Spanish researchers say a system using intelligent glasses will allows professors to get feedback from students on whether they\'re understanding lessons. The augmented reality system with a heads-up display enables a lecturer to see symbols above each student that indicates if they understand explanations or, on the contrary, are having doubts or difficulties. \"These symbols are activated by the students via their cellphones and are used to tell the professor that they don\'t understand the explanation, or that they have understood it, to ask the professor to go more slowly, or to say whether or not they know the answer to the question that the professor has just asked the class,\" Telmo Zarraonandia of the Universidad Carlos III of Madrid said. By simply by looking at the symbol displayed over each student\'s head the professor can see exactly what that student wishes to communicate, the researchers said. The system gives students a new way to communicate and be in contact with the professor both immediately and privately and without interrupting the class, they said. \"The channel that we\'ve created will help overcome the problems of timidity or fear of speaking in front of the class that some students have,\" computer scientist Ignacio Aedo said in a university release Monday.