Peter Schmutz

Abstract: In interface development, it is crucial to reflect the users' expectations and mental models. By meeting users' expectations, errors can be prevented and the efficiency of the interaction can be enhanced. Applying these guidelines to website development reveals the need to know where users expect to find the most common web objects like the search field, home button or the navigation. In a preliminary online study with 136 participants, the most common web objects were identified for three web page types: online shops, news portals, and company web pages. These objects were used for the main study, which was conducted with 516 participants. In an online application, prototypical websites had to be constructed by the participants. Data analysis showed that Internet users have distinct mental models for different web page types (online shop, news portal, and company web page). Users generally agree about the locations of many, but not all, web objects. These mental models are robust to demographic factors like gender and web expertise. This knowledge could be used to improve the perception and usability of websites.

Abstract: Web sites need fast and effective navigation systems. An eye tracking laboratory study with n=120 participants was conducted to compare the influence of different navigation designs (vertical versus dynamic menus) and task complexity (simple versus complex navigation tasks) on user performance, navigation strategy, and subjective preference. With vertical menus, users needed less eye fixations, were faster and more successful. We conclude that, firstly, vertical menus fit better to perception and cognition than dynamic menus, where the navigation items are hidden and must be accessed by an additional mouse click. Secondly, navigation systems should be extended with different kinds of navigation items adapted to the complexity of the users' navigation tasks, because users tend to switch their navigation strategy when confronted with complex tasks.

Abstract: Guidelines for designing usable interfaces recommend reducing short termmemory load. Cognitive load, that is, working memory demands during problem solving, reasoning, or thinking, may affect users' general satisfaction and performance when completing complex tasks. Whereas in design guidelines numerous ways of reducing cognitive load in interactive systems are described, not many attempts have been made to measure cognitive load in Web applications, and few techniques exist. In this study participants' cognitive load was measured while they were engaged in searching for several products in four different online book stores. NASA-TLX and dual-task methodology were used to measure subjective and objective mental workload. The dual-task methodology involved searching for books as the primary task and a visual monitoring task as the secondary task. NASA-TLX scores differed significantly among the shops. Secondary task reaction times showed no significant differences between the four shops. Strong correlations between NASA-TLX, primary task completion time, and general satisfaction suggest that NASA-TLX can be used as a valuable additional measure of efficiency. Furthermore, strong correlations were found between browse/search preference and NASA-TLX as well as between search/browse preference and user satisfaction. Thus we suggest browse/search preference as a promising heuristic assessment method of cognitive load.

Abstract: Online form validation can be performed in several ways. This article discusses two empirical studies with 77 and 90 participants, which have found evidence that the best way of presenting error messages is to provide the erroneous fields after users have completed the whole form. Immediate error feedback recommended by the International Organization for Standardization (ISO) showed the worst performance in these studies. Where presented with immediate feedback, users often simply ignored the messages on the screen and continued completing the form as if nothing happened. These results lead to the postulation of the ''Modal Theory of Form Completion'': Users are in either ''Completion'' or ''Revision Mode'' when filling out online forms. These modes affect the users' way of interaction with the system: During Completion Mode the users' disposition to correct mistakes is reduced, therefore error messages are often ignored.

Abstract: Product listing pages, where information on multiple products are displayed, represent a vital point of an E-commerce website on which consumer decisions are made. Prior research has shown that the design of product listing pages has an impact on users' performance and their recall of brand names. The aim of this study was to examine effects of presentation on cognitive load and consumer decisions. An online study was conducted comparing presentation type (matrix versus list presentation). List presentation was associated with lower cognitive load and more economic product selections. Eye-tracking data from an additional laboratory experiment suggest that list presentation triggers comparison processes which could account for the differences found.

Abstract: Part I. Experimental Studies: 2. Experiment in psychology 3. Experiments on perceiving III Experiments on imaging 4-8. Experiments on remembering: (a) The method of description (b) The method of repeated reproduction (c) The method of picture writing (d) The method of serial reproduction (e) The method of serial reproduction picture material 9. Perceiving, recognizing, remembering 10. A theory of remembering 11. Images and their functions 12. Meaning Part II. Remembering as a Study in Social Psychology: 13. Social psychology 14. Social psychology and the matter of recall 15. Social psychology and the manner of recall 16. Conventionalism 17. The notion of a collective unconscious 18. The basis of social recall 19. A summary and some conclusions.

Abstract: A growing reliance on the Internet as an information source when making choices about tourism products raises the need for more research into electronic word of mouth. Within a hotel context, this study explores the role of four key factors that influence perceptions of trust and consumer choice. An experimental design is used to investigate four independent variables: the target of the review (core or interpersonal); overall valence of a set of reviews (positive or negative); framing of reviews (what comes first: negative or positive information); and whether or not a consumer generated numerical rating is provided together with the written text. Consumers seem to be more influenced by early negative information, especially when the overall set of reviews is negative. However, positively framed information together with numerical rating details increases both booking intentions and consumer trust. The results suggest that consumers tend to rely on easy-to-process information, when evaluating a hotel based upon reviews. Higher levels of trust are also evident when a positively framed set of reviews focused on interpersonal service.

Abstract: Despite recent industry attention, questions remain about how native advertising is perceived and processed by consumers. Two experiments examined effects of language and positioning in native advertising disclosures on recognition of the content as advertising, effects of recognition on brand and publisher evaluations, and whether disclosure position affects visual attention. Findings show that middle or bottom positioning and wording using “advertising” or “sponsored” increased advertising recognition compared to other conditions, and ad recognition generally led to more negative evaluations. Visual attention mediated the relationship between disclosure position and advertising recognition. Theoretical, practical, and regulatory implications for disclosures in native advertising are discussed.

Abstract: Our research goal is to provide a better understanding of how users engage with online services, and how to measure this engagement. We should not speak of one main approach to measure user engagement --- e.g. through one fixed set of metrics --- because engagement depends on the online services at hand. Instead, we should be talking of models of user engagement. As a first step, we analysed a number of online services, and show that it is possible to derive effectively simple models of user engagement, for example, accounting for user types and temporal aspects. This paper provides initial insights into engagement patterns, allowing for a better understanding of the important characteristics of how users repeatedly interact with a service or group of services.

Abstract: This paper analyzes the relation between usability and aesthetics. In a laboratory study, 80 participants used one of four different versions of the same online shop, differing in interface-aesthetics (low vs. high) and interface-usability (low vs. high). Participants had to find specific items and rate the shop before and after usage on perceived aesthetics and perceived usability, which were assessed using four validated instruments. Results show that aesthetics does not affect perceived usability. In contrast, usability has an effect on post-use perceived aesthetics. Our findings show that the ''what is beautiful is usable'' notion, which assumes that aesthetics enhances the perception of usability can be reversed under certain conditions (here: strong usability manipulation combined with a medium to large aesthetics manipulation). Furthermore, our results indicate that the user's affective experience with the usability of the shop might serve as a mediator variable within the aesthetics-usability relation: The frustration of poor usability lowers ratings on perceived aesthetics. The significance of the results is discussed in context of the existing research on the relation between aesthetics and usability.