Daniel Kahneman. Think slowly... Solve quickly (№ 391357)

Zajonc argued that the emergence of sympathy when you repeat - the most important biological feature, which also applies to animals. To survive in a frequently dangerous world, an organism must respond to new stimuli carefully and with fear. For the animal, which belongs to the new without suspicion, the prospects for survival look bleak. On the other hand, the extinction of the initial fear of safe phenomenon - a sign of adaptability. Zajonc argued that the effect of a simple presentation arises from the fact that repeated clashes with the new stimulus is not the end of anything is bad. Such a stimulus will eventually become a safety signal, and safety is good. Obviously, this is not only true for humans.