At least, that's what an article in the Telegraph claims.
Scientists who asked volunteers to keep time with a drumstick before taking intelligence tests discovered that those with the best sense of rhythm also scored highest in the mental assessments.
Prof Frederic Ullen, from the Karolinska Institutet in Stockholm, concluded that there was a link between intelligence, good timing and the part of the brain used for problem-solving.
He said: "The rhythmic accuracy in brain activity that is observed when a person maintains a steady beat is also important to the problem-solving capacities measured with the intelligence tests."
There's more at the link.
I guess musical ability is a riff-lection of intelligence after all . . . you can't beat that!