This post is the fourth in a series of posts covering projects I worked on before my current postdoc position. Below I have included the abstract for my dissertation, Social Influences on User Behavior in Group Information Repositories. I have produced two papers from my thesis; one was published in CHI 2009, and the other was accepted to CHI 2010.

Rader, E. (2010). The Effect of Audience Design on Labeling, Organizing, and Finding Shared Files. To appear in CHI 2010. 

Rader, E. (2009). Yours, Mine, and (Not) Ours: Social Influences on Group Information Repositories. Proceedings of CHI 2009. 

Dissertation Abstract: 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 storage approach focuses on providing users with detailed information about the objects in the system—where they are, which users have been looking at them, how they’ve been used in the past, etc. However, group information repositories tend to grow and become disorganized over time, such that users have difficulty finding what they need. A different approach is to think of these systems as social tools that could be governed by the same processes as face-to-face communication, like grounding and audience design.

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. While the functionality and capabilities of these systems are essentially the same as the desktop metaphor of personal information management (PIM) systems, I argue that social pressures and processes affect the information structure of the repository, and how it grows and evolves over time. Through a series of interviews with users of a typical group information repository system and an 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 a two-part online experiment in which participants labeled and organized short text files into a file-and-folder hierarchy. Eighty-four participants were recruited from two intellectual communities (41 Computer Science graduate students, and 43 Information Science graduate students), such that some participants would share community membership common ground with each other, and some would not. Participants 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. Forty-eight participants returned four to six weeks later and completed a series of search tasks, in which they browsed hierarchies created by other participants to find specific files. Including both labeling/organizing and finding tasks in the experiment allowed me to detect potential performance differences when participants searched hierarchies created by others from the same community (or not), and tailored for different audiences. I found that when participants created hierarchies for an audience they imagined was like them, everyone found files in fewer clicks, regardless of whether they were from the same community as the person who created the hierarchy. Further, quantitative analyses of three aspects of the hierarchies (topology, vocabulary, and semantics) helped to explain these results. Users performed better when file and folder labels were more similar to the text of the documents they represented; this correlation was significantly stronger when participants organized the documents for someone who was similar to them.

These results confirm that audience design, a communication process, can in fact impact 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 so that others might access them. My research indicates that processes which have been shown to affect spoken communication also impact word choices when the “interaction” is mediated by a repository. Social factors affect users’ choices regarding how files in the repository are organized and labeled and what information is retained over time; this in turn affects access to information. Knowing that repositories are social systems will allow system designers to incorporate information that makes the users more salient and familiar to each other, so the process of negotiating shared meaning is better supported by the repository system.

This post is the third in a series about past projects.

Tagging provides a means for users to associate personally salient keywords or labels with content items, enabling them to find the content later via information they are predisposed to recognize or recall. Collaborative tagging systems such as del.icio.us publicly expose individual users’ associations between content items and tags, thereby providing visibility into words others have used to tag similar items. In this research, we focused on the social bookmarking website del.icio.us, as a case study of a collaborative tagging system supporting both personal and shared information management. del.icio.us is an online application that allows users to save and tag their own web bookmarks so they are accessible from any networked computer. Other research has suggested that a socially constructed shared vocabulary might emerge on del.icio.us. We conducted several investigations, including a qualitative interview study, computer modeling, and two quantitative analyses of tagging data scraped from del.icio.us, and found evidence for strong influence of a user’s existing organization and little evidence to support the formation of a socially constructed vocabulary.

Rader, E. and Wash, R. (2008). Influences on Tag Choices in del.icio.us. Proceedings of CSCW 2008. 

Wash, R. and Rader, E. (2008). Understanding del.icio.us Tag Choice Using Simulations. iSchools Conference 2008. 

Wash, R. and Rader, E. (2007). Public Bookmarks and Private Benefits: An Analysis of Incentives in Social Computing. Proceedings of ASIS&T Annual Meeting ‘07. 

Rader, E. and Wash, R. (2006). Tagging with del.icio.us: Social or Selfish? Poster Presented at CSCW 2006. 

I have a long-standing interest in the implications of different communications media for how people interact and communicate with one another. This has led to my involvement in a number of projects over the years exploring various aspects of mediated communication, ranging from navigation in virtual environments, to playing games with distributed groups via a videoconferencing system. This is a second in a series of posts covering projects I worked on before my current postdoc position.

Remote Participation in Research: This chapter uses the theoretical notion of common ground to explore remote participation in experimental research. On one hand, there is a desire to give remote participants the same views and capabilities that they would have as local participants. On the other, there are settings where experimental specimens and apparatus are large and difficult to effectively manipulate or view from a remote vantage point, and where multiple and diverse perspectives may be useful in decision making. In exploring these issues, the authors draw on two studies of researchers in the earthquake engineering community. The first, an interview study about attitudes toward teleparticipation, suggests that engineers are wary of remote participation because they fear the inability to adequately detect signs of potential failure. The second study, an observational study of researchers conducting an experiment in a centrifuge facility, illustrates that researchers adapt to the available information, and that diverse perspectives and information may be valuable in troubleshooting.

