of science, Auguste Comte, and has become a major topic for psychologists (especially evolutionary psychology researchers), evolutionary biologists, and ethologists. Whilst ideas about altruism from one field can affect the other fields, the different methods and focuses of these fields always lead to different perspectives on altruism. In simple terms, altruism is caring about the welfare of other people and acting to help them. Scientific viewpoints Anthropology Marcel Mauss's essay The Gift contains a passage called "Note on alms". This note describes the evolution of the notion of alms (and by extension of altruism) from the notion of sacrifice. In it, he writes: Evolutionary explanations In the science of ethology (the study of animal behaviour), and more generally in the study of social evolution, altruism refers to behaviour by an individual that increases the fitness of another individual while decreasing the fitness of the actor. In evolutionary psychology this may be applied to a wide range of human behaviors such as charity, emergency aid, help to coalition partners, tipping, courtship gifts, production of public goods, and environmentalism. Theories of apparently altruistic behavior were accelerated by the need to produce theories compatible with evolutionary origins. Two related strands of research on altruism have emerged from traditional evolutionary analyses and from evolutionary game theory a mathematical model and analysis of behavioural strategies. Some of the proposed mechanisms are: Kin selection. That animals and humans are more altruistic towards close kin than to distant kin and non-kin has been confirmed in numerous studies across many different cultures. Even subtle cues indicating kinship may unconsciously increase altruistic behavior. One kinship cue is facial resemblance. One study found that slightly altering photographs so that they more closely resembled the faces of study participants increased the trust the participants expressed regarding depicted persons. Another cue is having the same family name, especially if rare, and this has been found to increase helpful behavior. Another study found more cooperative behavior the greater the number of perceived kin in a group. Using kinship terms in political speeches increased audience agreement with the speaker in one study. This effect was especially strong for firstborns, who are typically close to their families. Vested interests. People are likely to suffer if their friends, allies, and similar social ingroups suffer or even disappear. Helping such group members may therefore eventually benefit the altruist. Making ingroup membership more noticeable increases cooperativeness. Extreme self-sacrifice