The evolution of intelligence.

How has humankind’s intelligence evolved over time? Or has it? Are we any more intelligent that the ancients were? Those who came before Aristotle, Plato, Socrates and the like. Before any written (recorded) history.

You need to be more specific about who “the ancients” were. Are you talking about people living just before recorded history (4th millennium BC), or further back in time than that? If the former, then probably not. There are some papers out there claiming that certain human groups may have evolved more/better intelligence even in the last 1,000 years, but I would say those are far from the consensus view.

Hard to say. Of the arguments out there one is (Dawkins “The Red Queens Race” IIRC) that the rise of intelligence is mainly due to human females wired in strong preference for mates with the best language skills, and the related ability to pitch quality woo. All the stuff like agriculture, tool making, civilization, etc. are just side effects of that poon chasing dynamic.

I mean just before recorded history, based on the idea that quite some intelligence was required to develop writing, and the interest in doing so.

Before written history, there’s not much to go on; but there is some evidence to make inferences by.

The record of artifacts- mostly stone tools- is far more extensive than the fossil record. Generally they show an increasing sophistication over time. One noteworthy thing is that for a long long time- a period of hundreds of thousands of years, when Homo Erectus is thought to have predominated- the tools show almost no innnovation at all. Almost like they were produced by hardwired instinct. The tools made by Neandertal/archaic Sapiens were more sophisticated in that they were “flake” tools, which evidently required the capacity to plan what the finished tool would be shaped like when struck off the core.

The biggest leap in artifacts before civilization was devised occurred about 30,000 years ago, when all of a sudden evidence of abstract thought appears: paintings, carvings and decorative items. Indeed, before predecessor fossils were discovered this was thought to mark the evolution of Sapiens.

Finally, there’s genetic evidence of mutations related to brain development, in some cases as recently as 6000 years ago, although the signifcance of these is not known yet.

On preview: on balance we probably aren’t innately more intelligent than our recent ancestors, although a case could be made that civilization has had a selective effect on what pesonality types are more prominent today.

High intelligence had to be pretty much universal before the developement of more complicated tools, such as points, knives with hafts, fishooks and the like. As these things came to be, each successive generation improved designs and taught these to the next. That’s what intelligence is, learning (but not teaching).
What’s hard to determine is when and how someone was able to reason that a flint flake could be fastened to a stick to make it longer. A very important developement, BTW.
Fire was available to people long before they figured out how to make it.
I doubt that intelligence could have evolved as quickly as knowledge increased. The intelligence had to be there first. And knowledge grew very fast, so reason must have been there pretty early.

This is sort of an extension to the OP, and obviously there’s no way to really know, but- I’d like to hear some of your opinions on this:
How far back in human history do you think the average baby, if sent to our present, could be raised to be a typical indistinguishable member of our society?

At least 90,000 years, likely 125,000 years and possibly 200,000 years or whenever the divergence point actually was.

I don’t find the supposed leap in artifacts c 30,000 years ago to be convincing evidence of a sudden leap in intelligence. There are too many signs that Homo sapiens had abilities that parallel our current ones long before that.

Of course, this brings us into the huge and contentious fight over what intelligence is. Is it some basic element of the brain? Is it a cultural trait that requires passed-along knowledge? Can intelligence increase within a species?

I doubt that any two of us are using the same definition of intelligence, because there isn’t one that is agreed upon.

Potatos helped…

Potatoes were unknown outside the western hemisphere until after Columbus. As were tomatoes and peppers. I would guess the concentrated protein and calories from meat were more important.

Babylonians 3500 knew how to solve quadratic equations, which most modern humans cannot do (granted most Babylonians probably couldn’t either). Even more significant is the fact that they cared enough to write scrolls about it. More precisely, they had a series of problems, given the sum and product of two numbers, find the numbers, but this is equivalent to solving a quadratic equation.

