Trying to find a balance: social support vs privacy during weight-management Abstract This work investigates current attitudes towards the involvement of others during weight-management (WM). It is prompted by ongoing attempts to harness social influence within system design so as to promote an increase in physical activity, with obesity often cited as a motivation. Through in-depth interviews, we have found that the complexities of sharing information in existing WM practices are not reflected in current system designs. Initial findings highlight the design tension raised by the need for social support as well as privacy. Preliminary design concepts of selective disclosure and relative comparison are offered to developers of sociocentric systems supporting WM- specific behavioural change. Keywords social support, health, behavioural change, obesity ACM Classification Keywords H.5.2 [User Interfaces]: User-centered design; J.3 [Life and Medical Sciences]: Health Introduction Addressing the problem of overweight and obesity is often identified as a potential benefit of the many recently developed physical activity monitoring systems. Early efforts to integrate social influence into these systems’ designs have so far had variable success in motivating an increase in activity, especially when compared to single-user counterparts. For example, while Consolvo et al [3] found that integrating social influence into the design of a physical activity monitor motivated a greater change in activity levels, others have found no significant effect [5, 8]. Despite the acknowledged influence that social support has on health [1] and behavioural change [4], it is not yet clear how best to harness social support within health-related behaviour management systems (HBMS) aimed towards helping people who are trying to lose or maintain weight. Current attempts to socialise activity monitoring systems have so far been relatively static: Copyright is held by the author/owner(s). CHI 2008, April 5 – April 10, 2008, Florence, Italy ACM 1-xxxxxxxxxxxxxxxxxx. Julie Maitland Dept of Computer Science University of Glasgow jules@dcs.gla.ac.uk Matthew Chalmers Dept of Computer Science University of Glasgow matthew@dcs.gla.ac.uk