We measured what students perceive physicists to believe about physics and solving physics problems and how those perceptions differ from the students' personal beliefs. In this study, we used a modified version of the Colorado Learning Attitudes about Science Survey which asked students to respond to each statement with both their personal belief and the response they thought a physicist would give. Students from three different types of university introductory physics courses were studied. Students who have not yet taken physics in college have a surprisingly accurate idea of what physicists believe about physics no matter what their high school background and what physics courses they choose to take in college. These ideas are largely unaffected by their college physics instruction. In contrast, students' personal beliefs about physics differ with varying high school physics backgrounds and college physics courses in which they enroll, and these beliefs are affected by college physics instruction. Women have a larger difference between their reported personal beliefs and their perceptions of physicists' beliefs than do men. (Contains 3 tables, 9 figures, and 21 notes.)