There are many theories that Gladwell's book ties together, and there's some pretty serious data on each of them. I know three, and all of this book I've read a

There are many theories that Gladwell's book ties together, and there's some pretty serious data on each of them. I know three, and all of this book I've read are excerpts. Each of his books includes a reading list and citations, and I don't think this will be any different. In particular, page 10 of Flynn's book is worth reading. It is not merely Gladwell's hypothesis. Terman et. al's studies of gifted children (http://books.google.com/books?id=MXwVAAAAIAAJ&printsec=frontcover&dq=terman&lr=&ei=-6IjSaSSD4L8lQSjubSUCA http://books.google.com/books?id=MXwVAAAAIAAJ&printsec=f...) Sherar et. al's study of physical maturity in hockey player development (http://www.informaworld.com/smpp/content~content=a778078133~db=all http://www.informaworld.com/smpp/content~content=a778078133~...) Flynn's book "On Intelligence" and review of the growing IQ of the worldwide population and ethnographic studies of Chinese. (http://books.google.com/books?hl=en&lr=&id=qvBipuypYUkC&oi=fnd&pg=PR8&dq=flynn+chinese+intelligence&ots=dI5FSqQ_c4&sig=SzsQ7umFTljNiYyaAkxhx7z04UI http://books.google.com/books?hl=en&lr=&id=qvBipuypY...) I don't think one should claim an insufficient justification of his hypotheses without actually examining the justification thoroughly. Oftentimes, for Gladwell in particular, people claim that he's being unrigorous, imprecise, or incomplete. He's not being incomplete. He's being concise. If he weren't concise, almost nobody would pay any attention. Almost nobody would learn anything from him. And almost nobody would, wanting to learn more, have the opportunity to follow the reference list that he carefully puts out. Which I guess few people do, anyway.