It's important to note that this article is talking about excessive optimism, i.e. taking a higher proportion of risks because you have a generally higher expec

It's important to note that this article is talking about excessive optimism, i.e. taking a higher proportion of risks because you have a generally higher expectation of reward. In effect, it's saying that being reckless is a sign of lower cognitive abilities. Which makes sense, as most people with sufficient cognitive ability would try not to be as reckless.