Variation in working memory capacity and forgetting over both the short and the long term: An application of the Population Dilution model

The current study examined the notion that individual differences in working memory capacity (WMC) are partially due to differences in retrieval from long-term memory. High and low WMC participants performed a running paired-associates task with 10 different lags across both the short and the long term. High WMC individuals outperformed low WMC individuals on both short and long lags, but were not different when tested immediately (i.e., lag of zero). Furthermore, low WMC individuals recalled more intrusions and recalled at a slower rate than high WMC individuals. The results are consistent with the notion that variation in WMC is partially due to differences in the ability to guide a strategic search process of long-term memory. Simulations based on the Population Dilution model were consistent with these notions. Thus, WMC is more than just active maintenance over the short term; retrieval of information that could not be maintained is also important regardless of the timescale.