Abstract
With the popularization of smartphones, many people cannot live without smartphones, even when walking. Using smartphones while walking may distract the users and affect their gaze and gait behavior such as walking more slowly and more unstably, taking a longer time to respond to the unexpected stimulus. The reason behind these behavioral changes is distraction from multi-tasking. When people operate smartphones while walking, their attention will be occupied. This may hinder people from allocating appropriate attention to the surrounding environment, which leads to the potential risks for both the user him-/her-self and other road users. However, the issue of distracted walking hasn’t been investigated much, and hence there is no compulsory regulation or effective solution. This study surveyed people’s related experience and subjective opinions first. Based on the results of the questionnaire, corresponding countermeasures were then generated. Subsequently, an objective experiment was conducted to analyze the behavioral changes due to distracted walking by smartphones in order to evaluate the effectiveness of the proposed solutions. In the first phase, a questionnaire survey completed by 200 respondents was used to collect self-reported information, experience of distracted walking and perspective toward the danger of distracted walking by smartphones. Each individual’s acceptance and perceived effectiveness toward 10 different solutions were also included. The results showed that among all age groups, people aged between 20 to 24 spent the longest time using smartphones per day (over 4 hours). Though most of the respondents (85%) disagreed with using smartphone while walking, 69% of the respondents reported the experience of using smartphone while walking within the last two weeks. For those who had the experience of distracted walking by smartphones, 36% of them were using social media applications. Hence, this study is mainly focused on the analysis of people’s behavior when distracted walking using social media applications. In addition, the most acceptable solution was “concise interface and workflow design” (scored 3.55/ 5.00), whereas “banning smartphone use while walking” was considered as the most effective solution (scored 3.90/ 5.00). Based on the results of questionnaire survey, the human information processing (HIP) model was used to analyze the process of using social media applications in the second phase. Participants were asked to operate Mandarin or English typing test, while chatting with the test giver. This study analyzed how the attention was allocated to different information processing components like perception, long-term memory, working memory, decision and response selection, and response execution. Findings showed that tasks associated with typing would lead to increased attentional demands. The possible reasons might be “over-focus on the smartphone” and “frequent gaze switching.” Simultaneously typing on the small virtual keyboard, checking typos and pondering over the incoming message make the tasks much more complex. Therefore, it requires improvement with a higher priority. In the simulation experiment, 20 young adults (10 male and 10 female) ranging from 20 to 24 years old, owning smartphones and operating the smartphones more than 1 hour per day were recruited. Participants were asked to complete the walking tasks under 11 different scenarios. There were three major scenarios (locked screen/ pop-up warning/ no interference involved), and under each program there were three minor scenarios including blocked notification, minimized notification, and displayed notification as usual. In addition to those 9 scenarios, there were 2 other scenarios without the operation of smartphones (free walking/ holding a smartphone without operation). Participants were asked to operate social media applications on smartphone while walking counter-clockwisely along a 5.1-meter by 3.6-meter rectangular track (with the width of 0.3 meters) for 4 laps. During the experiment, participants were asked to wear motion capturing suits and wireless eye tracking glasses in order to collect their gait data (walking speed, variability of medial-lateral deviation), attention allocation (the proportion of fixation time on the smartphone, number of gaze shifting away from smartphone and back to smartphone) and subjective responses (Situational Awareness Rating Technique score and NASA-Task Load Index). Besides, there were also unexpected visual and auditory stimulus given in the experiment. By measuring participant’s detection rate and reaction time to the stimulus, their residual attention can be estimated. This study has identified that when operating smartphones while walking, participants were generally found with decreased walking speed and more medial-lateral deviation. In addition, distracted walking by smartphone would lead to a higher probability of failing to notice the unexpected visual and auditory stimulus, less time spent looking over the environment, and slower reaction to the unexpected visual stimulus. Besides, when comparing with the 2 scenarios without operating smartphones, participants’ subjective situational awareness scores were lower than in other 9 scenarios involving smartphone operation. Although no certain solution was found to be able to effectively reduce the risks of distracted walking, the findings did suggest that solutions involving pop-up warning might be worse than others. Overall, distracted walking by smartphones will result in people’s behavioral change both physiologically and psychologically, leading to the serious risks for pedestrians. Further explorations on this issue are recommended to find out effective solutions for distracted walking by smartphones.