Neanderthal Brains: Bigger, Not Necessarily Better

By Bridget Alex | September 21, 2018 5:30 pm
Neanderthal and modern humans skulls were close in size, but differently shaped.

Neanderthal skulls (left) were on average slightly larger and differently shaped and than modern human skulls (right). (Credit: Weaver, Roseman and Stringer; Journal of Human Evolution Volume 53, Issue 2, August 2007)

Neanderthals had bigger brains than people today.

In any textbook on human evolution, you’ll find that fact, often accompanied by measurements of endocranial volume, the space inside a skull. On average, this value is about 1410 cm3 (~6 cups) for Neanderthals and 1350 cm3 (5.7 cups) for recent humans.

So does that quarter-cup of brain matter, matter? Were Neanderthals smarter than our kind?

While brain size is important, cognitive abilities are influenced by numerous factors including body size, neuron density and how particular brain regions are enlarged and connected. Some of these variables are unknowable for Neanderthals, as we only have their cranial bones and not their brains. But anthropologists have made the most of these hollow skulls, to learn what they can about the Neanderthal mind.

Intelligence is influenced by other factors than absolute brain size. Otherwise elephants would out-smart humans (credit: Herculano-Houzel 2009 Frontiers in Human Neuroscience).

Intelligence is influenced by other factors than absolute brain size. Otherwise elephants would out-smart humans. (credit: Herculano-Houzel S. (2009) The human brain in numbers: a linearly scaled-up primate brain. Frontiers in Human Neuroscience 3(31) doi:10.3389/neuro.09/031.2009

Two Paths to Big Brains

The question of Neanderthal intelligence has fascinated scientists since 1856, when the first fossils classified as Homo neanderthalensis were discovered. From the start, they got a bad reputation. In an early study of the skull, “The Reputed Fossil Man of the Neanderthal,” geologist William King speculated the Neanderthal’s “thoughts and desires… never soared beyond those of the brute.” The view persists today from GEICO ads to the Oxford English Dictionary.

But is there basis for this stereotype? After all, Neanderthals were our evolutionary cousins, sharing about 99.8 percent of our genetic code, including genes important for brain expansion and language. They were similar enough, in terms of biology and behavior, that Homo sapiens and Neanderthals interbred, in several periods and places between 40,000 and 100,000 years ago.

GettyImages-143064417_copy.0

Since diverging from a common ancestor over 500,000 years ago, Neanderthals and modern humans evolved distinctive anatomies (Credit: Encyclopaedia Britannica/UIG Via Getty Image)

At the same time, Neanderthals were distinct enough to be classified as a separate species. Sometime between 520,000 and 630,000 years ago, the shared ancestors of Neanderthals and Homo sapiens diverged and embarked on separate evolutionary paths. Members of that population that spread to Europe eventually evolved into Neanderthals, whereas those in Africa gave rise to Homo sapiens or modern humans. During this period of separation, the groups evolved distinctive anatomies. Modern humans were relatively tall and lean. Neanderthals became short and massive, with average males about 5 foot 4 inches, 170 pounds and females 5 foot 1 inch, 145 pounds, based on estimates from femur and pelvis size.

Since their common ancestor, the lineages also increased in brain size, but in different ways. To accommodate bigger brains, Neanderthal crania expanded lengthwise like footballs, whereas modern human skulls became more globular, like soccer balls. By 150,000 years ago, members of both species had brains surpassing 1400 cm3 — about three times larger than chimpanzees, our closest living relatives.

How Much Can that Skull Hold

To measure fossil brain volume, anthropologists have traditionally filled skulls with beads or seeds, and dumped the contents into a graduated cylinder (a precise measuring cup). They’ve also submerged molds of skulls into water, measuring the volume displaced. Today CT (computed tomography) scanning methods offer more accurate (and less-messy) measurements, but much of the data in textbooks and other references was collected the old fashioned way.

