Instead, new research by McMaster behavioural scientists shows that in certain cases evolution works in the opposite direction, reversing individual improvements to benefit related members of the same group.
The research appears in the Journal of Evolutionary Biology, where lead author David Fisher shows that the increased evolution of selfless traits — such as sharing food and keeping watch for one another — is mathematically equivalent to the decreased evolution of individually beneficial traits.
“They’re two sides of the same coin,” Fisher explains. “On one side, traits evolve that benefit your kin, but don’t benefit you, because you’re helping your siblings or cousins. On the other side, traits that benefit you but cost your neighbours don’t evolve, because you’re causing damage to related individuals.”