January 18, 2023

An essay on the human mind, body and species

I have been looking at a lot of my old writings and considering reblogging a lot of it. I also have some term papers from some university courses I did. Below is one I think is particularly good.
It is quite relevant to some ideas that are kicking around right now. I think it sets up a realistic view of human kind. It debunks on the one hand, the idea that humans are just a species of animal with some exceptional talents, and on the other hand, that we can exist outside of nature and our bodies.
The blog program has stripped out the footnotes. If these really interest you I can send them.

Introduction

The evolution of the human species has often been pitched as the rise of ‘higher intelligence’ or of the triumph of the mind. McBrearty and Brooks denounce this as the “hero myth”. I call it the ‘heroic brain’ trope. It led to the assumption that body evolution followed brain evolution, which resulted in many mistakes. But the opposite mistake is what I would call the ‘continuity’ error; the idea that everything humans do is a mere continuation from the higher animals; there is no break between humans and other species, nothing really special about us. It seems that McBrearty and Brooks lean toward this trope. To debunk all this is beyond the scope of this paper, and could take up a dozen papers like this. I merely offer a different explanation of the human species which I think avoids these two errors. I call it ‘the heroic hand’.
The greatest triumph of evolution is not the human mind, it is the human arm and hand. Everything that the human species is, is a consequence of the development of this incredible means of manipulating the surrounding environment. The human brain itself is nothing really special. It is made of the same stuff as primate brains. But what it does is qualitatively different from what any animal brain does; a sum much greater than it’s parts. Any mammalian species could have developed the same capabilities with the same basic materials. Any bird species could have. None have done so because they would have no use for such capabilities. The development of an upper limb free of any involvement in locomotion and dedicated exclusively to manipulation of the physical world, allowed us to reach outside of our skins and begin to adapt nature to us, instead of to adapt to nature, which is all the animals can do. This opened a space which the human brain could grow into, and eventually mind and culture could also grow in and begin an ‘evolutionary loop’ with each other. What really makes us qualitatively, not quantitatively, different from animals is not our so-called ‘higher intelligence’ or our ability to speak, make things, make music, and so on. All this came after our hands, and continues to depend on our hands.

The Cognitive Basis of Material Engagement

Malafouris’ hypothesis is that mind is the engagement of the brain with the body and the material world about it. Mind and nature are not separable. The ‘cognition’ of the human species extends out into the material world, and is “not limited by the skin”. As I understand this, mind does not simply react to the world, but interacts with it. Mind shapes the world around it, creating a material culture. The mind is in turn shaped by the natural world, this material culture, and the body, in a continuous interplay.

The revolution that wasn’t

According to McBrearty and Brooks, they offer an explanation of the emergence of modern humans that is more consistent with the evidence. Homo Sapiens emerged much earlier than the 100 000 years before present (ybp) which is the current wisdom. The ‘Homo Helmei’ which is dated as beginning at 260 ybp should be considered as a modern human and “rolled into” Homo Sapiens. The “Middle Stone age” (MSA), which they consider the next stage from Acheulian tools, began at about that time. All the ‘behaviors’ indicative of modern people did not develop suddenly, as in a ‘revolution’, but came together over a long period; they think 200 thousand years, as the “cognitive equipment” developed that could make use of new opportunities.
The authors note that the tendency to want to prove that the human species is distinct from animals leads to many mistakes, such as the idea that brain expansion or ‘intelligence’ preceded changes in the body, and that modern humans came about suddenly in a “revolution”. They insist that all animal species are unique, with their own form of ‘consciousness’. No “gulf” should be drawn between humans and the animal world.

