Saturday, February 16, 2008

II. Neoteny


In Mexican pools low on iodine
The axolotls can’t become adult –
Mature infants swimming as a result,
With pale pink gills all feathery and fine.
Here one observant infant species learns
Something about itself while watching children-
Adults that swim and mate. Is this where we’ve been,
In this old youth that our maturity yearns.
We look into these pools, these clearer mirrors
Which show a stage we even now go through,
Young apes immaturing to people who
Can love axolotls, which open doors.
In these large salamanders we can see
The deepest source of our humanity.

Neoteny, “which means literally stretching out, or holding on to, youth” gives a species the ability “to reproduce . . . while still in the juvenile form” (Gribbin & Cherfas, 152). This happened in a Mexican salamander, the axolotl, and happened too in the evolution of vertebrates, when a line of sea squirt larvae were unable to develop past their notochord form into the stationary, sack-like mature state. The larval stage of sea squirts (tunicates, subphylum Tunicata) looks very much like a primitive organism having a notochord that exists today, the lancelets (subphylum Cephalochordata), which gave rise to the vertebrates. We are fortunate in having each of these stages of chordate evolution still alive, starting with lancelets, which gave rise to the jawless cartilaginous fishes (lampreys and hagfishes, Agnatha), leading to the jawed cartilaginous fishes (sharks, skates, and rays, Chondrichthyes), and then to the bony fishes (Osteichthyes), which gave rise to the land animals. Neoteny “allows a species to spring itself from the trap of specialization” (Gribbin & Cherfas, 154) found in sea squirts, and become generalists, as fish indeed are by comparison. With a specialist species, each individual species has its own niche, and if something were to happen to that niche, that specialist would likely die out. Generalists, however, have unity in form, but such adaptability as to be able to live in a wide variety of niches. Neoteny involves “very few gene changes” (Bonner, 51) – typically just regulatory-timing genes, as “there has been a simple modification of a few genes governing the duration of development of some parts of the organism” (Bonner, 51). These “mutations that affect the early development of an animal are likely to set if off down a new path and enable it to exploit the opportunities that exist, and neoteny seems to have been responsible for some of the major evolutionary jumps” (Gribbin & Cherfas, 154). All of this is relevant because of the idea proposed as far back as 1926 by Louis Bolk that humans, who are indeed unified in form, but can live in almost any niche, are a neotenous species of ape. A quick survey of human versus infant chimpanzee traits shows how persuasive this idea is: a large brain (relative to body size) encased in a domed skull,

our face is flat, with no ridges above the eyes, no muzzle, small jaw and teeth. Human adults have a baby-face compared with other apes, and a baby chimp looks more like a human than like an adult chimp. Even the position of the human skull is neotenous - the hole by which the spinal chord enters the skull is below the skull and points downwards in man, so that as we stand on our two feet our eyes are pointing forward (Gribbin & Cherfas, 158).

As Gribbin and Cherfas point out, the physical features, “large brain, small jaws, upright posture – are the most distinctive marks that set humans apart from the other apes. All three owe part of their existence to neoteny” (158). Another neotenous feature includes the forward-pointing human vagina (also found in bonobos), which is found in infant chimpanzees, but which moves as the chimpanzee matures until it is angled toward the back in adults (158). There is plenty of suggestive anatomical evidence that humans are nothing more than a neotenous species – that we are a juvenile that has not grown up physically, while still managing to reach sexual maturity, including the fact that there is a “relatively small change in the development of man, involving simply a difference in the timing of developmental processes [which] led to man’s increased intelligence and elaborate culture” (Bonner, 51). Our interest in playing and games also suggests we are nothing more than a juvenile ape, since our interest in playing and games matches that of juvenile apes. This propensity to play is the same thing as saying a propensity to narrate, since in order to play, one must narrate. Play is a way hunters learn how to hunt, which requires narrative. The same would be true in a strongly social species, such as chimpanzees, where play would prepare the young for the serious politics of adulthood. Play is a way of testing alternative scenarios (narratives) in a safe environment, before the seriousness of adulthood has to take over. If we remained infants, we would have also continued narrating, playing our way into language.

