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View Full Version : May inconsistent human development be an important clue for evolution?



MPichetto
02-24-2017, 08:57 AM
This documents aims at highlighting the trait of human infants growth consisting of some senses fairly developed coupled with extended motor immaturity, and at speculating how it may have entered and shaped the human evolutionary path.
In particular it is suggested that the fact humans are born inconsistently developed may be the reason why we are different from the other big apes, and that the road to Homo sapiens may also be the result of a sudden genetic mutation.

Animals are sometimes divided in precocial vs altricial. There is no clear cut definition but it helps to think about newborns ability to move around and feed on their own soon after being born, something that obviously increase their chances of survival.

Nature offers a great variety of solutions tailored to specific circumstances and environments. For example, the cubs of the African Cape buffalo either follow the migrating herd few minutes after birth or they are left behind and cetacean newborns must move immediately after delivery to avoid drowning, even though both become independent from parents only after a while.

With concern to mammals, altricial species such as dogs and cats, normally give birth to many underdeveloped offspring, while precocial species such as horses and monkeys, give birth to a small number of relatively well developed infants, that they frequently feed with low-fat, high calorie milk.

Compared to the most sophisticated primates, humans have similar long gestation lengths (averaging 268 days vs 232 days for Chimpanzee and 257 days for Gorilla), but human babies are relatively larger than theirs (6.1% of maternal weight compared to about 3% in African apes) with relatively smaller brains (29% of adult brain size compared to 40-45% in African apes).

Given the above definition of the term, humans would clearly fall under the altricial category.
In fact, while great apes can immediately cling onto their mothers after birth, human babies are born in an exceptionally helpless condition called “exterogestatation”, meaning they continue to be embryos outside the womb for approximately another nine months.
Just to give you an idea, at birth ends of limb bones are not ossified and ossification centers of the finger bones are usually completely missing.

This means that human infants are totally dependent on their caregivers to provide protection and warmth, to feed them day and night and to help them with their physiological needs for a very long time, even when compared to all other altricial species.

Such rather inefficient setting has been traditionally explained with the combined results of two phenomena. On the one hand adaptation to bipedalism has restricted the width of the birth canal and on the other hand evolution has increased brain size to make men different from the other great apes.

The “cerebral Rubicon theory” goes as far as saying that earlier births had started when the adult brain reached 850 cubic centimeters. If the theory holds, based on paleoanthropologists findings so far, Homo ergaster might be the ideal candidate for the switch.

However, Dunsworth et al have recently pointed out that there is little evidence suggesting that difficult childbirth has affected the gestation length or fetal growth, therefore leaving room for other factors that must have kept newborns size in check.

On the other hand there are several findings suggesting brain size may have not been the reason behind our dramatic development compared to the other great apes.

First, the dimensions of the human brain have diminished ten percent over the past thirty thousand years, or in other words, not only the Cro-Magnons but also the less developed Neanderthals had bigger brains than us.

Second, both the Homo florensiensis and the more recently discovered Homo naledi had much smaller brains, but nonetheless showed non animal behaviors apparently including funeral habits.

One accredited theory for Homo florensiensis is that their overall smaller dimensions (including brain) could be the results of island dwarfing resulting from prolonged living in an isolated habitat providing limited resources.
Oddly enough, other researchers see the same food deprivation from poor environment as one reason for brain size increase in the long run, because it would trigger a response process that eventually transforms synapses into cortical neurons.

Human development is peculiar in another usually neglected way.

Cats and dogs are born with closed eyes and ear canals, but after four weeks they can run.
Apes are born with open eyes, but they almost immediately cling by reflex to the mother's body without external help.
Humans instead take months to first realize they have a body and then almost one year and a half to manage it completely but, on the other hand, we are born with fully developed hearing and partially developed sight and touch.

Moreover, according to Piaget and later research, during the “primary circular reactions” phase spanning between one and a half and four months of age, infants intentionally repeat actions that bring them pleasure and may as well have expectations about cause and effect situations.
For example, a baby of this age may learn that when they hear a switch sound, they can expect light to turn on or off.