Genes, Mind, and Culture; the coevolutionary process

However, according to Lumsden and Wilson, humans are qualitatively different from all other animals by being the only “eucultural” species, having true cultures. We imitate, teach, and reify; create an internal reality from external stimuli, from which new concepts can be derived and transmitted to others. Even the apes are only among the two dozen species at the next stage down, protocultural two; learning by imitation and teaching. Below them are numerous protocultural one species, who can learn by imitation. The rest of the animal kingdom are acultural; do not teach each other. In humans, cultures are transmitted epigenically, through an interaction between genes and cultural environment. Mind is not a mere reproduction of behavioral traits, but of cultural conditioning and the determinations individuals make in their lives. How the human mind developed has much to do with what earlier people considered to be beauty, intelligence, character, rationality, etc. These then created breeding advantages. Genes then reinforced these “culturgens.” It does not take eons for this epigenic process to have an effect; it can create a detectable genetic shift in only ten generations.

The Hand

According to Wilson, the earliest ancestors of humans were the Australopithecines, who existed two to four million years ago. They were the first primates to stand upright and they had an almost modern hand. After Australopithecus was Homo Habilis, soon followed by Homo Erectus, who was around from shortly after 2 million ybp until fairly recent times. In the last few hundred K ybp we have the Homo Heidelbergis and Homo Neandertalis type. There is a lot of confusion about classifying these early humans, but only in the past 100K ybp are people considered to be ‘modern’ found. Citing Washburn; the organs within an organism evolve in the same way the whole organism does, the upright posture and dedicated upper limb launched the human species, and that human brain evolution was driven thereafter by the brain itself and by ‘culture’, and “the brain was the last organ to evolve”.
The hand of the ‘Lucy’ Australopithecine from 3.8 million ybp could grip something between the thumb and the middle and index fingers, giving better control than chimps, who can only hold something between the thumb and index finger. Lucy could hold an object in a “three jaw chuck” grip and her pelvis could rotate to allow throwing, clubbing or stabbing. The Australopithecine hand was much better adapted than an ape hand to absorb the shock of pounding at something. Yet its brain was no larger than a modern chimps; 400 grams. There is a gap in the fossil record, and by the time we have a Homo Erectus hand to see, about a million years ago, the development of the hand was completed with the thumb fully rotated and the finger joints, particularly the rotation of the pinkie finger, more flexible, so that he could touch the ends of all his fingers with his thumb; the “precision grip”, and close the thumb over the little finger; the “power grip”. The wrist could fully rotate. The base of the thumb and the ends of all fingers were enlarged and padded, enabling a sure grip and shock absorption. The Erectus brain was effectively as large as ours; 1100 grams to our range of 900 to 2000 grams. Between Australopithecus and Erectus was the “Homo Habilis”, extant around 2 million ybp plus or minus .5 million years. He is associated with the first stone tools which can be recognized as such, and with the first controlled fire. His brain averaged about 600 grams. It is not certain from the archeological record whether the brain growth came before or after these last refinements to the hand. But after Erectus there was nothing the human hand could not do if the mind could master it.
Wilson writes;”Given a creature that loves to play, sharpens what it knows how to do with endless practice, and will try anything that comes into its head, one must expect that new skills, … will be regularly devised, and will be made part of the repertoire if they can be taught…to others.” However, early hominids were slow at first to exploit the opportunities presented by the hand. Lucy was anatomically capable of making the early “oldowan” stone tools but they only appeared with Habilis. Wilson cites Gould that once Erectus had developed the improved Acheulian stone tools, development stopped for about a million and a half years.
After hands, the other big step on the road to ‘higher intelligence’ was language. Wilson offers us a good explanation of the very hard “Chomsky problem”of how language developed. Of course, he says it followed as a consequence of the development of hands. Chomsky gives his three “incontrovertible facts”; that language is a heritable, species level trait, it is not a specific function of general intelligence, and most importantly for my thesis, it has no analogies in animal communication. This is said to threaten some widely held assumptions of cognitive scientists, anthropologists, and linguists. Wilson suggests that the functional origins of language are in the development of hands. To do any manual task requires what Plotkin called “manual intelligence”. It is the ability to produce a sequence of acts/ideas in their correct relation to each other, telling a kind of story that can be reproduced. This is the essence of building a sentence and is exactly what the apes who were taught ‘sign language’ do not do. Wilson refers to the Charles Turing test as well as Chomsky when he imagines a “Chom-Tur” in the human brain which processes speech. Lacking this, apes will never pass Plotkin’s test, or Turing’s test of convincing anyone they are talking to a person.
Spoken language began over 100 000 ybp, and the neural infrastructure of language must have been in place well before then. Such complicated traits must have been under development for a very long time and could only have been developed through the use of some sort of proto-language. The brain was wired to understand word symbols not as part of a chain, but by the intent of the symbols and their logical relation to each other. What apes are incapable of, human children pick up at a very early age. It is said by Vygotsky and Greenberg that speech acquisition in children is related to the manipulation of objects in the real world. That this does not require speech, the production of sound, is shown by the great speed and expressiveness of the sign language of the deaf. This is not mere signaling, but signifying; a true language. People who suffer from aphasia due to brain injury often have trouble with movements which had been automatic before the injury. And finally, deaf people who had used sign language and who suffer brain injuries in the same areas where injuries produce aphasia in speaking people, become unable to use sign language in the same way that the speakers could no longer speak. The hand, mind, language nexus is very strong, even though neurologists still have no clear idea about how speech works or even what parts of the brain are involved.

