Loneliness to Meaningless: Event-Related Potentials Reveal Loneliness Modulates Neural Responses of Semantic Processing in Healthy Older Adults

Loneliness (LS) is an aversive emotional response to the subjective-evaluated inadequacy in individuals’ social relationships and interactions, with its prevalence only to be exacerbated by the Covid-19 pandemic. Previous studies have associated loneliness in late adulthood with clinical affective disorders and cognitive functional declines. Yet few studies focused on the impact of loneliness on language comprehension, despite the obvious social nature of language abilities and its importance in maintaining one’s social network. We aim to fill this gap and investigate whether and how loneliness affects semantic retrieval in healthy older adults. Event-related potentials were recorded while participants were making category membership decisions on three types of targets: high typicality (HT), low typicality (LT), and
violation (VIO). The N400 effect between LT and VIO was negatively correlated with LS. The high loneliness group showed marginal HT-VIO differences on N400 with delayed onsets, in more restricted time windows from the successive 50ms analysis compared to the low loneliness group. These results suggest loneliness erodes and alters individuals’ semantic processing among healthy older adults. Loneliness modulates the efficacy of using category contexts in activating semantic associations. Overall, loneliness may further hinder language comprehension, which undermines one’s ability to communicate and reconnect with others, and then in return, feed into loneliness reciprocally.