In other words, it is like if babies would live in a straightjacket for several months.
They can hear, see something and sense touching, they gradually understand what is going on, but they can do nothing, not even moving their eyes.

If we would experience the same situation as adults, we would probably be somewhere in between scared to death and bored to madness depending on whether or not we feel exposed to danger.
Children are however accustomed to a dark and constricted place that is their home, even though boredom coming from new stimuli and the realization the new environment can be hostile quickly become common reasons for crying.

I wonder therefore if such unique arrangement made of developed senses, cognitive ability and extended motor immaturity, is forcing the human brain to develop in a direction unknown to other animals, that actually makes us different from all of them.

In other words, as brain development directed towards the management of the body into the environment is not effective for several months, babies may undergo a stressful mental development venting their mental energy towards the only available dimension of imagination.

This could result not only in exceptionally developed skills we share with other great apes, but also in specific abilities other animals do not show.

Sherman and Austin, the two famous chimpanzees from Language Research Center at Georgia State University, were first thought how to use a lexicon made by buttons with symbols representing verbs and objects, and then were able to learn a different new one on their own.
The experiment proved they were able to master indexical symbolic relationship, the ability by which someone can transfer a particular way of thinking to different situations.
Humans have the same ability, but we can knit indexes of symbols into several much more sophisticated and intricate systems. This document is just a simple example of this ability.

However, in addition to sharing some mental skills with other animals, we have some peculiar ones. We can imagine things outside past personal and social experience and we are self-aware.

By creating a symbol of ourselves we can even talk to, we can imagine in our minds what we are going to do before we do it. We can think about different scenarios and consciously make a choice, exercising what we call free will.

As Chip Walter has nicely put it: “We are not only an animal that can explore a life not yet lived, and dream of a future we desire, we can also take hold of those dreams and make them come true”.

Moreover, as pointed out by Vauclair, compared to the other great apes, humans have a much stronger inclination to experimenting once body development allows for it, possibly as a reaction to the extended powerlessness imposed by the straightjacket we are born into.

Such peculiar development must anyway be very hard to endure, if it drive us to a certain level of mental disorder.
The idea is that we may be so driven to seek refuge in imagination, that we eventually end up not being able to stop it.
In fact, we tend to think about something else when we do something not particularly demanding, and we cannot stop thinking even when we do nothing.

I also wonder if the fact babies are born inconsistently underdeveloped in the way described above is not the consequence of adaptation, but rather the reason for it.

Even if humans can be classified as altricial considering our extreme moto immaturity, they fit in to the mammalian precocial pattern in some other ways, including the fact we are fed with milk that is similar in composition to precocial mammals.
Since human initial growth requires an exceptional amount of energy, this may suggest that the change from precocial to altricial has not been the result of a lengthy adaptive evolution, but rather a sudden event.

Considering the threats posed by the environment when such adaptation had occurred, there must have been a significant advantage in sacrificing reproductive agility for high mortality of the fetus, infant and mother, otherwise natural selection would had found a smarter solution to offset narrow birth canal compared to brain size.

Moreover, if our unique setting were the result of adaptation, why would nature had given us senses at birth that we cannot act upon for a long time?

Rather than natural selection, could it be that an unexpected random genetic mutation may have intervened and produced individuals more successful in finding innovative solutions to cope with the environment (or in Darwinian terms having greater adaptability), finally leading mutants to become the main state?

The most likely candidate for this dramatic change might have been Homo heidelbergensis.

Neoteny, or in other words fetal physical traits that we share with apes but become permanent in adult humans, may just be an inheritance of such mutation.

Researchers tend to associate the evidence of the rise of the modern human with the findings of painted symbolic figures made around forty thousand years ago, but there may be something much earlier.

While the other great apes were retreating to increasingly smaller forests where they were comfortable because everything was at hand and they were genetically suited for them, some of them moved out in the savanna where it eventually turned out it was more efficient to walk on two legs. Hominids moved to the open space and potentially became bipedal because of this change.

