My perception is that I generally watch television programmes on demand, mainly through a personal video recorder. Yet I know I watched a lot of live Wimbledon tennis last week and a fair amount of news. I could not say with any accuracy how much television or video I saw last week, but I know the national average was about 25 hours, according to those that measure such things. Given that amounts to over a day a week, we still have remarkably little informed appreciation of why people watch television and what they get from the experience.