A producer played our group a short radio feature about a flooded footpath. It opened with rain drumming on a roof, followed by a woman describing how the water had spread across the path. At the end of the visit, the producer asked whether anyone thought the rain and the voice had been recorded at the same time. Almost everyone said yes. She then explained that the rain had been recorded weeks earlier, on a different street, and placed beneath the voice during editing. She had asked partly to show us how easily a combined recording could convince listeners that they were hearing a single moment. She also wanted to know whether anyone had noticed the join, because she was deciding whether to use the same method in her next programme. Nobody had.