As readers of this blog will know, it is usually Woodley of Menie who darkens these pages with talk of genetic ruin, while James Flynn is the plucky New Zealander bringing tidings of comfort and joy about rising intelligence. Now, after my foolishly letting the two of them talk unhindered together for two hours over a large convivial dinner in Montreal last July, while the rest of us swopped stories and jokes, Flynn appears to have gone over to the dark side.

In truth, it must be admitted that Woodley and Flynn go back some years now, and Flynn had come to the conference with his talk on Piaget already prepared, but it is funny what bedfellows one makes when one follows the data. James Flynn had long expressed surprise at the continuing rise in intelligence scores, and had charted their stagnation and then decline, though that has not happened in all countries, or not in the same way. However, here in 2017 we have none other than James Flynn worrying that our top thinkers have been decimated. What is going on?

I have never troubled you too much about Piaget. He stands outside the psychometric canon, and is no believer in proper samples. He studied his own children in great detail, thus being totally biased, unrepresentative, and at the same time very interesting. He was able to tease out what his children did not know, and what they could not work out at each stage in their development. Even as an undergraduate I was cautious about his work, and his stages of development. My dutiful rendering of his theories got me my highest ever marks, but I did not follow others in slavish admiration of his approach. Be reassured, the stages don’t just happen like sedimentary deposits. Brighter children go through them faster. However, his experiments have charm, and depth. Perhaps Bärbel Inhelder had a good influence on him, particularly on the tasks we will be looking at now.

The formal operations stage, achieved around 12 years of age (yes, sooner for brighter kids, and much later for the slower ones) was considered the apotheosis of cognition. Once you got there, you could start being a scientist. Not much point in teaching physics before that. What is lovely about these tasks, from our point of view, is that they are potential markers of the scientific frame of mind, the basic stepping stones of the empirical project. They have had the same logic (and probably level of difficulty) for ever, and certainly since Archimedes. As such, we can say that if a child cannot solve these problems, they can probably not solve the whole larger set of problems which require the scientific method.

Equilibrium in balance

Robert Siegler (1979) gave children a balance beam task in which some discs were placed either side of the centre of balance. The researcher changed the number of discs or moved them along the beam, each time asking the child to predict which way the balance would go.

He studied the answers given by children from five years upwards, concluding that they apply rules which develop in the same sequence as, and thus reflect, Piaget’s findings. Like Piaget, he found that eventually the children were able to take into account the interaction between the weight of the discs and the distance from the centre, and so successfully predict balance. However, this did not happen until participants were between 13 and 17 years of age.

Pendulum task

Formal operational thinking has also been tested experimentally using the pendulum task (Inhelder & Piaget, 1958). The method involved a length of string and a set of weights. Participants had to consider three factors (variables) the length of the string, the heaviness of the weight and the strength of push. The task was to work out which factor was most important in determining the speed of swing of the pendulum.

Participants can vary the length of the pendulum string, and vary the weight. They can measure the pendulum speed by counting the number of swings per minute. To find the correct answer the participant has to grasp the idea of the experimental method -that is to vary one variable at a time (e.g. trying different lengths with the same weight). A participant who tries different lengths with different weights is likely to end up with the wrong answer.

Volume and heaviness (Archimedes)

The way this has been studied by Michael Sayer is a whole lesson in itself. Students are taken step by step through the fundamental problems presented by floating and sunken objects. Sunken objects displace a quantity of water equal to their volume, floating objects displace a quantity of water equal to their weight. This is important because children, and many adults, think of volume and weight as highly correlated in everyday life. Of course, the dissection of these properties led to a milestone in the history of science: Archimedes’ principle of buoyancy. Archimedes realized that he could determine whether the king’s crown was made of pure gold by examining the amount of water it displaced.

Shayer takes the children through 12 experimental steps before they are presented with the Archimedes problem. This deals with a concern which I voiced to James Flynn in the question session after his talk: I assumed that the massive fall in students solving this task could be due to poor science teaching. The Shayer procedure is an extended, hands on, tutorial, and goes some considerable way to countering a lack of science teaching as an explanation for poor performance.

Having read these brief descriptions, you might like to rank them in order of difficulty.

