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The COVID-19 pandemic led to a sudden shift to virtual work and events, with the last two years enabling an appropriated and rather simulated togetherness - the hybrid mode. As we return to in-person events, it is important to reflect on not only what we learned about technologies and social justice, but about the types of events we desire, and how to re-design them accordingly. This SIG aims to reflect on hybrid events and their execution: scaling them across sectors, communities, and industries; considering trade-offs when choosing technologies; studying best practices and defining measures of "success"for hybrid events; and finally, identifying and charting the wider social, ethical, and legal implications of hybrid formats. This SIG will consolidate these topics by inviting participants to collaboratively reflect on previous hybrid experiences and what can be learned from them.

Excessive sedentariness can impair workers' health and productivity. The move to working from home as a result of the Covid-19 pandemic eliminated many workday opportunities for physical activity. This, coupled with a blurring of boundaries between work and non-work periods, put many at risk of overwork and musculoskeletal issues. We examined how the sudden transition to working from home influenced people's ability to take physically active work breaks. We found that the absence of social norms associated with the presence of colleagues in the work environment left workers uncertain about whether and when it is appropriate to take breaks. The pressure to demonstrate productivity while working asynchronously led to increased sedentariness and decreased break-taking. We propose that online tools that promote flexible social norms around break-taking could empower remote workers to incorporate regular physical activity into their days, without compromising the beneficial aspects of asynchronous working.

Background Burnout for doctors-in-training is increasingly cause for concern. Our objectives were to assess the feasibility, acceptability and impact of a novel intervention to reduce burnout and improve wellbeing. This is the first wellbeing intervention for medical doctors to include strategies for work-life boundary management and digital wellbeing. Methods Twenty-two doctors participated in face-to-face workshops which included group discussion of challenges experienced and strategies to enhance self-care and wellbeing. A pre-post-test mixed-methods evaluation was undertaken. Questionnaire measures were the Oldenburg Burnout Inventory, Warwick-Edinburgh Mental Wellbeing Scale and the boundary control subscale of the Work-Life Indicator (i.e., the degree of perception of control of the boundaries between work and personal life). Paired t-tests examined whether there were statistically significant differences. Eleven doctors also participated in post-intervention semi-structured interviews. Transcripts were analysed using thematic analysis. Results The intervention was well-received, with all trainees finding the workshop useful and saying they would recommend it to others. At baseline most participants had scores indicative of burnout on both the disengagement (82%) and exhaustion (82%) subscales of the Oldenburg Burnout Inventory. One month post-intervention, participants had a statistically significant reduction in burnout (both disengagement and exhaustion) and improvement in boundary control. Wellbeing scores also improved, but differences were not statistically significant. Qualitative analysis indicated participants had welcomed a safe space to discuss stressors and many had implemented digital wellbeing strategies to manage their smartphone technology, and increased self-care such as mindfulness practice and walking in green space. Conclusions The intervention reduced burnout and improved boundary control. We suggest that having protected time for doctors to share personal experiences, adopt digital wellbeing and self-care strategies are effective tools to support doctors’ wellbeing and should be investigated further.

Background Contextual cues play an important role in facilitating behaviour change. They not only support memory but may also help to make the new behaviour automatic through the formation of new routines. However, previous research shows that when people start a new behaviour, they tend to select cues that lack effectiveness for prompting behaviour. Therefore, it is important to understand what influences cue selection, as this can help to identify acceptable cues, which in turn could inform future behaviour change interventions to help people select cues that best fit their context and so ensure continued repetition. Methods We conducted a qualitative study to investigate what cues people select, how, and what influences their decisions. We recruited 39 participants and asked them to take vitamin C tablets daily for 3 weeks and later interviewed them about their experience. Quantitative habit strength and memory measures were taken for descriptive purposes. Results Cue selection was primarily influenced by a desire to minimise effort, e.g. keeping related objects at hand or in a visible place; prior experience with similar behaviours (regardless of whether the cues used in the past were reliable or not); and beliefs about effective approaches. In addition, we found that suboptimal remembering strategies involved reliance on a single cue and loosely defined plans that do not specify cues. Moreover, for many participants, identifying optimal cues required trial and error, as people were rarely able to anticipate in advance what approach would work best for them. Conclusions Future behaviour change interventions that rely on routine behaviours might fruitfully include the provision of educational information regarding what approaches are suboptimal (single factors, vaguely defined plans) and what is most likely to work (combining multiple clearly defined cues). They should also assess people’s existing beliefs about how to best remember specific behaviours as such beliefs can either enhance or inhibit the cues they select. Finally, interventions should account for the fact that early failures to remember are part of the process of developing a reliable remembering strategy and to be expected.

