Complex systems around us

Dissemination of culture

How does culture spread?

While fulfilling a role in bringing people together, culture also plays a role in discriminating between people. That is because although in some cases the nature of culture makes communication easier, in other cases it makes it more difficult. When communication between different sets of people is easy, their cultures come to resemble each other, making it easier still, whereas when communication is difficult such changes are unlikely to take place.


Communication is of course the role of language, but appearance (clothes, hairstyle, etc.) and factors such as culture, morals and customs also affect the ease or difficulty of communication. In that sense, culture is multifaceted and it is within this context that both verbal and non-verbal communication takes place. That is to say, in contrast to cases in which the cultural “distance” is below a certain level, leading to the cultures involved transforming to become more similar to each other, and the cultural distance is above a certain level, this process does not occur (⇒ Reference “How is culture expressed?”).


Communication occurs as a result of contact between people, but there are two extreme cases. One is when people move around, resulting in increased opportunities for mutual contact between a variety of people. The other is when people do not move around, and communication only occurs between people in the surrounding area. In the latter case, it was Robert Axelrod who modeled cultural dissemination with a focus on the level of cultural distance (⇒ Reference Axelrod's dissemination of culture model).

As the world becomes a larger place, does culture become more diverse?

The range over which humans can interact in geographical terms has expanded. In ancient times there were large hinterlands between different cities (states), and interaction was limited. Before long cities (states) were connected by transportation networks (highways and sea routes), leading to the formation in the distant past of empires in every part of the world. It was about this time that common languages expressed through script arose. Such ancient empires were as large as modern states, or in the case of the Roman Empire, controlled huge territories straddling a number of countries.


Today, there are large states with populations of more than a billion people. Such states have expanded to incorporate a variety of cultural groups without breaking up in the process. In addition, the process of globalization, which transcends space and compresses time, continues to advance. There we have transactions and communications being performed instantaneously, with highly diverse interactions conducted in huge numbers. Indeed, even today in New Guinea there is little interaction between different social groupings, resulting in the country being split into a number of minority cultural groups, who live their lives with only limited social contact with other groups.


What kind of relationship is there between the sphere of cultural interaction and the homogenization of culture? The dissemination of the culture model propounded by Axelrod et alia attempts to analyze what influence the size of geographic territory has on diversity of cultural patterns (⇒ Reference Axelrod's dissemination of culture model). According to this model, when the geographic territory is large, the tendency toward cultural homogeneity is high, but it indicates that minority cultures also remain in some cases.

How do languages and cultures change or disappear?

You may have heard of the term “endangered languages,” meaning languages that are under threat. It refers to languages that are spoken by almost nobody, and that are in danger of disappearing from the face of the earth. According to research by UNESCO, there are eight languages in Japan, of which the Ainu and Yaeyama languages are particularly endangered.


The number of speakers of language A declines because they begin to speak different language B in addition, leading to an increase in the number of people who only speak language B as the generations change. Before long, speakers of language A may become isolated. At the stage where speakers of language A disappear, language A becomes extinct, and cannot be revived.


It is likely that the occurrence of such phenomena is limited not only to languages but to culture in general. When people of different cultures maintain contact and interactions with each other, in some cases the “superior” culture gradually permeates the other group, and the “inferior” culture becomes extinct.

Or it may be that the two cultures mix and blend, leading to the birth of a third culture. In fact this latter phenomenon can also occur with languages, and the resulting language is commonly known as a creole. The Ogasawara language (which is heavily influenced by the Hachijo language) is a creole that is spoken in Japan.

We have explored the mechanism whereby such cultural elements (including language) change and become extinct, using the model of cultural dissemination proposed by Axelrod et alia (⇒ Reference Axelrod's dissemination of culture model).

Do animals also have culture?

It is likely that culture in animals other than humans was first demonstrated in an academic sense by Japanese researchers recording the potato-washing behavior of Japanese macaques.


In a group of Japanese macaques that were being fed on Kojima Island in Miyazaki Prefecture, one of the juvenile members (about 18 months old, equivalent to six or seven years old in human terms) learned by chance to wash food (sweet potatoes that had been planted on a sandy beach) in a stream before eating it. It was probably because immersing the food in water washes the sand away, making it easier to eat. Before long, the mother of this monkey began to copy her child (reverse vertical propagation), and its playmates also began to imitate it (horizontal propagation). However, this culture was not accepted by adult monkeys other than the mother.


In due course, female monkeys that had accepted the potato-washing behavior became mothers themselves, and this behavior was passed on to their children (vertical propagation). Also, rather than the freshwater of the river, there was a change to using the saltwater of the sea. This might be because the salt improved the flavor of the potato.

In terms of the culture of Japanese macaques, one famous example is their use of open-air hot springs in Jigokudani Hot Springs in Nagano Prefecture. In this case also, the trigger for the behavior was juvenile monkeys entering hot pools intended for human use. However, it was only juveniles and females who soaked themselves in the hot pools. Males did not enter.

It appears that rather than propagating uniformly among all members, culture disseminates more easily among those on intimate terms, or those who resemble each other. How should we go about capturing this principle at a more general level? (⇒ Reference “How is culture expressed?”).

How is culture expressed?

While fulfilling a role in bringing people together, culture also plays a role in discriminating between people. First, it would probably be convenient to be able to express the cultures of individuals who come together and move apart.  For example, one method would be to create specific lists of features that characterize differences in culture, such as language, religion and customs. In languages we would have Japanese, English, French, Chinese and so on, while in religion there would be Buddhism, Judaism, Christianity, etc.


Still, it is difficult to create exhaustive lists beforehand. For example, in the case of English, it might be better to divide the language into British English, American English, Australian English, and others. It may also be preferable to divide Christianity into finer categories such as Roman Catholic, Lutheran, Calvinism, and Russian Orthodox.


Moreover, it is possible that using language, religion and customs alone would be inadequate, and that the list would have to be made longer and longer through such additions as academic background, sex and so on. It is therefore impossible to generalize about the ability of culture to act to bring people together or push them apart.

In order to capture culture at a more general level, it is at the very least necessary to classify language and religion at the level at which they mingle as such (level 1), and at the level at which it is possible to say that each individual speaks such and such a language, or believes such and such a religion (level 2). So sex would be level 1, and being female or male would be level 2.

To generalize further, if focusing on the three categories of language, religion and customs at level 1 of culture, language (A), religion (B), and customs (C) are expressed as the three-character string “ABC.” Then, for each individual, level 2 is expressed as “123,” or “135,” or “222,” and so on. “123” and “135” differ in that they belong to the same A group, but belong to different groups for B and C. “123” and “222” differ in that they occupy the same group for B, but belong to different groups for A and C.

The important point here is that it is not the case that the distance between 123 and 135 is 12, and the distance between 123 and 222 is 99, so “123” and “135” are close, but “222” is distant. Values such as “123” are strings, not numbers. From among the three features contained within “ABC,” “123” shares just one value with “135” and also “222,” and so they are at the same distance.

By utilizing this ingenious generalization of culture, we are able to capture the way people come together and move apart in the form of changes in culture among individuals at the level of local communities (⇒ Reference Axelrod's dissemination of culture model).