The study led by the University of Edinburgh and the UK Medical Research Council has discovered a link between childhood intelligence and their voting preferences in later life.
They are also more likely to vote in general, and get involved in politics.
During the study, the IQs of more than 6,000 subjects were recorded at the age of 10, before any secondary schooling.
The participants were asked about their voting habits 24 years later, when they were aged 34. They were also asked about how they voted in the 2001 general election, how they intended to vote, and in what other political activities they had taken part.
The researchers found that people who reported voting in 2001 for the Green Party and Liberal Democrats had the highest average childhood intelligence scores.
Moreover, they took part in rallies and demonstrations, to sign petitions, and were found to be more interested in politics generally.
"The association between measured intelligence in childhood - before any secondary education - and how people participate in the democratic process is something that needs exploring," the Telegraph quoted psychologist Professor Ian Deary, of the University of Edinburgh, who led the research, as saying.
"Voting in the UK and elsewhere has been studied with respect to social class and education.
"Our new research shows that early-life intelligence needs to be considered along with these factors, and might be an additional factor influencing voting habits.
"How one votes and to what extent one takes part in the political process are the result of thinking and decision-making, so it makes sense to address cognitive ability as a possible part of the explanation," he added.