Based on these values, we can confidently say fossil Neanderthals and modern humans from the same time period had similar brain sizes. Twenty-three Neanderthal skulls, dating between 40,000 and 130,000 years ago, had endocranial volumes between 1172 to 1740 cm3. A sample of 60 Stone Age Homo sapiens ranged from 1090 to 1775 cm3.

Endocranial volumes measured from 23 Neanderthal and 60 modern human fossils (credit: Alex & Monfared with data from Holloway et al 2004 The Human Fossil Record: Brain Endocasts)

Endocranial volumes measured from 23 Neanderthal and 60 modern human fossils (Credit: Alex & Monfared with data from Holloway et al 2004 The Human Fossil Record: Brain Endocasts)

For recent humans, average adult brain size is 1,349 cm3 based on measurements from 122 global populations compiled in the 1980s. Excluding extreme conditions like microcephaly, people span from 900 to 2,100 cm3. That means the average Neanderthal brain volume, of roughly 1410 cm3, is higher than the mean value for humans today. But all the Neanderthals that we’ve measured fall comfortably within the range of living people.

Body Size and Brain Shape

So we know Neanderthals had similar-sized, if not bigger, brains. But their brains could have been organized or proportioned differently, resulting in important cognitive differences. Because Neanderthals had more massive bodies, they may have needed more brain volume for basic somatic maintenance — leaving less brain matter for other functions.

Some scientists also suggest that Neanderthals had relatively better vision. In a 2013 study, researchers estimated visual cortex volume based on the size of orbits, or the holes in skulls for eyes. Neanderthals had bigger orbits, implying larger visual cortices and better vision, which may have been an adaptation for higher latitudes, with less light (although it’s questionable whether orbital size is a reliable indicator of visual cortex volume in humans).

Neanderthal brains were digitally reconstructed, showing specific regions, based on CT scans of skulls (credit: Kochiyama et al 2018 Scientific Reports)

Neanderthal brains were digitally reconstructed, showing specific regions, based on CT scans of skulls (credit: Kochiyama et al (2018) Reconstructing the Neanderthal Brain Using Computational Anatomy. Scientific Reports 8:6296. doi:10.1038/s41598-018-24331-0)

And what did Homo sapiens do with our extra brain space? Some researchers have argued modern humans had larger cerebellums, making us better at information processing. Others have suggested we prioritized smell: Modern human brains had relatively large olfaction regions according to a 2011 study in Nature Communications, which compared the internal base of skulls. The authors propose that heightened sense of smell would have been beneficial for subconsciously identifying safe foods or detecting social information (like who is kin, angry or a suitable mate).

I know you’re thinking, “I’d take vision over smell any day.” That’s my reaction too. What matters here is this: We don’t know if this difference played any role in the success of modern humans and the extinction of Neanderthals. But identifying any such differences — in brains, bodies or culture — gives us a starting point for understanding what gave our species an evolutionary edge.

 

 

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  • http://www.mazepath.com/uncleal/EquivPrinFail.pdf Uncle Al

    … 1) Who among humans is consistently below the average cranial volume? That will speak wonders about cranial volume versus ability.
    … 2) Observing the enlarged picture, one easily sees the Devil peering out in both cases.
    … 3) How could that armored brute have been defeated by the gracile form? It was cheated at every turn – recreational condos, Ponzi schemes, lotteries, illegals voting.

    • Michael Cleveland

      In this context, cranial volume has little to do with ability. Surface area of the brain has everything to do with it. The modern human brain is deeply convoluted, with a much greater surface area than the smoother Neanderthal brain. Long-understood.

      • http://www.mazepath.com/uncleal/EquivPrinFail.pdf Uncle Al

        Agreed. Intelligence is all about a linen dinner napkin that is all sulci and gyri. The article fashionably waffles. I support kinetics not thermodynamics. The gracile form was quick and vicious. Evolution is not about who is right. Evolution is about who is left.

        • Michael Cleveland

          Granted, but in some circumstances, who is right IS who is left–or, ipso facto, vice versa.