Consumer neurotechnology is arriving en masse, even while algorithms for user state estimation are being actively defned and developed. Indeed, many consumable wearables are now available that try to estimate cognitive changes from wrist data or body movement. But does this data help people? It’s a critical time to ask how users could be informed by wearable neurotechnology, in a way that would be relevant to their needs and serve their personal well-being. The aim of this SIG is to bring together the key HCI communities needed to address this: personal informatics, digital health and wellbeing, neuroergonomics, and neuroethics.

The COVID-19 pandemic led to governments advising citizens to engage in ’social distancing’ measures. These measures included working from home rather than in an office. As a result, many people had to rapidly develop new working strategies. As we look to a new future of work, with many workplaces examining long-term remote or hybrid working set-ups, it is important to understand how people developed remote working strategies and the contextual factors that precluded workers from maximising the potential of technology. Using a two-stage approach including a qualitative survey and a series of in-depth interviews, we investigated the challenges people experienced in creating effective workspaces, getting work done and connecting with others that surfaced during the COVID-19 crisis. We adapt a framework used in healthcare to the work context to make sense of how people cope with this disruption to find a new normal. From this, we identify instances of how people adapt to the new normal, where they avoid adaption and where they anticipate future changes. This gives us an understanding of how people adapt to the changing nature of work in response to the pandemic and offers a lens that may help to understand other future disruptions to work.

Background A range of mobile apps for anxiety have been developed in response to the high prevalence of anxiety disorders. Although the number of publicly available apps for anxiety is increasing, attrition rates among mobile apps are high. These apps must be engaging and relevant to end users to be effective; thus, engagement features and the ability to tailor delivery to the needs of individual users are key. However, our understanding of the functionality of these apps concerning engagement and tailoring features is limited. Objective The aim of this study is to review how cognitive behavioral elements are delivered by anxiety apps and their functionalities to support user engagement and tailoring based on user needs. Methods A systematic search for anxiety apps described as being based on cognitive behavioral therapy (CBT) was conducted on Android and iPhone marketplaces. Apps were included if they mentioned the use of CBT for anxiety-related disorders. We identified 597 apps, of which 36 met the inclusion criteria and were reviewed through direct use. Results Cognitive behavioral apps for anxiety incorporate a variety of functionalities, offer several engagement features, and integrate low-intensity CBT exercises. However, the provision of features to support engagement is highly uneven, and support is provided only for low-intensity CBT treatment. Cognitive behavioral elements combine various modalities to deliver intervention content and support the interactive delivery of these elements. Options for personalization are limited and restricted to goal selection upon beginning use or based on self-monitoring entries. Apps do not appear to provide individualized content to users based on their input. Conclusions Engagement and tailoring features can be significantly expanded in existing apps, which make limited use of social features and clinical support and do not use sophisticated features such as personalization based on sensor data. To guide the evolution of these interventions, further research is needed to explore the effectiveness of different types of engagement features and approaches to tailoring therapeutic content.

A lot of academic and industrial HCI work has focused on making interactions easier and less effortful. As the potential risks of optimising for effortlessness have crystallised in systems designed to take advantage of the way human attention and cognition works, academic researchers and industrial practitioners have wondered whether increasing the ‘friction’ in interactions, making them more effortful might make sense in some contexts. The goal of this special interest group is to provide a forum for researchers and practitioners to discuss and advance the theoretical underpinnings of designed friction, the relation of friction to other design paradigms, and to identify the domains and interaction flows that frictions might best suit. During the SIG, attendees will attempt to prioritise a set of research questions about frictions in HCI.

