Thursday 6 March 2014

Comment to Greg Cochran on the decline of intelligence since Victorian times


Greg Cochran has been the most significant (intellectually substantial) critic and opponent of the idea (deriving from myself and Michael A Woodley) that historical reaction time data have shown a significant (approx. one standard deviation or 15 modern IQ point) decline in intelligence since Victorian times. 


In his latest blog posting, Greg takes another side swipe at the idea.

Here is my comment in response.



As you presumably know, I have an extremely high regard for your work (e.g. having provided a back page blurb for 10,000 Year Explosion and invited you to write for Medical Hypotheses on the germ theory of male homosexuality).

And I am – on the whole! – grateful for your opposition to the finding of an approximately 1SD (15plus IQ points by modern measurements) decline in general intelligence in England (and similar places) as measured by simple reaction times since about 150-200 years ago – grateful because it has stimulated me to organize my thoughts on the subject.

But I continue to think you are wrong! and that the evidence you bring against this decline is inadequate – so I continue to hope to persuade you otherwise.

I have three considerations to offer.


1.       The decline in question is (roughly) from IQ 115 to IQ 100 over the space of 150 years – about one IQ point per decade (whatever that means!). But I suggest that this would not be expected to have analogous functional consequences to a decline from 100 to 85, since IQ is not an interval scale.

(In a nutshell, I think Victorian English IQ was *about* the same or a little more than recent Ashkenazi IQ – but has declined.)

This 150 year decline measure in modern IQ units corresponds to a slowing of simple reaction times from approximately 180 to 250ms for men – about 70 milliseconds.

And the minimum RT in the Victorian studies was about 150 ms – which is probably near the physiological minimum RT (and maximum real underlying IQ) constrained by the rate of nerve transmission, length of nerves, speed of synapse etc.

So average Victorian RT was about 30 ms above minimum RT, while modern RT is about 100 ms above minimum.

By contrast – modern reaction times (in Silverman’s study) for men average approximately 250ms with a standard deviation of 50ms – however there are good recent studies with an average RT of 300ms for men.

I would argue (on theoretical grounds) that as RT declines there ‘must’ come a point when it comes-up-against the neural constraints of intelligence, such as short term/ ‘working’ memory (the metal ‘workspace’, activation of which lasts a few seconds, seemingly) – and therefore there would be a non-linear effect of reducing intelligence – intelligence would cross a line and fall off a cliff.

My assumption is that a reduction in (modern normed) IQ from average 115 to 100 would *not* have such a catastrophic effect on high level intellectual (abstract, systemizing) performance as a reduction from average 100 to 85. (At a modern average IQ of 85, top level intellectual activity is *almost* entirely eliminated.)

When we are dealing with the intellectual elites, the same may be more apparent – the initial reduction in RT may retain the possibility of complex inner reasoning; while after a certain threshold the number of possible operations in the mental workspace would drop below the minimum needed for high scale intellectual operations.


2.       It may be that your example of maths does not refute the observation of reduced intelligence. It may be that modern mathematic breakthroughs are of a different character than breakthroughs of the past – and do not require such high intelligence.

I think this may be correct in the sense that I get the impression that modern maths seems to be substantially a cumulative, applied science – somewhat akin to engineering in the sense of bringing to bear already existing techniques to solve difficult problems.

So a top level modern mathematician has (I understand) spent many years of intensive effort learning a toolbox of often-recently-devised methods, and becoming adept at applying them, and learning by experience (and inspiration) where and how to apply them.

This seems more like the Kuhnian idea of Normal Science than the Revolutionary Science of the past – more like an incremental and accumulative social process, than the individualistic, radical re-writings and fresh starts of previous generations. And, relevantly, a method which does not require such great intelligence.

I also note that many other sciences, from biology to physics, have observed the near-disappearance of individual creative genius over the past 150 years – and especially obviously with people born in the past 50 or so years - which would be consistent with reducing intelligence.


3.       Michael Woodley and I have discovered further independent – but convergent – evidence consistent with about 1 SD (15 IQ point) decline in intelligence from Victorian times, again using simple reaction time data – but, as I say, using a completely different sample and methods. The paper is currently under submission.

I mention it because the unchallenged consensus post-Galton has been that simple reaction times has some causal – although not direct – relationship to intelligence; and if we have indeed established that RT has substantially slowed over recent generations, then either this would need to be acknowledged as implying a similarly substantial decline in intelligence – or else the post-Galton consensus of IQ depending on RT would need to be overturned.


Note added: An e-mail correspondent writes:

Take the following claim of Cochran's:

"In another application – if the average genetic IQ potential had decreased by a standard deviation since Victorian times, the number of individuals with the ability to develop new, difficult, and interesting results in higher mathematics would have crashed, bring [sic] such developments to a screeching halt. Of course that has not happened."

