Social Influences on User Behavior in Group Information Repositories.

Group information repositories are systems for organizing and sharing files kept in a central location that all group members can access. These systems are often assumed to be tools for storage and control of files and their metadata, not tools for communication. The purpose of this research is to better understand user behavior in group information repositories, and to determine whether social factors might shape users' choices when labeling and organizing information. Through interviews with group information repository users and analysis of system log data, I found that users tend to restrict their activities in a repository to files they "own," are reluctant to delete files that could potentially be useful to others, dislike the clutter that results, and can become demotivated if no one views files they uploaded. I also conducted an online experiment in which participants labeled and organized short text files into a file-and-folder hierarchy, and later completed search tasks in the hierarchies created by others. Participants came from two intellectual communities, and were instructed to organize the files for one of three different audiences: themselves, someone from the same intellectual community, and someone from the other community. I found that when participants created hierarchies for an audience they imagined was like them, everyone searched more efficiently, regardless of whether they shared community membership with the hierarchy's creator. Further, analyses of the hierarchies showed that users performed better when file and folder labels were more similar to the text of the documents they represented. These results show that audience design, a communication process, can affect group information management tasks. The findings from both studies suggest that sharing files via a group information repository is more complicated than simply making them available on a server. Processes that affect spoken communication also impact word choices when the "interaction" is mediated by a repository. With this new knowledge, it is possible to begin design work on a new class of systems that go beyond mere storage, and better support the social aspects of user behavior in group information repositories.Ph.D.InformationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64758/1/ejrader_1.pd

Betrayed by Updates: How Negative Experiences Affect Future Security

Installing security-relevant software updates is one of the best computer protection mechanisms. However, users do not al-ways choose to install updates. Through interviewing non-expert Windows users, we found that users frequently decide not to install future updates, regardless of whether they are important for security, after negative experiences with past updates. This means that even non-security updates (such as user interface changes) can impact the security of a com-puter. We discuss three themes impacting users ’ willingness to install updates: unexpected new features in an update, the difficulty of assessing whether an update is “worth it”, and confusion about why an update is necessary

Evaluating the End-User Experience of Private Browsing Mode

Nowadays, all major web browsers have a private browsing mode. However, the mode's benefits and limitations are not particularly understood. Through the use of survey studies, prior work has found that most users are either unaware of private browsing or do not use it. Further, those who do use private browsing generally have misconceptions about what protection it provides. However, prior work has not investigated \emph{why} users misunderstand the benefits and limitations of private browsing. In this work, we do so by designing and conducting a three-part study: (1) an analytical approach combining cognitive walkthrough and heuristic evaluation to inspect the user interface of private mode in different browsers; (2) a qualitative, interview-based study to explore users' mental models of private browsing and its security goals; (3) a participatory design study to investigate why existing browser disclosures, the in-browser explanations of private browsing mode, do not communicate the security goals of private browsing to users. Participants critiqued the browser disclosures of three web browsers: Brave, Firefox, and Google Chrome, and then designed new ones. We find that the user interface of private mode in different web browsers violates several well-established design guidelines and heuristics. Further, most participants had incorrect mental models of private browsing, influencing their understanding and usage of private mode. Additionally, we find that existing browser disclosures are not only vague, but also misleading. None of the three studied browser disclosures communicates or explains the primary security goal of private browsing. Drawing from the results of our user study, we extract a set of design recommendations that we encourage browser designers to validate, in order to design more effective and informative browser disclosures related to private mode

Understanding del.icio.us Tag Choice Using Simulations

Understanding how users choose tags can help researchers better understand how tagging systems can be used and how to design better tagging systems for the future. We developed a simulation of del.icio.us, a popular so- cial bookmarking tool, that allowed us to simulate users choosing tags using one of four possible strategies for tag choice found in the literature. We then compared the resulting tag choices with empirical data retrieved from del.icio.us to determine which tag choice strategies would result in choices most similar to those seen in the real world. We were able to rule out three of the strategies as unlikely to be the primary means by which tags are chosen on del.icio.us

Understanding del.icio.us Tag Choice Using Simulations

Understanding how users choose tags can help researchers better understand how tagging systems can be used and how to design better tagging systems for the future. We developed a simulation of del.icio.us, a popular so- cial bookmarking tool, that allowed us to simulate users choosing tags using one of four possible strategies for tag choice found in the literature. We then compared the resulting tag choices with empirical data retrieved from del.icio.us to determine which tag choice strategies would result in choices most similar to those seen in the real world. We were able to rule out three of the strategies as unlikely to be the primary means by which tags are chosen on del.icio.us

Replication Materials for "Data Privacy and Pluralistic Ignorance"

Replication materials for the paper "Data Privacy and Pluralistic Ignorance" published at The Nineteenth Symposium on Usable Privacy and Security (SOUPS 2023) in Anaheim, CA, USA, August 6–8, 2023