Culture is a group thing
(appeared on 20th Nov 2013)

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A study has shown that larger groups are better at preserving cultural identity, says S.Ananthanarayanan.

Language skills and intelligence have made humans better at cultural evolution than chimpanzees, ants, bees or microbes. But does the number of individuals in a group also matter? There are intuitive and analytical answers to this question. Now there is also an experimental verification.

 Maxime Derex, Marie-Pauline Beugin, Bernard Godelle1 & Michel Raymond, social scientists at Monpellier, France, have described in the journal, Nature, last week, their trials with 366 persons engaged, in groups, in a dual-task computer game which tested the effect of group size on cultural transmission. The trial shows that simpler cultural traits are better conserved than complex ones and that expanding the group size increases the survival chances of the complex trait

The accumulation of socially learned information over many generations has enabled humans to develop powerful technologies that no individual could have invented alone, the authors note in the paper. That evolving and transmitting culture is unlikely outside humans is explained as being due to human specific mechanisms, like teaching, language or imitation. But this is not a complete answer, as transmission is not always exact and information loss is expected, particularly when there is greater complexity. Cultural loss, or the opposite of improvement has also been documented and regression is found to be associated with reduction of group size.

The work of Joseph Henrich, Professor of Psychology and Economics at University of British Columbia has delved into adaptive learning and culture transmission and it outlines a mechanism of how information is passed on, a mechanism which is similar to the preferred transmission of beneficial genetic traits. Learners are thus considered to be likely to imitate model persons who are successful or knowledgeable or endowed with prestige. As imitation is not exact copy, faithful transmission, and improvement, would presuppose a good number of transmission events, which would happen in a large population. But with low population, there may be regression, with imperfect learner becoming demonstrators, as low number would imply less successful models to follow.

But the mechanism is complex. There is the effect, for instance, of a model who is known to excel in one area gaining prestige and being imitated in his or her behavior in another domain. – like followers copying the hut building technique of one who is successful in fishing. This is a behavior pattern that advertisers use when they announce the preference for shaving cream of a tennis champion. And again, the factors that help creation of complex culture may also be the factors that leads to large population. It may hence be misleading to take the correlation of cultural complexity with large population and conclude that one was caused by the other. The experimenters hence devised a model where complicating factors were kept out and the test was only of the two things that the work of Henrich suggested – first, that for a given group size, there should be greater loss of information for a complex task, as compared to a simple task, and second, that the loss should come down when the group was larger.

The 366 participants of the experiment were randomly assigned to groups of 2, 4, 6, 8 or 16 players. Two tasks were assigned – a simple task of drawing an arrow head, and a complex task of building fishing net, both on the computer screen, and the objective was to get the best evaluation. The arrow head was evaluated based only on the shape while the fishing net was evaluated, at a higher level, based both on the shape and the steps followed to build it. The players could choose either task at each try and had to go through 15 trials. At each trial, the player could choose to take the help of either a ‘cultural model’ demonstration (this was for the first three trials) or the method of a fellow group member. The evaluation of all members of the group was there to make the choice.

The results of the trials, which can be seen in the diaigrams, demonstrate that simple tasks were generally conserved, and nearly always in the larger groups. Next, the complex tasks were clearly better conserved in the larger groups. And as for conservation of both tasks, or the diversity of cultural transmission, the larger groups scored significantly higher. In accuracy of transmission of the complex task, again, the larger groups had the clear advantage.

The results thus support Henrich’s hypothesis that changes in group size can affect both adaptive cultural evolution, when the group is large as well as deficiency in adaptation and loss of community skills, when the group is smaller. “In our evolutionary past, group-size reduction may have exposed human societies to notable risks, as humans live in many habitats to which they are ill-suited without specific cultural adaptations. Indeed, the more that we depend for our survival on large bodies of culturally transmitted knowledge, the more we rely on living in large groups. Under such conditions, group-size reduction could have triggered important loss of skills, leading to societal collapse,” the authors say in the paper.

Life in cities

In the same week that this paper was published by Nature, there was an event in Mumbai where Charles Correa, the noted architect and town planner released Naresh Fernades' book, ‘City Adrift’, a biography of Mumbai city that covers its many decades of dealing with land use and the demands of growing population. Now, “middle-class Bombay shops in access-restricted malls, exercises in parks operated by private developers, trades public transport for air-conditioned cars and aspires to live in gated communities. ... A city can flourish only if it has common ground to make common cause…”, says the book, at the end of the account of the city’s many strengths.

Charles Correa explained that what made cities great was not land use or building skill, it was providing places for people to come in contact with others. He cited a model where people in a village were represented by red dots on a computer screen. Interspersed among the red dots were blue dots, indicating enlightened individuals, or ‘role models’, which exist in all groups. When the model of a village of 250 inhabitants was scaled up to a thousand persons, there were similarly more red dots and distributed blue dots.

But when the model was of a city with 25,000 persons, there was a peculiar grouping together of blue dots – they had reached a critical number, at which the city facilitated the best in the city coming together, to grow. When the city grows to 1,00,000 persons, there are clusters of blue dots and dots at the periphery are turning …. Purple!

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