The brains of intelligent people are capable of solving tasks more efficiently, which is why they have superior cognitive faculties, scientists say.
“When a more and a less intelligent person are given the same task, the more intelligent person requires less cortical activation to solve the task,” said Elsbeth Stern, Professor for Research on Learning and Instruction at ETH Zurich in Switzerland.
Scientists refer to this as the neural efficiency hypothesis, although it is now accepted by experts as an undisputed fact, with ample evidence to support it.
Daniela Nussbaumer from Institute for Behavioural Sciences of ETH Zurich found evidence of this effect for the first time in a group of people possessing above-average intelligence for tasks involving what is referred to as working memory.
“We measured the electrical activity in the brains of university students, enabling us to identify differences in brain activity between people with slightly above-average and considerably above-average IQs,” said Nussbaumer.
Psychologists define working intelligence as a person’s ability to associate memories with new information as well as to adapt to changing objectives by filtering out information that has become irrelevant.
The researchers asked 80 student volunteers to solve tasks of varying complexity on a computer.
One task, for example, was to determine whether individual letters or faces were part of a selection of letters or faces that had been shown to the subjects immediately beforehand.
An especially difficult task involved identifying letters and faces shown to the subjects during past runs of the test within a time limit.
Electroencephalography (EEG) was used to measure the brain activity of the participants during the tests.
For the results analysis, the researchers had the subjects take a conventional IQ test and then split them into two groups – one with slightly above-average IQs and another with well above-average IQs.
The researchers found no differences in brain activity in either group of subjects when they performed very easy or very difficult tasks. They did, however, see clear differences in the case of moderately difficult tasks.
Stern attributes this to the fact that none of the subjects had any trouble whatsoever with the simple tasks and that the difficult tasks were cognitively demanding even for the highly intelligent subjects.
In contrast, all subjects succeeded in solving the moderately difficult tasks, but the highly intelligent subjects required fewer resources to do so.
The researchers’ intelligence study also suggests that it is impossible to “exercise” working memory.
As researchers have now shown in their study, people who have practised certain tasks do not have any advantage over their unpractised counterparts when confronted with new, yet similar tasks.