We concluded the previous post in this series with the question: Are we what we eat? This is not a facetious question. Rather, it is an attempt to explain significant variations in human behavior. We approach this explanation by exploring the extent to which our physical conditions and the imperatives of survival might have shaped our social and psychological responses. We speculated that existence as small and constantly warring bands during the hunting and gathering era must have engrained the importance of the distinction between friend and foe. Survival in these conditions must have depended upon the socialization of altruism within groups and hostility across groups. We still see this in the Us/Them syndrome that is often quite mindless in the present environment – a visit to some blogs would be proof enough.