But Geoffrey Miller argues in The Mating Mind that sexual selection could give rise to youthful traits, which would give the appearance of neoteny (214). This does raise the question (a question Miller himself raises) as to why humans, and not chimpanzees, would select for youthful traits. In The Red Queen, Matt Ridley too expresses some doubt about neoteny, but nonetheless notes that neoteny “could be a consequence of sexual selection, and since neoteny is credited with increasing our intelligence (by enlarging the brain size at adulthood), it is to sexual selection [for youthful features] that we should attribute our great intelligence” (342). One reason both writers reject neoteny is that they associate neoteny with our being a “retarded” ape. But neoteny can be the kind of step back that results in a leap toward more complexity. “Adult animals tend to be well designed – well adapted – for a particular way of life, but juveniles, still in the process of growing and developing, are generally less well fitted to a particular adult niche” (Gribbin & Cherfas, 154). We also do not have to choose between the options of neoteny or sexual selection for youthful traits. There could have been a feedback loop between both, driving us toward neoteny.

Current genetic evidence suggests humans, bonobos, and chimpanzees shared a common ancestor, with the line giving rise to chimpanzees branching off first, then the line giving rise to bonobos branching off from the line that gave rise to the hominids (bipedal apes). Bonobos are distinguished from chimpanzees in being slightly smaller, tending to move bipedally more often, having a forward-tilted vagina (like all infant mammals) rather than a rearward-tilted vagina (like all other adult mammals, excluding humans), and stronger social bonds created through increased sexual activity – including consistent bisexual behavior patterns. Among bonobos, most conflicts are resolved using sex. Bonobos being essentially bisexual suggests that humans too should be bisexual. So why are we not? This is perhaps the wrong question. We should instead be asking why very often humans have chosen to act in more stringently heterosexual ways (we do not always do what we feel like doing). There is evidence that suggests we are bisexual by nature (as evidenced by much behavior in ancient Greece and the Roman Empire), but that as we made the connection between sex and reproduction, we often chose in favor of more reproduction, over the possible social benefits. So while it is likely in our nature to act more like bonobos, we have chosen instead to direct sex toward reproduction rather than using it to strengthen social bonds.

As previously noted, the forward-tilted vagina is a neotenous trait. Thus, bonobos are slightly neotenous chimpanzees. Chimpanzees mate from behind, but the forward-tilted vagina makes face-to-face mating more comfortable. If mating is done from behind, the male and the female both are looking at things other than the one with whom they are mating – with the males focusing mostly on the backsides of the females, the retention of which would explain human males’ connection of sexual attraction to female bodies, especially the buttocks. The pleasure associated with mating gets distributed to the general environment, and no meaningful personal associations get made with mating. With a forward-tilted vagina, face-to-face mating is more comfortable, and the male and female both end up looking at each other during mating. The pleasure associated with mating gets connected with the face in front of the bonobo, and a meaningful connection is created – sexual pleasure becomes causally associated with the members of the troop, social bonds would be strengthened, and sexual contact would increase – as we see in bonobos. An entirely accidental retention of one neotenous trait in the common ancestor of humans and bonobos resulted in stronger social bonds and an increased importance given to sex by the social group, and to the individuals in that group. The added social benefits too would then select for those individuals who had the initial neotenous genetic change.

Small changes in gene regulation can result in large external changes in an organism. “All that neoteny requires is a minor modification to the genes that control development” (Gribbin & Cherfas, 154). This would explain the tiny genetic difference between humans and chimpanzees:

There are, in all likelihood, only a few genes that control the unfolding of development, so mutations to those genes will be quite rare. But when they do occur they are likely to have a profound outcome, affecting, as they would, all aspects of growth, maturation and development. All that external change balanced on a tiny internal change to the genetic code. (154-5)

We see a butterfly effect in evolution, with a developmental-gene butterfly creating the hurricane of human evolution. And with this genetic change,

neoteny accounts for the mechanics of the process whereby a minuscule change of just one per cent of the genetic blueprint can produce creatures as different in outward appearance as ourselves and the African apes. The final shape of an animal is dictated largely by the rate at which different parts develop and grow, and it is only the few genes that control the unfolding of development that would need to change in order to produce an upright ape from a knuckle-walker. (177)

Since neoteny comes from mutations that accelerated “the development of their sexual organs” (153), allowing the organisms to breed while still immature, we should not be surprised to see the first step in mammalian neotenous development is the forward-tilted vagina we find in bonobos.

