During the evolution of the human species, we appear to have lost the ability to rely on instinctive behavior as we developed extraordinary abilities to learn and adapt to the conditions facing us in our environment. In addition, we can pass on that learning to other members of our social group. This is the basis for culture, and the success of the human species is a testament to the advantages of this approach to survival. However, this transition from instinct to learning and culture has not resulted in the elimination of biological influences on our behavior. Certain groups of people, usually a minority of the population, retain biological predispositions to behave and react in certain distinct ways. To a lesser extent, all of us have some degree of these biological predispositions.