The use of this technology to read the emotional expressions of students in a classroom is valuable in some ways and some not because a computer knowing when your happy or sad could be beneficial in your classroom. For example if you smile when a web ad appears on your screen, a similar ad will follow. But if you frown, the next ad wll be different. A classroom computer could recognize when a student is becoming confused or bored and then it could modify the lesson, like an effective human instructor. But I bet your lab partner could recognize if you are happy, sad, or mad. Its all about muscular action units. They indicate the difference between a genuine smile and a forced smile. In a real smile the muscles that begin at your cheek bones lift the corners of your mouth. In a false smile, the mouth is strecthed sideways. Muscle clues are sometimes important. Which is why I think that this technology is better off not being useful in classes because you can detect a person being happy, sad, or mad by yourself by muscle clues. To an expert, faces dont lie.