This is how you play. You strap on a headband with three electrical sensors which measure your alpha and theta brain waves. Alpha waves are detected when you are that tricky mix of wakeful, relaxed and alert, while theta waves register when you are drowsy – too relaxed. Fixed to a table is a long thin plastic tube in which there is a little ball. A player sits at each end of the tube and the ball is controlled by your brain waves. Then it’s like blow football, only using your mind instead of your lungs and a straw. You try and push the ball to your opponent’s end by emptying your mind of all distractions but remaining alert. I started off well, focussing on the ball alone; but better able to become absorbed than I was, and for longer, my daughter grew into the contest and began to force it back. That, and the fact that two teenage boys came along and started a conversation right by my ear, which I couldn’t block out (tellingly my daughter could). Well, I wanted to know what they were saying. It was a nothingy conversation, the one explaining to the other the way the game worked, then suggesting they move on to a less busy exhibit, but my focus was shot. My daughter pushed the ball all the way to my end of the tube. I didn’t let her win; she beat me fair and square. I said, you must have an emptier brain than me. – It’s easy, she said, it’s like being on the sofa at home watching telly. So there may be some truth in what I suggested. Of course there is, she’s just a girl, and her mind is clear and brilliant. Overfull, mine is foggy and dull in comparison.