1) More generally, what if more intelligent people are more resistant to some biases, but equally prone to other biases? Then in opinions of more intelligent people we would see less of the former biases, but perhaps more of the latter biases; and also more of the correct answers. The exact values would depend on exact numbers in models.

Example model: Imagine that a person must first avoid an error A, then an error B, until they reach the correct conclusion C. The chance of making the error A is 70% for average person, 50% for intelligent person; the chance of making the error B is 90% for average person, 80% for an intelligent person.

Results for average people: 70% A, 27% B, 3% C. Results for intelligent people: 50% A, 40% B, 10% C. Possible interpretation: B is the correct answer, because here the difference is largest: 13%. (C is obviously a small minority even among intelligent people, so we can explain it away e.g. by signalling.)

2) Intelligence can correlate with something, e.g. education, which may be a source of new errors. Not necessarily new kinds of biases, just new ways to apply the same old biases. For example the "quantum mysterious consciousness" explanations will be more popular among more educated people, less educated will instead use words "spirits" and "magic" to explain the same concept.

3) An intelligent person can easily confuse "opinions of me and my friends" with "opinions of intelligent people". Because how do most intelligent-and-proud-of-it people judge the intelligence of others? In my experience, usually by similarity of opinions.

EDIT: Does author really give questionaires and IQ tests to large enough samples of randomly selected people? In other words, even if we trust the authors premises, should be trust his specific results too?