The importance of cultural evolution in the spread of Homo Sapiens
Tom Hymas
Most organisms on earth are confined to one particular environment and type of habitat. The evolution of their ‘selfish genes’ 52 exerting phenotypic effects on their survival vehicle has dictated which habitat the organism is likely to reside. In Homo Sapiens, however, genes have unprecedentedly given control to culture. No longer are we tied back by the slow process of genetic evolution, we have ‘thrown off the yoke of our genes’. 53 This transition was made possible by genetic evolution favouring traits in humans for cooperation and sociality. Perhaps the most important is social or observational learning, which is an ability apparently limited to humans. This enabled the cultural evolution which many believe to fit a Darwinian model, 54 although this is subject to debate. We should also recognize our development of language and the differential selection of human groups as crucial factors in our cultural evolution, as they facilitated increasingly advanced cooperation and ideas. The key difference between human and other early hominids was social learning. Many species of animals in the world appear to have culture. Chimpanzees, for example, tend to go about finding food in an identical way to their parents. However, this is not social learning; it is merely local enhancement. 55 That is to say the chimpanzee does not learn from its mother, merely that it goes to the same place for feeding each day means it is more likely to discover, from scratch, the same practice of foraging as its parent. Uniquely Homo Sapiens appears to possess a theory of mind. 56 Chimpanzees as an example do not understand they are doing actions for a reason; it is more a biological drive to find
food, how humans understand their neighbour is making his axe sharper for some motivation and will therefore copy him if he perceives this action bringing him success. Cumulative cultural evolution began like a ratchet effect after humans began to understand each other as mental agents, which is vital to social learning. Different ideas tend to be preferentially and socially learned due to transmission biases. The biases are analogous to environmental pressures in genetic evolution, in that a new idea will transmitted depending on whether the biases favour it. There are two types of biases: ‘content biases’ and ‘context biases’. Content biases appeal to something more innate within us, for example enjoying sugary foods. 57 The idea ‘eat sugary foods’ is therefore likely to be transmitted through the cultural group. Content biases also arise culturally. For example, if there is a food taboo, a member of the group is unlikely to develop a taste for the food due to social pressure. Context biases also drive the process of cultural evolution. The first is prestige bias where learners in the group are more likely to socially learn from someone who has achieved prestige, often indicated by the amount of deference paid to him by other group members. The second is skill bias, this might be determined by watching two different men performing the same particular skill, this direct observation can indicate who to learn from. Lastly, success bias. If a group member has many human skulls or animal skins, it may suggest he would be a good person to socially learn fighting from. This can give a more reliable picture than skill biases as it suggests consistency of a certain skill. The final context bias is conformity bias. Conformist biases allow individuals to aggregate information and behaviours from the behaviours of many other individuals. This
52 Dawkins (1976). 53 Pagel (2012), 4.
54 Not by Genes Alone: How culture Transformed Human Evolution. University of Chicago Press. 2005. 55 ‘Memes: Universal Acid or better than a mouse trap.’ June 1999 Cambridge Meeting on Memes. 56 Ehlrich and Ehlrich (2008), 78.
57 Henrich and McElreath (2007).
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