Neanderthal face reconstructed by Vendramini, Copyright themandus.org

He has written a book called “Them and Us”, in which he propounds the hypothesis that Neanderthals were:

• Very different looking from most modern representations – much uglier, hairier, and far less human-like.
• That they were brutal, intelligent, tool-using predators, who preyed upon modern man in the areas where they came in contact, specifically, the Levant.
• That being the prey of Neanderthals was the most important factor in human evolution, and that it was responsible for the flowering of art and sculpture, the technological innovations in the tool making industry, perhaps even the flowering of language – all of which happened around 40,000 to 50,000 years ago.
• And not only that, it was responsible for the evolution of the human body type, including features that distinguish us from other apes, such as decreased hairiness, the development of a prominent and protruding nose, different body posture and gait, etc.
• Finally, he lists a whole range of human behavioral traits, such as preference for symmetrical faces, fear of the dark, abominable snowman myths across various cultures, etc. as some sort of racial memory of Neanderthals, whom we fear and despise, because they preyed upon us.

Now at first read, this appears to be the work of a misguided though enthusiastic kook. He seems to have no formal qualifications in biology or paleo-anthropology, and is self-taught. He makes the first few chapters of his book available online, and from a quick read, he seems very dismissive of arguments that run counter to his thesis, for example, the loss of body hair in Homo sapiens. He mentions other theories, such as the thermoregulation during the transition from forest living to life on the savannah, but he dismisses them so hastily that it looks like he doesn’t really understand them all too well. Some of the examples he gives (such as big cats are predators, and some of them live in hot climates, why didn’t they lose their hair?) have reasonable answers in the literature, but he makes no mention of them. Instead, he pushes his theory, that we lost body hair because of sexual selection – we didn’t want to look like those ugly, murderous Neanderthals – it became a taboo to look like them.

Profile reconstruction of Neanderthal face, Copyright themandus.org.

Superficially, some of this may make sense. We certainly can’t rule out the role of sexual selection in the loss of body hair. But making the jump from “might be possible in a mundane way” to “it was a response to Neanderthal predation” is a very long stretch. He does this in many, many different areas, not just body hair.

Now I understand that he offers this as a hypothesis. He is not saying this is how it happened, just that this is how it might have happened. Which is fine, but the supporting evidence is very thin. Further, in his enthusiasm to bring in every possible argument to bear, he adds so much speculative and flimsy stuff that it makes it seem like he can’t distinguish between science and fantasy. To name a few, he finds some supposedly “universal” human traits such as xenophobia, preference for bathing and cleanliness, loyalty to the group, self-sacrifice, patriarchy, aggression, and many more, and ties them all into some imagined “prey psychology”, which developed as a result of humans being the victims of Neanderthals.

To be fair, he is not alone in this. Many so called “evolutionary psychologists”, or evolutionary biologists in general, make sweeping generalizations and assumptions, based on the flimsiest evidence. To me, this is an example of science turning into social narrative, the trivialization of science. You don’t need rigor and reasoning based on solid evidence, you don’t need to be cautious, to make no claim beyond the evidence – all you need to do is to tell a good story, preferably sensational enough to get picked up by the popular press, and give you your 15 minutes of fame.

Neanderthal with spear, Copyright themandus.org.

Part of it is the problem of generalists versus specialists. Evolutionary biologists or evolutionary psychologists (*shudder*) are generalists, tying together a lot of details from anthropology, genetics, sociology, psychology, etc. to make some broad claim. But in doing so, they often lack the specialized knowledge of each individual field – they lack sufficient knowledge to not over-generalize, and sometimes end up making silly blunders. They tend to trivialize and gloss over problems that are ambiguous and not resolved, picking the interpretation that favors their own theory, often not realizing that the foundation is very shaky.

