Identifying the Features of Friendly User Interfaces from Emotional Perspectives

Ever since people considered "user-friendly" as the key requirement of user interfaces, the term had been used in many cases. However, what do people really mean by saying an interface is user-friendly remains vague. In order to achieve successful user interface design, the requirements have to be precise and well-documented for designers. Therefore, the objective of this research is to identify the features that contribute to friendly user interfaces. A survey of user experiences was conducted to collect the cases of interactions and the emotional responses of users. After protocol analysis of these data, twenty features that contributed to positive emotions were identified. These features were further categorized into six groups, i.e., Ease of use, Reliability, Inclusiveness, Tolerance, Considerateness, and Attractiveness. The features with two levels of hierarchy could serve as a checklist to guide design. Furthermore, the checklist was applied to a case study, in which a bar table prototype with a multi-touch screen was evaluated by a focus group. The result showed that the requirements of design improvement could be determined systematically with the help of such a checklist.