1 One problem with the emphasis on giving grades in school is that this practice
encourages students to see grades as determining how worthwhile they are as
human beings. 2 One survey showed that 80 of college students based their
sense of self-worth on their academic grades. 3 Another problem with grades is
that they can make students fearful. 4 Although fear may be useful to motivate
people in some situations, it does not work well in education. 5 Studies have
repeatedly shown that fear of getting bad grades can interfere with the ability to
learn. 6 A third argument against grades is they can reduce students' willingness
to challenge themselves or to take risks. 7 A number of studies show that
student's willingness to take on challenging tasks diminishes when grades are
involved, but without grades, students left on their own tend to seek out more
challenging problems. 8 In short, grades are a distraction from the learning
process and, sometimes, even a deterrent to that process.
which sentence is the main idea sentence?