And then there are those who disconnect with reality altogether, like Vendramini, when he goes off about connecting “fear of the dark” to nocturnal predation by Neanderthals or similar arguments. The pity is that he doesn’t seem to realize what he’s doing. In trying to add weight to his arguments, he is throwing in every last thing he can think of. And so he’s mixing in things that have some weight and credibility (like, we don’t really know exactly what Neanderthals looked like, perhaps they were more ape like than modern representations; or we don’t know exactly what human-Neanderthal interactions were like, there may well have been violence), with things that are utter nonsense, such as fear of the dark. So the good stuff gets mixed with the bad, and taints everything as trash. Further, it creates a bad impression of the writer, in that he doesn’t seem to be able to distinguish science from fantasy.

To top it all, he really appears serious about this airy-fairy stuff. He has another theory (and another whole website devoted to it), which propounds something he calls “teem theory”. In simple terms, the theory is that nasty stuff that happens to us and creates powerful negative impressions gets imprinted on non-coding regions of our DNA, and thus becomes heritable to future generations. This is what he uses to explain things like fear of the dark, xenophobia, etc. – that these bad experiences with homicidal Neanderthals became imprinted on our DNA, and continues to manifest in modern behavior.

That would be a whole other discussion and a whole other blurb on this blog, so I don’t want to get into it at this time. Briefly, he looks at instinctive behavior of a certain kind, such as certain animals instinctively recognizing their predators and avoiding them, concludes that such behavior must be coded into the DNA, since it’s untaught and not learned, therefore DNA must provide a mechanism for coding our fears. Such ideas ignore a whole realm of evidence, that a huge range of predator-avoidance behaviors are in fact learned, and that interpreting specific instances where they don’t appear to be learned is over-generalizing. Yes, there are instincts that are heritable, but the actual mechanism of how they work, what exactly is coded in the DNA, are very much unknown. Making it out to be something as specific as xenophobia is very imaginative, but poor science.

Neanderthal, hunting. Copyright themandus.org.

I see evolutionary biologists make similarly specific claims, that generosity and altruism are hard coded in our genes – all sorts of stuff like that. I consider it all very unlikely, an over-specification of something much broader. Perhaps what we are inclined for is social cohesiveness, being social animals, and specific instances of it are just a manifestation, they are not individually hard coded. It’s possible to take a population of rats, breed for either aggressiveness or docility, and in a very few generations end up with two distinct populations that are behaviorally very different in that respect. It’s been done. It doesn’t show anything very specific, other than that “fight” responses and aggression are more marked in one population than another, perhaps through some simple hormonal trigger. Going from that to very specific theories about brain centers dealing with aggression, or “cooperation” or something similar is not warranted by the evidence.

While I find his theory not convincing, it did make me wonder about a few things. What exactly do we know about how Neanderthals looked like? Forensic recreations based on bones have to be somewhat an exercise in guesswork, on prior knowledge. I agree with his point that they are not at all comparable to forensic recreations of humans. After all, we have a huge body of knowledge of what humans are supposed to look like, so our guesses are founded in a great deal of prior information. We don’t have a similar body of knowledge of what Neanderthals looked like, so our reconstructions may err on side of making them look too human (or conversely, less human) than they really were.

We have no casts of their soft tissues. We don’t know how hairy they were. We don’t know how much their noses protruded. We don’t know how big their eyes were, how erect their spines, how prominent their musculature. For all of these things, we make educated guesses, but some guesses are more educated than others. For example, the musculature is hinted at by the shape of the bones, the sites of attachment of various muscles to the bones. So this kind of guess can be trusted to a greater extent than say, the guess about how hairy they were, or what their skin was like, or how symmetrical their faces were.

So our picture can’t be very precise, there is some range of possibilities, within the constraints set by the bones. Just how wide that range is, I don’t know, and I wonder if they could have looked like the pictures on his web site. I don’t personally know of any physical evidence that goes against his reconstruction. Perhaps some more knowledgeable people can add to this. But it occurs to me that if Neanderthals looked sufficiently ape-ish, sufficiently non-human, it would explain why we find no evidence of human-Neanderthal interbreeding in the genomes. It would discourage (though not necessarily prevent) the two species from interbreeding.

