Greeting rituals are considered to be a human universal, present in one form or another in all human societies. In 1991, the American Professor of Anthropology, Donald E. Brown, published a list of human behaviours found in all cultures without any known exceptions. In other words, features that can be found in language, society and psyche, whether deep in the jungles of Papua New Guinea or high in the chrome-and-glass towers of New York. The list covers hundreds of behaviours, spanning from ‘tickling’ and ‘envy’ to ‘wariness around snakes’ and ‘music’, and includes ‘customary greetings’ (interestingly, ‘customary farewells’ are not included in the list).

Not only is greeting behaviour a human universal, but common among animals as well. Pair animals (such as many birds) tend to display greeting behaviour only between ‘spouses’, while social animals greet not only their mates, but other animals of their own kind as well. Hoofed herd animals and pack animals such as wolves tend to greet each other by lowering their bodies and perhaps making themselves small (other animals might puff themselves up in a bristling display to look larger, stronger and more threatening, but whether this could be classed as ‘greeting behaviour’ is debatable).