Seeing and deciding to help: neural and attentional mechanisms of prosociality in younger and older adults.

Prosociality plays a crucial role in social functioning across the lifespan. However, the neural and attentional mechanisms underlying age-related differences in prosociality remain to be understudied. In this study, we used task-based functional magnetic resonance imaging and eye tracking to investigate the behavioural, neural, and attentional mechanisms underlying prosocial intentions in 35 younger adults aged 18-31 and 35 older adults aged 60-72 across helping, sharing, and comforting. Behaviourally, older adults reported a greater likelihood of helping than younger adults, while no age differences were observed in sharing or comforting. Older adults showed reduced activation in regions implicated in mentalising and cognitive control, including the right temporoparietal junction and right dorsolateral prefrontal cortex, during sharing and comforting. Older adults also showed attenuated connectivity between prefrontal and temporoparietal regions during sharing. Eye-tracking results revealed that older adults were more likely than younger adults to visually scan recipients across conditions. Brain-behaviour analyses indicated that helping intentions were associated with stronger connectivity of cognitive control regions with mentalising regions and weaker connectivity with affective processing regions. These findings suggest that distinct neural activation, functional connectivity, and attentional deployment patterns support age-related differences in prosociality, highlighting the value of a multimodal approach to understanding prosocial decision-making throughout adulthood.