Abstract
Some research reveals that by manipulating interface elements such as text, voice and animated character, the interface can be designed to represent the personality of a computer. Users can distinguish the personalities of the computer interfaces, and tend to treat computers like human beings. The theories of social psychology can apply to the situation of human-computer interaction. (Nass & Lee, 2000) In the study of Human-Computer Interaction, previous researchers have used many verbal and non-verbal cues to present the personalities of computers but not “visual elements”. Fogg et al. (2001) and Stanford Persuasive Technology Lab (2002) found that people quickly evaluate a site by visual design alone. This paper presents a recent study that applied the CASA paradigm to the web page interface by manipulating the visual elements. In order to directly measure the feelings of subjects, this research used a new method—the Barnum Effect. The Barnum Effect is the tendency for people to accept vague, ambiguous, and general statements as descriptive of their unique personalities (Dickson & Kelly, 1985). We used Lai’s personality scale to find the extroverted and introverted subjects, and designed a FAKE personality scale with an introverted and an extroverted interface by manipulating visual elements. After completing the fake scale, 87 subjects received favorable, neural and unfavorable statements on the screen. The results show that manipulating visual elements can represent the personality of interfaces well, and using extrovert interface leads more risks and using introvert interface is the relative safe way. When the conveyed information is positive, apply the similarity-attraction, while when the information is negative, apply the complementarity can raise the credibility to users. The overall result prone to support the complementarity. Furthermore, based on the results and previous studies, we conclude that similarity-attraction can apply to the field of human-computer interaction using verbal cues, while complementarity can do so using non-verbal cues to express personality of interface. The CASA paradigm can apply to the visual elements in web page interfaces. In addition, the results reveal that there is Barnum Effect within the computerized mental test.