Human Nature

Human beings are born as social creatures because the precursors of human beings were social creatures. And therefore the social bonds that connect people really determine their behavior. Human beings are bond with a very specific form of sociability which is defined by two principles:
  The first principle was developed by the great biologist William Hamilton, which is called "Kin selection or Inclusive Fitness". The principal says that, we are altruistic towards other creatures in proportion to the number of genes that we share. And so Mother and Father relations with their children is more altruistic than a second cousin, and so forth. It is a principle of nepotism. It doesn't actually just apply to human beings but really to virtually all sexually producing creatures. It is therefore determined as one distinct form of human sociability.
  The second principle is what biologist called "Reciprocal Altruism". Reciprocal altruism means an exchange of gifts on a face-to-face basis,  and in the natural world this can exist even between creatures of different species. Certainly, amongst most social species, it is based on the ability to remember favours and to turn them on a reciprocal basis.