How does the Medieval brain compare to the modern brain?

[Mallignamius]

Physiologically, is there much difference between the human brains of 500 to 1,000 years ago and today's brains? About when in our past would you say a minor difference in the comparison begins?

By "minor difference," I mean perhaps in overall intellectual and/or mental abilities at around 5%.

My curiosity is this: If in the next 500 to 1000 years we have little physiological difference in our brains' potential, then besides simply a lack of knowledge, what's keeping us from being intellectually/mentally advanced by as much as we will be in the future?

 

[BillJx]

Physiologically, is there much difference between the human brains of 500 to 1,000 years ago and today's brains? About when in our past would you say a minor difference in the comparison begins?

By "minor difference," I mean perhaps in overall intellectual and/or mental abilities at around 5%.

My curiosity is this: If in the next 500 to 1000 years we have little physiological difference in our brains' potential, then besides simply a lack of knowledge, what's keeping us from being intellectually/mentally advanced by as much as we will be in the future?

I don't have any knowledge in this area, but it seems to me that the human brain hasn't changed in a long, long time. During the many thousands of years that the various peoples have been separated, there has been divergent evolution of hair characteristics, facial features, body size, metabolism, melanin, and various other characteristics. The greatest sociological discovery of the past century is that there has been no divergent evolution of intelligence or even of personality. Why that should be the case, who knows?

For the second part of your question, and still keeping in mind that I'm a complete know-nothing, future intellectual advances could come in two ways:
- correction of minor but normal imperfections of brain development and
- implants.

Since these technologies probably wouldn't be universally affordable, then the universality of human nature might no longer be true.

 

[stickythighs]

Physiologically, is there much difference between the human brains of 500 to 1,000 years ago and today's brains? About when in our past would you say a minor difference in the comparison begins?

By "minor difference," I mean perhaps in overall intellectual and/or mental abilities at around 5%.

My curiosity is this: If in the next 500 to 1000 years we have little physiological difference in our brains' potential, then besides simply a lack of knowledge, what's keeping us from being intellectually/mentally advanced by as much as we will be in the future?

There is almost no difference between the human brains of 500 to 1,000 years ago (or even 20,000 years ago) and today's brains. If babies born 20,000 years ago were magically transported to 2008, the babies would be indistinguishable from the babies born in 2008 when they grew up.

 

[BWV]

The premise is that somehow the medievals were dumber than us, which is not the case. We simply have more knowledge and better tools.

 

[CRGreathouse]

Are there any sources for these assertions? I wouldn't be surprised if there was little change in the human brain over the last 1000 years (or even 5000 years), but I don't think it's at all obvious. I see two opposing forces at work:

1. The advantage of intelligence today is greater (I assert) than the advantage of intelligence 1000 years ago, relative to other genetic traits. All else equal, this would tend to increase average intelligence -- and could easily happen over only a few hundred years, if the change was strong enough.

2. Modern health services give better treatment for 'low-IQ' and otherwise mentally handicapped people, and legal systems have moved toward the protection of the rights of all, including people with low intelligence. In particular, their rights to life and procreation are relevant here (and I assert both have improved). All else equal, this would tend to decrease average intelligence.

Now there may be other trends in place, or these two might simply happen to cancel, or their effects might be weaker than I would expect -- but without evidence, I find neither of the following claims persuasive:
C1. Average human intelligence has not increased over the last thousand years.
C2. Average human intelligence has not decreased over the last thousand years.

Both are claimed in the posts above, but the arguments consider only C1. I would appreciate any sourcing for claims C1 or C2, for any reasonable values of "average" and "intelligence", and any timeframe within a factor of 10 (100 to 10,000 years).

 

[mgb_phys]

1. The advantage of intelligence today is greater (I assert) than the advantage of intelligence 1000 years ago, relative to other genetic traits.

An advantage only has a genetic effect if it causes you to have more surviving offspring.
Today number of offspring is inversely proportional to inteligence (measured in terms of educational and job performance)

In particular, their rights to life and procreation are relevant here (and I assert both have improved). All else equal, this would tend to decrease average intelligence.

I'm stilli guessing the village idiot in the 1500s had more chance of having kids than someone in a mental health institution today.

All this assumes that 50 generations is enough to have any selective effect anyway.

 

[CRGreathouse]

An advantage only has a genetic effect if it causes you to have more surviving offspring.
Today number of offspring is inversely proportional to inteligence (measured in terms of educational and job performance)


I'm stilli guessing the village idiot in the 1500s had more chance of having kids than someone in a mental health institution today.