However, it was only after millions of years of evolution including bipedalism and risk of extinction because of three ice ages and the most powerful volcanic explosion called Toba, that Homo sapiens wandered and settled into nearly all the world in the tiny space of “only” fifty thousand years.

In other words there has been a point in human evolution, where hominids invented and carried with them everywhere a set of new “technological” tools, that allowed them to cope with all new environments, without having to change themselves to them by a long process of adaptation.

Paleoanthropologists have a hard time in making deductions from what they find and sometimes new discoveries disrupt their previous hypothesis.
You can therefore expect a lot of speculation has been going on about human evolution.
We know there were several species of Homo, sometimes very different from each other. They lived in small scattered groups. They mated with each other and apparently they ate each other, but we do not know under what circumstances.

It could be that we originated from a random mutation, but it would very difficult to devise how it had happened.
If it had happened, it is however very likely there has been a consequent specific evolution of the human brain both at mental and physical level.

For example, the abilities to invent a language, to talk to ourselves in our minds, to think about how we think about ourselves (metaconsciusness), to shift our point of view and imagine ourselves in the shoes of the person who might be lying to us and to revert this to ourselves in order to spot faults in our own deceiving techniques (theory of mind) must have taken a long time to develop.

Jaynes even argues early humans thought that the voice in their heads was not their own. They instead believed they were listening to someone else who was observing them. This could explain the notion of god, but not necessarily nature worshipping.

From a physiological point of view, several studies show that the production of thoughts and memories transform chemically and physically our brains in real time.
In the long run, human brains have tripled in size and our prefrontal cortex has increased six times.

At the same time, if we accept the idea that a society made by hominids closely resembling apes nurtured and eventually promoted physically and psychically different cumbersome infants, because they made revolutionary inventions that made the life of the society much easier than before, we my view under a different light the ten percent of autistic people such as Lewis Carroll, Wolfgang Mozart, Andy Warhol, Thomas Jefferson, Isaac Newton, Charles Darwin, Albert Einstein, who have made our current lives easier and more interesting than the ones of our parents and grandparents.

In this respect, Bernard Crespi, Steve Dorus et al, by analyzing human DNA from current and prehistorical populations, found that almost 40% of gene variations strongly related to schizophrenia were favored by natural selection instead of being discarded.

To my knowledge, all babies’ interactive toys designed by men expect some, and are mostly aimed at, developing the ability of babies to interact with their environments through their bodies. Unfortunately it takes a long time for babies to reach the stage when they can play them.

Therefore, I finally wonder if a First Interactive Toy (FIT), similar to a current baby mobile / sound machine, but with additional interactive features, may support infants development process by relieving some boredom and powerlessness.
In fact, in addition to the boredom that can be partially overcome by using imagination, babies completely depend on caregivers - especially the mother - and there is nothing they can do about it.

As pointed out by Erickson, if caregivers are consistent sources of food, comfort, and affection, infants learn to trust the environment. If they are perceived as neglectful, infants instead learn that the world is an unpredictable, unreliable and possibly dangerous place.
If parents are there every time babies need them, babies may become unconsciously convinced that they can control it.
This may eventually result in individuals being optimistic or pessimistic and lay the foundation for building self-confidence when, at a later stage, children start dealing directly with the environment and caregivers support them from distance.

Of course, such process is very risky, first because parents have human limitations and second because the communication between infants and caregivers is limited and can be difficult.

Babies normally start cooing and then babbling since the first month and fully control vocalization by the age of six months when they enter the canonical stage and become capable of reproducing every one of the sounds required to speak the over 600 languages humans use around the world.

As motor immaturity lasts longer, sounds (not language) are probably the only and best candidates babies may use to provide input and therefore operate the FIT.

