Genes affect human personality, but only in more demanding climates
The surprising findings are the result of a new joint publication entitled ‘Dopamine genes are linked to Extraversion and Neuroticism personality traits, but only in demanding climates’ by AIAS Former Fellows Machteld N. Verzijden (Bioscience) and Ronald Fischer (Psychology) and co-author Anna Lee.
The article entitled ‘Dopamine genes are linked to Extraversion and Neuroticism personality traits, but only in demanding climates’ was published last week in Nature’s Scientific Reports (2018) 8:1733, and the ideas for the research behind it came about when two of the authors, Machteld N. Verzijden and Ronald Fischer who come from different research fields (Bioscience and Psychology), met during their fellowship at AIAS.
“Persons vary in how they behave when faced with social or economic choices, which can have far-reaching consequences for their life’s outcomes. Human personality traits, especially extraversion and neuroticism, affect economic and social choices, and people vary in their levels of extraversion and neuroticism both at a local and a global population level – e.g., people in some nations are on average more extravert or emotional than people in other nations.
It has remained a challenge to explain such differences. Attempts to explain differences in personality range from genetic to cultural hypotheses, and there is evidence that both genetic and cultural variation affect personality. Dopamine, a key neurotransmitter related to how we think about rewards in everyday life has long been speculated about to play a major role. There are a number of genes that encode how efficient our brains process dopamine and we looked into how such genes may play a role in explaining differences in personality around the world”, explains AIAS Former Fellow Machteld N. Verzijden, now a Postdoc at DANDRITE, Aarhus University.
Dopamine Genes in very hot or very cold climate
In their research, the authors found that these dopamine genes (quantified through a novel dopamine system index) correlated with personality traits, but only in countries with very hot or very cold climate. Specifically, when the brain produces and processes dopamine in a 'more efficient' way, people become more extravert and emotional stable, especially when they grow up and live in a climate that is more demanding (either hot or really cold). Just imagine how you feel when being on holiday in a very hot place. How you behave and react to daily stressors may partly depend on how efficiently your brain can process all these challenges and react to potential reward (or avoid challenges), while your body has to deal with the hot temperature.
This insight offers a new perspective on cross-cultural studies of personality and also some intriguing hints about previous replication failures with genetic linkage studies. The climate interaction is also something to consider in the light of global warming and what it means for genetic predispositions and vulnerabilities.
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Ronald Fischer, AIAS Former Fellow and Professor
School of Psychology
University of Wellington