Modelling Activity Switching

Abstract

How do people decide what to do when? Why is it that people often given up one task to begin another, only later to resume the first? In this talk I will briefly review some experiments on how people allocate their time adaptively across multiple texts and multiple tasks. I will then focus on how strategies for adaptive time allocation can be modelled. The model I develop derives from heuristic accounts of animal foraging behaviour. In the course of the talk I will review recent arguments by Roberts and Pashler to suggest that the standard criterion of fitting models to experimental data is too lax, even though the model I am considering has only two free parameters and even though it’s output is being fitted simultaneously to several quantitative dependent variables. Focussing instead on whether the model can predict the data leads to a more complicated but more interesting model. This model suggests that people orient to their activities in terms of either goal accomplishment or currency accumulation, and may switch between these orientations. To understand human activities and in particular the decisions that people make to continue or switch activities, we need to understand not only goal-subgoal hierarchies but also moment-by-moment gain curves.

Brief Biography. Stephen Payne is Professor of Interactive Systems Design in Manchester Business School. Previously he has been a lecturer in psychology and computing at the University of Lancaster, a research scientist in IBM T.J. Watson Research Centre, User Interface Institute, and a Professor of Psychology at Cardiff University (1991-2005). Stephen has consulted for several commercial organizations, including Xerox PARC. He has served on the editorial board of 4 major HCI journals (currently on the boards of Behaviour and Information Technology and Human-Computer Interaction). He is papers co-chair for the ACM CHI conference in 2007. Between 2000 and 2006 he was a member of the management committee for the Joint Research Councils’ PACCIT (People at the Centre of Communications and Information Technologies) programme. Stephen continues to be on the EPSRC computing college and to serve occasionally as a chair and committee member for EPSRC panels. He is also a member of BPS, EPS and ACM. Stephen Payne is interested in many aspects of the psychology of human-computer interaction, and more generally in the psychology of learning and performance. One major strand of work has been on users’ mental models. He is currently interested in user interactions with on-line information, multi-tasking, and social effects of communications technologies.