Sharable Interfaces and Co-Located Collaboration

Heath et al. (2002b) stated that computer workstations are designed for one user at a time interac- tion, rather than simultaneous use by multiple people. As a consequence, collaborators may often have restricted and incongruent access to information about the activities of their colleagues, and the single user nature of the technology may make it difficult to informally gather awareness information. As an example it may not be possible for someone to determine ‘at a glance’ the details a colleague may be entering via a keyboard, or to casually take note of what is currently displayed on another person’s computer screen.

This section discusses multi-user Sharable Interfaces for co-located interaction in collab- orative work contexts. Such interfaces begin to address the problems presented by single user devices such as desktop computers. Rogers et al. (2009) drew a distinction between ‘early group- ware technologies’ designed to support work within groups of geographically distributed individ- uals, and ‘Shareable Interfaces’ designed to support physically co-located people in tasks which require co-presence. Under the general umbrella of Sharable Interfaces a variety of collaborative shared-screen based systems have been developed, including multi-touch surfaces (Hornecker et al., 2008, Rogers et al., 2009), large public displays (Brignall and Rogers, 2003), and multi- user extensions to conventional desktop computers (Stewart et al., 1999). Given the focus of this thesis on co-located interaction, the more current research on sharable interfaces is especially relevant.

A central distinction between groupware and sharable interfaces is that while a distributed groupware application may be required to re-create, simulate or convey the functions of co- present verbal and non-verbal interaction (e.g., gaze, physical gesture, orientation) via software mechanisms such as telepointers (Gutwin and Penner, 2002), Shareable Interfaces designed for

co-located interaction do not need to provide explicit support for these aspects of interaction. Instead, Sharable Interfaces can attempt to leverage the affordances of co-located interaction to support collaboration which is more efficient, equal, free-flowing (Rogers et al., 2009) and serendipitous (Shen et al., 2003) than conventional single user interaction paradigms such as lap- tops and computer workstations. Similarly Stewart et al. (1999) defined Single Display Group- ware (SDG) as a model of co-present collaboration where people use private interface channels such as personal keyboards and mice to interact with a shared screen. Stewart et al. (1999) argued that the shared nature of these interfaces could enhance the collaborative experience by reducing social barriers between users, eliminating conflict over shared input channels, and encouraging more communication between users as the shared nature of the interface requires communication in order to resolve conflict. Negative aspects of SDG were identified, notably that new forms of conflict may arise through different users performing simultaneous incompatible actions, and that task completion time may be increased as SDG does not permit a single strong willed user to direct the collaboration through a monopolisation of the input channels. Finally Stewart et al. (1999) noted that the parallel nature of the interface might encourage users to work in isolation, rather than communicating or contributing to the primary group task.

Sharable Interfaces are most frequently evaluated through comparative studies of novel and conventional computer interfaces (Rogers et al., 2009, Stewart et al., 1999) or through compari- son to ‘pen-and-paper’ based approaches which do not incorporate digital technologies. As there are few instances of novel Shareable Interfaces being used in real-world scenarios the majority of studies in the literature take place in contrived or artificial situations. Observation, video, interac- tion log analysis and interviews are common techniques for studying interaction around Sharable Interfaces (Rogers et al., 2009). For instance Ryall et al. (2006) discussed observations of peo- ple interacting with multi-touch screens in public places, noting in general that people did not associated these interfaces with conventional computer systems, although during initial encoun- ters with the device, groups of people under-exploited their capacity for simultaneous multi-user interaction.

Using a generalised ‘Shared Information Spaces’ metaphor Rogers et al. (2009) presented a detailed analysis of groups performing a collaborative task using three different physical inter- face metaphors, a conventional laptop computer, a touch-surface and physical-digital interface which combines digital data representation with tangible control. Their analysis considered the

variance in the amount and type of conversational and interactional turn taking, turn negotiation, joint action and verbal and participatory equality. In addition they discussed the arrangement of physical resources and the ways in which location of collaborators and devices was observed to contribute to the structure of the interaction. Their study suggests that allowing users to have multiple points of ‘entry’ or interaction within a shared interface can be beneficial for creative ac- tivities such as design tasks, although the nature of the interface can have an effect on the equality of contributions between group members and the degree to which groups work in a parallel fash- ion. Similarly Scott et al. (2004) observed territorial behaviour in tabletop activities, discussing in particular spatial organisation, and the means by which groups utilise space to work, share and store items. Tse et al. (2004) studied the way people spatially separate an SDG interface to avoid overlapping or interfering with each-other’s work. They argued that spatial partitioning happened consistently between groups of people, and occurred naturally without verbal negotiation. They also argued that participants naturally avoided spatially interfering with each other in a shared workspace, however the exact patterns of spatial division were determined by factors such as the underlying structure of the task and the seating arrangement of the participants around the shared screen.