Examining Age-related Enhancement of Multisensory Gain: The Role of Sensory Decline and Inverse Effectiveness
Abstract
Older adults experience a greater benefit from multisensory integration than their younger counterparts, but it is unclear why. One hypothesis is that age-related sensory decline weakens unisensory stimulus effectiveness, producing a boost in multisensory gain through inverse effectiveness. Many previous studies present stimuli at the same intensity for both younger and older adults (i.e., stimulus-matched), as opposed to accounting for each participant’s unique perceptual ability (i.e., perception-matched). This makes it difficult to discern the source of age-related differences in multisensory gain. Through a combination of stimulus-matched and perception-matched tasks, I found that older adults exhibit enhanced multisensory gain at low levels of detection and speech-perception, and higher levels of processing like semantic processing. Critically, when accounting for individual differences in perception, I found no age-related enhancements. Together, these findings suggest that sensory decline paired with existing mechanisms such as inverse effectiveness function together to enhance multisensory gain among older individuals.