Birnholtz, J., Rader, E., Horn, D.B., and Finholt, T. (2009). Enabling Remote Participation in Research. In B. Whitworth and A. de Moor (Eds.) Handbook of Research on Socio-Technical Design and Social Networking Systems. (link)

Playing Games via Video: Video connections can establish a media space in which games may be played, just as people play games while collocated. Experiments were conducted in which eight groups of participants played the party game ‘Mafia’, which involves cooperative decision-making among subsets of players. Of the eight groups, four participated in collocated sessions with all participants in one room. The other participants joined four video sessions which were split between different sites, connected by a video conferencing system. Results suggest that people in a video condition have similar levels of satisfaction, fun, and frustration, to those that play while collocated. This finding holds for both those with prior experience using video systems and those without, suggesting it is not merely a “novelty effect.”

Batcheller, A. L., Hilligoss, B., Nam, K., Rader, E., Rey-Babarro, M., & Zhou, X. (2007). Testing the Technology: Playing Games with Video Conferencing. Proceedings of CHI 2007. (link)

Video Quality: The marketing literature for videoconferencing products often makes recommendations for settings that will yield acceptable subjective video quality; however, these recommendations have not been empirically validated. Additionally, a number of high bandwidth conferencing systems have been created that promise high video quality, but with extremely high bandwidth costs. An experiment was conducted investigating the subjective perception of video quality under the following conditions: 384 kbps, 1920 kbps, DVTS, and plain video. Four test scenes were used that differed in the amount and type of motion present in the video. Participants viewed sequences of reference and test scenes on a Samsung 42-inch plasma display, and made subjective ratings of all scenes using a discrete, 5-point scale. 1920 kbps scenes were given higher ratings than 384 kbps, but lower than both DVTS and a control. Ratings were also lower for scenes with more motion present in the video. No statistically significant difference was found between the DVTS and control test scenes. These findings suggest that while low bandwidth video may be acceptable for “talking heads”-type scene composition, medium bandwidth video offers a higher quality experience for users. Even higher bandwidth systems improve quality more, with the most dramatic improvements coming in scenes with high levels of motion.

Hofer, E., Rader, E., and Finholt, T. (2005). Toward supporting virtual collocation. WACE 2005 (Workshop on Advanced Collaborative Environments). (link)

Rader, E., Hofer, E. and Finholt, T. (working paper). High-bandwidth videoconferencing systems: When is the quality worth the cost? (link)

Navigation in Virtual Environments: Head-mounted displays for virtual environments facilitate an immersive experience that seems more real than an experience provided by a desk-top monitor [18]; however, the cost of head-mounted displays can prohibit their use. An empirical study was conducted investigating differences in spatial knowledge learned for a virtual environment presented in three viewing conditions: head-mounted display, large projection screen, and desk-top monitor. Participants in each condition were asked to reproduce their cognitive map of a virtual environment, which had been developed during individual exploration of the environment along a predetermined course. Error scores were calculated, indicating the degree to which each participant’s map differed from the actual layout of the virtual environment. No statistically significant difference was found between the head-mounted display and large projection screen conditions. An implication of this result is that a large projection screen may be an effective, inexpensive substitute for a head-mounted display.

Patrick, E., Cosgrove, D., Slavkovic, A., Rode, J.A., Verratti, T. and Chiselko, G. (2000). Using a large projection screen as an alternative to head-mounted displays for virtual environments. Proceedings of CHI 2000. (link)

I’ve been making some changes to my website, and transferring project summaries from old, static html pages to my new WordPress-powered website. This is the first in a series of three or four posts covering projects I worked on before my current postdoc position.

Push to View, Motorola Labs, 2002
We identified a user need through field research: people want to be able to share aspects of an experience with others, while it is happening. A prototype was designed and built to allow people to share photos using mobile phones during a conversation, as opposed to the “store and forward” approach taken by mobile multimedia messaging (MMS) applications. The Push-To-View application, based on our initial prototype [ link, archived ], was rolled out to several mobile phone carriers. More information here: [ link, archived | design ]

Family and Friend Communication Study, Motorola Labs, 2001
We conducted a “rapid ethnography” field study to identify communication breakdowns between friends and family members who do not see each other on a daily basis. Our focus was on how people use different kinds of communication media to keep in touch. Findings of this research led to the initial prototype for the Push to View mobile phone application (above). [ technical report ]

TI StudyCards, Carnegie Mellon University, 1999
Capstone group project for the professional Master of HCI degree at Carnegie Mellon University, sponsored by Texas Instruments. Our goal was to find ways graphing calculators could be utilized in high school humanities classrooms. Based on contextual inquiry studies with teachers and students, we created “TI StudyCards”, which consisted of a flash card viewer for the calculator and software for the PC that enabled the creation of sets of flash cards for the calculators. StudyCards now come pre-installed on all TI graphing calculators, and can be downloaded from the TI website: [ link | report ].