Artists' creativity soars when they are courting. Scientists, it seems, make discoveries at a similar sexual pitch. Raj Persaud reports
Is male scientific creativity basically an attempt to demonstrate intellectual prowess to attract potential marriage partners? A new study suggests it may be.
Satoshi Kanazawa, a sociologist at Indiana University of Pennsylvania, is about to publish data that indicates that the time when scientific productivity often peaks is linked to when a scientist is trying hardest to get a mate.
Kanazawa's research, due to appear in the journal Evolution and Human Behavior , arises from a question posed by evolutionary psychologists - why do we bother to make scientific discoveries? A possible answer, it seems, could be found by analysing a dictionary of scientific biography.
Evolutionary psychologists have recently come up with the radical suggestion that intellectual creativity and productivity are principally attempts to display intelligence.
They argue that intelligence is a characteristic potential that mates find attractive, as it boosts their offspring's chances of survival in the hostile environments we once lived in. If this is true then, as Geoffrey Miller, an evolutionary psychologist at University College London, predicts: "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."
Miller found support for this by studying the producers of jazz albums, modern paintings and books. In each case, he found cultural production rapidly rose after puberty, peaked in early to middle adulthood, and then declined throughout adulthood.
Kanazawa has found evidence that this also applies to scientists. He investigated the career peaks of 280 of the most eminent scientists from the 18th century to the present day. From Oxford University Press's The Biographical Dictionary of Scientists , (Porter 1994) he extracted their age when the discovery or experiment listed as their most significant was made. The mean age of pinnacle scientific achievement among male scientists - only 2.5 per cent of the sample was female - was 35.4 years old with half of scientists peaking within six years of their 35th birthday.
If this courtship model of scientific productivity is correct and "cultural display" tends to decline through adulthood, because parenting eclipses courtship, then a different pattern should hold for men who had not produced offspring. There would be no reason for these men to cease their "cultural display". Instead, they should be driven to continue being scientifically productive until they attracted a mate.
Indeed, when he was able to gather data on marital status from other scientific biographical dictionaries, Kanazawa found that male scientists who never marry do not decline in productivity as sharply with age. Half as many unmarried scientists make their greatest contributions in their late 50s as in their late 20s. The corresponding percentage among married scientists is just 4.3 per cent.
The average peak age for unmarried scientists is 39.9, while for married scientists it is 33.9.
Nearly a quarter of male married scientists made their greatest contribution within five years of marrying, and the average delay between getting married and experiencing a career peak was 2.5 years. It appears that once scientists get married, they quickly cease their cultural displays.
Cultural display or intellectual and creative activity is seen as a male strategy to attract female mates because biologists argue men compete for mates more fiercely than women.
Miller points out that men produce 20 times as many jazz albums, eight times as many modern paintings and three times as many books as women.
Kanazawa does not believe an alternative explanation of his data - that marriage inhibits creativity because it eats up time - is plausible. "Contemporary men think that getting married means having to take over half the childcare responsibilities and household work because their wives work," he said.
"However, the majority of the scientists in my data come from the 18th and 19th centuries, when married men made very little contribution... to household chores and childcare responsibilities. If anything, married men in the 18th and 19th centuries had more (rather than less) time than single men because they had someone in the house to cook for them and take care of their needs at all times."
Raj Persaud is a senior lecturer at the Institute of Psychiatry in London.