An introspection into getting it right

Some while ago I was in a course meeting and during the conversation I said " I've learnt some really important things whilst marking student exams ". To say there was a stunned silence would perhaps exaggerate, but certainly a few of my colleagues looked at me rather oddly. In fact I often find that when I set open-ended exam questions I find pertinent issues raised in the answers that weren't part of my sample solution. However, there was a particular incident which was in my mind. Some years ago I was teaching part of a course on visual-ization and virtual reality. One of the questions I asked was about factors that lead to a sense of 'engagement' in virtual reality and the question was set in the context of flight simulators and games. I'd discussed a wide range of issues in class: interactivity, realism, etc., but, when I marked the question all the best student answers started with a factor that I had never discussed in my class-indeed never heard of before-sub-seat woofers. After a moments thought I worked out what these were. In certain arcade games large bass speakers are placed under the seats to produce low frequency vibrations-a form of haptic as well as aural feedback. These students had far more practical experience than me: they spent large amounts of their lives in desktop and arcade VR games ... they were domain experts. A few weeks ago I was teaching our Masters students in an intensive week on HCI. One morning I talked to them about modelling state and gave them a group exercise to model the state of a four-function calculator. I knew from past experience that students find this more difficult than it at first sounds, but this time was worse than usual and no group made significant progress. I'm not sure what was different from previous years-perhaps a slightly different mix of students, perhaps I explained it slightly differently. As we came back together I talked through potential solutions but in particular was at pains to discuss three things. First, I emphasized that this was an area that I believed was important but I knew was conceptually difficult. Second , I pointed out (as was already in my printed materials) the places where I have made mistakes in this in the past and how to detect these. Third, I admitted that I had clearly …