Abstract
People often act hypocritically. One form of hypocrisy occurs when people blame others for transgressing moral principles they themselves have violated in the past. However, the psychological processes linked to this hypocritical blame are largely unknown. One possibility is that hypocritical blame is associated with the costs of being prosocial, such that a person could intend to help but is unwilling to put in the effort. Here, we test whether a measure of hypocritical blame that quantifies the discrepancy between willingness to profit from another's harm, and blaming somebody else for similarly profiting, is related to the motivation to choose and then exert physical effort to benefit themselves or a stranger. Results revealed that hypocritical blame is associated with reduced prosocial motivation specifically, and not with how willing people are to exert effort for their own benefit. This effect was found in both a reduced willingness to choose to be prosocial and for energising prosocial acts. This suggests that the discrepancy between moral standards and actions is related to the willingness to overcome the costs of being prosocial, with some people being simply unwilling to exert the effort required to live up to their moral principles.