The logical steps of the FIT would thus be:
- Automatic sampling of the baby’s sounds in order select a set of recurring sounds.
- Manual exclusion by caregivers of selected sounds that the baby associates with distressful situations, such as crying.
- Gradual automatic or manual association of the remaining selected sounds with the device embedded acoustic (gentle music themes, natural sounds, white noises, etc) and visual events (lights, movement, etc) that the baby can sense.

By letting babies using the FIT on their own under parental supervision, they may eventually learn how to start events.
In this way, they would be able to start playing at a much earlier stage, with all the related benefits in terms of cognitive, dexterity and imagination development.

In addition, it would also possibly relieve some boredom and related parents commitment, providing at the same time some perception of environment control, that may help to mitigate the effect of powerlessness during the motor immaturity stage.

Besides the above chore features, the FIT would also potentially provide a platform for creating interactive games possibly to explore specific areas, allowing babies to create games on their own, and for sharing games, data and gaming itself through an internet open platform (Wi-Fi excluded as long as there is no clear evidence it is not harmful on infants).

Last but not least, the FIT would only be an optional toy while parents, including wherever possible breast-feeding, remain the only essential and ultimate relievers.

Marco Pichetto
02.10.1968
[email protected]
I want to make the FIT

REFERENCES

On the Origin of Species: By Means of Natural Selection, Charles Darwin, Dover Thrift Editions
https://www.amazon.com/Origin-Species-Natural-Selection-Editions/dp/0486450066/ref=la_B000AQ3LK0_1_3?s=books&ie=UTF8&qid=1486921785&sr=1-3

Ever Since Darwin: Reflection in Natural History, Gould S.J., Norton & Company
https://books.google.it/books?id=nzavAgAAQBAJ&pg=PA71&lpg=PA71&dq=Altricial+longest+development&source=bl&ots=3fv5VXqsB_&sig=aYe11qP2EZjZrGICkmvQ0pNvW2E&hl=en&sa=X&ved=0ahUKEwjo987tqoDRAhXBWxoKHULnDtcQ6AEIMzAE#v=on epage&q&f=false

Adaptation and Natural Selection: A Critique of some Current Evolutionary Thought, Williams G.C., Princeton University Press.
https://brandvainlab.files.wordpress.com/2014/11/williams-1966.pdf

Bambini di ieri = adulti di oggi. Adulti di oggi, adulti di domani, Abbiate Fubini A., Cortina
https://www.amazon.it/Bambini-adulti-oggi-Adulti-domani/dp/8882391140

Development Across the Life Span, Feldman R.S., Pierson
https://www.amazon.com/Development-Across-Life-Span-7th/dp/0205940072

The status of the human newborn (child development)
http://what-when-how.com/child-development/the-status-of-the-human-newborn-child-development/

How the Mind Works, Pinker S., Norton
http://hampshirehigh.com/exchange2012/docs/Steven%20Pinker%20-%20How%20The%20Mind-Works.pdf

How the evolution of symbolic cognition transformed human morality / Moral Psychology, Volume 1: The Evolution of Morality, Peter Ulric Tse, MIT Press
http://www.dartmouth.edu/~petertse/TseMoralityChapter.pdf

Daly, M. & Wilson, M. (1984). Sex, Evolution, & Behavior. Second Edition. Boston: Willard Grant.
Learning from Animals?: Examining the Nature of Human Uniqueness, Louise S. Röska-Hardy, Eva M. Neumann-Held, Psychology Press
https://books.google.it/books?hl=en&lr=&id=Urt5AgAAQBAJ&oi=fnd&pg=PA89&dq=ape+infants+development&ots=DTu4RKbdQ3&sig=g25Fsgxa92zIYOIJwpQ__IVPcGk#v=onepage&q&f=false

