Environmental Change and the Emergence of Human Cognitive Variation

This thesis investigates whether the emergence of cognitive and psychological variability had a significant impact upon our species’ evolution. It explores the extent of this diversity, and its effect upon our ability to adapt to new, changing or fluctuating environments. An agent based model (ABM) is used to investigate whether an example of psychological difference, variance in extraversion, may have had an effect upon a key event of our evolutionary history: our dispersal out of Africa. The results of this study suggest that our psychological differences likely had a large impact upon both our ability to adapt to new environments, inventiveness, and our dispersal ability. In particular, reproductive advantages associated with extraversion may have provided individuals with an advantage when dispersing, albeit offset by the disadvantages of an increased mortality rate. More broadly, recognition that populations are evolving, diverse, and subject to different selective pressures while dispersing may significantly change how we view our dispersal out of Africa. This thesis suggests that our psychological diversity is an important, underappreciated feature of our species, which may have had a large impact upon key events during our evolution.