Different time-courses for consolidating information in working memory and long-term memory

The formation of memory representations requires the transformation of perceptual information into stable traces via short-term consolidation. In this study, we measured the time-course of forming color-object associations in working memory (WM) and in long-term memory (LTM), and examined whether a single consolidation process supports both memory systems. Across three experiments, we estimated consolidation time-accuracy curves in WM and LTM by varying the free time to consolidate the information from 300 to 8,050 ms in a continuous reproduction task. We found that both WM and LTM showed a consolidation onset at approximately the same time, but the process followed distinct trajectories: WM consolidation progresses faster and reaches an asymptotic performance earlier compared to LTM consolidation. Our findings indicate that the creation of robust WM and LTM representations can run partially in parallel, but follows different time-courses in each memory system. This suggests that different processes may contribute to memory formation for immediate and later retrieval, and that a substantial contribution of LTM to performance in WM tests is more likely with slower presentation rates.