The relationship of recency discrimination to explicit memory and executive functioning

Recency discrimination has been conceptualized as an executive ability by some investigators and as an aspect of episodic memory by others. We compared the performance of 261 neurologically healthy adults on a recency discrimination task (RDT) with their performance on measures of executive functioning and explicit memory. Mean z-transformed raw scores were used to construct indices of visual and verbal explicit memory, fluency, and executive functioning. Analyses revealed that RDT performance correlated more closely with visual (r = 0.32; p < 0.001) and verbal memory (r = 0.25; p < 0.001) than with fluency (r = 0.16; p < 0.05) and executive functioning (r = 0.13; p < 0.05). These findings suggest that recency discrimination might be better understood as an aspect of episodic memory that is subserved primarily by hippocampal and medial temporal structures than as an executive function that is subserved primarily by prefrontal cortex.