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Abstract
The purpose of this investigation was to examine the relationships among personality, affect and neuroendocrine arousal. It was hypothesized that individual differences in adrenal-medullary and adrenal-cortical responsivity to various stress and challenge situations can be predicted by the trait dimensions of Extraversion and Neuroticism, and their corresponding affect dimensions: Negative and Positive Affect.
Data for this study was obtained from a larger study examining the impact of aerobic exercise on neuroendocrine functioning. Only data from the pre-test lab sessions were used. Variables used in the analyses consisted of factor scores from the NEO Personality Inventory (Costa & McCrae, 1985), assessing Neuroticism and Extraversion, and Positive and Negative Affect scores (Watson & Tellegen, 1985) for subjects across lab sessions consisting of relaxation, stress, stress plus challenge, and familiar and complex challenge activities. Neuroendocrine functioning was assessed for each lab session through salivary samples assayed for cortisol (adrenal-corticol activation) and urine samples assayed for adrenaline, and noradrenaline (adrenal-medullary activation).
Multiple regression was used to predict neuroendocrine measures from personality and affect measures. Results indicate a moderate negative relationship between Neuroticism and adrenal-cortical arousal and a weaker positive relationship between Extraversion and adrenal-medullary arousal. Both affect dimensions were most closely associated with adrenal-medullary arousal.
A second set of analyses examined individual differences in adrenal-cortical arousal. Independent t-tests were run on groups based on extreme scores on Neuroticism. Results indicate a larger and more variable cortisol response across experimental conditions for individuals low versus high on Neuroticism; a larger and more variable affective response across situations was also found for individuals high on Neuroticism. Suggestions for further research are discussed.
