Influence of aging on visual attention and peripheral perception

When searching for an item among distractors, we distribute our attention to a certain degree within our peripheral visual field. It has been suggested that in aging, there is a reduced attentional distribution, leading to visual and attentional declines. To investigate attentional distribution, 27 younger and 16 older adults performed a pop-out visual search task. With gaze-contingent methods, we presented different visible window sizes around participants’ fixation during the task. We extracted the size of each participant’s attentional window based on their search times for the different visible window sizes. To test whether performance in the visual search task was related to peripheral visual function, participants performed a contrast detection task and two motion detection tasks (local and global motion perception). In these tasks, stimuli were presented at two different peripheral eccentricities (5° and 10° distant from fixation point). Overall, we observed that older adults took longer to report the target’s presence compared to younger adults, t(41) = 6.31, p<.001. Compared to younger participants, they also had a significantly smaller attentional window, t(41)=2.16, p=.036. In addition, older adults had higher contrast detection thresholds, F(1, 41) = 23.23, p < .001, and higher thresholds in local, F(1,41) = 4.53, p=.039, and global motion perception, F(1,41) = 27.58, p<.001, contrary to the idea that motion perception is preserved with aging. Overall, we observed a reduced attentional distribution as well as lowered contrast thresholds and lowered motion perception in aging. These findings, specific to the peripheral visual field, are compatible with the hypothesis of a functional decline of the visual dorsal stream in normal aging.