14 IQ Points Lost Since Victorian Times

According to a research published in the journal Intelligence, the human population has lost around 14 points of IQ since the Victorian Era. The Daily Mail  reports: 

Researchers compared reaction times - a reliable indicator of general intelligence – since the late 1800s to the present day and found our fleetness of mind is diminishing.

They claim our slowing reflexes suggest we are less smart than our ancestors, with a loss of 1.23 IQ points per decade or 14 IQ points since Victorian times.

While an average man in 1889 had a reaction time of 183 milliseconds, this has slowed to 253ms in 2004. 

They found the same case with women, whose speed deteriorated from 188 to 261ms in the same period.

The report in the journal Intelligence found: ‘The Victorian era was characterized by great accomplishments. As great accomplishment is generally a product of high intelligence, we tested the hypothesis that the Victorians were actually cleverer than modern populations.
Researcher Dr Michael Woodley said: ‘They actually indicate a pronounced decline in IQ since the Victorian era, three times bigger than previous theoretical estimates would have us believe.’

‘In conclusion however these findings do indicate that with respect to "genetic g" [general intelligence] the Victorians were indeed substantially cleverer than modern populations.’

Commenting on the study, Dr James Thompson, honorary senior psychology lecturer at UCL and member of the British Psychological Society, said: ‘This is a very intriguing paper, which seems to give the lie to the comforting notion that we have all been getting brighter for the last three or four generations.

‘Reaction times are a real measure, with a reasonably large correlation with IQ, so this is an alarming finding and needs further investigation.’

Compare this to the so-called "Flynn Effect," which argues for a secular increase in IQ of 7 points for decade. Which is correct? Probably both - but it's not the relevant question. The relevant question is which effect is correlated with g, the underlying factor of general intelligence.

And there we see the bad news. The Flynn Effect has been shown to be uncorrelated with g, whereas reaction times have been shown to be highly correlated with g. At best, then, the Flynn Effect suggests that we've been masking a genuine decline in intelligence with improvements in test-taking and education.

But, as my TEDx talk points out, the improvements in test-taking and education have been stagnant for the last thirty years - nothing is left to hide the decline.