I doubt this considerably. Aside from the fact that it is almost assuredly a combination of multiple of the hypotheses, from my in-person experience (i.e. not on the internet), age does not directly correspond to intelligence (specifically referring to the term as I believe the author would define it). When considering the entire population (i.e. not just the highly educated and the intellectually interested), I'd argue they are essentially entirely unrelated (though I know some would probably argue they are actually inversely related).