I actually just read a fascinating article about recent research that showed that the instinct for revenge and the instinct for forgiveness were both innate, yet influenced by environment.
Basically, the theory is that, in situations in which strength is paramount for safety, the instinct for revenge takes the lead because you're less likely to be attacked if you make an example of someone.
Similarly, in situations in which cooperation is more conducive to survival, the instinct for forgiveness becomes more pronounced.
not an either/or
Basically, the theory is that, in situations in which strength is paramount for safety, the instinct for revenge takes the lead because you're less likely to be attacked if you make an example of someone.
Similarly, in situations in which cooperation is more conducive to survival, the instinct for forgiveness becomes more pronounced.
(If you're interested, you can download the article at http://greatergood.berkeley.edu/greatergood/2008spring/.)