Comment by svat

I assumed the books were somewhat fictional (i.e. they were Gladwell-style) because if he meant to make a claim seriously he'd have published in a medical journal instead of a popular/literary book. But since writing the comment above, I've learned that over the years many people actually believed that all details in the books were literally true (you can search for e.g. [Sacks prime] to see many people who took the story seriously and analyzed them), which does put things in a different light.