Design for human interaction: communication as a special case of misunderstanding

In order to engineer effective and usable interactive computing systems we need to consider not just the human-system interface but the human-human interface. The success of many technologies depends not just on how easy they are to understand and operate but also on how effectively they integrate with the wider ecology of our interactions with others. This point has been made especially clearly by ethnomethodological studies of the use of technology in workplace contexts (e.g. Heath and Luff, 2000). It also helps to explain why, for example, the evolution of video and music technology has been driven as much by ease of sharing as it has been by image or audio quality and why some technologies, such as SMS messaging succeed despite having a poor human-system interface. As Kang (2000) succinctly put it "The killer application of the internet is other people" (p. 1150, cited in Bargh and McKenna 2004).

If technology acts, by accident or by design, as an interface between people then we might try to generalise human-system approaches to design by treating them as the basic building blocks of the larger human-system-human interface. This talk will argue, however, that this kind of 'scaling-up' approach is insufficient. In particular, the generalization of human-system models to contexts which involve multiple participants leads us to ignore some critical processes that underpin the effectiveness of human-human interaction. More specifically, a focus on the cognitive, behavioural or communicative capabilities of individual human beings does not provide an adequate understanding of how different people co-ordinate their understanding of what they are doing through communication.

This line of argument suggests that in addition to understanding the broader social context of interactive systems we can also benefit from focusing on the specific low level mechanisms that underpin human interaction. The recurrent need to co-ordinate understanding amongst multiple participants, across a variety of contexts, highlights the importance of the processes by which people collaborate to detect and recover from misunderstandings using whatever resources are to hand (Sacks, Schegloff, and Jefferson, 1974; Clark 1996, Healey, 2008).

This approach can feed into the design of interactive systems in a number of ways. It moves our understanding of human interaction beyond 'informational bandwith' and 'psychological bandwidth' approaches. It brings into focus co-ordination processes that are often impeded even by tools that are specifically designed to support human communication. This can provide new ideas for design, a diagnostic process for requirements gathering and formative analysis and comparative metrics for assessing how a technology impacts on the success of communication (Healey, Colman and Thirlwell, 2005).