Memory for everyday actions in schizophrenia

In healthy people, enacting actions by manipulating objects improves memory compared to verbal encoding of the description of the same actions. We used this paradigm to test memory for actions in 40 stable schizophrenia participants and 24 healthy volunteers. Three encoding conditions were used and consisted of action sentences that were: 1) self-performed by the participants, 2) performed by an experimenter (observed), or 3) encoded verbally. Memory for those actions was tested in two formats. First a cued-recall task with the object as a retrieval cue was administered. Secondly source recognition was examined by asking the participants to decide in which of the three conditions each action was encoded. On cued-recall, schizophrenia participants largely benefited from self-enacting actions, reaching performance levels comparable to that of the healthy volunteers. On the source recognition test however, they showed a substantial impairment. The present study thus indicates that people with schizophrenia can benefit from the enactment effect. However, the fact that their performance was reduced considerably during source recognition relative to healthy volunteers suggests that the beneficial effect provided by enactment was mostly implicit. (C) 2009 Elsevier B.V. All rights reserved.