So you would argue that intelligence has dropped over the last 500 years, then?

All this assumes that 50 generations is enough to have any selective effect anyway.

50 generations is easily enough if the factor is sufficiently strong.

 

[mgb_phys]

So you would argue that intelligence has dropped over the last 500 years, then?

If it has a genetic component then it might be dropping in the future, http://us.imdb.com/title/tt0387808/

If the leaking flat roof of my lab is anything to go by it's certainly dropped in the last 500 years.

 

[berkeman]

Physiologically, is there much difference between the human brains of 500 to 1,000 years ago and today's brains? About when in our past would you say a minor difference in the comparison begins?

By "minor difference," I mean perhaps in overall intellectual and/or mental abilities at around 5%.

My curiosity is this: If in the next 500 to 1000 years we have little physiological difference in our brains' potential, then besides simply a lack of knowledge, what's keeping us from being intellectually/mentally advanced by as much as we will be in the future?

Intriguing question. I googled brain size history (on the premise that brain size would be the main thing that has changed in the past few 1,000s to 10,000s of years), and got lots of interesting hits. Check out this one that is talking about a timeline on the order of the past 5800 years:

http://www.sciencemag.org/cgi/content/abstract/309/5741/1720

 

[Moonbear]

The only answer that can legitimately be provided here is, "We don't know." The sort of tools we have now to study and understand the brain were non-existent in medieval times, so there would be no records from then to use as a basis for making any comparison.

 

[mgb_phys]

there would be no records from then to use as a basis for making any comparison.

http://britastro.org/baa/images/stories/meetings/cavendish.jpg
http://www.freefoto.com/images/32/01/32_01_1---King-s-College-Chapel--Cambridge--England_web.jpg

Guess which one's roof leaks!

 

[CRGreathouse]

http://britastro.org/baa/images/stories/meetings/cavendish.jpg
http://www.freefoto.com/images/32/01/32_01_1---King-s-College-Chapel--Cambridge--England_web.jpg

Guess which one's roof leaks!

Selection bias, anyone?

 

[vanesch]

Also, brain size (especially when it goes about small differences) is not necessarily an indicator of differences in intelligence. Neanderthal had a slightly larger brain than sapiens sapiens for instance. Just random googling: http://hypertextbook.com/facts/2001/ViktoriyaShchupak.shtml and http://en.wikipedia.org/wiki/Neanderthal
Moreover, as they were smaller than we, their brain/body ratio was even bigger.

One has not found a correlation between the "intelligence" of a person and its brain size (Einstein's brain didn't have anything exceptional, anatomically speaking).

 

[somasimple]

Here are two examples of these ancient idiots =>
http://en.wikipedia.org/wiki/Archimedes
http://en.wikipedia.org/wiki/Pythagoras

Unfortunately, they are tons...

 

[Moonbear]

http://britastro.org/baa/images/stories/meetings/cavendish.jpg
http://www.freefoto.com/images/32/01/32_01_1---King-s-College-Chapel--Cambridge--England_web.jpg

Guess which one's roof leaks!

I'm not sure what point you're attempting to make here. What does leaky roofs have to do with physiological processes in the brain?

Also, the original question really is not asking if people were more or less intelligent (not that there's really a good objective way to even determine that), but if there are different physiological processes. That's talking about cellular level mechanisms. We certainly see individual variation in HOW people accomplish different tasks that would involve some physiological and anatomical variation without overall affecting intelligence, but we'd have no way to know if that differed in any meaningful way from people in the medieval period. It may have had nothing to do with intelligence. What if it is something like appetite regulation? People then made do with far less food than we do today, so something may differ in brains as food scarcity diminished. Or, what if it was the emotional response to loss/death that was different? The brain does a lot more than just solve problems or build roofs.

 

[vanesch]

The brain does a lot more than just solve problems or build roofs.

does it ?

 

[CRGreathouse]

One has not found a correlation between the "intelligence" of a person and its brain size

I can't speak for the rest of your post, but I know that there's a fairly strong (positive) correlation between g as measured and brain mass.

There's a whole website devotes to the correlates of intelligence (can't seem to Google it up right now; anyone know what I'm talking about here?) which summarizes several hundred papers, their methodologies, and their results. If I can find a link that would surely give some numbers.

 

[CRGreathouse]

If it has a genetic component then it might be dropping in the future, http://us.imdb.com/title/tt0387808/

I have no idea what the random movie has to do with anything, but intelligence is strongly heritable. Depending on what authority you use, the rate is generally 50% to 80%.

