A patient's memory of a past event turns out, on closer examination, not to be entirely accurate. Before revealing the answer, decide what single question distinguishes a screen memory from a false memory.

Ask whether a real event genuinely underlies the memory at all. In a screen memory, a real event did occur, and only part of it — typically one specific, painful detail — has been substituted, with the rest of the memory remaining accurate. In a false memory, there may be no real underlying event at all: the memory is held with full subjective conviction despite having no basis in fact, and the person is not lying, they experience it exactly as they would a genuine memory. The distinguishing question is not how confidently the memory is held, since both can be held with confidence, but whether any of the underlying event actually happened.