Erin Hecht

ERIN HECHT, Harvard University, Cambridge, Massachusetts, was awarded funding in October 2016 to aid research on ‘ Neural Adaptations in Response to Selection for Reduced or Increased Aggression.’ For over 100 years, anthropologists have theorized that some of the selection pressures experienced by our ancestors during the emergence of human society paralleled those experienced by animals during adaptation to life within human society, or domestication. However, direct tests of the human ‘self-domestication’ hypothesis have been limited, especially in the context of brain evolution. Moreover, an alternative to the ‘self-domestication’ hypothesis is that humans and chimpanzees have evolved increased aggression relative to a more peaceful, bonobo-like ancestor. This project uses neuroimaging to address these issues with a highly specific experimental model, foxes selectively bred for either reduced or increased aggression, to pinpoint neural systems that respond to these pressures. The project then tests whether those specific systems show differences in a bonobo/chimpanzee comparison, and finally, parallel analyses are carried out in humans. Preliminary results indicate that selection both increased and reduced aggression produces shifts in the morphology of gray matter regions within cortico-limbic circuits. However, the connectivity within these networks differs in response to selection for increased versus reduced aggression. Together, this research experimentally tests long-standing anthropological hypotheses about evolutionary pressures that may have shaped human ancestors’ behavior and brain organization.