Once neoteny had established itself in the forward-tilted vagina, sexual selection could certainly have become increasingly involved in further selection for neoteny. Those females with forward-tilted vaginas would carry the developmental genes for neoteny, and pass them on. Also, those with forward-tilted vaginas would likely breed more, since the face-to-face mating position would cause sexual pleasure to be directly associated with those partners. Males would prefer to mate with such females. The stronger social bonds created would also make the troop as a whole better able to survive. Survival of the fittest often means survival of the strongest social group, of those who can better cooperate. We also see suggestions of this initial neoteny in the bonobos’ tendency to walk upright more often than do chimpanzees, suggesting the initial neotenous change would not have been localized to the angle of the vagina. Since the toe has not turned out yet on infants, bipedal locomotion is easier, and thus more common. Since bonobos have some early neotenous features, we should not be surprised to find them acting like chimpanzees on the edge of infancy and adulthood. And not just physically.

Bonobos play more often than do chimpanzees (though much less than humans). Like humans, they are behaviorally more like infant chimpanzees. One would predict, then, that neoteny would create more youthful-acting males, who were more cooperative and easier to get along with (Ridley, 343) – easier to socially integrate. We see this in bonobos (and humans). Male chimpanzees tend to be more social among other males are than females, and more aggressive. Male and female bonobos, on the other hand, are more similar in their social behavior, and each is more likely to use sex (with both with males and females) to resolve problems than resort to aggression, as do chimpanzees. Since strongly social animals are better able to adapt – as a group – any selection for more social males would have an adaptive advantage. The ancestors of humans and bonobos were the first species to use domestication – on themselves. This is not to say that humans are necessarily behaviorally closer to bonobos than to chimpanzees in all ways. While human females act more like bonobo females, human males tend to act somewhat more like chimpanzee rather than bonobo males. Such differences are easy to understand if we see humans and bonobos diverging almost immediately after the forward-tilted vagina evolved – humans adapting to open woodlands/savannahs, bonobos to deep rainforests. It may be more likely the common ancestor of humans and bonobos acted more like humans, with bonobo behavior being the one that changed the most, deep in the rainforest. We act more like chimpanzees than bonobos do, despite the fact that we have language, and bonobos do not. But the neoteny that gave rise to bonobo behavior helped to mold us too, and there are many similarities between us and them.

We can even see a connection between neoteny and adult human love. The most obvious evidence for the connection between an adult’s love for its infant and the transfer of such feelings to adults is our use of baby-talk with those whom we love. The infant’s love for its mother would have resulted in neotenous males continuing to feel love toward females, and would have resulted in a feedback loop in females, strengthening female love-bonds. This would explain our need for touching and cuddling with those we love, a holdover from the infant ape’s need for touch and cuddling (as the famous baby monkey - cloth “mother” without food vs. wire “mother” with food experiment showed). Nietzsche also understood this connection, before the evolutionary evidence we have now existed: “The instincts of morality: maternal love – gradually turning into love in general. Sexual love likewise. I recognize transferences everywhere” (PT, 6).

The extension of the infant-mother bond to adults would create a greater tendency to create pair bonds in a species formerly polygamous, as this love-bond was created between adults. At the same time, our polygamous nature would still be there, an inheritance from our ape ancestors, driving us toward mild polygamy, though with an increasing drive toward monogamy, especially as notions of justice among men (an extension of the love–social-bond) and equality between men and women (another form of the notion of justice) developed and expanded. This expansion of the infant-mother bond into adulthood would also suggest Freud was tapping into something deep and fundamental in his Oedipus complex, though it is clear now that this is overridden by the Westermarck effect, already weakly expressed in chimpanzees, which creates a deep, gut-felt repulsion for having sex with those one was raised with from infancy. This would have resulted in more outbreeding, meaning fewer birth defects, and the behavior being passed on to more offspring. This would have counteracted the confusion created by the infant-mother bond becoming associated with sex in adults – though not perfectly, as the continued problem of incest shows. This neotenous retention of the love bond between infant and mother and its application to a sexually mature adult would explain both the sexual selection for youthful traits, driving neoteny, and the existence of pedophilia.

