Nassim Taleb on "they only lived until they were 30 meme"

The argument often heard about primitive people living on average less than 30 years ignores distribution around such average --life expectancy needs to be analyzed conditionally. Plenty died early, from injuries, many lived very long --and healthy --lives. This is exactly the very same elementary "fooled by randomness" mistake, relying on the notion of "average" in the presence of variance, that makes people underestimate the risks in the stock market.

In "Why I Do All This Walking"

Also see Stephan's take.