IQ decline and Piaget: Does the rot start at the top? James R. Flynn, Michael Shayer. Intelligence, Volume 66, January–February 2018, Pages 112–121.

https://ac.els-cdn.com/S0160289617302787/1-s2.0-S0160289617302787-main.pdf?_tid=a3f18f3c-de8b-11e7-b9c6-00000aacb35f&acdnat=1513007879_add85ccde0c352ae3d937bdaba85978c

What James Flynn and Michael Sayer now report is contained in their Table 5, which I find it difficult to understand. There are 3 tests, and for each test we have 3 factors jostling for position in a jumble of figures: the level of Piagetian development of the children, where “3A and above” relates to early Formal Operations and 3b and below Concrete Operations; the dates at which the data were collected; and whether the results of the Piagetian tests were different from what would be expected from test intelligence results at that time. Frankly, there were too many variables at one time for this reader. It would have been better as a Figure, showing the historical changes pictorially.

Bottom line: the scores have crashed dramatically.

The authors say:

In sum: at one time the best of Britons (aged 12–14) could cope with items on the formal level and blended into a smooth curve of performance. Now these items are beyond many of them and register as a huge decimation of high scorers. Piagetian gains at the bottom of the curve should not be dismissed as simply a phenomenon that offsets losses at the top. Consider the British results for Equilibrium and Pendulum. The decimation of top scorers means that by the age of 12 to 14, fewer British schoolchildren attain the level of formal operations. This means that fewer could think in terms of abstractions (without concrete examples), which limits their capacity for deductive logic and systematic planning. However, the fact that these losses are made up by gains over the rest of the “curve” means that far more of them are at the concrete generalization level. They are better at on the spot thinking (e.g. in playing demanding computer games). Their understanding of the physical world is limited to simple causation between two variables, but they can draw inferences from observations to make generalizations. The Piagetian results are particularly ominous. Looming over all is their message that the pool of those who reach the top level of cognitive performance is being decimated: fewer and fewer people attain the formal level at which they can think in terms of abstractions and develop their capacity for deductive logic and systematic planning. They also reveal that something is actually targeting that level with special effect, rather than simply reducing its numbers in accord with losses over the curve as a whole. We have given our reason as to why the Piagetian tests are sensitive to this phenomenon in a way that conventional tests are not. Massive IQ gains over time were never written in the sky as something eternal like the law of gravity. They are subject to every twist and turn of social evolution. If there is a decline, should we be too upset? During the 20th century, society escalated its skill demands and IQ rose. During the 21st century, if society reduces its skill demands, IQ will fall. Nonetheless, no one would welcome decay in the body politic, or among the elite who at present represent our best thinkers. Although it might be argued that the character of the electorate will be enhanced if it contained fewer lawyers and more plumbers and service workers.

This is sobering stuff. Unlike psychometric test scores, these are physics experiments which are essential for understanding the world. As a 12 year old I can certainly remember being taught about moments of force and the use of levers. I don’t think we did anything at that age on pendulums, and the Archimedes problem was explained to us in general terms in Maths and Physics classes (together with an explanation of the Plimsol Line), though I don’t recall doing experiments on it. I can certainly remember feeling, on being asked to weigh a beaker prior to doing an experiment, that the task was ridiculous because a beaker was too light to make any difference. I soon learned not to make my arms a reference point for the determination of the mass of the universe. I have no idea how I would have fared on these experiments. I assume the Equilibrium task would have been easy, the other two probably difficult.

Can we conclude from these results that youngsters today are helpless, confused and likely to believe any sort of rubbish about the physical world? Well, only Britain seems to have tracked this issue in any depth. Perhaps there are more historical Piagetian data from other countries out there somewhere. Let us, for the time being, consider Britain to be the canary in the mine. We seem to have a generation which cannot operate the levers of empiricism. If this were really true, what would we notice? An incapacity to fix material objects, and just buy instant replacements? A petulant requirement that everything in society should be fixed, but not by them? A belief in windmills? A belief that new batteries are just about to be invented that will solve everything?

Perhaps Flynn and Shayer are right about the numbers of logical thinkers being drastically reduced. They themselves talk about a “huge decimation”. My readers will of course know that “decimation” refers to the killing of one in every ten of a mutinous Roman legion as a punishment. The authors mean “a huge reduction”, but we will let that pass. The results are alarming because of the real nature of the test. The bits and pieces of the fundamental problem are laid before the adolescents, and if they cannot put them together, then they fail: a true zero. (Yes, given time we could count the hours taken over successive testing sessions until the solution emerged, if it ever did).

Because the results alarm me, I disagree with their final joke about lawyers, and the implication that students who fail to master the experimental method will turn out to be good plumbers and service workers. Not so. Plumbers, electricians, roofers and repairers need to have the minds of well-trained detectives and experimentalists. Remember that next time the light go out, and water starts dripping into the house.