Demands on perceptual and mnemonic fidelity are a key determinant of age-related cognitive decline throughout the lifespan

Abstract

Ageing is associated with less detailed memory recall. We tested whether poorer representational fidelity across perception, short-term and long-term memory (STM/LTM) are among the earliest signs of cognitive ageing. Our paradigm probed target-lure object mnemonic discrimination and precision of object-location binding. In a lifespan sample, cognitive deficits were observed in midlife when complex, detailed stimulus representations were required for perceptual and short/long-term Forced Choice mnemonic discrimination. A continuous metric of object-location source memory combined with computational modelling demonstrated that errors in short- and long-term memory in middle-aged adults were largely driven by a loss of precision for retrieved memories, not necessarily by forgetting. On a trial-by-trial basis, the fidelity of item and spatial information was more tightly bound in long- as opposed to short-term memory with this association being unaffected by ageing. Standard neuropsychological tests without demands on memory quality were less sensitive to age effects than memory precision. Perceptual discrimination predicted mnemonic discrimination across tasks. Neuropsychological proxies for prefrontal executive functions correlated with short-term, but not long-term, memory fidelity. Conversely, neuropsychological indicators of hippocampal integrity correlated with mnemonic discrimination and precision of both STM and LTM, suggesting partially dissociable mechanisms of inter-individual variability in short- and long-term memory fidelity.

Demands on perceptual and mnemonic fidelity are a key determinant of age-related cognitive decline throughout the lifespan.

“…In accordance with the Transparency and Openness Promotion Guidelines, all data, software code, and other methods developed by others are appropriately acknowledged. Materials pertaining to this study are available on the Open Science Framework at https://osf .io/24vqk/ (Gellersen, 2023; data and analysis code), except for the stimuli for the precision task (which are available on https://konklab .fas.harvard.edu/#) and for the perceptual task (which were kindly provided to the Cambridge Memory Lab by Morgan Barense and can be found at https://sites.google.com/andrew.cmu.edu/tarrlab/ stimuli?authuser=0). Code for the memory and perception tasks are available upon request.…”

“…The mnemonic discrimination metric is well suited to test for detailed object representations and for vulnerability to interference from feature overlap from other stimuli (Reagh & Yassa, 2014;Stark et al, 2019;Trelle et al, 2017). We chose to present target and lures simultaneously as to reduce the contribution of prefrontal cortex (PFC)-dependent processes (Gellersen, 2023;Gellersen, Trelle, et al, 2021) while maintaining demands on high-fidelity stimulus representations.…”

Visual Memory for Natural Scenes

“…Older adults Despite the memory of single objects or scenes remaining relatively intact among older adults, aging is associated with decreased associative memory performance as a result of cognitive and neural decline (Bouffard et al, 2024). A recent study examining ages 18 through 85 discovered that starting in midlife, observers' memories of object-location associations decrease due to reduced abilities in representing different associations distinctively during memory encoding and retrieval rather than memory decay (Gellersen et al, 2024). There are a few pieces of evidence supporting fidelity reduction but not a memory decay account: (1) researchers find that object and location information are more tightly associated in long-term memory than short-term memory across different age groups.…”