Age-Related Differences in Multimodal Information Processing and Their Implications for Adaptive Display Design.

Abstract

In many data-rich, safety-critical environments, such as driving and aviation, multimodal displays (i.e., displays that present information in visual, auditory, and tactile form) are employed to support operators in dividing their attention across numerous tasks and sources of information. However, limitations of this approach are not well understood. Specifically, most research on the effectiveness of multimodal interfaces has examined the processing of only two concurrent signals in different modalities, primarily in vision and hearing. Also, nearly all studies to date have involved young participants only. The goals of this dissertation were therefore to (1) determine the extent to which people can notice and process three unrelated concurrent signals in vision, hearing and touch, (2) examine how well aging modulates this ability, and (3) develop countermeasures to overcome observed performance limitations. Adults aged 65+ years were of particular interest because they represent the fastest growing segment of the U.S. population, are known to suffer from various declines in sensory abilities, and experience difficulties with divided attention. Response times and incorrect response rates to singles, pairs, and triplets of visual, auditory, and tactile stimuli were significantly higher for older adults, compared to younger participants. In particular, elderly participants often failed to notice the tactile signal when all three cues were combined. They also frequently falsely reported the presence of a visual cue when presented with a combination of auditory and tactile cues. These performance breakdowns were observed both in the absence and presence of a concurrent visual/manual (driving) task. Also, performance on the driving task suffered the most for older adult participants and with the combined visual-auditory-tactile stimulation. Introducing a half-second delay between two stimuli significantly increased response accuracy for older adults. This work adds to the knowledge base in multimodal information processing, the perceptual and attentional abilities and limitations of the elderly, and adaptive display design. From an applied perspective, these results can inform the design of multimodal displays and enable aging drivers to cope with increasingly data-rich in-vehicle technologies. The findings are expected to generalize and thus contribute to improved overall public safety in a wide range of complex environments.