Flint knapping

According to Whittaker, flint knapping is the oldest hand craft. It has been practiced from the time of the first Oldowan tool makers. It was not only used by the last stone age people, but for certain types of weapons and tools of the early industrial era. It takes some time to learn this craft, and it needs some instruction because if you do not know how to hold the pieces properly, you can injure yourself.
The Oldowan tools were made from about 2.5 million ybp. Whittaker beleives that the more advanced Acheulian tools were first made in Africa after 2 million ybp and spread through the old world with the Homo Erectus people. Only much later did the Mousterian tools arise; some time before 100 000 ybp.

“What’s So Special about Human Tool Use?”

Johnson-Frey provides additional information about the speciality of human tool use. The primates have the same systems of reach, grasp, and manipulation that humans do. But they cannot grasp the “causal relationships between self, tool, and goal object”. For example, a chimp can understand how to pull a rake in order to draw food toward itself. It can see that a broken rake will be no good. But if it must choose between a rake that would draw food to it and one that would draw it into a hole that is clearly visible to it, the chimp chooses wrong half the time.

Cooking as a biological trait

Humans began using fire and cooking food between 1.9 mybp and 1.6 mybp. This is at about the time the Erectus body form emerged, as well as the modern human life cycle, with a longer, learning enabling childhood facilitated by availability of softer foods. Teeth shrank. Modern humans are fully adapted to a cooked food diet which allows much greater absorption of nutrients and a higher energy level, and ability to meet the energy requirements of the human brain, which has 2% of the body’s mass and consumes 20% of the body’s total energy. Studies of modern humans who try to live on a raw food diet show that they would be unable to survive in the wild on raw food. Starting and maintaining a fire requires high manual dexterity and planning. Cooking is another cultural trait that led to genetic adaptations.

The evolution of speech

Fitch reminds us that there are talking parrots and seals, and chimps who can make sign talk. However, human speech evolved from, but is much more complex than, ape vocalizations. The primate vocal tract has three parts; a sound source, formants, and articulators. The sound source is the larynx and vocal cords, which produce pitch. The formants adjust the length of the vocal tract, allowing some frequencies to pass, but not others. The articulators are the tongue, lips, palate, etc., which give us our vowels and consonants. These enable humans to convey a great deal of information in a short time. The basic changes from apes to humans are that the larynx has descended in the throat, allowing greatly increased motion of the tongue. We have much greater motor control over our tongues, lips, etc., vastly expanding our ‘repertoire’. And of course we have the mental circuits to be able to create and receive heirarchically organized speech. All attempts to deduce from fossils when speech evolved, such as shape of the hyoid bone or the size of the hypoglossal canal, fail; there is as much variation of these features among living people as among early human fossils.

