Crowd work provides solutions to complex problems effectively, efficiently, and at low cost. Previous research showed that feedback, particularly correctness feedback can help crowd workers improve their performance; yet such feedback, particularly when generated by experts, is costly and difficult to scale. In our research we investigate approaches to facilitating continuous observational learning in crowdsourcing communities. In a study conducted with workers on Amazon Mechanical Turk, we asked workers to complete a set of tasks identifying nutritional composition of different meals. We examined workers' accuracy gains after being exposed to expert-generated feedback and to two types of peer-generated feedback: direct accuracy assessment with explanations of errors, and a comparison with solutions generated by other workers. The study further confirmed that expert-generated feedback is a powerful mechanism for facilitating learning and leads to significant gains in accuracy. However, the study also showed that comparing one's own solutions with a variety of solutions suggested by others and their comparative frequencies leads to significant gains in accuracy. This solution is particularly attractive because of its low cost, minimal impact on time and cost of job completion, and high potential for adoption by a variety of crowdsourcing platforms.

Since 2011, our research group, along with numerous local partners, has been building a platform and methodology for monitoring elections using social media. Historically, election monitoring has traditionally been the domain of trained monitors provided by international monitoring groups. But monitoring by domestic groups with fewer resources has been a growing phenomenon, supported in part by the availability of inexpensive digital technologies such as SMS. Social media represents a further, exciting step in this trend. We describe our five years of experience in this endeavor and report a series of key lessons learned. These lessons touch on issues such as source types and curation, collaboration with other election-related groups, human vs. automated analysis, varying stakeholder needs, and the value of falsification. We also share our vision for the next five years of this research.

Today is an exciting time to be a political activist in sub-Saharan Africa, particularly for the technically inclined. Online social media and other digital technologies are increasingly being used for political purposes. But this phenomenon raises the question of how, if at all, these new media actually perturb the political landscape. These questions have been well-studied in Western contexts, but remain relatively underexplored in developing regions where traditional media are often scarcer, democracies are younger, and the effect of social media on politics has the potential to be quite distinct. This paper explores these questions through a qualitative dual case study of social media use during general elections in Nigeria and Liberia in 2011. Participants suggested that social media helps to overcome previous scarcity of information during the electoral process, leading to increased transparency and reduced tension. Furthermore, social media-based monitoring shows encouraging signs of robustness concerning information quality and mobility. Together, these findings suggest that given sufficient civil-society coordination, social media can be an effective tool for electoral scrutiny and can help build public trust in the electoral process.

While the history of traditional media in post-conflict peace building efforts is rich and well studied, the potential for interactive new media technologies in this area has gone unexplored. In cooperation with the Truth and Reconciliation Commission of Liberia, we have constructed a novel interactive kiosk system, called MOSES, for use in that country's post-conflict reconciliation effort. The system allows the sharing of video messages between Liberians throughout the country, despite the presence of little or no communications infrastructure. In this paper, we describe the MOSES system, including several innovative design elements. We also present a novel design methodology we employed to manage the various distances between our design team and the intended user group in Liberia. Finally, we report on a qualitative study of the system with 27 participants from throughout Liberia. The study found that participants saw MOSES as giving them a voice and connecting them to other Liberians throughout the country; that the system was broadly usable by low-literate, novice users without human assistance; that the embodied conversational agent used in our design shows considerable promise; that users generally ascribed foreign involvement to the system; and that the system encouraged heavily group-oriented usage.

We present the results of a qualitative study of the sharing and consumption of entertainment media on low-cost mobile phones in urban India, a practice which has evolved into a vibrant, informal socio-technical ecosystem. This wide-ranging phenomenon includes end users, mobile phone shops, and content distributors, and exhibits remarkable ingenuity. Even more impressive is the number of obstacles which have been surmounted in its establishment, from the technical (interface complexity, limited Internet access, viruses), to the broader socioeconomic (cost, language, legality, institutional rules, lack of privacy), all seemingly due to a strong desire to be entertained.

We present results from a qualitative study examining how professionals living and working in Nairobi, Kenya regularly use ICT in their everyday lives. There are two contributions of this work for the HCI community. First, we provide empirical evidence demonstrating constraints our participants encountered when using technology in an infrastructure-poor setting. These constraints are limited bandwidth, high costs, differing perceptions of responsiveness, and threats to physical and virtual security. Second, we use our findings to critically evaluate the "access, anytime and anywhere" construct shaping the design of future technologies. We present an alternative vision called deliberate interactions--a planned and purposeful interaction style that involves offline preparation and discuss ways ICT can support this online usage behavior.

Liberia is a country emerging from years of protracted and devastating civil conflict. Left without any fixed line telephone infrastructure, it relies solely on the mobile phone for telephony. This study investigates the usage of mobile phones in this immediate post-conflict setting. In particular, we adopt the uses and gratifications approach to media research, giving focus to both instrumental and intrinsic motivations for use. Mobile phone users in both the capital city of Monrovia and in various rural areas were surveyed using the Q methodology, which identified distinct perspectives within these urban and rural groups. Participants were then sorted into groups where each group contained users with similar perspectives on their mobile phones. These identified groups included sets of users who saw their phones as productivity enhancers, means of connectivity to family and friends, essential business tools, technological curiosities, and sources of personal security. The idea of a phone as a stylish object was markedly rejected, especially in rural areas. We contrast these Q-sort results from Liberia with previous work from Kigali, Rwanda, finding differences especially as related to security.

We use a haptically enhanced mixing board with a video projector as an interface to various data visualization tasks. We report results of an expert review with four participants, qualitatively evaluating task), parallel coordinates interface (multi-dimensional combinato-rial search), and ExoVis (3D spatial navigation). Our investigation sought to determine the strengths of this physical input given its ca-pability to facilitate bimanual interaction, constraint maintenance, tight coupling of input and output, and other features. Participants generally had little difficulty with the mappings of parameters to sliders. The graspable sliders apparently reduced the mental exer-tion needed to acquire control, allowing participants to attend more directly to understanding the visualization. Participants often des-ignated specific roles for each hand, but only rarely moved both hands simultaneously.

Most users do not experience the same level of fluency in their interactions with computers that they do with physical objects in their daily life. We believe that much of this results from the limitations of unimodal interaction. Previous efforts in the haptics literature to remedy those limitations have been creative and numerous, but have failed to produce substantial improvements in human performance. This paper presents a new approach, whereby haptic interaction techniques are designed from scratch, in explicit consideration of the strengths and weaknesses of the haptic and motor systems. We introduce a haptic alternative to the tool palette, called Pokespace, which follows this approach. Two studies (6 and 12 participants) conducted with Pokespace found no performance improvement over a traditional interface, but showed that participants learned to use the interface proficiently after about 10 minutes, and could do so without visual attention. The studies also suggested several improvements to our design.

A high quality computer synthesis of an acoustic sound source does not necessarily yield a playable virtual musical instrument. A computer simulation of an acoustic musical instrument creates a disconnect between sound production and user input, and correspondingly, between hearing and feeling, in contrast to their interconnection in an acoustic instrument. This disconnect denies the user important haptic clues well known to help instrument control, impeding the user's ability to find, and remain inside, regions of playability. This research explores the addition of haptic feedback to a virtual reed model. In particular, we render the instrument's parameter space as a dynamic force field in order to support fine motor movements and, in turn, provide the user with cues regarding the instrument's oscillatory state and possible regions of playability. We then observe the effects that this additional feedback has on the user's ability to play the virtual instrument.