          • StanChaz

            Don’t argue with him- he’s too wrapped up in his scenario of “illegals voting”.

      • OWilson

        Not to be argumentative, but your dismissive certitude on the features of Neanderthal brains, leads me to ask, on what basis is your premise determined?

        Unless there are intact Neanderthal brains in some pickle jars in some labs somewhere, Is it possible that their larger brain size was a factor, by interbreeding, in the rapid development of modern man?

        Maybe they are us, and we are them? :)

        • Michael Cleveland

          Contours on the inner surface of the skulls shows the difference. Also long known. DNA comparison between modern humans and Neanderthal does not show that “we are them.”

          • Michael Cleveland

            OWilson: Endocasts. Sorry, couldn’t think of the word. The degree of convolution can be inferred from endocasts of the skulls.

          • OWilson

            Thank you.

            “Inferred” sounds better than long known:)

            According to Nat Geo Genographic Project: ” A team of scientists comparing the full genomes of the two species concluded that most Europeans and Asians have approximately 2 percent Neanderthal DNA. Indigenous sub-Saharan Africans have none, or very little Neanderthal DNA because their ancestors did not migrate through Eurasia”.

            That s interesting, given that it was these same Europeans and Asians with the 2% Neanderthal DNA that gave rise to what most consider the greatest civilizations.

            2% of shared DNA can be quite significant in human evolution, about the same difference between ourselves and the apes.

            Maybe even enough to change them into us? :)

          • StanChaz

            We are all us.
            Please don’t try to divide us by trying to justify your prejudicial racial superiority theories via your embrace of European Neanderthals as the driving force behind our so-called greatest civilizations.

          • OWilson

            Thanks for gratuitous insult! :)

            But I only came across these facts yesterday, in answer to the on topic conversation with the OP, and was surprised myself. No pre-conceived notions on race at all. That’s all in YOUR head, as usual!

            My black DR partner would be most offended by your inference! :)

            But if it gets you through the day, believe what you want!

            Peace!

          • Michael Cleveland

            You make educated inference sound like a guess. It’s based on solidly established principles of comparative anatomy that can be observed between living entities. “Long understood” is a valid observation. I also think your math is a little skewed. The1% DNA difference between chimpanzees and us most certainly does not make them us, or vice versa.

          • OWilson

            I got this from Scientific American:

            “Tiny Genetic Differences between Humans and Other Primates

            chimps and bonobos in particular take pride of place … sharing approximately 99 percent of our DNA, with gorillas trailing at 98 percent”

            Obviously apes and neanderthals are not us, that’s why “maybe”, smileys, and question marks accompanied my statements. :)

            But inference and long understandings aside, it is obvious that small differences in DNA makeup can have a major impact on animal development.

            The question to me therefore, is how much of the ape and DNA humans carry today, is responsible for our current position at the top of food chain?

          • Michael Cleveland

            I think the question is over-simple, but to the extent that we are our DNA, then that’s surely a significant factor in our position. Also note that the exercise in Political Correctness that claims there are no genetic markers for race needs to be taken in the context of the size of that difference. If a difference of only 1 percent in DNA can account for the enormous difference between Chimpanzee and Human, does it not seem that racial markers would necessarily be almost invisibly subtle?

          • Michael Cleveland

            Sorry, just re-read the question, which I misread the first time. 2% Neanderthal DNA is too little to significant in that respect, even poetically.

          • OWilson

            I think you see my point.

            DNA studies keep providing surprises, that overturn previous assumptions.

            I always prefer the “scientists scratching their heads” approach, over “we know for a fact…!”

