Students are supremely aware of the learning environment in the classroom. Gladwell, in his Blink book, points us to a Stanford prof (Indian name) who found that students could accurately predict the final evaluation of a prof from a 10-second video shown to them at the beginning of the course. 5 seconds, and even 2-second clips of the prof yield high correlations with final evaluations (by other students).
Visible Learning, a book by John Hattie (an Aussie) from his meta-study of 50,000 pieces of research find 139 different effects on learning. Top one? "Self-report grades" or Expected performance. Students know what grade they are going to get. (Hattie argues it is our job to improve that.)
The problem is not with perception. It is with remediation. There is no reward, no value in the classroom economy to figure out stuff yourself, or even ask questions. Intrinsic learning is sometimes even frightening to the teacher.