It’s possible that growth-mindset interventions boost some students, but not others. In one of the largest experiments, which focused on ninth graders in the U.S., students were given a relatively brief intervention (less than an hour, in total) in which they learned about mindsets and how behaviors such as putting in effort and changing one’s strategy could be helpful. For lower-achieving students, the researchers reported, the intervention was followed by an average gain of 0.10 GPA points.