Individual differences in contextual storage: Evidence from the list-strength effect

Strengthening some items in a list of words impairs free recall of the remaining items in the list-a phenomenon known as the list-strength effect (LSE; e.g., Tulving & Hastie, 1972). Research indicates that whether the LSE is observed depends on the nature of the strengthening manipulation, and the effect is attributed to the enhancement of the contextual information in the memory trace of the items (e.g., Malmberg & Shiffrin, 2005). We investigated the magnitude of the LSE as a function of individual differences in working memory capacity (WMC). The findings indicate that low-WMC participants do not show the LSE, suggesting that they do not accumulate as much contextual information in the memory trace as the remaining participants do. These results suggest that the low-spans' deficits in utilizing contextual cues during retrieval (e.g., Spillers & Unsworth, 2011) could be partly linked to their deficits in encoding and storing contextual information. Implications for global theories of memory are discussed.