Are human infants altricial?, Rosenberg K.R. Trevathan W.R., The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)
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Phylogenetic Approach to Object manipulation in Human and Ape Infants, Vauclair J, Institute de Neurophysiologie ed Psychophysiologie de Marseille
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The Evolution of Difficult Childbirth and Helpless Hominin Infants, Dunsworth H Eccleston L, The University of Rhode Island Faculty
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Metabolic hypothesis for human altriciality, Dunsworth H.M. Warrener A.G. Deacon T Ellison P.T. Pontzer H, Proceedings of the National Academy of Sciences of the United States of America
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The evolution of the nutrient composition of mammalian milks
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Saetro
02-25-2017, 12:43 AM
Any artificial parental substitute needs to be responsive 1) in real time, 2) in a way that is immediately understandable by infants.
A nanny is a traditional substitute. With deficiencies liberally described in literature. (Memoirs, biographies, novels, folk tales.)
Any artificial version would be expected to be inferior to such a substitute human, at least for a while.

Technical challenges therefore include:
1) understanding what a baby is trying to express
2) appropriate facial responses
3) vocal response with way more variation and subtlety than I have seen from robots so far
4) in-built understanding of infant development and normal variability (and departures therefrom).
5) an understanding of when a response needs to be modified or even denied (one size does not fit all occasions or all infants)
Note that appropriate responses are the cause of much human discussion. Not everyone agrees as to what is required.
And different infants may require different handling.
6) different handling for each different society involved

Humans often don't get this stuff right.
Much experimentation is probably required.
The ethics of doing so with real human subjects is interesting, and so are the legalities.

A really good mechanical substitute would also tend to distance an infant from its parents.
The better it was, the worse this would be.

There is a traditional forum for discussing such dilemmas: literature.
Science fiction has usually borne the brunt. At least until higher-paid mainstream authors take over.

Or you could take the route of Sweden and just provide substantial parental leave.
But it takes not just a village, but a whole society to do that.

MPichetto
02-28-2017, 02:30 PM
Any artificial parental substitute needs to be responsive 1) in real time, 2) in a way that is immediately understandable by infants.
A nanny is a traditional substitute. With deficiencies liberally described in literature. (Memoirs, biographies, novels, folk tales.)
Any artificial version would be expected to be inferior to such a substitute human, at least for a while.

Technical challenges therefore include:
1) understanding what a baby is trying to express
2) appropriate facial responses
3) vocal response with way more variation and subtlety than I have seen from robots so far
4) in-built understanding of infant development and normal variability (and departures therefrom).
5) an understanding of when a response needs to be modified or even denied (one size does not fit all occasions or all infants)
Note that appropriate responses are the cause of much human discussion. Not everyone agrees as to what is required.
And different infants may require different handling.
6) different handling for each different society involved

Humans often don't get this stuff right.
Much experimentation is probably required.
The ethics of doing so with real human subjects is interesting, and so are the legalities.

A really good mechanical substitute would also tend to distance an infant from its parents.
The better it was, the worse this would be.

There is a traditional forum for discussing such dilemmas: literature.
Science fiction has usually borne the brunt. At least until higher-paid mainstream authors take over.

Or you could take the route of Sweden and just provide substantial parental leave.
But it takes not just a village, but a whole society to do that.

Dear Saetro,

Thank you for taking your time reading and commenting my post.

The FIT is not really meant to be a substitute of parents (parenting is an exceptionally difficult task also for very good parents).
It would just be a toy like many others, but it would come earlier.
To my knowledge in fact, all other active toys (therefore mobile cribs and partially play gyms are excluded) expect babies to do some manual handling.
By linking recurring sounds (the baby can repeat) to acoustics and visual events, the FIT would instead allow babies to play with the latter's even if they cannot master properly their bodies.

I myself do not know to what extent speech recognition would be efficient in selecting recurring sounds.

For sure, I do not expect technology to assess if a recurring sound is possibly associated with something bad in the baby’s mind.
This is why the second logical step of the FIT would be parents intervention to exclude potentially troublesome sounds.

Instead, I expect the FIT to adapt to each baby development unique timing, as it would listen silently in background until vocal development is up to requirement.

You are right when you say that experimentation is required.
Actually, I am looking for someone keen to work together on an Arduino open source project (able to perform at least the 3 logical steps) and then test it on a baby under parents supervision.