The Effects of Simulated Driving on Perceived Urgency Elicited by Vibration Stimulation

Even though audio-visual stimuli are widely used for information communication, vibration feedback offers an attractive alternative due to its confidentiality, high ability to attract attention, and effectiveness in conveying an appropriate level of urgency. In this study, we investigate how the perceived level of urgency is modulated by a simulated driving task. To examine this, we conducted two experiments. The first experiment aimed to design vibration stimuli capable of eliciting three levels of urgency (low, medium, and high) by leveraging critical vibration parameters, such as vibration intensity, vibration duration, upper body part, and surface area. Results of the first experiment show significant differences in the perceived urgency of the three stimuli, which validates the ability of vibration to elicit the three levels of urgency (Kruskal-Wallis test, Bonferroni-Holm correction, p<0.05). In the second experiment, we evaluate how the perceived urgency of the three vibration stimuli is modulated during a simulated driving task. Results indicate that medium urgency vibration is sufficient to elicit a high sense of urgency (there is no significant difference in the perceived urgency between the medium and high urgency vibration). On the other hand, high urgency vibration significantly increases annoyance as compared to medium urgency vibration (One-way ANOVA test, Bonferroni-Holm correction, p<0.05). The results show that the perceived urgency of the same stimulus can vary due to the driving simulation task. From these results, we also suggest that a primary task significantly modulates the perceived urgency and must be considered while designing vibration stimulation to convey a desirable level of urgency.