Cochran is completely correct in his reasoning, and in his prediction that higher mathematics would have crashed given a one sigma decline in g. His last sentence is however empirically false, because a crash is precisely what the data indicate happened.

Charles Murray, in his 2003 Human Accomplishment presents graphic data of the rate of eminent mathematicians and major accomplishments in mathematics (p. 313). The trends reveal a precipitous decline in the occurrences of both of these between the years 1825 and 1950. Extrapolating the decline in this period out to the year 2000 would place the rate of eminent mathematicians and their accomplishments below the rate observed in 1400, despite massive population growth in the West during this interval. The peak of mathematical accomplishment clearly occurred during the heyday of eugenic fertility in the West, between 1650 and 1800, and actually occurred earlier than the peaks experienced in other areas of science and technology, perhaps suggesting greater sensitivity to shifting population levels of g (a testable prediction incidentally).

These data completely concur with my sense that modern 'mathematics' has stagnated. There are virtually no valid proofs being offered for the long-standing mathematical problems these days. Six of the seven Millennial prize problems remain unsolved. More worrying still, no one seems to have grasped the enormity of the problem posed to the foundations of mathematics by Georg Cantor's work on transfinite numbers, and we are no closer to understanding how these fit into the foundations of mathematics today than we were in the 1900's.

The two greatest mathematicians alive today are Andrew Wiles, who solved Fermat's Last Theorem, and Grigori Perelman, who amongst other things, solved Poincare's Conjecture (the only Millennial prize problem to have been unambiguously solved thus far). Of the two of these, Perelman is the only one who would compare favorably with the great mathematicians of the past. Wiles, whilst having undoubtedly made a major discovery, is clearly second rate by historical standards, as he had to marshal enormous amounts of time and effort into solving just one problem, which was not completed until he was more than 40 years old - an achievement pattern atypical of great mathematicians who typically reach peak accomplishment at less than 35 years of age.

That leaves Perelman, who has been prodigious and productive from a  relatively early age. He is nothing if not scathing about the state of modern mathematics either, having claimed the following in a 2006 interview on why he turned down various prestigious mathematics prizes:

"Of course, there are many mathematicians who are more or less honest. But almost all of them are conformists. They are more or less honest, but they tolerate those who are not honest."

This could of course equally well apply to every area of scientific inquiry in the modern world. Data, such as that presented by Murray and others clearly reveal that what you have today are hoards of 'mathematicians' who are collectively not one iota as accomplished as the relatively less numerous, but vastly more talented individuals who dominated this field in centuries past.

Just because these over-promoted self-promoters claim something is 'interesting', 'new' or even a 'breakthrough' in their field doesn't make it so - the decline in eminence in point of fact makes it antecedently highly implausible that 'mathematicians' today are even capable of generating anything approaching a breakthrough (ultra-rare individuals such as Perelman and Wiles excepted).


Commodore said...

Perhaps you have covered this before, but how much of this could be because of the English killing their best and their brightest off in war? I know the World Wars reduced the average height of men in England, and the culture of leading from the front/highborn officers and cavalry/general courage must have had a major effect.

I am broadly sympathetic to this research, because it is clear that Western Civilization is declining to anyone with eyes to see.

Bruce Charlton said...

@C - Yes I have covered this before. It must have had some effect, but this process began probably around 1800 in England, when the mortality rates for the poorest and those of lowest intelligence began to drop, and for perhaps the first time in history the poor began to out reproduce the rich - and this has continued. Galton wrote about this from the mid 1800s.

Also, the filtering-out of deleterious genetic mutations by high rates of child mortality was much less evident through the 1800s, so presumably these mutations began to accumulate generation upon generation. This was noted by WD Hamilton in the 1960s.

stephen c said...

