Posted at 11.02.2018
The breakthrough of mirror neurons in the frontal lobes of monkeys, and their potential relevance to mind evolution - that i speculate on in this article - is the solo most important "unreported" (or at least, unpublicised) storyline of the decade. I forecast that reflection neurons will do for mindset what DNA did for biology: they'll provide a unifying framework and help make clear a host of mental capabilities that contain hitherto remained strange and inaccessible to tests.
There are numerous puzzling questions about the advancement of the real human head and brain:
The hominid brain reached almost its present size - as well as perhaps even its present intellectual capacity about 250, 000 years back. Yet many of the attributes we regard as uniquely human made an appearance only much later. Why? What was the brain doing through the long "incubation "period? Why achieved it have all of this latent prospect of tool use, open fire, art music as well as perhaps even language- that blossomed only noticeably later? How did these latent capabilities emerge, considering that natural selection can only just select expressed talents, not latent ones? I shall call this "Wallace's problem", following the Victorian naturalist Alfred Russell Wallace who first suggested it.
Crude "Oldawan" tools - made by only a few blows to a key stone to produce an irregular edge - emerged 2. 4 million ago and were probably made by homo habilis whose brain size was 50 % way (700cc) between modern humans (1300) and chimps (400). After another million years of evolutionary stasis visually satisfying "symmetrical" tools commenced to seem associated with a standardisation of production approach and artefact form. These required turning from a hard hammer to a very soft (wooden?) Hammer while the tool had been made, to be able to ensure a smooth rather than jagged, irregular edge. And lastly, the invention of stereotyped "assembly lines" tools (complex symmetrical bifacial tools) that were hafted to a cope with, took place only 200, 000 years back. Why was the advancement of the real human brain "punctuated" by these relatively sudden upheavals of scientific change?
why the unexpected explosion (often called the "great leap" ) in technological sophistication, popular cave skill, clothes, stereotyped dwellings, etc. Around 40 thousand years back, even though the brain possessed achieved its present "modern" size almost a million years before?
did language appear completely out of the blue as advised by Chomsky? Or achieved it evolve from a far more primitive gestural dialect that had been in place?
humans tend to be called the "machiavellian primate" discussing our capability to "read heads" in order to predict other peoples' behaviour and outsmart them. What makes apes and humans so excellent at reading other individuals' intentions? Do higher primates have a specialised brain centre or component for creating a "theory of other thoughts" as suggested by Nick Humphrey and Simon Baron-Cohen? If so, where is this circuit and exactly how and when achieved it evolve?
The solution to numerous of these riddles comes from an improbable source. . The analysis of one neurons in the brains of monkeys. It is suggested that the questions become less puzzling considering Giaccamo Rizzollati's recent breakthrough of "mirror neurons' in the ventral pre-motor area of monkeys. This cluster of neurons, i dispute, holds the main element to understanding many enigmatic aspects of human development. Rizzollati and Arbib have already described the relevance with their discovery to terms evolution. But i really believe the significance of their results for understanding other similarly important areas of human evolution has been typically overlooked. This, in my own view, is the main unreported "story" within the last decade.
Unlike many other human characteristics such as humour, fine art, dancing or music the survival value of dialect is clear - it can help us converse our thoughts and intentions. However the question of how such an extraordinary ability might have actually developed has puzzled biologists, psychologists and philosophers at least since the time of Charles Darwin. The issue is that the individuals vocal equipment is significantly more superior than that of any ape but minus the correspondingly sophisticated terms areas in the brain the vocal equipment by themselves would be unproductive. So how does these two mechanisms with so many superior interlocking parts progress in tandem? Pursuing Darwin's lead it is suggested our vocal equipment and our remarkable capability to modulate voice advanced mainly for producing psychological cell phone calls and musical looks during courtship ("croonin a toon. "). Once that developed then your brain - especially the remaining hemisphere - could progress language.
But a bigger puzzle remains. Is dialect mediated with a advanced and highly specialised "language body organ" that is unique to humans and emerged completely out of nowhere as suggested by Chomsky? Or was there a more primitive gestural communication system already set up that provided a scaffolding for the introduction of vocal language?
Rizzolatti's finding can help us solve this age-old puzzle. He saved from the ventral pre-motor area of the frontal lobes of monkeys and found that certain cells will fire when a monkey performs a single, highly specific action with its hand: pulling, pushing, tugging, grasping, picking right up and adding a peanut in the mouth area etc. Different neurons flame in response to different activities. One might be lured to think that these are motor "command" neurons, making muscles do certain things; however, the amazing truth is that any given mirror neuron will also open fire when the monkey involved observes another monkey (or even the experimenter) performing the same action, e. g. Tasting a peanut! With knowledge of these neurons, you have the basis for understanding a bunch of very enigmatic aspects of the human head: "mind reading" empathy, imitation learning, and even the evolution of terms. Anytime you watch another person doing something (or even starting to do something), the matching mirror neuron might open fire in your brain, thereby letting you "read" and understand another's motives, and thus to build up a complex "theory of other imagination. " (i suggest, also, a loss of these mirror neurons may clarify autism - a cruel disease that afflicts children. Without these neurons the kid can't understand or empathise with other folks emotionally and therefore completely withdraws from the entire world socially. )
(another important piece of the puzzle is Rizzolatti's observation that the ventral pre-motor area may be considered a homologue of the "Broca's area" - a brain centre from the expressive and syntactic aspects of words in humans).
