Has Humanity Reached Peak Intelligence?

That’s the title of a post at BBC Future by David Robson, a journalist who has written a book called The Intelligence Trap: Why Smart People Make Dumb Mistakes. Inasmuch as “humanity” isn’t a collective to which “intelligence” can be attached, the title is more titillating than informative about the substance of the post, wherein Mr. Robson says some sensible things; for example:

When the researcher James Flynn looked at [IQ] scores over the past century, he discovered a steady increase – the equivalent of around three points a decade. Today, that has amounted to 30 points in some countries.

Although the cause of the Flynn effect is still a matter of debate, it must be due to multiple environmental factors rather than a genetic shift.

Perhaps the best comparison is our change in height: we are 11cm (around 5 inches) taller today than in the 19th Century, for instance – but that doesn’t mean our genes have changed; it just means our overall health has changed.

Indeed, some of the same factors may underlie both shifts. Improved medicine, reducing the prevalence of childhood infections, and more nutritious diets, should have helped our bodies to grow taller and our brains to grow smarter, for instance. Some have posited that the increase in IQ might also be due to a reduction of the lead in petrol, which may have stunted cognitive development in the past. The cleaner our fuels, the smarter we became.

This is unlikely to be the complete picture, however, since our societies have also seen enormous shifts in our intellectual environment, which may now train abstract thinking and reasoning from a young age. In education, for instance, most children are taught to think in terms of abstract categories (whether animals are mammals or reptiles, for instance). We also lean on increasingly abstract thinking to cope with modern technology. Just think about a computer and all the symbols you have to recognise and manipulate to do even the simplest task. Growing up immersed in this kind of thinking should allow everyone [hyperbole alert] to cultivate the skills needed to perform well in an IQ test….

[Psychologist Robert Sternberg] is not alone in questioning whether the Flynn effect really represented a profound improvement in our intellectual capacity, however. James Flynn himself has argued that it is probably confined to some specific reasoning skills. In the same way that different physical exercises may build different muscles – without increasing overall “fitness” – we have been exercising certain kinds of abstract thinking, but that hasn’t necessarily improved all cognitive skills equally. And some of those other, less well-cultivated, abilities could be essential for improving the world in the future.

Here comes the best part:

You might assume that the more intelligent you are, the more rational you are, but it’s not quite this simple. While a higher IQ correlates with skills such as numeracy, which is essential to understanding probabilities and weighing up risks, there are still many elements of rational decision making that cannot be accounted for by a lack of intelligence.

Consider the abundant literature on our cognitive biases. Something that is presented as “95% fat-free” sounds healthier than “5% fat”, for instance – a phenomenon known as the framing bias. It is now clear that a high IQ does little to help you avoid this kind of flaw, meaning that even the smartest people can be swayed by misleading messages.

People with high IQs are also just as susceptible to the confirmation bias – our tendency to only consider the information that supports our pre-existing opinions, while ignoring facts that might contradict our views. That’s a serious issue when we start talking about things like politics.

Nor can a high IQ protect you from the sunk cost bias – the tendency to throw more resources into a failing project, even if it would be better to cut your losses – a serious issue in any business. (This was, famously, the bias that led the British and French governments to continue funding Concorde planes, despite increasing evidence that it would be a commercial disaster.)

Highly intelligent people are also not much better at tests of “temporal discounting”, which require you to forgo short-term gains for greater long-term benefits. That’s essential, if you want to ensure your comfort for the future.

Besides a resistance to these kinds of biases, there are also more general critical thinking skills – such as the capacity to challenge your assumptions, identify missing information, and look for alternative explanations for events before drawing conclusions. These are crucial to good thinking, but they do not correlate very strongly with IQ, and do not necessarily come with higher education. One study in the USA found almost no improvement in critical thinking throughout many people’s degrees.

Given these looser correlations, it would make sense that the rise in IQs has not been accompanied by a similarly miraculous improvement in all kinds of decision making.

