This paper discusses the relations between three forms of altruism: behavioural, evolutionary and motivational. Altruism in a behavioural sense is an act that benefits another person. It can range from volunteering to a charity and helping a neighbour, to giving money to a non-profit organisation or donating blood. People often dedicate their material and nonmaterial resources for the benefit of others to gain psychological, social and material benefits for themselves. Thus, their altruistic acts are driven by egoistic motivation. Also, the final goal of an altruistic act may be the increase in the welfare of a group or adherence to a certain moral principle or a social norm. However, at least sometimes, the welfare of others is the ultimat...