Answers from Module 3
In some cases, it has been shown a number of times that disorders in the genome and other
physical problems can impact personality (Michael, Morris, & Soroker, 1957) and various
chemical theories of personality have been early considerations in psychology since at least 1929
(McDougall, 1929) showing that chemical composition and disorders in the body can impact
personality. Take Schizophrenia for example of both a disorder that may be genetic and impact
personality. While some evidence still is needed in the genetic study of the disorder, many
scholars see schizophrenia as genetic (Kavanagh, Tansey, O'donovan, & Owen, 2015) while at
the same time there is research that points to the idea that Schizophrenia impacts personality
(Cann & Donderi, 1986; Ohi et al., 2012).
Understanding that Evolution could be an informer of how humans develop, Darwin argued that
the domestication of animals is evidence of evolution. As breeders bred animals based on
temperament to produce a more domesticated version of primitive animal in the wild, Darwin
postulated this was in alignment to his theory on evolution (Bouchard, 2001). This makes a
strong case that personality is, at least to some degree, genetically derived. Humans are
complex, but seeing how animals differ in personality can also determine how people are
Studies have indicated that people can change their personality over time (Hudson & Fraley,
2016). Hudson and Fraley (2016) even noted that people who attempt to change their personality
experience better well-being, indicating that personality change is not detrimental to the human
psyche. For this reason, personality is both a part of the human genome but also something that
can be developed through time and changed without any major psychological harm to the
Thus, it is the conclusion of this post that genetics are a contributing factor in personality, but not
the sole contributing factor. While we can certainly reject the behaviorist view that all we are is
a result of our environment, we can also reject the notion that we are merely philosophical
determinists controlled completely by our genetics.
Bouchard, T. J. (2001). Genes, environment, and personality. Science-AAAS-Weekly Paper
Edition, 264(5166), 1700-1701.
Cann, D. R., & Donderi, D. C. (1986). Jungian personality typology and the recall of everyday
and archetypal dreams. Journal of Personality and Social Psychology, 50(5), 1021-1030.
Hudson, N. W., & Fraley, R. C. (2016). Changing for the better? longitudinal associations
between volitional personality change and psychological well-being. Personality and Social
Psychology Bulletin, , 0146167216637840.
Kavanagh, D. H., Tansey, K. E., O'donovan, M. C., & Owen, M. J. (2015). Schizophrenia
genetics: Emerging themes for a complex disorder. Molecular Psychiatry, 20(1), 72-76.
McDougall, W. (1929). The chemical theory of temperament applied to introversion and
extroversion. The Journal of Abnormal and Social Psychology, 24(3), 293-309.
Michael, C. M., Morris, D. P., & Soroker, E. (1957). Follow-up studies of shy, withdrawn
children: II: Relative incidence of schizophrenia. American Journal of Orthopsychiatry, 27(2),
Plasticity refers to changes in the organization in the brain, for example, through maturation, as a
process of learning, or after damage (Taupin, 2008). My first thought in reading this question
was that the cerebral cortex was the primary area of the brain to exhibit neuroplasticity, as the
plasticity research that came to mind all involved cortical structures. Consider the research with
cats that showed that visual deprivation re-wired areas of the visual cortex (Hubel & Wiesel,
1970), the research that showed rats raised in enriched environments had thicker, heavier
cortexes than did their counterparts raised in more barren cages (Rosenzweig, Krech, Bennett, &
Diamond, 1962) and research that shows that the sense of touch takes over areas of the visual
cortex among Braille users who were born blind (Barinaga, 1992). On the other hand,
specialized sub-cortical areas seem less likely to demonstrate plasticity. How many people
recover from damage to the medulla or other areas of the brainstem? And then there was the
case of H.M., a man who was left with a permanent case of anterograde amnesia after suffering
damage to his hippocampus (Scoville & Milner, 1957). Other areas of H.M.’s brain did not take
over the function of encoding long-term memories. Yet, while the brain seemingly does not
recover from the destruction of a hippocampus, there is evidence of neuroplasticity does occur
there. For example, London taxi drivers have larger-than-average hippocampi, presumably due
to their years spent navigating through a busy city (Maguire, Woollett, & Spiers, 2006). In fact,
Chalupa, Berardi and Caleo (2014) reported that the occipital cortex and in the hippocampus
were primary areas for neuroplasticity.
Barinaga, M.B. (1992). The brain remaps its own contours. Science, 258, 216-218. Retrieved
Chalupa, L. M., Berardi, N. and Caleo, M. Cerebral Plasticity: New Perspectives. Cambridge,
US: MIT Press. Retrieved from
Scoville, W. B., & Milner, B. (1957). LOSS OF RECENT MEMORY AFTER BILATERAL
HIPPOCAMPAL LESIONS. Journal of Neurology, Neurosurgery, and Psychiatry, 20(1), 11–
21. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC497229/pdf/jnnpsyc002850015.pdf
Taupin, P. (2008). Hippocampus : Neurotransmission and Plasticity in the Nervous System.
Hauppauge, US: Nova Biomedical. Retrieved from
Maguire, E.A., Woollett, K., & Spiers, H.G. (2006). London taxi drivers and bus drivers: A
Structural MRI and neuropsychological analysis. Hippocampus, 16, 1-12. Retrieved from
Rosenzweig, M. R., Krech, D., Bennett, E. L., & Diamond, M. C. (1962). Effects of
environmental complexity and training on brain chemistry and anatomy: A replication and
extension. Journal Of Comparative And Physiological Psychology, 55(4), 429-437.
Hubel, D. H., Wiesel, T. N., (1970), The period of susceptibility to the physiological effects of
unilateral eye closure in kittens. The Journal of Physiology, 206 (2), 419-436. doi:
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