So much for the bright people who promote and pledge allegiance to socialism and its various manifestations (e.g., the Green New Deal, and Medicare for All). So much for the bright people who suppress speech with which they disagree because it threatens the groupthink that binds them.

Robson, still using “we” inappropriately, also discusses evidence of dysgenic effects in IQ:

Whatever the cause of the Flynn effect, there is evidence that we may have already reached the end of this era – with the rise in IQs stalling and even reversing. If you look at Finland, Norway and Denmark, for instance, the turning point appears to have occurred in the mid-90s, after which average IQs dropped by around 0.2 points a year. That would amount to a seven-point difference between generations.

Psychologist (and intelligence specialist) James Thompson has addressed dysgenic effects at his blog on the website of The Unz Review. In particular, he had a lot to say about the work of an intelligence researcher named Michael Woodley. Here’s a sample from a post by Thompson:

We keep hearing that people are getting brighter, at least as measured by IQ tests. This improvement, called the Flynn Effect, suggests that each generation is brighter than the previous one. This might be due to improved living standards as reflected in better food, better health services, better schools and perhaps, according to some, because of the influence of the internet and computer games. In fact, these improvements in intelligence seem to have been going on for almost a century, and even extend to babies not in school. If this apparent improvement in intelligence is real we should all be much, much brighter than the Victorians.

Although IQ tests are good at picking out the brightest, they are not so good at providing a benchmark of performance. They can show you how you perform relative to people of your age, but because of cultural changes relating to the sorts of problems we have to solve, they are not designed to compare you across different decades with say, your grandparents.

Is there no way to measure changes in intelligence over time on some absolute scale using an instrument that does not change its properties? In the Special Issue on the Flynn Effect of the journal Intelligence Drs Michael Woodley (UK), Jan te Nijenhuis (the Netherlands) and Raegan Murphy (Ireland) have taken a novel approach in answering this question. It has long been known that simple reaction time is faster in brighter people. Reaction times are a reasonable predictor of general intelligence. These researchers have looked back at average reaction times since 1889 and their findings, based on a meta-analysis of 14 studies, are very sobering.

It seems that, far from speeding up, we are slowing down. We now take longer to solve this very simple reaction time “problem”.  This straightforward benchmark suggests that we are getting duller, not brighter. The loss is equivalent to about 14 IQ points since Victorian times.

So, we are duller than the Victorians on this unchanging measure of intelligence. Although our living standards have improved, our minds apparently have not. What has gone wrong?

From a later post:

The Flynn Effect co-exists with the Woodley Effect. Since roughly 1870 the Flynn Effect has been stronger, at an apparent 3 points per decade. The Woodley effect is weaker, at very roughly 1 point per decade. Think of Flynn as the soil fertilizer effect and Woodley as the plant genetics effect. The fertilizer effect seems to be fading away in rich countries, while continuing in poor countries, though not as fast as one would desire. The genetic effect seems to show a persistent gradual fall in underlying ability.

Woodley’s claim is based on a set of papers written since 2013, which have been recently reviewed by [Matthew] Sarraf.

The review is unusual, to say the least. It is rare to read so positive a judgment on a young researcher’s work, and it is extraordinary that one researcher has changed the debate about ability levels across generations, and all this in a few years since starting publishing in psychology.

The table in that review which summarizes the main findings is shown below. As you can see, the range of effects is very variable, so my rough estimate of 1 point per decade is a stab at calculating a median. It is certainly less than the Flynn Effect in the 20th Century, though it may now be part of the reason for the falling of that effect, now often referred to as a “negative Flynn effect”….

Here are the findings which I have arranged by generational decline (taken as 25 years).

  • Colour acuity, over 20 years (0.8 generation) 3.5 drop/decade.
  • 3D rotation ability, over 37 years (1.5 generations) 4.8 drop/decade.
  • Reaction times, females only, over 40 years (1.6 generations) 1.8 drop/decade.
  • Working memory, over 85 years (3.4 generations) 0.16 drop/decade.
  • Reaction times, over 120 years (4.8 generations) 0.57-1.21 drop/decade.
  • Fluctuating asymmetry, over 160 years (6.4 generations) 0.16 drop/decade.