It is possible that the replenishment rate of geniuses is not at all, contrary to Greg Cochran's comprehensive, powerful, and high-SAT equivalent ( but nevertheless simplistic ) understanding of bell curves and long tails, dependent on a simple accounting of unchanging ratios based on historical standard deviations and the historical outliers thereto, if (as I believe to be the case) the replenishment rate (based on replenishment mechanisms that nobody I am aware of understands) of those humans capable of generating genius children remains steady (while the replenishment rate of non-geniuses skyrockets - imagine a circle near Leeds 1800 - 10 genius potential, 90 genius spouse potential, 800 middle level as to IQ folks, and 100 super left end of bell curve folks - Leeds 1900, same numbers, because history is usually uneventful - Leeds 2000, after lots of unprecedented historic changes, what we have is once again 10 genius potential, 90 genius spouse potential individuals, but 3200 middle level, and 1200 super left end of bell curve folks - all equally loved by God of course, but in their "here comes everybody"
exuberance wrecking havoc on the non-anecdotal statistics so beloved by those who have erected their intellectual castles in defiance of the way the world of humans, created in the image of God, works). Thus, if there were 100 genius-gene carriers in 1800 and 1900 England near Leeds, there is no reason why their descendants' multiple freewill decisions over the next several generations would not result in 100 normal-reaction-time geniuses in 2010 England - while, pursuant to a totally different process, the myriad 4,600 neighbors of the 100 geniuses produced, say . 100,000 random IQ descendants (all equal in the eyes of God, of course, but disproportionately multiplied by virtue of better sanitation, unprecedentenly generous welfare payments, and domestic engineering and vermin control). So, Bruce, your hypothesis would not be disproved by multiple contemporary math geniuses , due to the (stable from generation to generation) free will decisions to avoid genetic downfall made by the genius potential individuals of earlier generations, who thereby have avoided the secular degeneration and diminishment of genius which your a faulty version of your thery might seem to predict). (For the record, I don't think anyone has sufficient knowledge to say that Wiles, Tao, Witten, maybe Wolfram, Penrose, Yau, Perelman, Connes, Guy, Diakonis and at least three or four others could not have engaged as equals with Gauss, Euler, and Ramanujan, so the whole topic of the current number of mathematical geniuses is beyond all of us).

Bruce Charlton said...

@sc - It is hard to follow what you are saying.

But clearly there is no reason to suppose the rate of creative geniuses would remain constant when it has varied so much around the world, over time, and according to subject matter (see Charles Murray's Human Accomplishment).

My impression is that modern insiders of sciences, arts etc simply assume that the highest status among them is equal to the geniuses of the past - well, in the country of the blind, the one-eyed man is king; but that doesn't make him have 20:20 vision. Mostly it is pygmies calling their tallest man a giant.

Really, there is zero serious doubt about the collapse and near disappearance of genius from the West (including England) - that is hard data: what is uncertain is the best causal explanation/s for it.

stephen c said...

Sorry my comment was hard to follow. To make my comment more simple, I believe that the replenishment rate of individuals with genius potential has been constant over the last several generations (a rate of constancy which throws off calculations based on the generally accepted bell curve patterns, almost all such calculations being premised on generic mixing principles), because the limited group of people who constitute the potential parents and grandparents of such people (i.e., of geniuses) have the same incentives to meet up and reproduce as they had 100 or 200 years ago (and they exist in the same numbers), regardless of what other couples might be doing. I named several potentially Ramanujan level mathematicians in my last comment because, let's face it, mathematicians do not care as much as others about the surrounding culture; I have already admitted that it is beyond me to guess whether there is a real, or only an apparent, collapse in mathematical genius, so I am unable to agree or disagree with you on that point. On the other hand, I did not name any contemporary composers, novelists, poets, or architects, because I feel certain (as do you) that there is an unquestionable collapse in composing music, writing of novels and poetry, and design of buildings. Those collapses are due, I believe, not to any genetic loss among the artistically elite portions of the populace, but rather, on the one hand, to a combination of God's choice, from approximately 1880 on, not to send his inspirational angels to composers, writers, poets, and architects in these debased times, and, on the other hand, to the choices of the potentially inspired composers, writers, poets, and architects, to decline to work for the powerful, non-God-fearing, and all too human denizens and patrons of the Modern Age. That last sentence (beginning with Those and ending with Age)expresses a belief that every atheist, every agnostic, and most modern semi-religious people would (incorrectly) find ridiculous; maybe I am at fault for being too aware of that circumambient murmur of potential criticism, and for not having made (or for not having been able to make) my belief clearer.

Bruce Charlton said...

@sc- Well I don't agree with your comments on replenishment - because intelligent/ educated women have opted for increasingly near sterility for about 8 generations - but I do agree with your point about God's choice.

That is what it looks like, and that is what any loving Father would do if he perceived that his children were becoming unrepentantly evil - he would take steps to reduce their power.

Creative Genius is power, and The West has *grossly* misused the power from its Geniuses (witness The Twentieth Century - especially communism and the reaction against it - fascism) - so the obvious answer is to strip us of this enhanced power.

Subtract a few hundred creative geniuses, from the world, and that goal is now well advanced - only we are too dishonest and corrupted to admit the obvious. But that d&c is exactly why it needed to happen.

Bruce Charlton said...

My response to Greg Cochran's response:


I suppose there is nothing to be done about our different perception of the abundance of creative genius in modern science - you see it almost everywhere; but I see it almost nowhere.

However when you say "The data is unreplicable and not known to be representative. " I would first argue that Michael has shown that the data is sufficiently representative

If the Victorian sample was not representative to any significant degree then there would be some significant attenuation of the size of difference when relevant controls were applied. But this didn't happen - so modern and old samples *are* sufficiently similar.

As for being un-replicable... well, obviously we can't get any more historical data than exists - but after 18 months of brooding Michael and I came up with a way of checking (and, as it turned-out, confirming) the predicted size of the decline, details of which will be unveiled in due course...

