Interactions on the Move: Understanding Strategy Adaptation in Dynamic Multitask Environments

With computers having been untethered from the relative safety of the desktop there comes a growing need to understand the implications of interface design for how people interact with information communication technologies on the move. Nowhere is this need greater than in situations where people interact with technology systems in safety critical environments, such as when driving a car. In many such multitasking situations, people can often only actively attend to a single task at a time because of competition for limited attentional resources between tasks. At the same time many of our interactions with technology systems tend to be shaped by prior knowledge of how to perform routine procedural tasks on that device. It is therefore not clear to what extent decisions about how to interleave attention between tasks is constrained by this prior experience of using a device. If people do not adjust their interaction style to the demands of the task environment this could be potentially dangerous. There are a number of accounts for how people might choose to interleave resources between tasks. One possibility is that task interleaving is constrained to natural break points in the execution of a task. For example, consider a driver dialling a telephone number. In this situation, the driver might choose to enter only the area-code part of the telephone number (or indeed select the 'Address Book' option from an interactive menu), and then return attention to monitoring the road ahead before completing another small step of the secondary task. In this way, natural break points in the representational structure of the task act as a cue to switch from one task to another. Alternatively, drivers might simply set a limit (or threshold) on the amount of time they are prepared to look away from the road and complete as much of the secondary task as possible within this window of opportunity. A further possibility is that task interleaving strategies are selected that optimally trade the time required to complete the secondary task against any additional time taken to switch to the primary driving task in order to maintain a stable lane position while dialling.This research proposal sets out a series of planned experiments that will be conducted to investigate how people allocate resources between multiple ongoing tasks while driving. Experiments will be conducted in a desktop driving simulator using specially instrumented devices for secondary task interactions. The experiments will be informed by various computational accounts of how people might choose to schedule resources between tasks, and will investigate the consequences of manipulating the representational structure of secondary in-car tasks and features of the functional task environment on performance and strategy adaptation. In tandem with the running of these experiments, modelling will be conducted that will implement these various computational accounts of human multitask scheduling, deriving key quantitative performance predictions for each. This modelling work will be aimed at determining which account provides the best characterisation of human behaviour, and in doing so, will set the foundation for future work directed towards developing design tools for rapidly predicting the efficiency of design alternatives for supporting the multitasking user on the move.This programme of research will lead to greater understanding of human behaviour in complex multitasking environments and the knowledge gained will be of potential value to the designers of mobile interactive systems. The empirical data will give insights into how interfaces for in-car devices might be redesigned to support users' needs in a safe and efficient manner. These conclusions will be of value for understanding behaviour in a variety of contexts where people must allocate attention between multiple concurrent task while monitoring safety critical systems.