Role of Culture in Bounded Rationality

golden-naped-barbetThis post examines Chapter 19 of Bounded Rationality.
That chapter looks at three ways  that cultural processes produce boundedly rational heuristics/algorithms. They are:

  1. Simple imitation and learning heuristics
  2. Over  cultural evolutionary time scale, the aids in number one have given rise to complex motivations, rules, cues, etc.
  3. From these first two, group processes that distribute cognition, knowledge, skill, and labor have arisen.

The authors state that culture is information and that it does not have to be shared, but it usually is.

Two of the imitation processes are prestige based transmission and conformist transmission.  We tend to copy the behaviors of prestigious individuals. By imitating a bundle of their traits, we can upgrade solutions to the problems of life.  Societies also make it easy to identify the prestigious individuals by signals of respect. High prestige people get interrupted less, speak more, and get more compliments. Conformist transmission implies copying the most common behaviors in a population.  These imitation processes can create effective decision making, even when the individual participants do not understand how they work.

The authors point to the Kantu of Borneo.  Each Kantu farmer selects a new garden location based both on the bird found there and the call it makes when first seen there.  This tends to randomize decisions and reduce chances of catastrophic failure for the group as a whole.  It helps to prevent the gambler’s fallacy and diversifies the locations. Of course, it only works because the farmers believe in the bird omens.

Another example suggests that cultural evolutionary processes can create effective mental models of complex systems.  A inland living California native population developed a cultural model of lunar phases and tides to tell them when to visit the ocean to harvest shellfish.

Finally, cultural transmission can give rise to a higher level selection process called cultural group selection.  The authors examine this through three different areas: reciprocity and cooperation, mate selection, and food selection.

Reciprocity and Cooperation

  1. People have a natural propensity to reciprocate and behave fairly, but are sensitive to cues that allow them to adjust their degree of trust and expectations of fairness and punishment.  Simple heuristics like “give half” or “take almost everything” can work quite well if your group members all know and follow the same rules, and this tends to be the case in groups.  However, outside your group, you may do poorly.
  2. People come predisposed to cooperate with only kin and close friends or tribe.  Thus the development of anonymous exchange and cooperation results from cultural evolutionary processes.  This requires each individual to acquire an entire behavioral model about how to deal with situations.

Mate Selection

  1. Although there are some regularities in mate selection like women’s preference for wealthy powerful men, people living in different groups select mates in a large variety of ways.
  2. Among the Kipsigis, brides are sold for cows with the fattest brides being worth the most.
  3. Among many Amazonian groups, the ideal partner is someone who does not speak your language or may your mother’s brother’s daughter.

Food Choice – This is a much more common decision than mate selection, but still culture dominates.

  1. Many people in the Midwest of the United States will not eat lamb and people in the U.S or U.K. won’t eat horse. Germans often think that drinking water after eating cherries is deadly. Certain native South Americans will not eat snake, but close by groups enjoy snake.  The Chinese hunt snakes and raise them for food.  Chile peppers can be physically unpleasant, but can be a store for vitamins, preserve other food, and even help control parasites.
  2. Some cultural practices are maladaptive. Favism is an example especially in Sardinia. Fava beans tend to be eaten most in areas around the Mediterranean where malaria was endemic.  Fava beans contain a malarial prophylactic.  Men with a certain mutation also were less vulnerable to malaria.  However, when those men eat fava beans, they become ill because they overdose on malaria medicine.  Eating brains of relatives by the Kuru has brought so called mad cow disease. Manioc root went from the Amazon to Europe to Africa, but the cultural practice to remove the cyanide did not follow.

Cultural processes can quickly become maladaptive when environments change or when people move.  Different groups punish norm violators differently. Very strict enforcement is likely to inhibit within group process changes.  Group size and isolation affect cultural evolutionary rates.  For example, sophisticated stone age aborigines settle in Tasmania about eight thousand years ago. By 1835, they had lost the knowledge of how to make fish hooks, canoes, nets, and how to make fire.

Henrich, J., Albers, R., Boyd, R, Gigerenzer, G., McCabe, K., Ockenfels, A., Young, H (1999) Group Report: What is the Role of Culture in Bounded Rationality? Gigerenzer & Selten eds. Bounded Rationality the Adaptive Toolbox, Cambridge: The MIT Press.


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