Psychological defense mechanism refers to the adaptive tendency of individuals to consciously or unconsciously relieve their anxieties in their internal psychological activities when they are faced with stressful situations of frustration or conflict, in order to restore psychological balance and stability. According to the above definitions, Which of the following are not in the category of psychological defense mechanisms:. ["When students fail the exam, they say that the teacher's grades are unfair or the questions are too biased.", 'Athletes experience headaches, numbness of hands and feet when they encounter difficult training beyond their ability.', 'An employee is dissatisfied with his superior, and vents to his loved ones at home.', 'Someone who studies hard because of his physical development defects and wins respect from others.']