Tricks of memory

Remembering an episode from even the recent past may involve a blend of fiction and fact. We discuss a straightforward laboratory paradigm that is proving useful in the study of false memories of simple opisodes. In this paradigm, subjects study list of 15 related words (bed, rest, awake . . .) that are all related to a critical word that is not presented (sleep). Later, subjects recall and recognize the critical missing word with about the same probability that they remember words from the list. This memory illusion is resistant to people's attempts to avoid it. We argue that similar memory errors are commonplace and are a natural outcome of an intelligent cognitive system, which makes inferences about incoming information. Therefore, memory illusions, like perceptual illusions, are a consequence of normal human information processing and offer a window for examining basic cognitive processes.