Sally is taking AP Calculus and is very anxious that she won't do well. On her first test, Sally scores a 60%. She is discouraged, but decides that that she could study harder. For the unit 2 test, Sally studies more and this time scores a 63%. She decides to try harder and study even longer for unit 3. Sally scores a 59% on that test.
At this point, Sally decides that Calculus isn't for her and she just isn't smart enough to learn it.
What psychological concept explains what Sally is feeling?