Finding interventions which can address the decline of cognitive function as people get older is of great importance to policy-makers, especially in post-industrial societies with rapidly ageing populations. We examine the impact of several different types of mentally stimulating activities on cognitive function in a sample of community-dwelling Europeans aged 50 and older. The data were drawn from the fourth, fifth and sixth waves of the Survey on Health, Ageing and Retirement in Europe (SHARE). The activities analysed include non-formal learning activities such as education and training courses; informal learning activities such as reading books, newspapers and magazines; and some other types of cognitively stimulating activities including crossword puzzles and playing chess or card games. The cognitive function outcomes under investigation were memory and verbal fluency. Our longitudinal analysis of data on these older adults show that all the activities constituted a potential source for the delay or reduction of cognitive decline, even after a short period -- only 4 years -- of engagement in such activities and regardless of their age.