These arguments do not at all negate the idea that we now have specialised brain areas for words in humans. Our company is working, here, with the question of how such areas may have advanced, not if they exist or not.
Mirror neurons were uncovered in monkeys but how do we know they exist in the human brain? To find out we studied patients with a weird disorder called anosognosia. Most patients with a right hemisphere stroke have complete paralysis of the still left side of the body and can complain about any of it, as expected. But about 5% of these will vehemently deny their paralysis even though these are mentally in any other case lucid and smart. This is the so-called "denial" symptoms or anosognosia. To our amazement, we discovered that many of these patients not only rejected their own paralysis, but also refused the paralysis of another patient whose lack of ability to go his arm was obviously visible to them and also to others. Denying ones one paralysis is peculiar enough but why would an individual deny another patient's paralysis? We suggest that this bizarre observation is most beneficial understood in terms of damage to Rizzolatti's mirror neurons. It's as though anytime you want to make a judgement about someone else's motions you have to perform a vr (virtual reality) simulation of the matching movements within your own brain and without mirror neurons manage to survive do that.
The second piece of evidence originates from learning brain waves (eeg) in humans. When people move their hands a brain influx called the mu influx gets blocked and disappears completely. Eric Altschuller, Jamie Pineda, and i recommended at the culture for neurosciences in 1998 that suppression was caused by Rizzolati's mirror neuron system. In keeping with this theory we discovered that such a suppression also occurs whenever a person watches someone else moving his hands but not if he pieces a similar motion by an inanimate subject. (we anticipate that children with autism should show suppression if indeed they move their own hands however, not if indeed they watch someone else. Our laboratory now has initial hints in one highly operating autistic child that might be true (communal neuroscience abstracts 2000).
The hominid brain grew at an accelerating tempo until it come to its present size of 1500cc about 200, 000 years back. Yet uniquely human abilities such the technology of highly advanced "standardised" multi-part tools, personalized clothes, art, religious belief and perhaps even language are believed to have emerged quite speedily around 40, 000 years ago - an abrupt explosion of human being mental skills and culture that may also be called the "big bang. " If the mind come to its full individuals potential - or at least size - 200, 000 years back why did it remain idle for 150, 000 years? Most scholars think that the top bang took place because of some undiscovered hereditary change in brain structure. For example, the archeologist Steve Mithen has just written a booklet where he boasts that before the big bang there have been three different brain modules in the mind that were specialised for "social or machiavellian intelligence", for "mechanical intellect" or tool use, and then for "natural background" (a propensity to classify). These three modules remained isolated from each other but around 50, 000 years ago some genetic change in the mind suddenly allowed those to communicate with the other, leading to the enormous overall flexibility and adaptability of human consciousness.
I disagree with Mithen ingenious suggestion and provide a very different way to the situation. (this isn't incompatible with Mithen's view but its some other idea). I would recommend that the so-called big bang occurred because certain critical environmental causes acted over a brain that got already become big for some other reason and was therefore "pre-adapted" for those cultural innovations which make us uniquely individuals. (one of the key pre adaptations being reflection neurons. ) Innovations like tool use, artwork, math and even aspects of language might have been invented "accidentally" in one place and then spread rapidly given the real human brain's amazing capacity for imitation learning and mind reading using mirror neurons. Perhaps any major "innovation" happens because of a fortuitous coincidence of environmental circumstances - usually at a single place and time. But given our varieties' remarkable propensity for miming, this invention would have a tendency to spread very quickly through the populace - once it emerged.
Mirror neurons naturally cannot be the only answer to all these riddles of evolution. In the end rhesus monkeys and apes have them, yet they lack the ethnical sophistication of humans (though it has recently been shown that chimps at least do have the rudiments of culture, even in the open). I would argue, though, that mirror neurons are necessary but not sufficient: their introduction and additional development in hominids was a decisive step. Associated with that once you have a certain lowest amount of "imitation learning" and "culture" set up, this culture can, in turn, exert the choice pressure for growing those additional mental traits that make us human. As soon as this starts taking place you have set in motion the auto-catalytic process that culminated in modern individual consciousness.
