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
Science and technology of the Song dynasty clocks of Europe. Su's clock tower also featured the earliest known endless power-transmitting chain drive in the world, as outlined in his horological treatise of 1092. The cases of these two men display the eagerness of the Song in drafting highly skilled officials who were knowledgeable in the various sciences which could ultimately benefit the administration, the military, the economy, and the people. Intellectual men of letters like the versatile Shen Kuo dabbled in subjects as diverse as mathematics, geography, geology, economics, engineering, medicine, art criticism, archaeology, military strategy, and diplomacy, among others. On a court mission to inspect a