ERP correlates of source memory: Unitized source information increases familiarity-based retrieval

Abstract

Source memory tests typically require subjects to make decisions about the context in which an item was encoded and are thought to depend on recollection of details from the study episode. Although it is generally believed that familiarity does not contribute to source memory, recent behavioral studies have suggested that familiarity may also support source recognition when item and source information are integrated, or “unitized”, during study (Diana, Yonelinas, and Ranganath 2008). However, an alternative explanation of these behavioral findings is that unitization affects the manner in which recollection contributes to performance, rather than increasing familiarity-based source memory. To discriminate between these possibilities, we conducted an event-related potential (ERP) study testing the hypothesis that unitization increases the contribution of familiarity to source recognition. Participants studied associations between words and background colors using tasks that either encouraged or discouraged unitization. ERPs were recorded during a source memory test for background color. The results revealed two distinct neural correlates of source recognition: a frontally-distributed positivity that was associated with familiarity-based source memory in the high unitization condition only and a parietally-distributed positivity that was associated with recollection-based source memory in both the high unitization and low unitization conditions. The ERP and behavioral findings provide converging evidence for the idea that familiarity can contribute to source recognition, particularly when source information is encoded as an item detail.

Fluency affects source memory for familiar names in younger and older adults: Evidence from event-related brain potentials

“…Our ERP findings suggest that within-modality repetition priming underlies the fluency effect associated with correct source memory decisions. Importantly, while this specific mechanism has not been demonstrated before, the mutual interpretation of our behavioral and ERP findings does not suggest a beneficial effect of fluency on source memory as implied by previous ERP studies (Diana et al, 2011;Mollison & Curran, 2012). Therefore, these findings represent an important and novel contribution to the current debate on the interplay of fluency-based processes and source memory.…”

“…Supporting the notion of beneficial familiarity effects on source memory in young adults, Diana and colleagues (Diana, Van den Boom, Yonelinas, & Ranganath, 2011) observed a mid-frontal ERP effect for correct versus incorrect source judgments. This effect was restricted to a condition emphasizing unitization of an item with its context (such as representing an object with the background color as one single unit).…”

Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes

“…However, for other events sources are encoded as separate units from the item and so memory of the event requires an association to be made between item and source. Retrieval of this integrated memory requires recollection (Diana et al 2011;Diana et al 2008;Yonelinas, 1999). In the case of the present study, itemcontext associations might have been encoded through the latter process, where weather conditions were encoded as a separate unit to the object.…”

Binding neutral information to emotional contexts: Brain dynamics of long-term recognition memory

“…However, recent behavioral (Diana, Yonelinas, & Ranganath, 2008, 2010 and electrophysiological studies (Addante, Raganath, & Yonelinas, 2012;Diana, Van den Boom, Yonelinas, & Ranganath, 2011;Ecker, Zimmer, & GrohBordin, 2007a, b;Mollison & Curran, 2012;Peters & Daum, 2009;Speer & Curran, 2007;Tibon, Ben-Zvi, & Levy, 2014;Tibon, Gronau, Scheuplein, Mecklinger, & Levy, 2014;Tibon & Levy, 2014;Tsivilis et al, 2001;Zheng, Li, Xiao, Broster, & Jiang, 2015) have found that familiarity-related processes could also contribute to source recognition (Johnson, Hashtroudi, & Lindsay, 1993;Yonelinas, 2002). In an attempt to shed light on the familiarrelated processes embedded in source memory, Diana et al (2008Diana et al ( , 2010Diana et al, 2011) investigated the impact of encoding processes on familiarity-based recognition. The authors observed that exclusively high-unitized associations--that is, item-context pairings encoded as a single unit--elicited frontal ERP old/new effects, whereas low-unitized associations only elicited recollection-related ERPs (Diana et al, 2011).…”