How Much of Our Personality is up to Us? The Effects of Nature and Nurture on Childhood Aggression

Updated: Aug 22, 2018

By Nick Fontaine

Art by Olivia Baccellieri

One of the most significant debates present throughout the history of science has been that of Nature vs. Nurture. The debate is especially relevant within social sciences like psychology and behavioral neuroscience as it compares the amount of a person’s behavior that they have control over. The nature side of the debate states that people are predisposed to behave they way they do. Though this argument predates knowledge of genetics, it has seen an increase in prevalence with recent advancements in genetics. The nurture side of the argument believes that behavior is determined by the environment during development. Like most things in science, and pretty much every aspect of life for that matter, this is not a black and white issue as many things exist in an intermediate space between the two extremes.


A recent study by Michelle Achterberg and colleagues at Leiden University in the Netherlands looked at the influence of genetics, and the environment has on aggressive behavior in response to social feedback in middle childhood (7 years old-puberty). The study was done on twins in order to account for both genetic and environmental factors (all twin pairs were raised in the same household). To assess aggression the children were shown faces of people roughly their age with an indication of whether they liked, disliked, or were neutral about the personal profiles they had previously filled out. These were not actual children judging each other— because that would be kind of mean— the faces were instead two faces morphed together from a standardized set of face pictures. After seeing what their “peers” thought of them, the participating children were then able to press a button to activate a noise directed at the person judging them, with longer presses making the noise louder and more intense as a form of retaliation. This was all done in a scanner to see the activation of certain brain regions of interest, previously shown to be important in aggression and/or social feedback.


It was found that the social feedback was related in the anterior cingulate cortex gyrus and anterior insular brain regions. These brain regions are known to be involved in this process in adults, showing the neural machinery needed for social feedback is present at a fairly young age. Aggressive behavior was related to supplementary motor area and dorsolateral prefrontal cortex activation, this is also in agreement with previous adult studies of aggression. The researchers found that 10-14% of the variance in this aggressive response could be described by genetic factors.


Overall, these findings show that while people may be slightly predisposed to act in a certain way (i.e., express more aggressive behavior following negative social feedback) based on the genetic factors they have no control over, the environment they are raised and live in has much more effect. This big implications for child raising and education, as a nurturing and kind environment, can work wonders in helping ensure the child grows up to act in a healthy and socially productive way. However, the environment is not 100% responsible for a person’s behavior, and somethings are just out of our control.

This research adds to the idea that nature and nurture are not as dichotomous as the idea of a “nature vs. nurture” debate would make it seem. There is much interplay between the two, shaping nearly every aspect of our lives. As we learn more about this interplay, the debate of nature vs. nurture is seeing less and less prevalence. We see a shift from the nature vs. nurture debate to the nature and nurture conversation.


References:


Achterberg, M., Duijvenvoorde, A. C., Meulen, M. V., Bakermans-Kranenburg, M. J., & Crone, E. A. (2018). Heritability of aggression following social evaluation in middle childhood: An fMRI study. Human Brain Mapping. doi:10.1002/hbm.24043

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