          • Michael Cleveland

            As good a time as any to address this, since we are talking about DNA science. I’m afraid I have real issues with the existence of Neanderthal DNA in H. Sapiens. Neanderthal DNA is supposedly found in all humans except modern Africans, even though, to the best of current knowledge, Neanderthals never lived in the far east. The usual explanation is that matings between N and H took place in the Middle East just as humans were migrating out of Africa and came into contact with Neanderthal for the first time, and those humans carried those DNA strands as H spread across Europe and the East. If N/H mating was possible, and capable of producing reproductively viable offspring (instead of mules), then why was it only then? There is plenty of evidence that N and H lived in close proximity for thousands of years in Europe. So why, if that mating was possible, are many of us not more than that tiny 2% Neanderthal? There should have been cross breeding going on throughout that history, even if they didn’t get along particularly well. Human males are notoriously prone to rape, if nothing else, with a history of willingness to stick it to about anything convenient that came along, so such matings, if they happened in the Middle East early in the diaspora, not only would not have stopped there, but would have happened with some frequency. If any of the story is true, we should be carrying a much larger percentage of Neanderthal DNA in our own.

          • OWilson

            All good points, and I obviously don’t have the answers, but to your first point it may be that human migrations were not monolithic and took place over millennia, by trial and error.

            A branch of a tree that left its forebears where they were in Africa, and encountered other branches of hominids and exchanged DNA with them as they continued their human dispersion to Asia.

            All conjecture, of course, but there is hope that a lot of these questions can be reasonably determine in our own lifetimes, by our newly discovered DNA technology!

            I’ve no more to add. Thanks for the interesting conversation.

          • Michael Cleveland

            There is another problem: Humans world wide supposedly share the same percentage of Neanderthal DNA. If the part of the family that went east got it from that initial period of encounter in the middle east, then fell out of contact with Neanderthal as they migrated east, while Europeans experienced prolonged contact until N went extinct, there should be a larger percentage of Neanderthal DNA in Europeans than in Asians. If I understand correctly that there is not, then we have a problem.

          • yetanotherbob

            Migration of populations goes right up to the 1300’s and continues today. Look at the current population of Australia for example.

            the Huns invaded China in the 500’s, and the Mongols invaded Europe in the 1300’s we know that the Indus peoples were invaded by Arayans in chariots in around 2000 BC. We don’t have any reliable information from before that.

            But the process has been going on for at least that long. European and Asian lineages are rather mixed on such a scale.

            I saw once that China’s First Emperors favorite wife was a redhead. The Ainu of China have many light brown haired people. The list just goes on and on.

            Don’t make the mistake that the amount of Neanderthal DNA from disparate peoples means that the Neanderthals themselves had to be there. There’s a lot of history behind us.

          • Michael Cleveland

            Well, for starters, to take small points, the Ainu are from Japan, not China. As for the rest, what you say is true, but you have the problem backwards. The relevant issue has to do with the time modern humans lived in proximity to Neanderthal, not what happened after Neanderthal was gone. Until very recent times, contact between Europe and the far east has been too limited to account for the general presence of Neanderthal DNA in far eastern populations, where Neanderthal did not live. The problem is that if Humans and Neanderthals mated in the Middle East early in the human migration out of Africa, it is very difficult to account for the lack of mating thereafter, since Neanderthal and modern humans lived in close proximity for thousands of years in Europe. There should be a larger percentage of Neanderthal DNA in Europeans than in Asians, yet the actual percentage is slightly higher in Asians.

          • yetanotherbob

            Ainu also live in Siberia. There is a large population in Kamchatka and more in central Asia. within the last two thousand years, they had all of Japan to themselves. Then the Japanese arrived.

            I’m not sure though that we really disagree. There is no evidence that Neanderthals ever made it east of the Middle East. Still, the DNA had to come from somewhere.

            I’m not sure we know enough to really say. And as I send at the end, “There’s a lot of history behind us.” and most of it is unknown.

