Lighting the Flame

By Debra Viadero

Rochester, N.Y.

Two students attend the same school. One never asks for help, and he puts in just enough effort to earn a passing grade. The other pesters the teacher with questions, breathes life into classroom discussions, and turns in top-notch work on time.

Why are some students more motivated to learn than others? Psychologists have spent nearly three decades trying to answer that question. But now, just as researchers are beginning to think they know some of the reasons, they are running up against an unlikely obstacle:...