Why are people (un)willing to reward cooperation and punish non-cooperation?

One of the most straightforward ways to protect the collective welfare is to use sanctions. Numerous experiments have consistently shown that positive sanctions (rewards) for cooperation and negative sanctions (punishments) for non-cooperation can effectively enhance cooperation. Although this is an important insight, a critical question remains: Are people actually willing to sanction? This question is of critical importance, if only for the obvious reason that someone should first be willing to administer rewards and punishments before they can show their effects. My research is aimed at answering the question of why people are (un)willing to reward cooperation and punish non-cooperation.