Most of the students in dr. hunt's introductory psychology class are taking the course as part of their social science requirement. however, 10 students are psychology majors, and all firmly believe they will become psychologists. this tendency to make predictions about one's future with such certainty reflects a flaw in thinking called:

Overconfidence    

Explanation: Overconfidence is the characteristic that describes about the excessive confidence shown by an individual. It displays that the confidence on subject ability is higher than objective conduction .

As per the case mentioned in the question, students are showing extra confidence for becoming psychologist as they are psychology major students so subjective confidence is high but the objective performance is not focused by them.Thus, they have the flaw of overconfidence .