Flanked by tanks and under the cover of a smoke screen, Scottish guards charge into action on the Egyptian front at El Alamein during the second world war. Were the brightest at the front? (Image: AP/PA)

Being dumb has its benefits. Scottish soldiers who survived the second world war were less intelligent than men who gave their lives defeating the Third Reich, a new study of British government records concludes.

The 491 Scots who died and had taken IQ tests at age 11 achieved an average IQ score of 100.8. Several thousand survivors who had taken the same test – which was administered to all Scottish children born in 1921 – averaged 97.4.

The unprecedented demands of the second world war – fought more with brains than with brawn compared with previous wars – might account for the skew, says Ian Deary, a psychologist at the University of Edinburgh, who led the study. Dozens of other studies have shown that smart people normally live longer than their less intelligent peers.


“We wonder whether more skilled men were required at the front line, as warfare became more technical,” Dear says.

His team’s study melds records from Scottish army units with results of national tests performed by all 11-year-olds in 1932. The tests assessed verbal reasoning, mathematics and spatial skills.

“No other country has ever done such a whole-population test of the mental ability of its population,” Deary says. Other studies have found that childhood IQs accurately predict intelligence later in life.

Equal intelligence

A previous study found a fall in intelligence among Scottish men after the war, and at the time Deary’s team theorised that less intelligent men were more likely to be rejected for military service. The new study appears to refute that suggestion. Men who didn’t serve were more intelligent than surviving veterans, and of equal intelligence to those who died.

Analysing their data by rank offers some insight. Low-ranking soldiers accounted for three-fifths of all deaths, and their IQs measured by their childhood tests averaged 95.3. Officers and non-commissioned officers made up for about 7% and 20% of war deaths respectively. Officers scored 121.9, bringing up the average IQ for those who died. Non-commissioned officers scored an average of 106.7.

“We also wondered whether there was an overall small tendency for more intelligent soldiers to want to do the job well, perhaps meaning they ended up in more threatening situations,” Deary says.

Phil Batterham, an epidemiologist at Australian National University in Canberra, wonders what aspects of intelligence made soldiers more likely to die in the war. “One could hypothesise that the association between greater intelligence and higher war-related mortality might be driven by the more crystallised verbal abilities, leading to greater leadership roles,” as opposed to other forms of intelligence, he says.

Journal reference: Intelligence (DOI: 10.1016/j.intell.2008.11.003)