Institutional obstacles, such as poor classroom climate, under-representation, faculty issues and "weed-out" courses are the most significant detriments to female success in engineering. STEM courses commonly have low exam averages and involve grading on a curve. According to a report put out by the American Association of University Women, "low scores increase uncertainty in all students, but they have a more negative effect on students who already feel like they don't belong, as many women in STEM majors do." Female engineering students, accustomed to performing well, see low raw scores as evidence they are unqualified in a way male students do not. A boy may see himself as an engineer because of a love for engines or computers honed as a child, and persist despite less than stellar grades, whereas a few mediocre scores often push girls into a different major. This is compounded by the fact that girls are more likely to view academic challenges as insurmountable. Studies suggest that adults generally praise girls for intelligence while they praise boys for effort. Consequently, girls grow up believing their "smartness" is innate and finite, while boys learn challenges are overcome through effort.