Gist more than non-gist representation interferes with associative memory in older adults: The role of inhibitory function

Associative memory deteriorates with age. One possible reason for this associative memory deficit in older adults is a deterioration in inhibitory function. However, it remains unclear whether gist representations are more likely to interfere with older adults' associative memory than non-gist representations and what role of inhibitory function plays in age-related associative memory deficits, as well as whether and how acute inhibitory function training could ameliorate the detrimental effects of inhibitory deficits on associative memory in older adults. In Experiment 1, 80 participants (40 younger and 40 older adults) studied scene-word pairs while attempting to inhibit interfering words during encoding. An immediate associative recognition memory test was performed, followed by a modified Stroop task to measure the inhibitory function. Experiment 2 included 66 older adults randomly assigned to either an inhibitory function acute-training or a control group. The Flanker task was employed for acute inhibitory function intervention, and eye-tracking technology was used to record eye movement indicators. The results showed that older adults showed more gist memory under gist representation interference, and inhibitory function mediated the relationship between age and associative memory accuracy. Notably, although acute inhibitory training did not improve associative memory accuracy, the older adults in the acute-training group exhibited shorter fixation durations and frequencies within the interference region, and then made less inaccurate response in associative memory recognition, leading to better associative memory. These findings elucidate that gist representation more than non-gist interferes with associative memory in older adults, and inhibitory deficits play a mediation role in age-related associative memory decline, as well as the feasibility of inhibitory training to improve associative memory. Our study provides direction for clinical interventions targeting associative memory improvement.