Connectedness matters more than feeling isolated: A 12-year longitudinal study of age-related decline in naming ability.

Naming ability supports effective communication and functional independence in late life, yet it declines variably. Psychosocial factors like loneliness may exacerbate this trajectory, yet research often treats loneliness as a unitary construct. This study examined whether overall loneliness and its subdimensions, subjective isolation and structural lack of connections, differentially predict naming trajectories, and whether naming and social connectedness are bidirectionally related. Using four biennial waves of Health and Retirement Study data (2008-2020; N = 3504), we applied hierarchical linear models to analyze trajectories and cross-lagged panel models to test directionality, adjusting for demographics, health, and family factors. Greater overall loneliness predicted faster naming decline. Crucially, decomposing loneliness revealed that the lack of available social connections, a structural dimension, robustly predicted decline even after rigorous adjustment, whereas subjective isolation did not predict decline when covariates were included. Cross-lagged effects were small and stage-specific, showing that naming ability predicted later connectedness (in early and late stages) and that connectedness predicted later naming performance (in the mid-stage). These findings highlight that structural connectedness, defined as the actual availability of a social network, is more critical for preserving linguistic function than the mere feeling of isolation. Furthermore, the link between language and connection is dynamic and mutually reinforcing. Interventions should therefore prioritize maintaining social engagement and providing communication support, targeting structural connectedness as a modifiable factor to preserve language and cognitive health in aging populations.