Memory for perceived and imagined pictures--an event-related potential study.
Event-related potentials (ERPs) and behavioural measures were used to investigate recognition memory and source-monitoring judgements about previously perceived and imagined pictures. At study, word labels of common objects were presented. Half of these were followed by a corresponding picture and the other half by an empty frame, signalling to the participants to mentally visualise an image. At test, participants in a source-monitoring task made a three-way discrimination between new words and words corresponding to previously perceived and imagined pictures. Participants in an old/new-recognition task indicated whether test words were previously presented or not. In both tasks, correctly identified old items elicited more positive-going ERPs than correctly judged new items. This widely distributed old/new effect was found to have an earlier onset and to be of a greater magnitude for imagined than for perceived items. Task (source versus item-memory) affected the old/new effects over prefrontal areas and the reaction times to remembered old items. The present findings are consistent with the view that a greater amount, or a different type, of information is necessary for accurate source-memory judgements than for correct recognition, and moreover, that different types of source-specifying information revive at different rates. In addition, the results add weight to the view that the late widespread ERP-old/new effect is sensitive to the quality or the amount of information retrieved from memory.
Johansson
Mikael
M
Department of Psychology, Lund University, P.O. Box 213, SE-22100 Lund, Sweden. mikael.johansson@psychology.lu.se
Stenberg
G
G
Lindgren
M
M
Rosén
I
I
D000328:Adult; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D021641:Recognition, Psychology; D014796:Visual Perception