Unfortunately he doesn’t really get around to discussing it. He cites research that suggests that old people are more emotional because their intellectual capacities decline and examines the question of age related political orientation as it relates to a shift in the relative importance of emotional and informational processing.
From the abstract, it isn’t clear that the declining ability to reason suggests an equal decline in the willingness to reason is established. Just because someone isn’t any good at something any more (relative to his youth) doesn’t mean he’ll be unwilling to do it.
For these purposes I much prefer the data set the OKCupid folks use. Hopefully Robin will give us a more complete analysis of the OKCupid post later.