Episodic remembering is highly susceptible to distortion and errors. One prominent explanation is the overuse of gist instead of verbatim memory traces. Verbatim traces preserve the surface form of original information, enabling accurate discrimination between previously encountered and novel, yet highly similar information. In contrast, gist traces hold conceptual information. The neurocognitive mechanisms underlying verbatim trace formation are largely unknown. In the current study, we address this issue by using event-related potential (ERP) measures of successful memory formation.

Participants studied lists of arbitrary word pairs, for example Ebb – Pepper, Flood - Basil… Word pairs within a list shared a common theme, e.g., tides – spices. To vary the demands on verbatim trace formation, we manipulated the typicality of the word pairs within the list theme (high vs. low). In the memory test, participants had to discriminate between highly similar distractor pairs (Ebb – Basil) and previously encountered word pairs (Ebb – Pepper), which could only be achieved by using verbatim memory traces.

Against our expectations, the typicality manipulation neither affected memory performance for highly similar distractors, nor the respective ERP effects. However, replicating the findings from Cheng and Rugg (2010, Int. J. Psychophysiol.) we found an ERP correlate of successful memory formation at parietal recordings. Contrary to their findings, we observed a frontopolar instead of a parietal ERP effect associated with verbatim trace formation, which emerged exclusively in participants with high verbatim memory performance. Based on its spatiotemporal characteristics, it likely reflects inter-item binding supporting successful verbatim memory formation.