I look forward to more information which should become available as the Neanderthal genome is fully sequenced and annotated.

I’ve come across a number of articles that talk about the importance of a change in diet in human evolution. The theory is that human diet suddenly improved dramatically, and this marked increase in the availability of calories and nutrients was responsible for the growth of the brain. The improvement in diet is generally tied to either the switch from a primarily herbivorous diet to meat eating, and/or to cooking.

Both make sense in terms of calories and nutrients. Meat is certainly a more densely packed source of nutrients than plants. And cooking increases the bioavailability of nutrients, as it breaks up cell walls and structures that hinder our digestive enzymes from reaching the goodies inside cells.

Of course, this still leaves us without an actual mechanism. Evolution requires heritable changes in the genome. These happen largely by  accident, though their selection depends upon what is advantageous to survival and reproduction. At this point, we don’t know very well exactly which genes are responsible for the differences in our brains, say compared to chimpanzees. We don’t know when these changes first appeared. We don’t know what connection they have to an improved diet.

So one part of evolution, that which is related to the genomic changes responsible for our large brains, is mostly unknown to us. Therefore, I think that ideas such as the change-in-diet leading to big brains scenario, tend to ignore the unknowns and focus only on the natural selection side of evolution. They make certain assumptions, for example, that a large brain will be selected, because it enhances survival and the chance to reproduce. This can be somewhat justified if one thinks about  it (large brains, specially the growth of the forebrain is what allows us to make long range plans, analyze complex problems, etc.), and also there is fossil evidence that shows that in fact it was selected. Then there is the assumption that a large brain requires a nutrient rich diet, which can also be justified on the basis of the caloric expenditure in maintaining a large brain. A commonly offered statistic is that for a person at rest, of the amount of energy required to stay alive, the brain uses 20%, or 1/5th. The brain is obviously much less than a fifth of the body in terms of mass, yet it uses an extraordinary amount of energy, in proportion. If you keep the total mass of an organism constant, but increase the size of the brain in proportion to the rest of its body, then such an organism will require a more nutrient rich diet. In effect, you have increased its energy requirements, but have not given it bigger jaws to chew food, a bigger gut to digest it, bigger claws to hunt with, etc.

In fact, both anatomy and the fossil record show that humans became less capable of acquiring food as their brains grew, if we look solely at such biological markers such as tooth/jaw size. Homo erectus had smaller jaws than his ancestors, which would have made it harder for him to grind foods down and extract the most energy from them. Our gut became smaller, and less capable of extracting energy from plants. Our muscles became weaker, less capable of overpowering other animals through brute strength alone.
One would think that the timing of these changes would have some correlation with our behavior or change in diet, or the control of fire (for cooking). Unfortunately, the timing is much harder to pin down. No one really knows when humans first learned to control fire. Homo erectus, with his small jaws, evolved 2 million years ago, but the evidence for the widespread use of fire by humans at this time is scanty at best. Most anthropologists don’t believe that fire was used by humans this early, at least, not in any regular, controlled manner, such as would be needed for cooking. Soft tissues don’t fossilize well, so while we can study humans and chimps today and recognize that the chimp gut is much more suited for eating raw plant material than the human gut, we don’t really know when we evolved our more carnivorous digestive systems.

This leaves a chicken versus egg conundrum. Which came first, the big brain or the adaptations to the big brain lifestyle? Which was responsible for the other? This may be a silly question on the face of it, because obviously one is useless without the other. What’s the point of having a modern jaw or gut if you don’t also have the bigger brains that give you the means for filling that gut with food? On the other hand, how do you sustain that brain and give it energy without eating a more nutrient-rich diet?

