Human beings spread rapidly across the world because they were falling out with each other, an academic has suggested.
New research by an archaeologist at York University suggests that “betrayals of trust” could be the missing link in understanding the rapid spread of our own species around the world.
Dr Penny Spikins, of the University’s Department of Archaeology, says that the speed and character of human dispersals changed significantly around 100,000 years ago.
Before then, movement of archaic humans were slow and largely governed by environmental events due to population increases or ecological changes.
Afterwards populations spread with remarkable speed and across major environmental barriers. Dr Spikins, a senior lecturer in the Archaeology of Human Origins, relates this change to changes in human emotional relationships. In research published today in Open Quaternary, she says that neither population increase nor ecological changes provide an adequate explanation for patterns of human movement into new regions which began around 100,000 years ago. She suggests that as commitments to others became more essential to survival, and human groups ever more motivated to identify and punish those who cheat, the ‘dark’ side of human nature also developed. Moral disputes motivated by broken trust and a sense of betrayal became more frequent and motivated early humans to put distance between them and their rivals. Dr Spikins argues that betrayals of trust were a significant reason for people dispersing into apparently unwelcoming environments .
Offenders and any allies within their social network would feel driven to get out of harm’s way.
She says: “Active colonisations of and through hazardous terrain are difficult to explain through immediate pragmatic choices. But they become easier to explain through the rise of the strong motivations to harm others even at one’s own expense which widespread emotional commitments bring.
“Moral conflicts provoke substantial mobility -- the furious ex ally, mate or whole group, with a poisoned spear or projectile intent on seeking revenge or justice, are a strong motivation to get away, and to take almost any risk to do so.
“While we view the global dispersal of our species as a symbol of our success, part of the motivations for such movements reflect a darker, though no less ‘collaborative’, side to human nature.”
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