Ageing increases prosocial motivation for effort

Social cohesion relies on prosociality in increasingly ageing populations. Helping others requires effort, yet how willing people are to exert effort to benefit ourselves and other people, and whether such behaviours shift across the lifespan, is poorly understood. Using computational modelling we tested the willingness to exert effort into self or other benefitting acts in younger (age 18-36) and older adults (55-84, total n=187). Participants chose whether to work and exert effort, (between 30-70% of maximum grip strength) for rewards (2-10 credits) accrued for themselves or prosocially for another. Younger adults were self-biased, choosing to work more at higher effort levels for themselves, but also superficial, exerting less force into prosocial work. Strikingly, compared to younger adults, older people were more willing to put in effort for others and exerted equal force for self and other. Increased prosociality in older people has important implications for human behaviour and societal structure.