An electrophysiological study of boundary conditions for control of recollection in the exclusion task

Event-related potentials (ERPs) were collected in a memory retrieval task that was designed to assess the resolution with which people exerted control over memory retrieval. Participants were first required to indicate whether the objects denoted by concrete nouns (i) had pleasant or unpleasant connotations, (ii) were typically smaller or larger than a shoebox, or (iii) were easy or difficult to draw. They then completed a retrieval task where old (studied) and new words were presented. Participants pressed one key for words encountered in the drawing task, and a second key for all other test words (new words as well as those encountered in the pleasantness and size judgment tasks). The left-parietal ERP old/new effect--an electrophysiological index of recollection--was reliable for words from the drawing task only. This finding is consistent with the view that participants were successful at prioritising recollection of some kinds of information over others. The data also provide an insight into the resolution with which this prioritisation can be implemented, because there was little evidence of a left-parietal ERP old/new effect for words to which a size judgment was made, despite the fact that visual imagery is likely to have been employed for drawing as well as for size judgments.