Description: There are fewer left-handed people than right-handed people in the world, right? Yes, that is true, but the proportions vary from place to place and maybe from time to time. So, how does handedness play out from an evolutionary perspective? It is often difficult to think through how the interaction of nature (genetics) and nurture (experiences in the world) interact with each other on either an individual level or on the much broader level of long-term socio-historical time. This partly due to our not yet complete understanding of how such processes work but it is also due to our history of typically thinking of nature and nurture as reflecting distinct contributors to development. We need to get past this tenacious but outdated thought bias if we are to think clearly about naturenurture (a new hybrid word that will keep us from biased thinking) questions. The article linked below provides a very useful and instructive overview of how naturenurture has played out over socio-historical evolutionary time in relation to handedness and specifically to left-handedness. Think for moment about what you believe or think you now about the evolution of handedness and then have a read through the linked article.
Source: The Evolutionary Mystery of Left-Handedness, Brian Pickings and Mary Popova, Brain Pickings.
Date: December 24, 2019
Photo Credit: Vladimir Radunsky for “on a Beam of Light: A Story of Albert Einstein”
So, did you know about Broca’s interest in handedness and brain symmetry in addition to the study of the loss of speech production in stroke patients that is typically attributed to him? And how did the higher incidence of lefties in combative social groups? Handedness is a very useful example through which to consider historical questions of naturenurture and what it helps us to see more clearly can be applied to other important Psychological questions such as the naturenurture of mental illness, mental health and wellbeing.
Questions for Discussion:
- What is the incidence of handedness (or why is the answer to this question not simple)?
- Why might naturenurture be a better term for the ongoing interaction of genetics and environment?
- What are some things you picked up from the linked article that might be useful in thinking about similar issues related to mental illness and mental health?
References (Read Further):
Wolman, David (2006) A Left-handed Turn Around the World: Chasing the Mystery and Meaning of All Things Southpaw. Hazelden Publishing.
Corballis, M. C. (2003). From mouth to hand: gesture, speech, and the evolution of right-handedness. Behavioral and Brain Sciences, 26(2), 199-208. https://pdfs.semanticscholar.org/c9ae/4d51655a527f7994cb9d1cf4f444f880d4e9.pdf
Cashmore, L., Uomini, N., & Chapelain, A. (2008). The evolution of handedness in humans and great apes: a review and current issues. Journal of Anthropological Sciences, 86(2008), 7-35.
Schaafsma, S. M., Geuze, R. H., Riedstra, B., Schiefenhövel, W., Bouma, A., & Groothuis, T. G. (2012). Handedness in a nonindustrial society challenges the fighting hypothesis as an evolutionary explanation for left-handedness. Evolution and Human Behavior, 33(2), 94-99.
Pollet, T. V., Stulp, G., & Groothuis, T. G. (2013). Born to win? Testing the fighting hypothesis in realistic fights: left-handedness in the Ultimate Fighting Championship. Animal behaviour, 86(4), 839-843. http://www.rug.nl/research/portal/files/6800162/2013AnimBehavPollet.pdf
Faurie, C., Llaurens, V., Alvergne, A., Goldberg, M., Zins, M., & Raymond, M. (2011). Left-handedness and male-male competition: insights from fighting and hormonal data. Evolutionary Psychology, 9(3), 147470491100900307. https://journals.sagepub.com/doi/pdf/10.1177/147470491100900307