The effect of unisensory and multisensory information on lexical decision and free recall in young and older adults

Studies using simple low-level stimuli show that multisensory stimuli lead to greater improvements in processing speed for older adults than young adults. However, there is insufficient evidence to explain how these benefits influence performance for more complex processes such as judgement and memory tasks. This study examined how presenting stimuli in multiple sensory modalities (audio-visual) instead of one (audio-only or visual-only) may help older adults to improve their memory and cognitive processing compared to young adults. Young and older adults completed lexical decision (real word vs. pseudoword judgement) and word recall tasks, either independently, or in combination (dual-task), with and without perceptual noise. Older adults were better able to remember words when encoding independently. In contrast, young adults were better able to remember words when encoding in combination with lexical decisions. Both young and older adults had better word recall in the audio-visual condition compared with the audio-only condition. The findings indicate significant age differences when dealing with multiple tasks during encoding. Crucially, there is no greater multisensory benefit for older adults compared to young adults in more complex processes, rather multisensory stimuli can be useful in enhancing cognitive performance for both young and older adults.