The role of notification modality in smartwatches: A context of sedentary behavior interventions

Sedentary behavior associated with prolonged computer use poses significant health risks. Smartwatch-based stand-up reminders offer a promising intervention, yet the effectiveness of different notification modalities remains unclear. This controlled laboratory study used a within-subject design to compare four notification modalities: visual-only, visual-auditory, visual-tactile, and visual-auditory-tactile, evaluated using metrics including response times, response rates, compliance times, compliance rates, and user preferences. Twenty participants performed computer-based data processing tasks at a sit-stand workstation while receiving stand-up reminder notifications at random intervals every 7-10 min, prompting them to stand. We hypothesized that multimodal notifications would outperform the visual-only modality in terms of user responsiveness and user preferences. The results supported this hypothesis: both bimodal modalities (visual-auditory and visual-tactile) significantly reduced response times and increased response rates as well as user preferences compared to the visual-only condition (p < 0.001), while performing as effectively as the trimodal condition. Furthermore, response rates were positively correlated with two dimensions of user preferences, confirmation (ρ = 0.497, p < 0.001) and continuance intention (ρ = 0.422, p < 0.001), indicating that user trust and willingness to continue using the system were associated to the system performance. These findings suggest that smartwatch developers and manufacturers should avoid using visual-only notifications as the default and instead promote the use of at least bimodal reminders to enhance user responses and preferences.