Around the same time, if you believe Fred Hoyle’s explanation of Stonehenge (and I do, especially for his discussion of the “errors” in the alignments) then the builders of the original Stonehenge (without the massive center stones) had a theory of the earth’s rotation and the moon’s orbit. What Hoyle said very convincingly is that he could have predicted eclipses at the time (precession of the equinoxes renders the alignments out of date now).

Cave paintings convince me that human intelligence has not evolved in at least 30,000 years. In fact, one might ask if it has devolved. Sometimes I wonder.

If you’ll read the linked article, you’ll see that starches have been available almost worldwide from sources other than potatoes (such as other tubers) forever. The need for protein in meat is greatly exaggerated in the minds of americans. I’m not familiar with the diets of other countries, but I suspect a similar myth exists in some of them too.
Now be quiet and eat your rutabagas.

Linda Gottfredson asked essentially that question (“How did humans evolve such remarkable intellectual powers?”) in this paper

She hypothesized that fatal accidents may have played a large role.

Obviously hard to test, but it’s an interesting idea.

I can’t really contribute much in the way of an answer, but I’m curious what people think of the Flynn effect, which, as you may know, is the observation that people’s average IQ increases steadily every generation. Is this a reflection of actual change in the average person’s IQ, or something else? If the former, would humans have kept this pace up for all of history and prehistory?

I like vegetables including rutabaga (especially pickled as served in a nearby Lebanese restaurant) and not a lot of meat. But one thing that distinguishes us from the other great apes is that we get a lot more meat. It doesn’t follow, of course, that that was necessary for the development of intelligence (I am aware of the post hoc fallacy), but there is a temporal correlation.

I am aware that there are all sorts of other starchy tubers and roots, but the apes dine on them too. But the OP specified potatoes and they could not have had any effect.

No one knows what is causing the Flynn effect:

Clearly, it can’t simply be a genetic tendency for intelligence to increase at that rate. It’s just not possible for a population to change its genetic potential that fast. If it were possible, it would mean that just since the introduction of I.Q. tests, in about 1915, the average I.Q. in the world has increased such that compared to us, the people of 1915 were borderline mentally retarded.

That date keeps getting pushed back. We have artifacts from 75k years ago now that show evidence of abstract thought.

That’s why I pushed the intelligence line back as far as I did. The “leap” at 30,000 years appears to be an artifact of the available data rather than a true change.

Since 1915 the average person’s nutrition intake as also improved greatly (as the increase in tall people shows), as well as education, and educational techniques. Also we’re steadily improving medical technology so diesee aren’t as devastating and avoided.

Would any of these of had a substantial effect on brain development? Are there any studies on explantions?

Guess modern people are in like Flynn.

Yeah, there’s a debate among paleoanthropologists as to whether or not the so-called anatomically modern humans prior to roughly 70k years ago had the same mental abilities as those who came afterwards. The former were making the same stone tools that Neanderthals were making in Europe and some scientists go so far as to say that fully articulate language didn’t evolve until that critical time around 70k years ago, even though our species emerged about 200k years ago.

The Tao’s Revenge writes:

> Since 1915 the average person’s nutrition intake as also improved greatly (as
> the increase in tall people shows), as well as education, and educational
> techniques. Also we’re steadily improving medical technology so diesee aren’t
> as devastating and avoided.

As the article in Wikipedia says, nutrition and medicine can’t be the complete explanation. We can calculate how much apparent increase in I.Q. these would cause, and it’s not nearly enough. We have examples of populations with strict limits on food for a few years, and they didn’t show any I.Q. decrease. We would have to assume that in 1915 the population was at the edge of starvation all the time and were constantly ravaged by plagues to get enough effect to explain the difference in average I.Q. scores. People in 1915 had more limited diets and less medical technology, but it wasn’t that much different.

As the article says, that leaves cultural differences. There have been changes in education. It’s claimed that there are more of the sort of abstract thinking in ordinary life that is relevant to I.Q. test. Maybe there are other differences in our culture. No one really knows.