Conclusions

The thesis is that the human species is qualitatively different from all other species, but that the original cause of this difference is in the development of hands, not brains. This will challenge some “central assumptions widely shared among anthropologists, cognitive scientists, and linguists”. I consider most of these assumptions foolish or irrelevant and I am interested in getting beyond them, not arguing against them. Therefore, I hope this paper is assessed within its own frame.
The archeological sequence of events in human development is uncertain. My sources give differing timelines. However, some things are clear. The ‘Lucy’ skeleton is dated at four to three million ybp. The Oldowan stone tools appeared about 2 to 2.5 million ybp. The Habilis type, with a somewhat larger brain, but no evidence about the hands, was a relatively short interlude between Australopithecus and Erectus. The Erectus type, with a brain as big as ours, appeared in the fossil record shortly after 2 million years ybp and was around until about .25 Million ybp. The first evidence of the use of fire is from 1.9 to 1.6 million years ybp. A more sophisticated type of stone tools, the Acheulian, appeared before one million ybp.
So, essentially modern hands developed, and then nothing happened for a long while. Then stone tools and the use of fire happened, at about the same time as a dramatic increase in brain size. It is impossible to say from the archeological record which of these latter came first. The point is that they happened well after hands and completed the first stage of the development of the mind; driven by the structural development of the human body. After that the brain became more complex, not bigger. This was driven by the genetic feedback between practical know-how which made life easier with more leisure time, sources of higher energy foods to feed the brain’s demands, and an increasing social life. It has been a slowly accelerating process, with the development of language at the center of it. Unlike hands, the speech production mechanism could not have come about by good fortune. Speech had to have evolved in the brain before it manifested itself in structural change to the body. It could only have evolved through the use of sign language until vocalization could supplement and then replace it. This was the second stage of development of the mind, the cultural development enabled by tools and fire. The mind is brain plus culture plus technology, and high technology has developed recently, after another long, slow buildup since neolithic times; the third stage of development which was enabled by speech.
However, our advanced technology and culture still depend totally on the hand. If the human race kept our magnificent brains but were returned to the bodies of apes, we would be unable to cope. A computer requires significant manual skill to operate. Its manufacture requires many hours of very precise hand assembly work. Ask yourself how you would cope with your daily activities if your hands lacked the power and precision grips, and dextrous fingers. Our technology would degenerate back to primitive levels, where we would have trouble even getting a fire lit. Our superior brains would no longer have a stimulating environment to play in, and would be an impediment to survival. There is nothing “LaMarckian” in saying that what an organism can no longer use, and which has considerable costs, it will lose over generations. Humans can no longer live as animals, any more than animals can live as people.
The hand was a very fortunate accident of evolution, although no doubt sooner or later some species would have happened to develop something equivalent to hands, had we not. First, our tree dwelling ancestors developed the rotating shoulder in order to be able to move through the trees. They also developed the basic hook grip and independently working fingers. The apes developed the pincer grip with which to hold something between finger and thumb. But it is when Australopithecines developed a habitually upright posture that the opportunity was there. It was not about bipedalism; kangaroos never grew hands. Their front limbs withered away because they never evolved the shoulder motion which can move the hand around. But Lucy could throw, club and stab, making her a formidable opponent. When the hand was perfected by the early Homos, with rotating wrist, fully opposable thumb, and grip adaptions, the master species began to arise. People began to use fire, to make real tools, and to communicate in real language.
No animal without the equivalent of a hand will ever use tools, fire, or language. The ability of even the most primitive people to use tools and fire have given them the time and energy for mind developing recreational and contemplative activities which animals will never be capable of. It has given them the quality nutrition to support their enlarged brain. A chimp which does clever things with rocks and twigs is not in this way “using tools”. To make anything properly called a tool requires mastering a hand craft, which requires true hands. No wild chimp will ever be able to get a fire going and keep it going. Many animal species have the ability to signal in various ways. No existing animal species will ever use true speech. Arm and hand have resulted in a creature which is qualitatively, not quantitatively, different from any other animal; the only eucultural species, the only species which can extend its intelligence into the material world around it, to interact with it instead of merely to react.
Whether McBrearty and Brooks like it or not, we are the master species. Unless we use our superior brains to destroy ourselves, our dominance precludes any other species from following a similar path of development.