How do YOU make decisions?

In game theory, mathematicians & economists (among others) try to structure a game and study how the people play the game to win.

This article from the Economist points out two interesting facts:

1. Being selfish or cooperative in a game, does not give you any sort of long term advantage. Nice guys finish equally as well as the selfish
2. The way we choose to play may not really be a result of voluntary choice but one of evolutionary stability
   

Do we have free will or are we bound to act along our genetic predisposition?