Memory-conjunction errors: miscombination of stored stimulus features can produce illusions of memory

We demonstrate that subjects will often claim to have previously seen a new stimulus if they have previously seen stimuli containing its component features. Memory for studied stimuli was measured using a "yes"/"no" recognition test. There were three types of test stimuli: target stimuli, which had been presented during study, conjunction stimuli, constructed by combining the features of separate study stimuli, and feature stimuli, in which studied stimulus features were combined with new, unstudied, features. For both nonsense words and faces, the subjects made many more false alarms for conjunction than for feature stimuli. Additional experiments demonstrated that the results were not due to physical similarity between study and test stimuli and that conjunction errors were much more common than feature errors in recall. The results demonstrate that features of stored stimuli maintain some independence in memory and can be incorrectly combined to produce recognition errors.