A pedophile is one whose brain has applied the infant-parent-sex bond to individuals who look even more like infants. This is a prime example of why we should not make the mistake of associating the “natural” with the good, Rousseau as does. Neoteny explains pedophilia – it does not excuse it. While tragedy shows us what happens when we attempt to push ourselves beyond our physis-bound natures, morality is how we keep in check the overextension of elements of our nature. We live in a delicate balance between the two. The overapplication of the connection between infant-mother love and adult sex results in pedophilia. The underapplication of it results in loveless sex, often resulting in children abandoned by their fathers. Each is immoral. The median application of such behaviors creates stronger social bonds within a community of adults, and the creation of children loved by fathers and mothers. The first is perversion, the second is antisocial. Between the two is the kind of love that creates strong families and strong communities, as that love is extended to more and more people.

The way neoteny expressed itself in the common ancestor of bonobos and humans gave rise to species which were more strongly social than the social apes from which they evolved. Bonobos are forest dwellers, so they remained quadrupedal – no environmental pressure drove them to become bipedal. But it would not be difficult to imagine an ape who already stood upright more often than its ancestors, due to neoteny, being driven by environmental changes which expanded savannahs and made the forests more patchy toward walking upright more often. Since neoteny was already at work on the species, one group, on the edge of the receding forests, could have had members with toes less turned out as they became adults, making upright walking much easier on flatter feet. To the extent upright walking allowed for more rapid crossing from one patch of food-bearing trees to another than did knuckle-walking (a very high-energy mode of transportation, especially compared to bipedal walking), it would have certainly been selected for (by hungry predators). What started out as an “accidental” mutation (they all are), then sexually selected for, would have then met with natural selection. Since “The correct positioning of the large human head for walking on two feet is achieved by neoteny – the angle of man’s head on his neck is the same as that of a neotenous ape” (Gribbin & Cherfas, 158), neoteny would have doubly allowed for upright walking. Overall, neoteny

gave our ancestors a vital package of adaptations: it allowed upright stance (useful to spot predators and freeing the hands to carry and manipulate things), delayed brain development (useful for the young to acquire new tricks of survival in a changing world by learning rather than waiting for inheritance), and, as a kind of bonus, provided a hairless skill (which helped our ancestors to keep cool as they ran across the plains, either to catch food or avoid being caught). Neotenous development also enhanced the natural ape curiosity of our ancestors, and the very powerful selection pressure of the new way of life rapidly weeded out those individuals who couldn’t walk well, or didn’t use their height to watch out for predators, or weren’t inquisitive enough to try new kinds of food. (Gribbin & Cherfas, 202)

Chimpanzees and bonobos are generally quiet (bonobos less so than chimpanzees) in the wild. Some of their communication is vocal, but most is facial and gestural (visual). Gibbons, however, sing. Gibbons are members of the “lesser apes,” and move through the trees using brachiation – they swing through the trees using their arms. This gives them and orangutans both more upright stances, since their legs hang down under their bodies as they swing. To attract mates and maintain social bonds, gibbons sing. So it would not be too much of a stretch to suggest the ancestor of humans could have been a singing ape too. Especially once our ancestors became bipedal, and our larynx dropped and stretched out, giving them a wider range of sounds. This would suggest that music could have been a primary precursor to language. Certainly, music “has a generative structure similar to that of language” (Corballis, 269), and Corballis goes further to suggest as I am, that “Given the rather diffuse yet pervasive quality of music in human society, it may well have been a precursor to language, perhaps even providing the raw stuff out of which generative grammar was forged” (269).

