Encoding processes during retrieval tasks

Episodic memory encoding is pervasive across many kinds of task and often a rises as a secondary processing effect in tasks that do not require intenti onal memorization. To illustrate the pervasive nature of information proces sing that leads to episodic encoding, a form of incidental encoding was exp lored based on the "Testing" phenomenon: The incidental-encoding task was a n episodic memory retrieval task. Behavioral data showed that performing a memory retrieval task was as effective as intentional instructions at promo ting episodic encoding. During fMRI imaging, subjects viewed old and new wo rds and indicated whether they remembered them. Relevant to encoding. the f ate of the new words was examined using a second, surprise test of recognit ion after the imaging session, fMRI analysis of those new words that were l ater remembered revealed greater activity in left frontal regions than thos e that were later forgotten-the same pattern of results as previously obser ved for traditional incidental and intentional episodic encoding tasks. Thi s finding may offer a partial explanation for why repeated testing improves memory performance. Furthermore, the observation of correlates of episodic memory encoding during retrieval tasks challenges some interpretations tha t arise from direct comparisons between "encoding tasks' and "retrieval tas ks" in imaging data. Encoding processes and their neural correlates may ari se in many tasks, even those nominally labeled as retrieval tasks by the ex perimenter.