          • Michael Cleveland

            I’d like to know more about your source. I was living in Okinawa 30 years ago, studying cultural anthropology, among other things, where I first encountered the Ainu as part of my studies. Certainly we know more now because of DNA studies, but the big question then involved their origins. No one could place them. They were indigenous and exclusive to Hokkaido, Sakhalin Island and the Kirils. The problem was interesting because their ethnicity and language could not be connected with anyone else in the region. They were never in Kamchatka or Siberia and there is no central Asian population, though they may have relatives in those places, since they surely arrived from the west. One thing that has come to light in the time since I lived in that part of the world is their close genetic connection with the non-Japanese Ryukyu people, whose ethnic history was also something of a mystery when I was there. I have to say that I have real problems with the idea of interbreeding between Neanderthal and Sapiens. Their morphological differences are just too great. The science is new, and I’m just jaded enough to recognize that many such things are these days subject to shading by political correctness. The issues I raised above are not, as you seem to be agreeing, adequately explained by early encounters in the Middle East, if they did not continue throughout the time and regions where the two coexisted. But DNA is not my area of expertise. I know enough to be dangerous and possibly wrong, but there are things that need explaining.

          • Michael Cleveland

            True, they did take place over millennia, probably in waves, but all of this can be taken in that context without changing the question, including the one below:

          • OWilson

            If I may add!

            I have traveled extensively through Mexico (not Acapulco, Puerta Vallarta, Cancun, or Cabo :) and you can see the Mayan physiology in many of the remote native people, to this day.

            Like the Peruvians and the Incas, and the Taino in my DR, can it be that the ones, that took on Spanish DNA (integration, forced, voluntary or whatever) are the ones that actually survived?

            The survivors do tend to have a lot of Spanish blood!

          • Michael Cleveland

            There is an interesting theory that the Basque people are actually Neanderthal remnants, with a considerable mix of H. Sapiens genes. It is supposed to explain why they are so different both genetically and culturally from all other modern humans, and speak a language that is unrelated to any language family in the world. It is attractive because it the Basques lived so near the last hold-out Neanderthal communities. It does not, however, stand up to genetic analysis, which ascribes the origins of the Basque people to a mixing of late arriving farmers and indigenous hunter-gatherer groups between 7000 to 5500 BCE, much too late for any kind of Neanderthal interaction. The differences derive instead (and in part) from long isolation of the population due to the barrier created by the Pyrenees.

  • NYBamBam

    Sometimes science operates from a wrong, underlying premise and that just keeps stunting analysis. Consider this: Neanderthals sexually matured later and had fewer children, further apart. Human sexually matured young and had more kids. When human migration flooded Neanderthal regions, the full range of human interactions – from killing to partnering – meant there were fewer neanderthals than humans and that sexual interaction breed the local populations together.

    As additional modern humans flooded those communities, only those Neanderthals that rejected modern human contact would be able to sustain a distinct gene pool. Most hunter/gatherers positively engage new people, because their wealth is measured in social relations, encouraging exogamy (oldest human law) or ‘marrying out’. Over time, the two populations would blend and the group with the fewest members, would have the least impact on descendant genetic makeup. Since modern humans had babies earlier and more often, Neanderthal populations were eventually subsumed into the modern population.

    We make a fetish out of difference, but it means less than we think it does. Unlike other animals, we can potentially ‘go into heat’ any day of the year. That’s the genetic advantage that subsumed the Neanderthal population into our own. A sex drive that’s always there and an earlier onset of puberty.

  • Michael Cleveland

    There is nothing new in this article. The difference in brain size has been long known. However, the article omits a critical piece of information. Human brains have a greater surface area because the brain is more convoluted than Neanderthal’s brain, which is smoother. It’s surface area, not volume that makes the difference, and defines the superiority of the human brain.

    • StanChaz

      Really?
      How do you know that Neanderthal’s brains were less convoluted with less surface area if we only have their skulls to examine?

      • OWilson

        Already covered, above!

        Take a moment off from trolling to read the thread! :)

  • iThinker2

    Compare ratios of brain weight to body weight.

  • bwana

    Until we resurrect a Neanderthal this discussion will continue ad nauseam. Neanderthals were amazingly successful right through an ice (or two) and may have simply outlived their usefulness much like mastodons, mammoths, cave bears, woolly rhinos, etc.

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