Betrayal is behind the spread of humans around the world


Around 100,000 years ago, the "speed and character" of human dispersals -- how human beings moved around the planet -- changed significantly. Why? According to new research from the University of York, it all came down to "betrayal of trust".

Previous studies had put this alteration in human behaviour down to ecological changes. Until 100,000 years ago, the movement of humans was mainly predicated on environmental factors and was, reflecting this, extremely slow. But after this point, movement around the planet became much more rapid, and even traversed major ecological barriers and events.

The new research, published today in Open Quaternary, says that this change was actually down to a shift in human relationships. Emotional relationships became more important at this point, the paper says, and social groups became more motivated to identify "the dark side of human nature" -- things like lying and cheating. Subsequently, disputes -- mainly caused by broken trust -- became far more common, leading groups to fracture and put distance between themselves and their new rivals.

Prior to this development, dispersal into different regions was largely based on how hospitable the environment was. After the change, however, many groups moved into risky or inhospitable areas much more frequently. This included extremely cold areas of Northern Europe and areas such as the Ganges.

This, researchers say, was all down to the betrayals of trust -- a desire to avoid physical harm from rivals was a more terrifying prospect than entering an inhospitable region. "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," said Penny Spikins, senior lecturer in the archaeology of human origins and co-author of the study. "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."