The View From Here; How can some lecturers teach without looking at their students?

Human vision is quite remarkable. Only a tiny two- or three-degree arc is in pin-sharp focus, but we can see virtually 180 degrees round without moving our heads. Try extending your arms fully sideways and waggling your fingers while staring straight ahead. Do this in private, by the way, as people have been arrested for less. You can see movement right to the periphery. Amazing.

The importance of eyes in human communication is clearest when you are lecturing. I tend to favour full eye contact with the audience, even to the point of developing Wimbledon neck through constantly looking left and right, especially when speaking in short but wide rooms. You can recognise lecturers out shopping on a Saturday. Their eyeballs constantly rotate, giving the hunted look of a fugitive master spy.

Some people avoid eye contact. When my daughter began her university course, one first-year lecture was given by a speaker who looked anywhere but at the new students. "Good morning," he began, addressing his shoes. Then he moved over to the window and delivered a little homily to the distant horizon, before returning to communicate with the blackboard. Eventually he bade his Hush Puppies farewell and retreated.

I have never understood how people can teach without looking at the audience. We read, and occasionally misread, an enormous amount of information with our eyes: interest or boredom, attention or inattention, comprehension or bewilderment. The information can help decide whether to change pace, recapitulate, summarise, ask or invite questions.

Scanning the auditorium can produce irresistible challenges. The worst assignment at any conference is the lecture after dinner on the first day, especially in June or July. Many people have got up early, travelled some distance, sat through introductory sessions, settled into their room, dined well, and then dutifully turned up on a hot summer's evening for the 9pm-10pm lecture, the death slot.

The earnest scanner soon spots someone fighting slumber. The warm evening, ample food and drink, a tiring day, conspire to lower eyelids. I never mind the smart somnolent who surrenders to Morpheus subtly in a corner, head buried in hands, as if pondering deeply over the lecture. It is the bugger lolling backwards, mouth agape and dribbling, who gets me cross, so I hurl words and eye contact aggressively at him. Wake up, damn you!

Even if you scan the audience assiduously, however, you can still make mistakes. I was once lecturing to a group of students who were about to spend a year teaching in Germany. I explained how German teachers, after a longer undergraduate course, came into teaching in their late, rather than early twenties. After a quick scan of the room to check the state of everyone's hair, I slipped in a little hairist joke: "So the new teacher in a German school is probably the little, wizened, bald chap sitting in the corner."

At this point a bald headed man, whom I had not spotted in my quick eye- sweep, got up and walked out. Horrified at the consequence of my crass joke, I carried on. After the lecture I apologised to the organising tutor. "No, it's quite all right," he said. "The man told me in advance that he had a dental appointment at 11am, so he had to leave early."

My biggest misreading of a member of the audience occurred when I once addressed a conference of members of Her Majesty's Inspectorate. While the rest made copious notes, laughed at the jokes, nodded wisely at the analysis, one inspector in horn-rimmed glasses stared ahead: no emotion, no reaction, never the tiniest flicker of a response.

As time went on, I began to hate Mr Glasses more and more. Moving into overdrive, I hurled laser eye contact straight at his bifocals. Out came the jokes. The rest of the HMI clutched their sides, but Mr Glasses remained inscrutable. I launched my best research findings straight at him. HMI wrote them down assiduously. Mr Glasses sat impassively. Eyes on stalks by now, I piled on deep analysis, classical references, medical and scientific analogies, all aimed in his direction. Nods from HMI, nothing from Mr Glasses.

At the end of the lecture there was prolonged applause. Mr Glasses did not join in, but got out of his seat and strode purposefully down the aisle towards me. Slowly my eyeballs returned to their sockets. "I just wanted to say," he began - silently I composed a dignified reply - "that was the best lecture on education I have ever heard." I was speechless. I wonder what he looked like when he was angryn

The writer is professor of education at Exeter University.