So it seems that speaking in terms of absolute causality, one thing causing the other is somewhat simplistic. They probably both happened together, one reinforcing the other, and happened gradually. We didn’t go suddenly from a chimp-sized brain to a human-sized one, as we know from the fossil record. There are many intermediate stages of the brain growing progressively larger. The change in diet, therefore, and the behavioral changes accompanying both the change in diet and the larger brain, must have happened concomitantly.

It’s interesting at this point to bring in the factor we’ve ignored all along – that there must be genomic changes that produce all the anatomical differences – jaws, teeth, gut and brains. These genomic changes also need to be accounted for, and tied into the selection mechanism. A high nutrient diet is obviously not enough; otherwise large cats such as lions and tigers would be smarter than us. They might not cook, but they eat enough high nutrient food to be able to support bigger brains. They have evolved as long as us, why didn’t they learn to cook,  why didn’t they evolve bigger brains?

This brings us back to selection, and fuzzier areas of anthropology such as social behavior and interactions, etc. We have bred dogs for a few thousand years, for example, and we have breeds of dogs today that look very different from each other. Not only is there is a difference in size and color of the fur, but there are also differences in the brain. Some breeds of dogs are smarter than others. We did this by a fairly simple process of selection – pick dogs that have the traits you want, breed them to produce a new generation, keep selecting for the desirable traits and reinforcing them through successive generations. Even with no knowledge of DNA or even Mendellian genetics, our ancestors were able to do this for dogs. We have also bred cows, pigs, goats, sheep, etc. – the modern domesticated forms of which are quite different from their wild ancestors. Not to mention the similar and parallel process of breeding food plants.

So even without postulating major and sudden changes in the genome, those which suddenly introduced a “game changer” mutation so far as the brain was concerned, it’s possible to see that humans could have become progressively smarter simply if the natural variation in smartness among a population was selectively reinforced over generations, the same way we breed dogs. Of course, this doesn’t mean that you can breed dogs to a human level of intelligence, there may well be certain required mutations, and these have to happen first. You can’t select for what doesn’t exist. But at a point where we don’t fully understand the nature of these key mutations, we can’t really talk about how essential they were. Perhaps they could happen in other species too. Perhaps there are a dozen different ways to get the same result, and if mutation “A” doesn’t happen, mutation “X” can provide the similar benefits. I’d rather not speculate about this until we have more information to speculate with.

So I think such articles (as the one referenced above, which talks about the relation of diet to human evolution) speculate about the remainder of the problem, the mutually reinforcing effect of the selection of traits which are part of the natural variability of a population, and the behavioral consequences of selecting such traits. You set a species on a certain path, on which a greater reliance on the brain cuts out some options while expanding others, and the options that are promoted require even greater brain power to work well. It’s interesting to speculate what put us on this path, why we seem to be the only species on it. What set of circumstances came together at the right time for this to happen. The drying climate and spread of grasslands, the change from an arboreal to a savannah type lifestyle, the appearance of bipedality at this critical juncture when these big new ecological niches suddenly opened up, the development of more and more hand flexibility with a greater range of movement in the opposable thumb (compared to other primates), the social interactions, etc. There were so many changes happening at roughly the same time to the same species, somewhere this set us off on a path to bigger brains.

The article that set me off on this line of thought, of course, talks about something narrower. It talks about the relationship of cooking to gender roles, the development of the male-female bond, which is marriage today. This seems less an evolutionary question than an anthropological one. The evolutionary part is the importance of cooked food in the development of our brains, which I have speculated about. The anthropology part is relating this importance to something else, namely male-female pairing. I am not qualified to speculate about the anecdotal evidence offered about some primitive societies where food is more important than marital fidelity. Nor do I have any evidence that women tended the home fires, though it seems likely if men were the hunters and spent less time at the home camp. This seems to be supported by fossil evidence, such as hunting related injuries, as well as by anthropological evidence. You can speculate that the importance of cooked food was critical enough to shape our behavior patterns in other ways, such as pair-bonding between males and females. But just because a theory seems to make sense doesn’t mean it’s true, so I guess we’ll need to see some more physical evidence before placing much value on it.