Research On Social Stress Response And Autonomic Nervous Regulation Mechanism Of Individuals With Positive Personality Traits

Personality trait is important to individuals' social adaptation, mental and physical health. It is the important basis in explaining individual difference in psychophysiological response to stress, In the past, influenced by negative psychology, a lot of research focused on dysfunctional personality trait' psychophysiological response characteristics to stress and its pathogenesis. Recently, with the rise of positive psychology, personality research has gradually turned to the benign function of personality. Studies have found the promoting effect of benign function of personality to adaption and physical and mental health. However, it remains lack of studies to explore what is the neurophysiological mechanism of benign functioned personality in promoting individual social adaptation and in protecting physical and mental health. Based on the theory of big five personality, the present study proposed "positive personality trait" concept according to benign function of personality. Positive personality trait refers to the more adaptively and health protection personality characteristics, and high extroversion, low neuroticism, high openness, high conscientiousness, and high agreeableness of big five personality model were defined as positive personality traits. Based on previous studies, the present study adopted psychophysiological research method, with college students as participants, through five studies to systematically examine positive personality trait individuals' psychophysiological response to social stress, psychophysiological recovery after stress, psychophysiological habituation in facing repeated stress, and the autonomic nervous regulation mechanism throughout the stress stages.Study1showed that in social stress, compared with neutral group and low extraversion group, high extraversion group had relatively lower anxiety, heart rate and systolic blood pressure reactivity, and relatively faster anxiety, heart rate and systolic blood pressure response recovery. During the whole stress stages, high extraversion group had relatively lower vagal withdrawal reactivity and relatively faster vagal response recovery. When repeatedly exposed to social stress, there were no significant differences of psychological and physiological response adaptation among groups with high extraversion, neutral and low extraversion.Study2showed that in social stress, compared with neutral group and high neuroticism group, low neuroticism group had relatively lower heart rate and systolic blood pressure reactivity, and relatively faster heart rate and systolic blood pressure response recovery. During the whole stress stages, low neuroticism group had relatively lower vagal withdrawal reactivity and relatively faster vagal response recovery. When repeatedly exposed to social stress, there were no significant differences of psychological and physiological response adaptation among groups with low neuroticism, neutral and high neuroticism.Study3showed that in social stress, compared with low openness group, high openness group had relatively lower heart rate and systolic blood pressure reactivity, and relatively faster heart rate and systolic blood pressure response recovery. During the whole stress stages, high openness group had relatively lower vagal withdrawal reactivity and relatively faster vagal response recovery. When repeatedly exposed to social stress, there were no significant differences of psychological and physiological response adaptation among groups with high openness, neutral and low openness.Study4showed that in social stress, compared with low conscientiousness group, high conscientiousness group had relatively lower heart rate reactivity, and relatively faster heart rate response recovery. During the whole stress stages, there were no significant differences of vagal changes among groups with high conscientiousness, neutral and low conscientiousness. When repeatedly exposed to social stress, there were no significant differences of psychological and physiological response adaptation among groups with high conscientiousness, neutral and low conscientiousness.Study5showed that in social stress, there were no significant differences among high agreeableness group, neutral group, and low agreeableness group in psychological and physiological response to stress, psychological and physiological response recovery after stress, psychological and physiological response adaptation to repeated social stress or autonomic nervous regulation changes throughout the stress stages. It indicated that there were no typical psychological and physiological stress response patterns of individuals with high agreeableness.Taken together, all the five studies reveals that individuals with positive personality trait (high extraversion, low neuroticism, or high openness) have unique psychophysiological changing characteristics in social stress. They had relatively lower physiological stress reactivity in facing social stress and relatively faster physiological response recovery after the stress, their autonomic nervous regulation mechanism were relatively lower vagal withdrawal reactivity and relatively faster vagal response recovery. It indicates that individuals with positive personality trait have better physiological flexibility and better ability to maintain homeostasis during social stress. The flexible model of physiological changes and better autonomic nervous regulation might be the internal neurophysiological mechanisms that positive personality trait protects health under stress. There were no significant differences between positive personality group and other personality groups in psychological and physiological stress response adaptation in the repeated social stress. It indicates that the psychological and physiological stress response adaption in repeated social stress might not be the important aspect of the mechanisms that positive personality trait protects physical and mental health under stress.