Tuesday, 24 July 2018

Memes and neoteny

The term "neoteny" refers to the retention of youthful characteristing into adulthood. It is a type of developmental delay, and it is widely thought to have been important in human evolution. Neoteny is what makes baby chimpanzees resemble adult humans.

It seems that only a few have speculated about the possible links between cultural evolution and neoteny. However, there are some rather obvious possibilities. For most of the last 3 million years, selection appears to have favored larger brains. According to my favorite theory this was because big brains can hold more memes. If large brains were selectively favored, an increase in size would have required a genetic basis, and neoteny is one way of making adult brains larger - since a large head to body size ratio is a juvenile trait. This hypothesis is the polar opposite of Steven J Gould's bizarre idea that large brains could have been a side effect of neoteny - and so didn't require any special adaptive explanation.

Delvelopmental delay creates larger adult brains, but it also prolongs brain plasticity - helping adults to continue to learn new things. Like large cranial volume, this attribute could well be a shared interest of many memes.

Another common theory is that neoteny triggers "helping" behavior from other individuals. A "cultural evolution" spin on that idea might say that neoteny triggers "teaching" behavior.

Discussions of neoteny frequently mention the idea that neoteny could have been favored by sexual selection. The preference by men for young women is often cited in this context, with younger women having a longer streak of child rearing ahead of them and with them being rated by men as being more attractive. Sexual selection is all very well, but it generally doesn't explain why we have stronger preferences in this area than chimpanzees do. Preferences are like fashion. They fossilize badly and it isn't easy to explain what traits are favored.

Another hypothesis is that humans are attracted to and interested in their young. Humans produce young which are born helpless and immature. They need help. A preference for youth could help to promote parent-child bonding and childcare responsibilities. Childcare is especially important for humans as young children are so helpless this is also when much enculturation takes place.

There are quite a few ideas explored in this article. It will be a challenge to future researchers to figure out which ideas are primarily responsible, abd which effects are bit players. The first ones mentioned - that developmental delay leads to larger brains and lifelong learning - seem like the big ones to me. However maybe the other ideas have merit - and maybe there are other ideas which I haven't yet thought of.

Overall, neoteny looks like a fertile subject area for students of cultural evolution.

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