What motivates an individual to cooperate

In the present day world it is seenthat people have become more self centered and materialistic. But still people cooperate to achieve a common goal. The general impression is that people have to sacrifice some of their personal interests inorder to cooperate with others. But people are not ready to sacrifice their interests without expecting anyhting in return for it. So it could be said that people give more importance to self interests than the common goal.
All of us know that group farming of rice is beneficial to the members of the group. But most of the people dont prefer to do it. It is seen that poor and marginal farmers are more willing to cooperate with others in case of group farming as they are the ones who are going to benefit more. In case of group farming all the activities are done based on a common understanding among the members. It helps to reduce the cost of cultivation and there would be an equal distribution and accessibility to resources. Even if the farmers are willing to cooperate there are many external factors that hinder cooperation among the people. The distribution of land can be considered as one of these factors.
Another factor is the self interests of the people. The poor and marginal farmers are willing to cooperate because group farming would help in reducing the cost of cultivation and improve the yields. The rich farmers are not inteersted in group as it would force them to share the benefits thatthey used to enjoy with the other members of the group. Their self interest is to get greater yields than others. So it could be said that self interests motivates people to cooperate with others as well as not to cooperate with others.