My greatest discovery? My wife
Far-fetched? Evolutionary psychologists have recently suggested creativity and productivity are effective displays of intelligence, a characteristic that potential mates find attractive. In the adverse environments faced by our distant ancestors, intelligence would have boosted the survival chances of any offspring.
Evolutionary psychologist Geoffrey Miller from University College London says that, if this is true, "cultural production should increase rapidly after puberty, peak at young adulthood, when sexual competition is greatest, and gradually decline over adult life as parenting eclipses courtship".
And Satoshi Kanazawa, a sociologist from the Indiana University of Pennsylvania, has uncovered evidence that scientists choose their profession partly to attract a mate. In an article in a forthcoming issue of the journal Evolution and Human Behaviour, he reports on an investigation into the career peaks of 280 eminent scientists, from the 18th century onwards.
When Kanazawa analysed the date of individual scientists' most significant discovery or experiment, he found the mean age among male scientists (only 2.5 per cent of the sample were female) was 35.4, with 50 per cent of scientists peaking within six years either side of 35.
But if this courtship model of scientific productivity is correct, a different pattern should hold for men who have not reproduced. They should continue to be scientifically productive until they attract a mate.
Indeed, Kanazawa found that the productivity of male scientists who had not married declined less sharply with age. Of unmarried scientists, the proportion making their greatest contribution in their late 50s was 50 per cent higher than for those doing so in their late 20s. The corresponding figure among married scientists was 4.3 per cent. The average age for reaching the peak of their career was 39.9 for unmarried scientists and 33.9 for married, a six-year difference, which is, statistically, highly significant.
Almost one in four married male scientists made their greatest contribution within five years of marriage, the average being a mere 2.5 years. So it seems that once scientists marry, they quickly cease their cultural displays, while unmarried scientists continue to make great contributions.
Evolutionary psychology arguments such as these attract criticism because they appear sexist; for example, "cultural display" or intellectual and creative activity is seen as a male strategy to attract mates because biologists argue that men compete for mates more fiercely than women.
Kanazawa comments: "Contemporary men think that getting married means having to take over half the childcare responsibilities and household work because their wives work as corporate executives. However, the majority of the scientists in my data come from the 18th and 19th centuries, when married men made very little contribution (in terms of time and energy) to household chores and childcare responsibilities.
"If anything, married men in the 18th and 19th centuries had more time than single men because now they had someone in the house to cook for them and take care of their needs at all times."
Professor Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London. He is this year's visiting Gresham professor for public understanding of psychiatry and will give free public lectures at Barnard's Inn Hall, London EC1 on October 20 and November 29. See www.gresham.ac.uk for more details. Email: email@example.com