Adopting Maximum Pupil Diameter to Detect Subtle Usability Issues of a Smartphone Application, Conflict Solver

With the increasing popularity and unparalleled ubiquity of smartphones, researchers in various fields are designing and developing novel applications for this platform as part of the solution to the challenging problems they face. Usability lies at the core of the user experience of such applications. However, the assessments used are often limited to summative and post-event methods, which can overlook subtle yet impactful issues. Objective and instantaneous measures of cognitive workloads provide a solution to this shortcoming. Our previous research has established the reliability of maximum pupil dilation, measured with Tobii Pro Nano, as a preeminent indicator of cognitive workload surges in mobile application users. In this study, we used this measure to locate user cognitive workload peaks while using Conflict Solver and discovered subtle user interface issues that were not reported in the post-usability interview. A total of 30 participants completed a Conflict Solver usability experiment with two phases. In phase 1, the participants performed two “Add a Term” tasks on the original Conflict Solver, followed by a semi-structured interview about their experience with the application. A few subtle usability issues with a drop-down menu were detected through identifying user cognitive workload peaks. In phase 2, the same participants completed the same tasks on Conflict Solver with a redesigned and extended drop-down menu. The results showed that the new design solved the usability issues, and the participants became more favor the drop-down menu over the input box. In conclusion, including maximum pupil dilation into the usability assessment toolkit would provide a more objective and comprehensive usability assessment of a smartphone application. It can also be used to verify the successfulness of a user interface design solution.

随着智能手机的普及程度日益提高，且其无所不在的广泛性无与伦比，各领域的科研人员正致力于设计和开发针对该平台的新型应用，以期解决他们面临的挑战性问题。用户体验的核心理念在于易用性。然而，当前所采用的评估方法往往局限于总结性和事件后方法，这些方法可能忽视了微妙而具有影响力的相关问题。通过客观且即时的认知负荷度量，可以弥补这一不足。我们之前的研究已经确立了使用 Tobii Pro Nano 测量最大瞳孔扩张作为移动应用用户认知负荷激增的卓越指标的可信度。在本研究中，我们利用这一指标来定位用户在使用 Conflict Solver 时的认知负荷峰值，并发现了在事后易用性访谈中未被报告的细微的用户界面问题。共有30名参与者完成了两个阶段的 Conflict Solver 易用性实验。在第一阶段，参与者对原始的 Conflict Solver 执行了两个“添加术语”任务，随后进行了一次关于他们使用该应用程序经验的半结构化访谈。通过识别用户认知负荷峰值，发现了与下拉菜单相关的几处细微的易用性问题。在第二阶段，相同的参与者对重新设计和扩展的下拉菜单版本的 Conflict Solver 完成了相同的任务。结果显示，新的设计解决了易用性问题，参与者对下拉菜单的偏好超过了输入框。总之，将最大瞳孔扩张纳入易用性评估工具箱，将能够为智能手机应用程序提供更加客观和全面的易用性评估。此外，它还可以用于验证用户界面设计解决方案的成功性。