ERP differences between processing of physical characteristics and personality attributes

Abstract

Background: Limited data from behavioral and brain-imaging studies indicate that personality traits and physical characteristics are processed differently by the brain. Additionally, electrophysiological results of studies comparing the processing of positive and negative words have produced mixed results. It is therefore not clear how physical and personality attributes with emotional valence (i.e., positive and negative valence) are processed. Thus, this study aimed to examine the neural activity associated with words describing personality traits and physical characteristics with positive or negative emotional valence using Event Related Potentials (ERPs).

Methods: A sample of 15 healthy adults (7 men, 8 women) participated in a computerized word categorization task. Participants were asked to categorize visual word stimuli as physical characteristics or personality traits, while ERPs were recorded synchronously.

Results: Behavioral reaction times to negative physical stimuli were shorter compared to negative personality words, however reaction times did not significantly differ for positive stimuli. Electrophysiological results showed that personality stimuli elicited larger P2 and LPC (Late Positive Component) amplitudes compared to physical stimuli, regardless of negative or positive valence. Moreover, negative as compared with positive stimuli elicited larger P2 and LPC amplitudes.

Conclusion: Personality and physical stimuli were processed differently regardless of positive or negative valence. These findings suggest that personality traits and physical characteristics are differentially classified and are associated with different motivational significance.

Figure 1

Reaction times of personality trait and physical characteristic words with positive and negative valences.

Figure 2

Grand average waveform of the stimulus-locked ERPs for P2 and LPC at F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, PO3, POz, PO4 for negative personality (thick solid lines), positive personality (thin solid lines), negative physical (thick dotted lines) and positive physical (thin dotted lines) words.

Figure 3

Top view of voltage distribution maps showing the whole brain activity about stimulus type (personality versus physical). a: the P2 voltage distribution at 192 ms at FCz. b: the LPC voltage distribution in the 400–700 ms at Pz.