The curious case of altruism.

World Science suggests that

Giving among strangers more nurture than nature, study suggests

Al­tru­ism has long been a sub­ject of in­ter­est to sci­en­tists. Su­per­fi­cially at least, ev­o­lu­tion­ary the­o­ry sug­gests al­tru­ism should­n’t ex­ist. Ev­o­lu­tion oc­curs be­cause some genes in a popula­t­ion are usu­ally more ad­van­ta­geous than oth­ers. The fa­vor­a­ble genes spread through the popula­t­ion be­cause their bear­ers are able to out-reproduce oth­er in­di­vid­u­als, grad­u­ally chang­ing the whole group’s char­ac­ter­is­tics. This does­n’t seem to al­low for al­tru­ism, as pre­sumably only those who help them­selves ul­ti­mately get ahead in the ev­o­lu­tion­ary race.

Now I wonder how that would work with apes? Oh wait, threy groom each other all the time, don't they ;-?