Why Did Jared Diamond Allow One Student's Own Project?

Jared Diamond negotiated with his graduate students and postdocs so each project interested both him and the student. He made the investment only when the project also made sense for him.

He could take only two or three students at a time. A student stayed for three or four years, and he had worked hard to find the funds. On only one occasion a student asked for his own project. A wonderful Argentinian student said he had been told that, in the physiology department, a postdoc spends half his time on the advisor's project and half the time on his own. Jared Diamond says the claim was untrue, though the student had found another postdoc of whom it was true. Taken aback, Jared Diamond agreed, and the student did a project of his own as well as the project with him. The Argentinian case was the only time a student did a project that did not interest Jared Diamond.

Every other project interested both of them. Jared Diamond says a student gets his full attention and can learn from him only on a subject he knows how to think about. A student cannot learn from him on a subject he does not know how to think about.