How old is the modern brain?

How far back in time could you go and find a human with an essentially modern brain. Turns out the answer is surprisingly obvious


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How far back in time could you go to adopt a baby? That’s the question that comes from Eric today. He’s curious as to how far our modern brain stretches back. Remember, if you’re curious about something you can get in touch through the website. 

I understand that Homo sapiens have been anatomically the same as we are today for about 180,000 years. I also understand that the first time any Homo sapiens ventured outside of Africa was about 60,000 years ago. My question is, how far back in time could we go and bring a newborn from that time and raise them in present day and they could be mentally and intellectually the same as we are now?

This question hints at an interesting debate in human evolution that has been going on for some time. Are we the sum of our parts?

As Eric correctly points out, the human species is around 200,000 years old. 195,000 years if you want to be precise. Since then our species hasn’t really changed in any substantial way, beyond minor regional adaptations. In particular, the brain appears to have remained the same. It hasn’t changed in size or shape for those 195,000 years.

Thus, some argued that since we had a modern brain all that time, we must have been as smart as modern people for that long. There’s no notable physical changes that would point to a change in intelligence. As such, Eric could go looking for his adopted child at any point Homo sapiens existed and get a perfectly smart baby.

A super modern brain

However, some contend that there’s more to the human brain than just its size and shape. Neuronal structure, development, organisation, etc. are all important in making a modern brain as well. And we can’t really tell how long they’ve been in the modern structure. Fossil evidence just doesn’t have that high a resolution.

So they speculate that the modern brain may have emerged later than the 195,000 year mark. In particular, they narrow it down to around 50,000 years. This is when the bulk of the out of Africa movement happened. With it a whole new suite of technologies began to appear too. All of this dramatic change, they claim, indicates that something critical happened in our brain. Some sort of mutation shifted our brain structure, making it possible for us to start doing all this cool stuff.

Thus if Eric was to go looking for a foster kid >50,000 years ago it wouldn’t turn out like a modern human. Even though externally they might look the part.

The unique traits which appeared with behavioural modernity. Allegedly.

Smart Africans

At least, Eric would have trouble if you believe their interpretation. And whilst it was once fairly popular it has fallen out of favour in recent years. This is because all of the evidence that there was this “cognitive revolution” that might indicate a mutation has fallen apart.

One of the crucial pieces of evidence was so-called “behavioural modernity”. This was the suite of traits only seen after humans left Africa, indicating that something may have happened around this time in our brain. Except it turns out that there’s evidence of behavioural modernity gradually evolving along with our species. Things like fancy tools, fishing, art, and more are all seen before the modern brain is supposed to have evolved.

Some of the cool stuff our ancestors made of before they left Africa

This gradual change is more consistent with cultural evolution than some sort of sudden mutation. As such, most now accept that the underlying brain has been essentially modern the whole time. And so Eric could pick his baby from any point in modern human pre-history and it would be “normal”.

His biological parents might just be a bit behind the times.

References

d’Errico, F., Henshilwood, C., Lawson, G., Vanhaeren, M., Tillier, A.M., Soressi, M., Bresson, F., Maureille, B., Nowell, A., Lakarra, J. and Backwell, L., 2003. Archaeological evidence for the emergence of language, symbolism, and music–an alternative multidisciplinary perspective. Journal of World Prehistory, 17(1), pp.1-70.

Henshilwood, C.S., D’errico, F., Marean, C.W., Milo, R.G. and Yates, R., 2001. An early bone tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language. Journal of Human Evolution, 41(6), pp.631-678.

Henshilwood, C.S. and Marean, C.W., 2003. The origin of modern human behavior. Current anthropology, 44(5), pp.627-651.

4 thoughts on “How old is the modern brain?”

  1. BrandonSP says:

    I agree with the premise that our intelligence probably hasn’t changed much since Homo sapiens first appeared in Africa 195,000 years ago. Unfortunately there is a sizable contingent of people (the so-called “human biodiversity” crowd) that essentially insists that, to the contrary, those modern humans who left Africa and became Europeans and Asians evolved higher intelligence than the ones who stayed in Africa. More often than not, they seem to have a anti-African racist agenda. But it would be nice if there was a better way of gauging when in our evolution did modern human cognition develop. If the major changes all happened before any migrations out of Africa, that would shut down the “human biodiversity” racialist case pretty good.

    1. Adam Benton says:

      To do that I think we need to get a good definition of what makes up modern human cognition. So many characteristics have been proposed, only for it to be later discovered that the Neanderthals did it too.

    2. szopeno says:

      You seem to not understand “HBD crowd”. It does propose that every environment selects for something, and brain is not immune for selection. If selection pressure over long periods of time are different for Germans, Inuits or Hindu, then it will affect their bodies… and the brain is part of the body. It does not mean that the changes are fundamental and qualitative in nature; but most from “HBD crowd” I read do not say that. They mostly say that there may be statistical differences in different traits, both physical AND mental.

      At least one theory which was very popular amongst HBD crowd (that church shaped european culture with bans on cousin marriage) was recently proposed independently (I believe) by mainstream science.

      Moreover, I do not see the post here to be a proof that a child of human from 100.000 ago would be exactly the same as child of modern human. Yes, his brain would be modern and there would be no qualitative differences. But it does not mean his brain would be exactly the same. After all, there are no qualitative differences between our teeth and our ancestors from 250.000 years ago, but they are not identical and some subtle changes DID happened.

  2. Mario Díaz Díaz says:

    I do not know, but I throw the following hypothesis: Probably, something happened in a first anthropological meeting about 100,000 years ago between Sápien and Neanderthals. A cultural and biological hybridization that resulted in the existence of some African (sapiens), predatory (Eurasian) and Neanderthal sapiens that perished some 25 years ago. From the disappearance of Neanderthal begins the cultural explosion sápiens-predator. That is the sapiens who today see Africans only as the sapiens, or the Latin American or Asian indigenous peoples who do not come from the sapiens-neanderthal hybridization. The eventu was something cognitive-behavioral-mental.

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