Michael Woodley, the co-author, claims that people in Victorian times were quicker, smarter, and more creative than we are.
Using response times as an indicator of general intelligence he found these had slowed down by 14% since 1889.
Then, average response times for men were 183 ms and 187 ms for women. Now they are 250 ms for men and 227 ms for women.
The researchers suggest that this means there has been a decline in creativity and innovation since Victorian times and said; “These findings strongly indicate that the Victorians were substantially cleverer than modern Western populations”.
It wasn’t possible to compare IQ scores because of different levels of education, health and nutrition so visual response times were used instead as these have a large correlation with intelligence.
Woodley thinks that our declining intelligence is a result of a reverse in natural selection as clever people have fewer children than in previous times.
These finding fly in the face of the Flynn effect – a steady increase in measured intelligence over time.
The authors, as far as I know from the news article, make no comment about the difference in response times between men and women, both then and now, which, assuming the differences are statistically significant, would imply that men are more intelligent than women – an argument that has been made before but now generally refuted. Nor about the politically sensitive issue of immigration and whether increases in immigration with larger families from poorer countries has contributed to the decline.
Intelligence is notoriously difficult to define and measure but this study contributes to that debate.