Age-Related Neural Dedifferentiation Is Driven by Declining Reliability
Abstract
Neural dedifferentiation, characterized by reduced distinctiveness of neural representations, is a robust feature of cognitive aging. Multivoxel pattern analyses often operationalize neural distinctiveness as the difference between within-category similarity (reliability) and between-category similarity (confusability). However, it remains unclear whether age-related reductions in distinctiveness are driven by decreases in reliability, increases in confusability, or both, and whether these components demonstrate similar longitudinal trajectories. Using cross-sectional and longitudinal data from the Michigan Neural Distinctiveness (MiND) study, we decomposed distinctiveness into its two components across visual, auditory, and motor cortex in more than 200 young (18-29 years) and older adults (65-94 years) and estimated cross-sectional between-person age differences and longitudinal within-person change simultaneously in mixed-effects models. We found that reliability was lower in older vs. younger adults cross-sectionally, and this reduction was significantly larger than the corresponding effect on confusability. Moreover, reliability also declined longitudinally within individuals across a mean interval of four years. These findings indicate that age-related dedifferentiation is driven primarily by declining reliability rather than increasing confusability, and that reporting distinctiveness alone can conceal substantial age-related change in its components. Keywords: Dedifferentiation, distinctiveness, reliability, confusability, aging, longitudinal study
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BibTeX
@misc{yang2026agerelated,
title = {{Age-Related Neural Dedifferentiation Is Driven by Declining Reliability}},
author = {Tiantian Yang and Molly Simmonite and Ethan Maddox and Bingjie Liu and Thad Polk},
howpublished = {PsyArXiv},
year = {2026},
month = oct,
doi = {10.31234/osf.io/jb5zn_v1},
url = {https://osf.io/preprints/psyarxiv/jb5zn_v1/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Age-Related Neural Dedifferentiation Is Driven by Declining Reliability
AU - Tiantian Yang
AU - Molly Simmonite
AU - Ethan Maddox
AU - Bingjie Liu
AU - Thad Polk
PY - 2026
DA - 2026/10/24
PB - PsyArXiv
DO - 10.31234/osf.io/jb5zn_v1
UR - https://osf.io/preprints/psyarxiv/jb5zn_v1/
AB - Neural dedifferentiation, characterized by reduced distinctiveness of neural representations, is a robust feature of cognitive aging. Multivoxel pattern analyses often operationalize neural distinctiveness as the difference between within-category similarity (reliability) and between-category similarity (confusability). However, it remains unclear whether age-related reductions in distinctiveness are driven by decreases in reliability, increases in confusability, or both, and whether these components demonstrate similar longitudinal trajectories. Using cross-sectional and longitudinal data from the Michigan Neural Distinctiveness (MiND) study, we decomposed distinctiveness into its two components across visual, auditory, and motor cortex in more than 200 young (18-29 years) and older adults (65-94 years) and estimated cross-sectional between-person age differences and longitudinal within-person change simultaneously in mixed-effects models. We found that reliability was lower in older vs. younger adults cross-sectionally, and this reduction was significantly larger than the corresponding effect on confusability. Moreover, reliability also declined longitudinally within individuals across a mean interval of four years. These findings indicate that age-related dedifferentiation is driven primarily by declining reliability rather than increasing confusability, and that reporting distinctiveness alone can conceal substantial age-related change in its components. Keywords: Dedifferentiation, distinctiveness, reliability, confusability, aging, longitudinal study
ER -