Modelling rational user behaviour as games between an angel and a demon

Formal models of rational user behavior are essential for user-centered reasoning about interactive systems. At an abstract level, planned behavior and reactive behavior are two important aspects of the rational behavior of users for which existing cognitive modeling approaches are too detailed. In this paper, we propose a novel treatment of these aspects within our formal framework of cognitively plausible behavior. We develop an abstract, formal model of rational behavior as a game between two opponents. Intuitively, an Angel abstractly represents the planning aspects, whereas a Demon represents the reactive aspects of user behavior. The formalization is carried out within the MOCHA framework and is illustrated by simple examples of interactive tasks

Verification-guided modelling of salience and cognitive load

Well-designed interfaces use procedural and sensory cues to increase the cognitive salience of appropriate actions. However, empirical studies suggest that cognitive load can influence the strength of those cues. We formalise the relationship between salience and cognitive load revealed by empirical data. We add these rules to our abstract cognitive architecture, based on higher-order logic and developed for the formal verification of usability properties. The interface of a fire engine dispatch task from the empirical studies is then formally modelled and verified. The outcomes of this verification and their comparison with the empirical data provide a way of assessing our salience and load rules. They also guide further iterative refinements of these rules. Furthermore, the juxtaposition of the outcomes of formal analysis and empirical studies suggests new experimental hypotheses, thus providing input to researchers in cognitive science

Interaction design issues for car navigation systems

We describe a study on the interaction design of in-car navigation systems. It focused on a commercial product. Critical incident analysis was performed based on natural use of the system by a usability analyst. A cognitive walkthrough was then performed based on actual scenarios from the natural use. This is a non-classic application of cognitive walkthrough. It allowed anecdotal critical incidents to be theoretically grounded. We draw conclusions about the interaction design of car navigation systems

Using FRAM beyond safety: A case study to explore how sociotechnical systems can flourish or stall

FRAM (Functional Resonance Analysis Method) is a relatively new method that has been proposed to explore how functional variability can escalate into unexpected, and often unwanted, events. It has been used for accident analyses and risk assessments in safety. We apply (and slightly modify) FRAM, to analyse how functions are configured to create systems that excel. Our case study focuses on how functions in human factors project work positively resonate to improve the delivery of value. From interviews with 22 practitioners we derived 29 functions and 6 subsystems showing how functions are coupled. Practitioners validated this model through respondent validation. Our case study evaluates the applicability and usability of FRAM. It shows how we adapted the method to make it more usable. It shows that FRAM can be used to examine positive and negative resonance in systems, to investigate how complex sociotechnical systems can flourish or stall.This work was supported by the UK Engineering and Physical Sciences Research Council under Grant [GR/S67494/01], [GR/S67500/01] and [EP/G059063/1

Exploring organisational competences in Human Factors and UX project work: Managing careers, project tactics and organisational strategy

Organisational competence in Human Factors and UX (user experience) has not been looked at before despite its relevance to project success. We define organisational competence as the collective competence of the individuals, bringing together their complementary abilities to deliver an outcome that is typically more than the sum of its parts. Twenty-two UX and Human Factors practitioners were interviewed about their project work in two contrasting domains: web design and safety-critical systems to explore organisational competences. Through doing a FRAM analysis 29 functions and six main areas of competences were identified: the central project process; the process of learning about the problem; maintaining and developing client relations; staff development; evolving practices; and the management of documentation for audit and quality control. These dynamic and situated competences form a web of interactions. Managing competences is essential for project success. Implications for managing careers, project tactics and organisational strategy are discussed