We present a series of mHealth applications and studies pursued as part of the Fittle+ project. This program of research has the dual aims of (1) bringing scalable evidence-based behavior-change interventions to mHealth and evaluating them and (2) developing theoretically based predictive models to better understand the dynamics of the impact of these interventions on achieving behavior-change goals. Our approach in the Fittle+ systems rests on the idea that to master the complex fabric of a new healthy lifestyle, one must weave together a new set of healthy habits that over-ride the old unhealthy habits. To achieve these aims, we have developed a series of mHealth platforms that provide scaffolding interventions: Behavior-change techniques and associated mHealth interactions (e.g., SMS reminders; chatbot dialogs; user interface functionality; etc.) that provide additional support to the acquisition and maintenance of healthy habits. We present experimental evidence collected so far for statistically significant improvements in behavior change in eating, exercise, and physical activity for the following scaffolding interventions: guided mastery, teaming, self-affirmation, and implementation intentions. We also present predictive computational ACT-R models of daily individual behavior goal success for data collected in guided mastery and implementation intention studies that address goal-striving and habit formation mechanisms.

Automated coaching systems offer a convenient, cost-effective way to reduce stress, which can be a serious health issue. However, one concern with such systems is compliance; users fail to achieve daily stress reduction goals because goals are too easy or too difficult. To address this, we built DStress (Design for Stress), a theoretically grounded system that sets adaptive goals in three coaching dimensions: Exercise, Meditation and Accessibility. DStress modifies goal-difficulty based on the individual's immediately previous performance. In a 28-day deployment with 65 users, DStress reduced scores on one direct measure of stress almost in half, significantly more than two other non-adaptive coaching strategies. However, on a second direct stress measure, no improvement was found. There were also no improvements on other indirect stress measures. Analysis of 2842 user-generated reports suggests our findings were the result of DStress balancing compliance against the degree of challenge of the goals it would set.

Understanding gaming motivations is important given the growing trend of incorporating game-based mechanisms in non-gaming applications. In this paper, we describe the development and validation of an online gaming motivations scale based on a 3-factor model. Data from 2,071 US participants and 645 Hong Kong and Taiwan participants is used to provide a cross-cultural validation of the developed scale. Analysis of actual in-game behavioral metrics is also provided to demonstrate predictive validity of the scale.

Examining how in-game behavior preferences map onto real world demographics provides important empirically-derived insights into how to match game-based mechanisms to target demographic segments. Using behavioral and demographic data from 1,037 World of Warcraft players, we use multiple regressions to provide this mapping. Given current interest in "gamifying" applications, we believe these findings are relevant for both gaming and non-gaming research.

Personality inference can be used for dynamic personalization of content or system customization. In this study, we examined whether and how personality is expressed in Virtual Worlds (VWs). Survey data from 1,040 World of Warcraft players containing demographic and personality variables was paired with their VW behavioral metrics over a four-month period. Many behavioral cues in VWs were found to be related to personality. For example, Extraverts prefer group activities over solo activities. We also found that these behavioral indicators can be used to infer a player's personality.

Studies in the Proteus Effect have shown that users conform to stereotypes associated with their avatar's appearance. In this study, we used longitudinal behavioral data from 1,040 users in a virtual world to examine the behavioral outcome of conflicting gender cues between user and avatar. We found that virtual gender had a significant effect on in-game behaviors for both healing and player-vs-player activity.

More and more web users keep up with newest information through information streams such as the popular micro-blogging website Twitter. In this paper we studied content recommendation on Twitter to better direct user attention. In a modular approach, we explored three separate dimensions in designing such a recommender: content sources, topic interest models for users, and social voting. We implemented 12 recommendation engines in the design space we formulated, and deployed them to a recommender service on the web to gather feedback from real Twitter users. The best performing algorithm improved the percentage of interesting content to 72% from a baseline of 33%. We conclude this work by discussing the implications of our recommender design and how our design can generalize to other information streams.

In prior work we reported on the design of a social annotation system, SparTag.us, for use in sensemaking activities such as work-group reading and report writing. Previous studies of note-taking systems have demonstrated behavioral differences in social annotation practices, but are not clear in the actual performance gains provided by social features. This paper presents a laboratory study aimed at evaluating the learning effect of social features in SparTag.us. We found significant learning gains, and consider implications for design and for understanding the underlying mechanisms in play when people use social annotation systems.

