RESUMEN
BACKGROUND: The effects of age on the ability to manage everyday functioning, crucial to ensure a healthy aging process, have been rarely examined and when, self-report measures have been used. The aim of the present study was to examine age effects across the adult lifespan in everyday functioning with two performance-based measures: the Everyday Problems Test (EPT), and the Timed Instrumental Activities of Daily Living (TIADL) tasks. The role of some crucial cognitive abilities, i.e. working memory (WM), processing speed, reasoning, vocabulary, and text comprehension in the EPT and the TIADL were also assessed to see whether or not they have a similar influence (and to what extent) in accounting for age-related effects in these two performance-based measures. METHOD: Two hundred and seventy-six healthy participants, from 40 to 89 years of age were presented with the EPT, the TIADL, as well as WM, processing speed, reasoning, text comprehension, and vocabulary tasks. RESULTS: Path models indicated an indirect effect of age and education on the EPT, which was mediated by all the cognitive variables considered, with WM and reasoning being the strongest predictors of performance. An indirect quadratic effect of age, but not of education, was found on the TIADL score, and an accelerated decline in processing speed mediated the relationship between age and the TIADL score. CONCLUSION: This study revealed age-related effects in performance-based measures, which are mediated by different cognitive abilities depending on the measure considered. The findings highlight the importance of assessing everyday functioning even in healthy older adults.