How Children Succeed: Grit, Curiosity, and the Hidden Power of Character

by Paul Tough

few years later, two researchers from the University of South Florida elaborated on Edlund’s experiment. This time, after the first, candy-less IQ test, they divided the children into three groups according to their scores on the first test. The high-IQ group had an average IQ score on the first test of about 119. The medium-IQ group averaged about 101, and the low-IQ group averaged about 79. On the second test, the researchers offered half the children in each IQ category an M&M for each right answer, just as Edlund had; the others in each group received no reward. The medium-IQ and high-IQ kids who got candy didn’t improve their scores at all on the second test. But the low-IQ children who were given M&M’s for each correct answer raised their IQ scores to about 97, almost erasing the gap with the medium-IQ group. The M&M studies were a major blow to the conventional wisdom about intelligence, which held that IQ tests measured something real and permanent—something that couldn’t be changed drastically with a few candy-covered chocolates. They also raised an important and puzzling question about the supposedly low-IQ children: Did they actually have low IQs or not? Which number was the true measure of their intelligence: 79 or 97?