In the Light of Evolution Volume V: Cooperation and Conflict (2011) / Chapter Skim
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17 The Cultural Niche: Why Social Learning Is Essential for Human Adaptation--ROBERT BOYD, PETER J. RICHERSON, and JOSEPH HENRICH
17 The Cultural Niche: Why Social Learning Is Essential for Human Adaptation--ROBERT BOYD, PETER J. RICHERSON, and JOSEPH HENRICH
Pages 363-382
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From page 363... ...
Here we argue that humans may be smarter than other creatures, but none of us is nearly smart enough to acquire all of the information necessary to survive in any single habitat. In even the simplest foraging societies, people depend on a vast array of tools, detailed bodies of local knowledge, and complex social arrangements and often do not understand why these tools, beliefs, and behaviors are adaptive.
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From page 364... ...
, wellengineered shelters, local knowledge about game, and techniques for creating light and heat. This is just the northern Eurasian steppe; each of the other environments occupied by modern human foragers presented a different constellation of adaptive problems.
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From page 365... ...
Humans, by contrast, have evolved "improvisational intelligence," a suite of uniquely flexible cognitive capacities that allow our species to acquire locally adap tive behavior in a wide range of environments. In short, we are adapted to the "cognitive niche" (Tooby and DeVore, 1987; Pinker, 2010)
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From page 366... ...
However, we do not think this is sufficient to explain our ecological success. The cognitive niche hypothesis overestimates the extent to which individual human cognitive abilities allow people to succeed in diverse environments and misunderstands the role that cul ture plays in a number of important ways.
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From page 367... ...
During the winter most Inuit lived in substan tial driftwood and sod houses, but the Central Inuit wintered on the sea ice, living in snow houses. These round vaulted structures were ≈3 m high, made of snow blocks cut with a serrated bone knife.
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From page 368... ...
. During the high summer, the Central Inuit used the leister, a special three-pronged spear with a sharp central spike and two hinged, backwardfacing points, to harvest Arctic char in large numbers.
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From page 369... ...
. There are no convincing examples in which social learning allows the gradual
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From page 370... ...
King William Island is the heart of Netsilik territory, and the Netsilik have lived there for almost a millennium. King William Island is rich in animal resources -- the main harbor is named Uqsuqtuuq which means "lots of fat." The British sailors starved because they did not have the necessary local knowledge and, despite being endowed with the same improvisational intelligence as the Inuit and having 2 years to use this intelligence, failed to learn the skills necessary to subsist in this habitat.
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From page 371... ...
Explorers Elisha Kane and Isaac Hayes wintered with the Polar Inuit in 1853 and 1861, respectively, and reported that the Polar Inuit lacked kayaks, leisters, and bows and arrows and that their snow houses did not have the long heatsaving entryways that were seen among other Inuit populations. They could not hunt caribou, could only hunt seals during part of the year, and were unable to harvest Arctic char efficiently, although char were plentiful in local streams (Mary-Rousselière, 1996)
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From page 372... ...
It may be costly for individuals using improvisational intelligence to discover locally adaptive information, but once it is acquired, others can get it by teaching or imita tion at relatively low cost. As a result, social learning acts to spread the cost of innovations over all who benefit.
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From page 373... ...
Second, cultural learning allows the gradual accumulation of small improvements, and if small improvements are cheaper than big ones, cultural learning can reduce the population's learning costs. Finally, by comparing "teachers" and learning selectively from those that seem most successful, "pupils" can acquire adaptive information without making any inferences based on environmental cues.
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From page 374... ...
that selection can lead to a psychology that causes most individuals to rely on cultural learning most of the time, and also simultaneously increases the average fitness of the population relative to the fitness of a population that does not rely on cultural information. These models assume that our learning psychology has a genetically heritable "information quality threshold" that governs whether an individual relies on inferences from environmental cues or learns from others.
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From page 375... ...
In contrast, cultural species can learn how to make bows from others after these have been improved by experience. Therefore, cultural learners start their search closer to the best design than pure individual learners and can invest in further improvements.
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From page 376... ...
These models predict that an adaptive evolved psychology will often cause individuals to acquire the behaviors they observe used by in others even though inferences based on environmental cues suggest that alterna tive behaviors would be better. In a species capable of acquiring behavior by teaching or imitation, individuals are exposed to two different kinds of cues that they can use to solve local adaptive problems.
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From page 377... ...
EVIDENCE FOR CULTURAL ADAPTATION The cultural niche hypothesis and the cognitive niche hypothesis make sharply different predictions about how local adaptations are acquired and understood. The cognitive niche hypothesis posits that technologies are adaptive because improvisational intelligence allows some individuals to figure out how they work and why they are better than alternatives.
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From page 378... ...
Food taboos targeting these species during pregnancy and lactation prohibit women from eating these species and reduce the incidence of fish poisoning during this period. Although women in these communities all share the same food taboos, they offer quite different causal explanations for them, and little information is exchanged among women save for the taboos themselves (Henrich and Henrich, 2011)
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From page 379... ...
CULTURE AND MALADAPTATION Cultural adaptation comes with a built-in tradeoff. The cumulative cultural evolution of complex, hard-to-learn adaptations requires indi viduals to adopt the behavior of those around them even if it conflicts with their own inferences.
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From page 380... ...
The evolution of the psychological capacities that give rise to cumulative cultural evolution is one of the key events in our evolutionary history. The availability of large amounts of valuable cultural information would have favored the evolution of bigger brains equipped to acquire, store, organize, and retrieve cultural information, a fact that may explain the rapid increase in human encephalization over the last 500,000 years and the evolution of specialized cognitive abilities that emerge early in life, such as theory of mind, selective social referencing (Stenberg, 2009)
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From page 381... ...
Despite earnest efforts, chimpanzees cannot be socialized to become humans and have little or no cumulative cultural evolution. Beginning early in human ontogeny, our psychology allows us to learn from others, powerfully and unconsciously motivates us to do so, and shapes the kind of traits that evolve.
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