Personality psychology is a field of research that investigates the development of comprehensive taxonomies of personality traits in order to understand the individual differences in behavior, emotion, motivation, and cognition (Deyoung, et al). Personality traits alone have been a controversial concept in which the validity of their ability to predict behavior has been heavily debated. Psychologist Walter Mischel published research postulating that people do not behave consistently across different situations, thus personality traits are not indicative of understanding behavior (Mischel, 1968). Since then, personality psychologists have worked to defend the validity of personality traits, further promoting evidence demonstrating that personality traits not only do exist, but should be considered valid predictors of important outcomes. Contradicting the suspicions concerning the legitimacy of personality traits, a study exploring the validity of personality traits concluded that the magnitude of effect sizes for personality traits ability to predict important life outcomes including mortality, divorce, and occupational attainment, were substantial and were found to be just as revealing as other valid predictors including socioeconomic status and cognitive ability (Roberts et al).
After learning about the fundamental aspects of personality psychology and determining the validity of personality traits further sparked my interest in the neurological mechanisms surrounding individual personalities and traits. One study that I found linked personality psychology and neuroscience by examining the associations between biological bases of personality traits and volume sizes of concordant brain regions (DeYoung et al). Based on their research, a biological model of the Big Five personality traits associated five different personality traits with the volumes of certain brain regions that were believed to be involved in the underlying biological processes that result in behaviors associated with each trait. Results supported hypotheses about the association of each trait with volume sizes of specified brain regions for four out of the five traits: extraversion, neuroticism, conscientiousness, and agreeableness. For example, high extraversion was hypothesized and found to be associated with increased volume of orbitofrontal cortex, due to that brain region’s involvement in reward processing. See article for hypotheses for all traits and associated brain regions at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049165/pdf/nihms-275680.pdf
While this study posited plausible hypotheses to support associations between certain brain region size and psychological behavior and traits, associations are only tentatively indicative that volume correlates positively with function. It has not been indefinitely determined that increased volume results in greater execution of functions associated with that region, however more evidence supports that claim than not. If this theory is validated in future research, this model of brain functioning could be utilized in the examining of zombie brains. If valid, it could be presumed that the neurological functioning of zombie brains could be due to relatively larger or smaller specific brain regions that correlate with their unique behavior, as we have been learning in Do Zombies Dream of Undead Sheep, by Timothy Verstynen and Bradley Voytek.
Mischel, W. (1968). Consistency and specificity in behavior. In Personality and assessment (pp. 13-39). New York, NY: Wiley.
Roberts, B. W., Kuncel, N. R., Shiner, R., Caspi, A., & Goldberg, L. (2007). The power of personality: The comparative validity of personality traits, socioeconomic status, and cognitive ability for predicting important life outcomes. Perspectives on Psychological Science, 2, 313-345.
DeYoung, C. G., Hirsh, J. B., Shane, M. S., Papademetris, X., Rajeevan, N., & Gray, J. R. (2010). Testing Predictions From Personality Neuroscience: Brain Structure and the Big Five. Psychological Science, 21,6, 820–828.