Attentional Deficits Do Not Explain Age-Related Impairments on the Mnemonic Similarity Task

The Mnemonic Similarity Task (MST) is increasingly used to assess mnemonic discrimination and has become a valuable tool for detecting subtle cognitive decline in aging and early Alzheimer's disease. Although designed to target hippocampal function, it is unlikely to be immune to attentional effects, leading to the possibility that age-related declines in the MST stem from attention rather than mnemonic impairments. Across three experiments, we found that attentional measures or modulations did not account for a substantial portion of age-related variance in mnemonic discrimination, underscoring that age-related deficits in the MST primarily reflect declines in memory and strengthening the MST's validity as a marker of hippocampal function.