Food for thought...
By ROGER DOBSON
Take a 50-year-old IQ test and it's likely that you will emerge a genius. In fact, most of the population would almost certainly be classed as super-intelligent if they were scored on tests set half a century ago.
"If people taking an IQ test today were scored with the norms of their grandparents' performances 50 years ago, more than 90 per cent of them would be classified as geniuses, while, if our grandparents were scored today, most of them would be classed as borderline mentally retarded," says Dr Stephen Ceci, who is professor of developmental psychology at Cornell University.
Average IQ has increased around 20 points a generation over the past 60 or so years, an increase that has been seen in more than a dozen countries, including New Zealand, Britain, the United States, Japan, Africa, and Australia.
Just why is unclear. Genetic factors, better-educated parents, more sophisticated toys, television and computers have all been given the credit, but with little supporting evidence.
Now, new research has given a considerable boost to the idea that nutrition and diet are largely responsible for the huge rise in IQ. It is suggested that the right nutrition at the right time increases intelligence, possibly by boosting the physical growth of the brain.
Although average intelligence has increased, it is not clear whether everyone has benefited. Have the very intelligent pushed up the average by becoming even brighter, has the increase in IQ been across the board, or have those at the lower end benefited the most?
Many of the explanations that have been put forward require either an across-the-board increase, or for those at the top end to have pulled further ahead. But if nutrition is the explanation, then the increase in IQ would be mainly in deprived groups who, over time, have gained access to better diets.