The number of exceptionally intelligent teenagers is far lower than a generation ago, a new study claims.
Researchers at King's College London asked 800 young teenagers to take tests measuring their understanding of abstract scientific concepts such as volume, weight and density. The results were then compared with similar exercises undertaken in 1976.
In an examination known as the 'pendulum test', just over one in 10 achieved top grades which demanded a 'higher level of thinking' - a significant drop from the 1976 result of one in four.
In another test that assessed mathematical thinking skills, one in five youngsters in 1976 achieved high grades, while the figure from the latest study was just one in 20.
Professor Michael Shayar, who led the study, believes the decline in brainpower was due to target-based teaching.
"The moment you introduce targets, people will find the most economical strategies to achieve them," said Shayar. "In the case of education, I'm sure this has had an effect on driving schools away from developing higher levels of understanding."
The study found the average grade on tests remained the same.