Are motivational benefits of adequately challenging schoolwork related to students' need for cognition, cognitive ability, or both?

One important predictor of students' intrinsic motivation and schoolwork engagement is the balance between schoolwork difficulty and student skill level, such that students are adequately challenged. However, the question arises whether this is equally true for all students or whether there are students for whom having adequately challenging schoolwork is even more important than for others. In this study, we investigated whether students'...