A curious thing happened at a concert of mine last week. We had rehearsed in the afternoon (piano plus string quartet) and when everyone was comfortable with the positions of their chairs and instruments, we marked up the stage with various colours of sticky tape so that the backstage team knew where to put everything in the evening.

A few hours later, we all came back in concert clothes. We went on stage, bowed to the audience and sat down. Almost at once, one of the string players turned round to me and said, ‘I’m sorry, I haven’t got room to play. You’ll need to move the piano back a bit.’ I glanced down and saw that the piano was exactly in the agreed place, its legs precisely within the yellow tape box. And my colleague’s chair was precisely in the same spot as it had been. However, he was waving his arms agitatedly to demonstrate that he didn’t have room to play, so I stood up, and several of us moved the piano a foot or so backwards.

Afterwards, we mused on what had happened. Why did my colleague feel that he had enough room to move during the rehearsal, but not enough during the concert? We agreed that subtle things happen in the performer’s mind between rehearsal and performance. When an audience is present, some performers seem to feel suddenly bigger, others suddenly smaller. I often find that the piano stool, which I’ve carefully left at ‘the right height’, suddenly feels too high or too low when I come on stage for the performance. Even coming back in concert clothes may make a difference. Whatever the reason, it seems that people change in size between rehearsal and performance.