The research has found pensioners who engaged in more intellectual activities did have greater cognitive abilities when they were tested.
However, the study authors then looked back at results the same people scored in tests they sat at school.
The people who had the best brains in their seventies also had the highest IQ when they were 11.
The university's Professor Ian Deary said: "We found that people who took part in more of what we called socio-intellectual activity tended to have better thinking skills at about age 70.
"But then we looked at their IQ scores from age 11 and we found that brighter children tended to be the ones that took part in socio-intellectual activities later in life, but not that these activities boosted thinking skills."
:: Professor Deary will discuss his findings at the British Academy Big Debate in Edinburgh this evening.