Neoteny

[Diebert van Rhijn]

Neoteny (IPA: /niːˈɒtɨniː/), also called juvenilization, is the retention, by adults in a species, of traits previously seen only in juveniles (a kind of pedomorphosis), and is a subject studied in the field of developmental biology.

Interesting term I encountered: neoteny.

There is controversy over whether adult humans exhibit certain neotenous features, or juvenile characteristics, that are not evidenced in other great ape species. Stephen Jay Gould was an advocate of the view that humans are a neotenous species of chimpanzee. The argument is that juvenile chimpanzees have an almost-identical bone structure to humans, and that the chimpanzee’s ability to learn seems to be cut off upon reaching maturity.

Another theory suggests that humans' neotenous characteristics were an evolutionary strategy that enabled Cro-Magnons (Homo sapiens) to gain predominance over H. neanderthalensis (and possibly H. erectus and H. heidelbergensis) by appealing to these species' nurturing instincts through paedomorphic cuteness to avoid territorial aggression.

While neoteny is not necessarily a physical state experienced by humans, paedomorphic characteristics in women are widely acknowledged as desirable by men. For instance, vellus hair is a juvenile characteristic. However, while men develop longer, coarser, thicker, and darker terminal hair through sexual differentiation, women do not, leaving their vellus hair visible.

Paedomorphic variations exist not only between the sexes, but also between ethnic groups and even between individuals.

Bruce Charlton suggests that there may be such a thing as "psychological neoteny", with cultural causes: "In a psychological sense, some contemporary individuals never actually become adults."[2] Delayed maturity might be a consequence of later parenthood, itself caused by more prolonged formal education.[3]

Similarly, Juliet Schor suggests in Born to Buy that people raised in a modern consumer culture never attain an adult level of self-sufficiency. These "infantilized adults" remain dependent on mass-produced products in the same way that a child is dependent upon parents.

There's an interesting link with retardation or even the 'feminine mind' as often defined on this forum. It could mean that feminization [with its appeal to nurturing and protective instincts] had several evolutionary benefits in terms of competition and development.

Will humanity on its population peak consist of 12 billion grey haired babies?

[vicdan]

Neoteny is a well-known result of selection pressure. For example, much of domestication is due to neoteny. Adult dogs exhibit characteristics of juvenile wild canines. An experiment in russia with breeding polar foxes for temperament, IIRC, replicated a similar effect in about a dozen generations; cotemporaneously, the foxes started exhibiting physical neoteny as well as behavioral -- they retained cub fur tufts longer, had bigger heads, and somesuch.

Whether neoteny applies to humans is a big question though. We are genetically programmed to recognize and like juvenile features (large eyes, large head, and somesuch), so exploiting this might provide a reproductive advantage; see the common liking for large eyes.

My dog used to have the same thing. he retained baby-fur tufts behind his ears until his death. he remained a playful puppy all his life, too.

Kinda sad, in a way. For our enjoyment, we are sorts denying these animals the chance to fully grow up.

[brokenhead]

Whether neoteny applies to humans is a big question though.

I think Gould's point was to compare mammalian species and see at which percentage of total expected life span members of a given species normally become self-sufficient. Humans as a species can pretty clearly be seen as neotonous in this light. It is more difficult to compare branches of human species. It can be argued that modern humans in a technologically more complex world require a longer training period to become contributing members of a technologically advanced society. At the same time, life expectancy has been increasing, so the percentage point might be unchanged as to when a member is ready to "leave the nest." If you are speaking of physical changes from one generation to the next, such as delayed onset of puberty, that does not seem to be happening.

[Shahrazad]

broken,

If you are speaking of physical changes from one generation to the next, such as delayed onset of puberty, that does not seem to be happening.

I've heard people claim that it is happening -- that girls are reaching puberty earlier than two or three generations ago. But I don't believe them. If anything, we should be evolving such that girls reach puberty at 18, when they are mature enough to face the consequences of unprotected sex.

[brokenhead]

broken,

If you are speaking of physical changes from one generation to the next, such as delayed onset of puberty, that does not seem to be happening.

I've heard people claim that it is happening -- that girls are reaching puberty earlier than two or three generations ago. But I don't believe them. If anything, we should be evolving such that girls reach puberty at 18, when they are mature enough to face the consequences of unprotected sex.

Yes, Shah, I agree with you here.

Remember that neotony would be the term if puberty began to happen later in an average life. I think the reverse it what has been observed, at least over the last century or so. This may not be due to differential mortality, or the environment affecting the gene pool through natural selection, but rather the better medical care and nutrition and public knowledge of health issues than before this past century.