Cognitive support at encoding attenuates age differences in recollective experience among adults of lower frontal lobe function

Abstract

Free recall and recollective experience were investigated in relation to neuropsychological measures of frontal lobe function (FLF) among 105 healthy adults divided into three age groups; young (M = 21.82 years), young-old (M = 64.69 years), and old-old (M = 70.69 years). Participants were tested on free recall and recognition of word lists in each of two study conditions. In the first, semantically related words were organizable into one of four taxonomic categories, whereas in the second (random) condition, words were semantically unrelated. Results in respect of free recall showed memory performance was inferior with increasing age, lower FLF, and random encoding condition. There were no interactions involving those variables. With regard to recollective experience, a similar pattern of results was obtained. However, analyses also identified a significant interaction, suggesting old-old adults of lower FLF to exhibit poorer recollective experience. This interaction was significantly modified when semantic organization was available at study. Recognition measures classified as familiar did not vary as a function of age, neuropsychological function, or encoding condition. The results are consistent with the view that autonoetic consciousness, supported by the neural systems of the prefrontal cortex, underpins recollective experience. Further, among older adults, cognitive support at encoding attenuates the detrimental effects of individual differences in those neural systems, in relation to recognition performance.