International students often comment that U.S. students are competitive, but don't seem to study very hard, and beyond the informality of the classroom, the professors are very demanding. Some of these apparent contradictions can be explained by the values that underpin them. Creativity, tolerance, and flexibility are, in general, valued above tradition and respect for authority in the United States. Teaching styles and classroom attitudes vary widely and are influenced by many different factors. Even where tradition does dictate professorial or student behavior, the patterns may not be evident to someone coming from a different tradition.
Professors are the core of the teaching staff at most institutions in the United States.
Full professors generally teach lecture courses, seminars, and courses for graduate students and upper-class undergraduates. A professor's informal style of dress or speech must not be taken to mean that he or she has a relaxed attitude toward assignments, class attendance, or the quality of your work. Teaching assistants are most often graduate students pursuing a master's or doctoral degree. Since research universities began operating in the United States, graduate students have assisted professors by teaching undergraduate students. In many fields, the experience and training gained as a TA are viewed as necessary preparation for becoming a faculty member.