Neoteny is a word from the Greek νέος (neos), meaning 'young' and τείνειν (teínein), meaning to 'stretch' or 'extend'.

In Biology and zoology it refers to when after the onset of sexual maturity, bodily features from before puberty are retained. Broadly speaking, neoteny is a delay in adult development due to the retention of youthful characteristics. Biologists have studied this phenomenon extensively primarily in tailed amphibians, but neoteny has become almost a separate field of study as the evolutionary benefits it conveys have been explored across species including humans.

In mammals, the characteristic features of infancy usually trigger protective and caring responses, hence they confer a benefit. Pets in particular often are bred to show such characteristics.

Even a pig baby looks cute:

For humans, who only reach sexual maturity much later, the concept of neoteny has been applied to evolutionary aspects, to the deliberate imitation of it, to behavioural/ psychological neoteny.

The evolution of human faces has been described as the retention of youthful features:

From left to right: Erectus, Neanderthal and Sapiens. Evolution of neoteny probably made sapiens more sexually attractive. Some neotenic traits above: Reduced brow ridges, higher forehead, thinner jaw, and larger eyes. Sources: National Geographic, London Natural History Museum. Source: Phys.org - News and Articles on Science and Technology.

Behaviourally we tend to mimic youth into later adulthood. Be it in terms of how we dress, our lifestyles, etc, in our culture youthfulness has become an obsession. Just look at the marketing of products, especially cosmetics, that promotes ‘looking younger’.

A very prominent body feature that we still share with other animals is hair., not only on our head but all over our body e.g. body hair only really appears after puberty and the almost ‘mandatory’ removal of it from legs, arms, etc in women, but also recently in men, is meant as a signal that age really hasn’t set in. An interesting read on this is here: Consumer Neoteny: An Evolutionary Perspective on Childlike Behavior in Consumer Society https://journals.sagepub.com/doi/10.1177/1474704916661825.

See also: How to feign neoteny: an instruction manual for women The following instruction video from the Fascinating Womanhood Movement teaches women how to feign neoteny to get their own way with husbands. (1.37 to 2.33): Group facilitator: Another thing IR… https://gynocentrism.com/2018/07/06/how-to-feign-neoteny-an-instruction-manual-for-women/ Psychologically too we have extended immaturity. Youth is essential for culture's future both in the promise it holds for future life (making parents grandparents) and for novel ideas that advance for society and culture. But in the Western world, this has led to a delay in ‘adulthood’ where you truly take care of your need yourself to well into your twenties. Indeed, a major cause of psychological neoteny is prolonged formal education. That neoteny can be advantageous in modern culture is a view that has been advanced by Bruce Charlton who argues that it confers flexibility - something youth is better at than older people. The rise of the boy-genius: psychological neoteny, science and modern life - PubMed The mid-20th century saw the rise of the boy-genius, probably because a personality type characterized by prolonged youthfulness is advantageous both in science and modern life generally. This is the evolution of 'psychological neoteny', in which ever-more people retain for ever-longer the character … https://pubmed.ncbi.nlm.nih.gov/16750307/ PDF here The rise of the boy-genius: psychological-neoteny, science and modern life Charlton BG. The rise of the boy-genius: psychological neoteny, science and modern life. Medical Hypotheses . 2006; 67: 679-81 The rise of the boy-genius: psychological-neoteny, science and modern life ABSTRACT The mid-twentieth century saw the rise of the boy-genius, probably because a personality type characterized by prolonged youthfulness is advantageous both in science and modern life generally. This is the evolution of ‘psychological-neoteny’, in which ever-more people retain for ever-longer the characteristic behaviours and attitudes of earlier developmental stages. Whereas traditional societies are characterized by initiation ceremonies marking the advent of adulthood, these have now dwindled and disappeared. In a psychological sense, some contemporary individuals never actually become adults. A child-like flexibility of attitudes, behaviours and knowledge is probably adaptive in modern society because people need repeatedly to change jobs, learn new skills, move to new places and make new friends. It seems that this adaptation is achieved by the expedient of postponing cognitive maturation – a process that could be termed psychological neoteny. (‘Neoteny’ refers to the biological phenomenon whereby development is delayed such that juvenile characteristics are retained into maturity.) Psychological neoteny is probably caused by the prolonged average duration of formal education, since students’ minds are in a significant sense ‘unfinished’. Since modern cultures favour cognitive flexibility, ‘immature’ people tend to thrive and succeed, and have set the tone of contemporary life: the greatest praise of an elderly person is to state that they retain the characteristics of youth. But the faults of youth are retained with well as its virtues: short attention span, sensation- and novelty-seeking, short cycles of arbitrary fashion and a sense of cultural shallowness. Nonetheless, as health gets better and cosmetic technologies improve, future humans may become somewhat like an axolotl – the cave-dwelling salamander which retains its larval form until death. * * * The mid twentieth century saw the rise of mathematicians and physicists who looked and behaved in a markedly youthful style, and this boy-genius stereotype spread to include most other branches of science. My suspicion is that that a personality type characterized by prolonged youthfulness is advantageous not just in science, but in most areas of modern life due to its need for flexible specialization. We are witnessing the evolution of ‘psychological-neoteny’, in which ever-more people retain for ever-longer the characteristic behaviours and attitudes of earlier developmental stages. Perhaps the most famous boy-genius was James Watson around the time he co-discovered DNA. Iconic is the famous 1953 publicity photograph of a gangly, shock-haired Watson gazing-up in wide-eyed wonder as a balding, middle-aged-looking Crick points at a big molecular model [1]. But surveying photos of the https://www.hedweb.com/bgcharlton/ed-boygenius.html There are instances when people need to keep