Either the measures are considerably different, and do not tap the same underlying loss of mental ability, or the drop is unlikely to be caused by dysgenic decrements from one generation to another. Bar massive dying out of populations, changes do not come about so fast from one generation to the next. The drops in ability are real, but the reason for the falls are less clear. Gathering more data sets would probably clarify the picture, and there is certainly cause to argue that on various real measures there have been drops in ability. Whether this is dysgenics or some other insidious cause is not yet clear to me.

My view is that whereas formerly the debate was only about the apparent rise in ability, discussions are now about the co-occurrence of two trends: the slowing down of the environmental gains and the apparent loss of genetic quality. In the way that James Flynn identified an environmental/cultural effect, Michael Woodley has identified a possible genetic effect, and certainly shown that on some measures we are doing less well than our ancestors.

How will they be reconciled? Time will tell, but here is a prediction. I think that the Flynn effect will fade in wealthy countries, persist with fading effect in poor countries, and that the Woodley effect will continue, though I do not know the cause of it.

Here’s my hypothesis, which I offer on the assumption that the test-takers are demographically representative of the whole populations of the countries in which they were tested: The less-intelligent portions of the populace are breeding faster than the more-intelligent portions. That phenomenon is magnified by the rapid growth of the Muslim component of Europe’s population and the rapid growth of the Latino component of America’s population.

(See also “The Learning Curve and the Flynn Effect“, “More about Intelligence“, “Selected Writings about Intelligence“, and especially “Intelligence“.)

The Learning Curve and the Flynn Effect

UPDATED 09/14/19

I first learned of the learning curve when I was a newly hired analyst at a defense think-tank. A learning curve

is a graphical representation of how an increase in learning (measured on the vertical axis) comes from greater experience (the horizontal axis); or how the more someone (or something) performs a task, the better they [sic] get at it.

In my line of work, the learning curve figured importantly in the estimation of aircraft procurement costs. There was a robust statistical relationship between the cost of making a particular model of aircraft and the cumulative number of such aircraft produced. Armed with the learning-curve equation and the initial production cost of an aircraft, it was easy to estimate of the cost of producing any number of the same aircraft.

The learning curve figures prominently in tests that purport to measure intelligence. Two factors that may explain the Flynn effect — a secular rise in average IQ scores — are aspects of learning: schooling and test familiarity and a generally more stimulating environment in which one learns more. The Flynn effect doesn’t measure changes in intelligence, it measures changes in IQ scores resulting from learning. There is an essential difference between ignorance and stupidity. The Flynn effect is about the former, not the latter.

Here’s a personal example of the Flynn effect in action. I’ve been doing The New York Times crossword puzzle online since February 18 of this year. I have completed all 210 puzzles published by TNYT from that date through the puzzle for September 15, with generally increasing ease:

The difficulty of the puzzle varies from day to day, with Monday puzzles being the easiest and Sunday puzzles being the hardest (as measured by time to complete). For each day of the week, my best time is more recent than my worst time, and the trend of time to complete is downward for every day of the week (as reflected in the graph above). In fact, in the past week I tied my best time for a Monday puzzle and set new bests for the Thursday and Friday puzzles.

I know that that I haven’t become more intelligent in the last 30 weeks. And being several decades past the peak of my intelligence, I am certain that it diminishes daily, though only fractionally so (I hope). I have simply become more practiced at doing the crossword puzzle because I have learned a lot about it. For example, certain clues recur with some frequency, and they always have the same answers. Clues often have double meanings, which were hard to decipher at first, but which have become easier to decipher with practice. There are other subtleties, all of which reflect the advantages of learning.

In a nutshell, I am no smarter than I was 30 weeks ago, but my ignorance of TNYT crossword puzzle has diminished significantly.

(See also “More about Intelligence“, “Selected Writings about Intelligence“, and especially “Intelligence“, in which I quote experts about the Flynn Effect.)