Why do humans do good to each other?

Humans are the dominators of the world, and we did not achieve it by chance or luck. We have qualities no other animals have, and these qualities place us on top of other organisms. Of course, interllect plays a very important part in this, but we could not have done it with brains alone. The most determining factor is that we know how to accomplish things as a team, and care for each other and do good to each other. But why do we?

According to the Hamilton's Rule, altruism evolves when the relatedness between individuals multiplyed by the benefit that a recipent obtained is greater than the cost of an act of goodness to that recipent. Interestingly enough, this is almost always the case. The cost of an act of goodness normally is much lesser than the good it can do to others. For example, a piece of bread may mean nothing to you, but if you give it to a beggar it can help him a lot. Thus, considering that the Hamilton's Rule is true, humans will always help each other.

However, the Hamilton's Rule does not explain all altruism. Another big chunk of goodness falls under the category of reciprocity. If I do good to you, you will do good back to me. This forms a cycle of goodness whereby people helps one another and one another helps people. One will like to help people thinking that they will help them when they are in need of it.

Thus, humans have many reasons to do good to each other, regardless of the cost or the consequenses.