"The posited amount of change is implausible, given the time available and what we know of demographics."

But is it implausible? Only if you assume there is the single cause of differential reproductive success - but if other causes are also operating (such as the accumulation of intelligence-deleterious mutations due to the near-elimination of childhood mortality among the least intelligent) then the rapid rate of decline is *not* implausible.

Despite the amount of ink spilled disagreeing with the 1SD size of intelligence decline - nobody has yet come-up with anything that refutes it.

If 1SD decline in average intelligence was as absurd as you say it is, objective refutation should be easy and unambiguous - but seemingly it isn't!

Bruce Charlton said...

Greg Cochran replies to the above...

gcochran9 says:
March 7, 2014 at 10:32 am

” I see it almost nowhere.”

You don’t know enough to have any opinion.
gcochran9 says:
March 7, 2014 at 11:00 am

Like when Rasmus Nielsen was saying that the Tibetan altitude adaptations were all developed in the last 3000 years. I said that was obviously wrong, because the Tibetan adaptations worked so well compared to those in the Andes, and because humans of some sort had lived for much longer in Tibet than in the Andes. Nielsen seemed to think that it was somehow illegitimate to consider evidence other than the genetic sample he was looking at – but of course that’s not true. Any more than it is illegitimate to consider genetic facts when thinking about language dispersals. West seems to think that you must keep the evidence streams separate, but in fact, you must cross the streams.

Or when the vast majority of human geneticists were really sure that anatomically modern humans had never admixed with Neanderthals, presumably because it was forbidden in Leviticus or something. Sure, we hadn’t seen any Neanderthal mtDNA, but that just means that one locus had a fitness disadvantage. We see lots of gene deserts in modern humans that are free of Neanderthal alleles – as well as ones in which they were neutral and around at a few percent, as well as ones which conferred an advantage and are common.

Only this notion of Charlton’s is roughly a thousand times worse. To be fair, having a halfway decent picture of science in general is not so easy. Something as simple as the fact that science really doesn’t really exist at all in large parts of the world is apparently unknown by almost everybody, including people you might consider pretty smart. I remember having to explain this in annoyed detail to a closed list a few years back which had some fairly high-powered members.

Now in people with no pretensions to being serious thinkers, that kind of ignorance is well-nigh universal. For example, I remember seeing somebody in the New York Times talk about how Idi Amin had ruined the great universities of Uganda – but of course there never were any ‘great’ universities in Uganda. I saw another such comment in Nature, where some dweeb explained that the insignificant research output of South American universities was the fault of the CIA, presumably before World War II as well, with the help of the time machine at Langley.


...and with that Dr Cochran stuck his tongue out, spat in my face, stamped on my foot, snatched his football and ran away shouting "I'm going to get a gang onto you!"


George said...

I see he's not above making a sly reference to your Christian faith to really drive home the ad hominem attack. While I am certainly far from qualified to judge who wins, I think you've been very gentlemanly to stay on topic and not dredge up lots or irrelevant nonsense. It makes me really sad to see an example of the "they" us masses often reference as the ultimate authority figures who will "figure it out" just as easily turn to defensive egotism as the rest of us foolish schmucks.

Bruce Charlton said...


"I see he's not above making a sly reference to your Christian faith to really drive home the ad hominem attack."

I didn't notice anything like this - but I don't think it is likely to be true, because Greg Cochran is also a Christian: a Methodist.

So far as I know, we are just about the only Christians who are active in 'Evolutionary Psychology' - it is just about the most atheistic specialty in all of science.

George said...

Sorry, I assumed the worst from "because it was forbidden in Leviticus or something" and interpreted as part of a personal attack. The rest of his references appear to be a wide dismissal of certain types-of-people, which I thought he was trying to lump you in with.

Bruce Charlton said...


It's well-known as the technique of high-end scholarly disputation pioneered by Professor FJ Lewis, Emeritus Professor of History at All Saints College, Oxford...

George said...

A very funny sketch :-)

magpies! said...

Re: accumulation of deleterious genetic mutations

It seems you attribute them solely to differences in fertility rates. I don't recall seeing you considering that other (biological) factors might be at work. Is there a reason why?
Wouldn't it be plausible to think that such mutations are caused by industrial civilisation itself (by exposure to pollution, to endocrine disruptors, whatever)? Is is probably no coincidence that the decline you discuss occurred precisely at the time when industrial civilization began to take off.

What are your thoughts on studies like this one? (degradation of semen count/quality linked to pesticide use)
doi: 10.1530/REP-13-0499

Bruce Charlton said...

@m "It seems you attribute them solely to differences in fertility rates. "

Either I misunderstand this - or you are wrong: I don't. It is the opposite. A decline in child mortality rates. I got this from WD Hamilton which is one reason I think it likely to be true.