A second problem with my recommendation is that it generally does not explain why the countless human inventions that constitute the best bang occurred during a relatively short period. If its just a subject of chance discoveries distributing quickly, why would most of them have took place at exactly the same time? You can find three answers to this objection. First, the evidence that everything took place at the same time is tenuous. The invention of music, shelters, hafted tools, customized clothing, writing, conversation, etc. Might have been disseminate between 100k and 5k and the so-called great jump may be a sampling artefact of archaeological excavation. Second, any given creativity (e. g. Speech or writing or tools) may have served as a catalyst for the others and could have therefore accelerated the rate of culture all together. And third, there may indeed have been a hereditary change, but it may well not have been a rise in the ability to innovate (nor a break down of barriers between modules as recommended by Mithen) but an increase in the class of the reflection neuron system and therefore in "learnability. " The resulting increase in capacity to imitate and find out (and coach) would then explain the explosion of cultural change that people call the "great revolution" or the "big bang" in individuals evolution. This argument implies that the complete "nature-nurture controversy" is largely meaningless as far as human are worried. With no genetically specified learnability that characterises the mind homo sapiens wouldn't need the name "sapiens" (wise) but without being immersed in a culture that may take advantage of this learnability, the title would be evenly inappropriate. In this sense human being culture and mind have co-evolved into obligatory shared parasites - without either the result would not be considered a human being. (only you can have a cell without its parasitic mitochondria).
My suggestion that these neurons provided the initial impetus for "runaway" brain/ culture co-evolution in humans, isn't quite as bizarre as it appears to be. Envision a martian anthropologist was studying people evolution a million years from now. He would be puzzled (like Wallace was) by the relatively immediate emergence of certain mental features like advanced tool use, use of hearth, art and "culture" and would make an effort to correlate them (as much anthropologists now do) with purported changes in brain size and anatomy triggered by mutations. But unlike them he would also be puzzled by the tremendous upheavals and changes that took place after (say) 19th century - what we call the methodical/industrial revolution. This trend is, in lots of ways, much more remarkable (e. g. The rapid introduction of nuclear power, automobiles, air travel, and space travel) than the "great leap forward" that occurred 40, 000 years back!!
He might be enticed to claim that there must have been a hereditary change and corresponding change in brain anatomy and behavior to account for this second leap forward. (just as many anthropologists today seek a hereditary description for the first one. ) Yet we know that present one occurred solely because of fortuitous environmental circumstances, because Galileo invented the "experimental method, " that, as well as royal patronage and the technology of the printing press, kicked off of the scientific revolution. His experiments and the sooner invention of an sophisticated new words called mathematics in India in the first millennium ad (predicated on place value notation, zero and the decimal system), set the stage for Newtonian mechanics and the calculus and "the others is background" even as say.
Now the thing to note is that none of the need have happened. It really didn't happen because of a hereditary change in the human being brains during the renaissance. It just happened at least partly because of imitation learning and swift "cultural" transmission of knowledge. (indeed you can almost dispute that there is a larger behavioural/cognitive difference between pre-18th hundred years and post 20th century humans than between homo erectus and archaic homo sapiens. Unless he recognized better our martian ethologist may conclude that there was a bigger hereditary difference between the first two groupings than the latter two varieties!)
Based upon this analogy i would recommend, further, that even the first great revolution was made possible mainly by imitation and emulation. Wallace's question was correctly sensible; it's very puzzling how a set of extraordinary abilities appeared to emerge "out of nowhere". But his solution was incorrect. . . the apparently sudden emergence of things such as art or sophisticated tools was not because of god or "divine intervention". I would claim instead that just as a single technology (or two) by Galileo and Gutenberg quickly distributed and transformed the top of globe (although there is no preceding genetic change), innovations like fire, designed clothes, "symmetrical tools", and skill, etc. May have fortuitously emerged within a place and then multiply very quickly. Such inventions might have been made by preceding hominids too (even chimps and orangs are incredibly inventive. . . who understands how inventive homo erectus or Neanderthals were) but early hominids simply might not have had an advanced enough mirror neuron system to allow a rapid transmission and dissemination of ideas. Therefore the ideas quickly drop from the "meme pool". This system of skin cells, once it became sophisticated enough to be harnessed for "training" in tool use and then for reading other hominids thoughts, may have played out the same pivotal role in the introduction of human awareness (and substitution of Neanderthals by homo sapiens) as the asteroid impact does in the triumph of mammals over reptiles.
So it creates no more sense to ask "why does complex tool use and fine art emerge only 40, 000 years ago even though the brain experienced all the required latent capability 100, 000 years before?" - than to ask "why performed space travel appear only a few decades in the past, even though our brains were pre-adapted for space travel at least as considerably again cro magnons?". The question ignores the key role of contingency or plain old luck in individual evolutionary record.
Thus i respect Rizzolati's finding - and my strictly speculative conjectures on their key role inside our advancement - as the most important unreported report of the previous decade.