How Individual Differences in Working Memory and Source Monitoring matter in Susceptibility to False Memory

Using the DRM word list paradigm (Roediger & McDermott, 1995) we investigated the role of individual differences in working memory capacity (WMC) and source monitoring (SM) ability in protection from false memories (FM) in recall and recognition. Both spreading activation and monitoring are cognitive processes associated with working memory (Anderson, 1983; Cantor & Engle, 1993), and previous research demonstrates working memory’s relation to goal maintenance (Kane & Engle, 2003) and importance for withholding irrelevant information (Conway & Engle, 1994). However, whether higher WMC constitutes activation or monitoring and predicts increased or decreased FM production respectively, remains inconclusive (Watson et al., 2005; Peters et al., 2007; Bixter & Daniel, 2013). When considering SM ability, a relationship has been found between WMC and FM in recall, suggesting that SM mediates this relation (Unsworth & Brewer, 2010). Other work suggests that SM and WMC interact based on the role of memory monitoring in constraining task irrelevant information (Rose, 2013; Lilienthal et al., 2015). From an activation-monitoring perspective (Gallo, 2010), we investigated individual differences in WMC and SM predicting FM in recall and recognition, testing whether the relationships are additive or interactive. Our findings support moderation, suggesting that when SM ability is too high, working memory cannot work as well to monitor and constrain activation in order to reduce FM. Only when WMC was higher and SM was lower did we show a predicted decrease in FM during recognition. This work suggests that protecting mental resources in WMC is more important for constraining FM production than SM ability and we consider the implications for real world false memories and eyewitness testimony.