From the "correlation is not causation" department

This article discusses a recent paper which summarizes a ton of papers that find a positive correlation between happiness and longevity. It also concluded that anxiety, depression, and pessimism were linked to higher rates of disease and a shorter lifespan. Interesting correlations except that the lead author of the paper makes a causal connection (happiness etc causes greater longevity) which doesn't follow for reasons that are all too familiar.
Of course its plausible that being a happy dude makes you live longer but it's also plausible that not expecting to live long is a bit of a downer. I, for one, am delirious that I am going to outlive you all. Alternatively, you could have "the right stuff" which makes you both happy and healthy.

Smart boy wanted: longevity and intelligence

Economists are interested in the returns to cognitive ability. One fairly basic return is longevity: smarter people live longer. But why? An obvious explanation is that they make better choices, avoiding the Darwin Awards for example. A more specific hypothesis is that they cope better with adversity and hence live longer. Some experimental evidence is detailed here. Don't worry: it uses bees.