The next further advance was the introduction of the concept of inclusive fitness by the British biologist W.D. Hamilton in 1964 in his paper on The Genetical Evolution of Social Behaviour.
O seguinte avance foi a introdución do concepto de fitness inclusiva polo biólogo británico W.D. Hamilton en 1964 na súa obra The Genetical Evolution of Social Behaviour (Evolución xeética do comportamento social).