Tagging systems such as del.icio.us and Diigo have become important ways for users to organize information gathered from the Web. However, despite their popularity among early adopters, tagging still incurs a relatively high interaction cost for the general users. We introduce a new tagging system called SparTag.us, which uses an intuitive Click2Tag technique to provide in situ, low cost tagging of web content. SparTag.us also lets users highlight text snippets and automatically collects tagged or highlighted paragraphs into a system-created notebook, which can be later browsed and searched. We report several user studies aimed at evaluating Click2Tag and SparTag.us.

Plasma Posters are large screen, digital, interactive poster-boards situated in public spaces, designed to facilitate informal content sharing within teams, groups, organizations and communities. While interest i interactive community poster boards has grown recently, few successful examples have been reported. In this paper we describe an ongoing installation of Plasma Posters within our organization, and report qualitative and quantitative data from 20 months of use showing the Posters have become an integral part of information sharing, complementing email and Web-based sharing. Success factors include our design process, the reliability and flexibility of the technology and the social setting of our organization. We briefly describe three external installations of the Plasma Poster Network in public places. We then reflect on content posting as "information staging" and the ways in which the public space itself becomes part of the "interface" to content.

In this paper, we describe the YeTi information sharing system that has been designed to foster community building through informal digital content sharing. The YeTi system is a general information parsing, hosting and distribution infrastructure, with interfaces designed for individual and public content reading. In this paper we describe the YeTi public display interface, with a particular focus on tools we have designed to provide lightweight awareness of others' interactions with posted content. Our tools augment content with metadata that reflect people's reading of content - captured video clips of who's reading and interacting with content, tools to allow people to leave explicit freehand annotations about content, and a visualization of the content access history to show when content is interacted with. Results from an initial evaluation are presented and discussed.

We introduce the AttrActive Windows user interface, a novel approach for presenting interactive content on large screen, interactive, digital, bulletin boards. Moving away from the desktop metaphor, AttrActive Windows are dynamic, non-uniform windows that can appear in different orientations and have autonomous behaviours to attract passers-by and invite interactions.

No abstract available.

No abstract available.

Quiet Calls is a technology allowing mobile telephone users to respond to telephone conversations without talking aloud. QC-Hold, a Quiet Calls prototype, combines three buttons for responding to calls with a PDA/mobile phone unit to silently send pre-recorded audio directly into the phone. This permits a mixed-mode communication where callers in public settings use a quiet means of communication, and other callers experience a voice telephone call. An evaluation of QC-Hold shows that it is easily used and suggests ways in which Quiet Calls offers a new form of communication, extending the choices offered by synchronous phone calling and asynchronous voicemail.

This paper describes an application-independent tool called Anchored Conversations that brings together text-based conversations and documents. The design of Anchored Conversations is based on our observations of the use of documents and text chats in collaborative settings. We observed that chat spaces support work conversations, but they do not allow the close integration of conversations with work documents that can be seen when people are working together face-to-face. Anchored Conversations directly addresses this problem by allowing text chats to be anchored into documents. Anchored Conversations also facilitates document sharing; accepting an invitation to an anchored conversation results in the document being automatically uploaded. In addition, Anchored Conversations provides support for review, catch-up and asynchronous communications through a database. In this paper we describe motivating fieldwork, the design of Anchored Conversations, a scenario of use, and some preliminary results from a user study.

No abstract available.

The Palette is a digital appliance designed for intuitive control of electronic slide shows. Current interfaces demand too much of our attention to permit effective computer use in situations where we can not give the technology our fullest concentration. The Palette uses index cards that are printed with slide content that is easily identified by both humans and computers. The presenter controls the presentation by directly manipulating the cards. The Palette design is based on our observation of presentations given in a real work setting. Our experiences using the system are described, including new practices (e.g., collaborative presentation, enhanced notetaking) that arise from the affordances of this new approach. This system is an example of a new interaction paradigm called tacit interaction that supports users who can spare very little attention to a computer interface.