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007439:Introversion, Psychological; D009068:Movement / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values; D011984:Sensory Receptor Cells / Q000502:physiology*