Altruism (biology) most common mechanism of reciprocity in nature, this kind is present in humans, primates, and many other mammals. Also known as, "If you're nice, I'll be nice too." This mechanism of reciprocity is similar to the heuristic of the golden rule, "Treat others how you would like to be treated." Parties mirror one another's attitudes, exchanging favors on the spot. Instant attitudinal reciprocity occurs among monkeys, and people often rely on it with strangers and acquaintances. Also known as, "what have you done for me lately?" Individuals keep track of the benefits they exchange with particular partners, which helps them
Locard's exchange principle Locard's exchange principle In forensic science, Locard's exchange principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence. Dr. Edmond Locard (13 December 1877 – 4 May 1966) was a pioneer in forensic science who became known as the Sherlock Holmes of France. He formulated the basic principle of forensic science as: "Every contact leaves a trace". Paul L. Kirk expressed the principle as follows: Fragmentary or trace evidence is any type of material left at (or taken from) a