1.How Much We Think of Ourselves and How Little We Think of Others: An Investigation of the Neuronal Signature of Self-Consciousness between Different Personality Traits through an Event-Related Potential Study
Auwal Bello Hassan ; Tahamina Begum ; Mohammed Faruque Reza ; Nasir Yusoff
Malaysian Journal of Medical Sciences 2016;23(6):70-82
Background: Previous studies have revealed that self-related tasks (items) receive more
attention than non-self-related, and that they elicit event-related potential (ERP) components
with larger amplitudes. Since personality has been reported as one of the biological correlates
influencing these components, as well as our behavioural differences, it is important to examine
how it affects our self-consciousness in relation to tasks of varied relevance and the neurological
basis.
Methods: A total of 33 male and female undergraduate Malaysian medical students of
Universiti Sains Malaysia (USM) participated in the study. The participants were divided into two
groups, Ambivert (n = 18) and Extravert (n = 15) groups, using the USM personality inventory
questionnaire. In the ERP experiment, squares containing standard stimuli of any word other
than self and non-self-related nouns (e.g., Bola, Gigi, Anak, etc.; in English: Ball, Teeth, Kids, etc.,
respectively), those containing self-related pronouns (Saya, Kami or Kita; in English: I, Us or We,
respectively), and non-self-related pronouns (Dia, Anda or Mereka; in English: He/She, You or
They, respectively), were shown 58%, 21% and 21% of the time, respectively, in a three-stimulus
visual oddball paradigm. All words were presented in Bahasa Melayu. The participants were
instructed to press 1 for self and 2 for non-self, and ignore standard stimuli.
Results: Comparison of both N200 and P300 amplitudes for self-related and non-selfrelated
pronouns in the Extravert group revealed significant differences at seven electrode sites,
with self-related having larger amplitude at anterior electrodes and less at posterior. This was not
seen in the Ambivert group.
Conclusion: The present study suggests that self-relevant pronouns are psychologically
more important to extraverts than to ambiverts; hence, they have more self-awareness. This may
be due to large amount of dopamine in the brains of extraverts, which is more concentrated in the
frontal lobe.