Parietal EEG Theta/Beta Ratio as an Electrophysiological Marker for Extraversion-Related Differences

Abstract

Personality traits describe the typical behavior of a person. These traits are related to cognitive processing. While extraversion represents a Behavior Activation System (BAS), neuroticism is a part of the Behavior Inhibition System (BIS). Independence of these systems allows assuming the existence of several personality types with different Extraversion and Neuroticism scores. These traits are also related to monoaminergic systems functioning, differences in EEG alpha asymmetry, and attention control during processing of emotionally laden stimuli. However, personality traits-related EEG differences are not consistent within studies. To investigate these relationships between EEG waves and personality, a study with 235 participants was conducted. After fulfilling the EPI questionnaire, resting-state EEG with closed eyes was recorded. Attention control and dominance of subcortical processes were evaluated with theta/beta ration (TBR) and the delta/beta ratio (DBR). Cluster analysis revealed the existence of two personality types with high Extraversion and low Neuroticism, and low Extraversion and high Neuroticism. These clusters had a small difference in TBR in the right parietal lobe. Spearman correlation supported this finding, revealed a connection of Extraversion with higher TBR in all areas except lateral prefrontal lobe and DBR in the parietal lobe, and left medial areas. Due to this, existence in attention control between introverts and extraverts is concluded.