As to the specific case: Foster, though a professor, apparently did not subject his claims to peer review and critique (he went straight to the popular press). He does not even mention Stevenson's contrary study. The book bears a strong smell of self-aggrandizement, a sense that his words are a godlike revealed wisdom: e.g.: "Foster reveals [that] our identities are encoded in our own language. Foster has discovered how to unlock that code, and has invented an entire new field."

IMHO, Foster suffers from what I call "smart person's disease": a diminished ability to recognize that one's own views might conceivably be mistaken. I emphasize that that is just MHO -- but it is a HO opinion backed by specific evidence.