An event-related potential study of word-stem cued recall.

Event-related potentials (ERPs) were recorded from 13 scalp sites while subjects attempted to recall studied words using word-stems. If recall failed, stems were to be completed with the first suitable word to come to mind. To distinguish between correct completions accompanied and unaccompanied by explicit memory, subjects were required to make an overt recognition ("old/new") judgement for each completion. Semantically studied words were associated with higher levels of recall and recognition than were words subjected to non-semantic study. The sole ERP effect was a sustained positive shift in ERPs evoked by stems attracting correct completions that were correctly judged to be old. The shift was anteriorly distributed, and onset was around 300 ms post stimulus. It is interpreted as a reflection of processes either contributing to, or contingent upon, explicit memory retrieval.