It was a long trek from singing to speaking: “the first hominids discovered upright walking and social graces, Homo habilis discovered tools, Homo erectus discovered fire, and Homo sapiens discovered language” (McCrone, 47-8). If we start with our common ancestor with bonobos, the neotenous forward-tilted vagina gave rise to face-to-face mating, strengthening social bonds and selecting for more neoteny; the neotenous unturned big toe gave rise to upright walking, which gave rise to a wider vocal range with the repositioned larynx; neotenous hands better able to grip than adult hands (as infant chimpanzees grip their mothers’ fur) allowed for finer manipulation of objects, leading to tool-making; more neotenous brains made for greater curiosity, leading to the discovery of fire and to trying different kinds of foods, food which could be made more nutritious by cooking, allowing the brain to grow even more as it had plenty of high-quality, high-energy food available. Our ancestors’ neoteny-created curiosity led to better nutrition, which led to the retention of more neotenous brains, as the energy was available to support them. Larger, denser brains led to more curiosity, leading to greater efficiency in getting food and in locating better sources of it, which drove the creation of larger, denser brains. Social behaviors became stronger and more complex, giving rise to new instincts from combinations of older ones as the brain created more, denser neural connections. We would have become more playful the more neotenous we became, as “Most mammals start out cute, playful, and innovative, and gradually become grim, pragmatic, and habit-ridden” (Miller, 407). And we are far more playful and innovative than bonobos and chimpanzees. Play allows us ways to test plans before we commit to them, as play does for infants learning how to become adults, and this ability to test plans in a safe play-space more than makes up for the high amounts of energy such play requires – which would have been solved, too, by our increasingly better nutrition. And as better nutrition led to larger, denser brains, we would expect, too, to find more connections in the brain, connecting specialized regions, turning the brain, and thus our behavior, more generalist.

Chimpanzees are specialists, and their brains compartmentalize functions more than human brains do. Games and playing (and narrating, which would include hunting) are separate from oral communication in chimpanzees (they do communicate during play, but they do not play with their communication, meaning the relationship is unidirectional and linear and not a bidirectional feedback loop, or nonlinear) and/or symbolic thinking. The nonlinear combination of these (the ability to play with communication and the mapping of communication onto narrative structures of the brain) is something you would expect to see in a nonspecialist’s brain. If grammar and syntax are nothing more than the application of rules – specifically, the rules of narrative, combined with the generative structure of music – to verbal communication, which has now entered the realm of play, we can see how language could arise in humans. The elements are all there, existing independently of humans, in pre-humans. Our linguistic abilities arose because, through neoteny, our brains became less specialized, causing overlap in specialized regions of the brain, allowing for more associations than are found in the brains of our pre-human ancestors. If language is a game, it needs rules. Fortunately, there was already a set of rules available in the rules of narrative that communication could be mapped onto. Those combined rules of narrative and of music are what we call grammar and syntax. Differences in grammar and syntax would arise as different groups settled on different rules with which to play their language games. Why else would adjectives come before nouns in English, while adjectives tend to go after nouns in French? It does not really matter where adjectives are located, so long as the rule is consistent. Some of the rules, including the association of particular sounds or series of sounds with particular objects, actions, or qualities, are arbitrary.

We would also expect some rules to be more stringent than others. While English adjectives precede the noun, English adverbs can be placed almost anywhere in a sentence. As in chess, we have different rules for different pieces, restricting some pieces more than others – and different rules for different languages, as we would see different rules for different, though similar, games (think of all the games we play with balls). This is what one would expect if language were a form of play, and grammar and syntax the rules our brains developed in order to play with words. As any good artist (and every game designer/inventor) knows, creating rules actually increases rather than restricts creativity and freedom. So when the brains of our ancestors evolved to connect narrative, play, and communication, which naturally led to rules for this communication, we should not be surprised to see a sudden “explosion” into language.

The only jump made in the evolution from languageless humans to languaging humans was when narrative mapped onto communication in the brain, and communication was thus given rules. Rules developed regarding what order sounds representing things or actions were to be placed. Give us a bunch of new objects – be they literal objects, or sounds – and we will play with them, associating new sounds with more objects. The rules of playing with communication are grammar and syntax. We were immature apes playing with a new toy – a toy created by our ability to make more sounds with our lowered, lengthened larynx, which were then mapped onto the narrative-creating structures in our brains. By playing with communication, we could have driven our brains to be better at it, pushing us into evolving language. If we started off as a singing ape, narrative could have created more complex songs, which could then have been sexually selected for, as more complex songs would have been a sign of intelligence, and intelligent mates would be better at finding food. Other than that, the foundations for each of the elements of language – symbolic thought, communication, rules, narrative, the generative structure of music – were all already present in our pre-linguistic ancestors.

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