If there was ever a paper which was in danger of refuting itself by its title, this is it. “Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time” in the peer-reviewed journal Intelligence says that human beings have been growing steadily stupider since the late Nineteenth Century.
If so, one wonders if that is true of the press who uncritically reported the work as well.
We might guess college teachers Michael Woodley, Jan te Nijenhuis, and Raegan Murphy, the authors of this work, had grown suspicious that the decline in student intelligence was part of a larger effect. “Is everybody,” they must have wondered, “surer of their own abilities with less and less cause? If so, how can we prove it?”
How about unambiguously measuring IQ of a fair sample (not neglecting the dark corners of the earth) of similarly aged human beings each year for many years and then showing how the distribution of scores changes through time?
Too tough, that. Better to measure how long it takes people to swat a paddle after they hear a bell.1
The idea is reaction time is correlated to intelligence, or so people claim. Quicker times are not always associated with bigger brains—think of poor Admiral Nelson!—but it kinda, sorta is.
One thing we don’t want to do is just look at a numerical average of scores. Masks far too much information. Think about it. It could be that, in a certain time and place, a lot of folks test slow-stupid and a similar amount score fast-smart; a sort of U-shape in the distribution of scores. Its numerical mean would be identical to the scores of a different group of folks who all scored about the same.
Better to look at the distribution—the full range, the plus and minuses—than just the numerical mean.
Our authors looked at the numerical mean of reaction times. But don’t hold it against them. The mistake they made is so ubiquitous that it is not even known to be one.
Anyway, the authors gathered their data from a study of another man, one Irwin Silverman2, who searched through the archives and found papers which experimented on reaction times. The average times from most of these papers (our authors tossed some out) were used in the current study.
A picture of the machine used back in Francis Galton’s day, the Hipp chronoscope, is pictured above. Modern-day chronoscopes do not look the same. A show of hands, please: how many think that measuring the same man first on the Hipp chronoscope and then again on a computer will result in identical scores? They’d have to be, else people (to whom electricity was new and freaky) who hit Morse-code paddles in 1888 would not be comparable to people (who grew up with video games and cell phones) clicking a mouse in 2010.
How did our authors adjust for these differences? Shhhhh.
The plot shows where the magic happened. Each dot represents the average reaction time for a reaction-time study (y-axis) in the year the study was conducted (x-axis). Small dots are studies with fewer than 40 folks, larger open circles are those studies with more than 40.
See the way the line, made by a fancy statistical model, slopes upward? That line says people are growing stupider. Never mind you have to squint to see it. Never mind reaction time isn’t IQ. Never mind the enormous gaps in time between the old and new studies. And never mind that if you extrapolate this model it proves that Eighteenth Century denizens would have all bested Einstein at Chess and that those fifty years from now will listen exclusively to NPR. Concentrate instead that a wee p-value has been produced, therefore the the authors’ hypothesis is true.
Our authors apply a generous coating of theory (“dysgenic model”) to explain this crisis. Silverman disagrees with “dysgenics” and says it’s because of “the buildup of neurotoxins in the environment and by the increasing numbers of people in less than robust health who have survived into adulthood”.
My theory is that instead of IQs shrinking, people are increasingly able to find patterns in collections of meaningless dots.
Update Occurred after chatting with Stijn de Vos (â€@StijnDvos) that if this research were true, we should hang out by the Whack-A-Mole to discover future Nobel Prize winners.
Thanks to John Kelleher for alerting us to this topic. See comments here, too.
1I have in mind the “sobriety test” taken by Dr Johnny Fever, WKRP; a clip of which I could have showed except for the massive greed of the recording industry; but never mind, never mind.
2“Simple reaction time: it is not what it used to be”, American Journal of Psychology. 123.1 (Spring 2010): p39.