 

[mgb_phys]

I'm not sure what point you're attempting to make here. What does leaky roofs have to do with physiological processes in the brain?

Someone said there was no records of medieval intelligence, I was just pointing out that there are a lot of buildings, literature and philosphical works that show that people 500years ago were more than a match for your average daytime soap watcher.

 

[CRGreathouse]

Someone said there was no records of medieval intelligence, I was just pointing out that there are a lot of buildings, literature and philosphical works that show that people 500years ago were more than a match for your average daytime soap watcher.

That statement is consistent with the proposition that average intelligence has increased since that time. But I think this is a strawman: no one on this thread has argued that average intelligence has increased at all over the last 500-1000 years, let alone the much stronger statement that the average person today is more intelligent than all people 500-1000 years ago.

 

[Andre]

If it were medieval brains that produced the Malleus Maleficarum and our brains are still thinking along the same lines, could it be that there are still parallels to those ideas? For instance:

...And yet there are some who rashly opposing themselves to all authority publicly proclaim that witches do not exist, or at any rate that they can in no way afflict and hurt mankind. Wherefore, strictly speaking those who are convicted of such evil doctrine may be excommunicated, since they are openly and unmistakably to be convicted of false doctrine...

 

[CRGreathouse]

I could write a book that says that disbelief of witches is grounds for being banned from physicsforums.com, but I have no idea why that or Malleus Maleficarum would have any special insight into the question of the human brain.

 

[jim mcnamara]

mb is referring to things like thermoregulation - homeostasis in general terms.

Anyway, I don't understand a lot of the 'ideas' here since I don't think they rate the label of hypothesis.

What you are seeing is an artifact of the number of humans in the world. The number of people with really amazing intellects has never been higher (you can take this same argument and apply it to traits or socially-induced behaviors. These go in other 'good' and 'bad' directions like maybe 'serial killer'). As well - the increasing number of people competing for common resources like farmland, food, and gasoline is going to continue to escalate strife and brutal behavior as well as allow for a large number of genius level people. Or great musicians. Or sociopaths.

Let's hope that the super geniuses out there are not forced into the brutal behavior aspect of things because of horrible social conditions. The world does not need a version of Hitler with immense intellectual abilities and fantastic social skills. My opinion.

 

[vanesch]

The world does not need a version of Hitler with immense intellectual abilities and fantastic social skills. My opinion.

Damn.

 

[CRGreathouse]

As well - the increasing number of people competing for common resources like farmland, food, and gasoline is going to continue to escalate strife and brutal behavior

Aren't you http://www.ac.wwu.edu/~stephan/malthus/malthus.0.html for that prediction?

 

[Cincinnatus]

As I recall, the most recent evolutionary changes thought to have occurred in the human brain are related to the development of language around 100,000 years ago. I'm not at home right now so I can't find a citation for this though.

 

[TheStatutoryApe]

mb is referring to things like thermoregulation - homeostasis in general terms.

Anyway, I don't understand a lot of the 'ideas' here since I don't think they rate the label of hypothesis.

What you are seeing is an artifact of the number of humans in the world. The number of people with really amazing intellects has never been higher (you can take this same argument and apply it to traits or socially-induced behaviors. These go in other 'good' and 'bad' directions like maybe 'serial killer'). As well - the increasing number of people competing for common resources like farmland, food, and gasoline is going to continue to escalate strife and brutal behavior as well as allow for a large number of genius level people. Or great musicians. Or sociopaths.

Let's hope that the super geniuses out there are not forced into the brutal behavior aspect of things because of horrible social conditions. The world does not need a version of Hitler with immense intellectual abilities and fantastic social skills. My opinion.

IQ is measured on a curve. So if there were a significant increase in the percentage of geniuses in the world their collective IQ would drop (so to speak).

And as a part answer to the OP the Flynn Effect has shown a world wide average increase in IQ of approximately three points per decade during the twentieth century. If intelligence is genetically heritable then this may show the possibility of evolution of intelligence over time. The actual reason for the observed increase though is highly debatable.

 

[CRGreathouse]

If intelligence is genetically heritable then this may show the possibility of evolution of intelligence over time. The actual reason for the observed increase though is highly debatable.

IMO, the Flynn effect is too fast to be explained by selection. I do think selection* can be rapid, but this effect is two standard deviations per century -- a phenomenal upward movement.

* N.b. not evolution, just selection. Evolution involves not just selection but mutation, and finding beneficial mutations takes a long time compared to just selecting out bad traits. Bacteria can gain immunity to an antibiotic in perhaps a dozen generations, but actually creating new traits (not just selecting existing ones) takes time.