Background The development of mobile computing technology has enabled the delivery of psychological interventions while people go about their everyday lives. The original visions of the potential of these “ecological momentary interventions” were presented over a decade ago, and the widespread adoption of smartphones in the intervening years has led to a variety of research studies exploring the feasibility of these aspirations. However, there is a dearth of research describing the different dimensions, characteristics, and features of these interventions, as constructed. Objective To provide an overview of the definitions given for “ecological momentary interventions” in the treatment of common mental health disorders, and describe the set of technological and interaction possibilities which have been used in the design of these interventions. Methods A systematic search identified relevant literature published between 2009 and 2020 in the PubMed, PsycInfo, and ACM Guide to the Computing Literature databases. Following screening, data were extracted from eligible articles using a standardized extraction worksheet. Selected articles were then thematically categorized. Results The search identified 583 articles of which 64 met the inclusion criteria. The interventions target a range of mental health problems, with diverse aims, intervention designs and evaluation approaches. The studies employed a variety of features for intervention delivery, but recent research is overwhelmingly comprised of studies based on smartphone apps (30 of 42 papers that described an intervention). Twenty two studies employed sensors for the collection of data in order to provide just-in-time support or predict psychological states. Conclusions With the shift towards smartphone apps, the vision for EMIs has begun to be realised. Recent years have seen increased exploration of the use of sensors and machine learning, but the role of humans in the delivery of EMI is also varied. The variety of capabilities exhibited by EMIs motivates development of a more precise vocabulary for capturing both automatic and human tailoring of these interventions.

Personal informatics technologies support the collection of and reflection on personal data, but enabling people to learn from and act on this data is still an on-going challenge. Sharing and discussing data is one way people can learn from it, but as yet, little research explores how peer discourses around data can shape understandings and promote action. We ran 3 workshops with 5-week follow-ups, giving 18 people the opportunity to swap their data and discuss it with another person. We found that these workshops helped them to recontextualise and to better understand their data, identify new strategies for changing their behaviour and motivated people to commit to changes in the future. These findings have implications for how personal informatics tools could help people identify opportunities for change and feel motivated to try out new strategies.

The collection of participant data ‘in the wild’ is widely employed by Human-Computer Interaction researchers. A variety of methods, including experience sampling, mobile crowdsourcing, and citizen science, rely on repeated participant contributions for data collection. Given this strong reliance on participant data, ensuring that the data is complete, reliable, timely, and accurate is key. Although previous work has made significant progress on ensuring that a sufficient amount of data is collected, the accuracy of human contributions has remained underexposed. In this article we argue for an emerging need for an increased focus on this aspect of human-labelled data. The articles published in this special issue demonstrate how a focus on the accuracy of the collected data has implications on all aspects of a study – ranging from study design to the analysis and reporting of results. We put forward a five-point research agenda in which we outline future opportunities in assessing and improving human accuracy in mobile data collection.

This paper explores how a design fiction can be designed to be used as a pragmatic user-centred design method to generate insights on future technology use. We built HawkEye, a design fiction probe that embodies a future fiction of dementia care. To learn how participants respond to the probe, we employed it with eight participants for three weeks in their own homes as well as evaluating it with six HCI experts in sessions of 1.5h. In addition to presenting the probe in detail, we share insights into the process of building it and discuss the utility of design fiction as a tool to elicit empathetic and rich discussions about potential outcomes of future technologies.

IntroductionIntravenous medication administration has traditionally been regarded as error prone, with high potential for harm. A recent US multisite study revealed few potentially harmful errors despite a high overall error rate. However, there is limited evidence about infusion practices in England and how they relate to prevalence and types of error.ObjectivesTo determine the prevalence, types and severity of errors and discrepancies in infusion administration in English hospitals, and to explore sources of variation, including the contribution of smart pumps.MethodsWe conducted an observational point prevalence study of intravenous infusions in 16 National Health Service hospital trusts. Observers compared each infusion against the medication order and local policy. Deviations were classified as errors or discrepancies based on their potential for patient harm. Contextual issues and reasons for deviations were explored qualitatively during observer debriefs.ResultsData were collected from 1326 patients and 2008 infusions. Errors were observed in 231 infusions (11.5%, 95% CI 10.2% to 13.0%). Discrepancies were observed in 1065 infusions (53.0%, 95% CI 50.8% to 55.2%). Twenty-three errors (1.1% of all infusions) were considered potentially harmful; none were judged likely to prolong hospital stay or result in long-term harm. Types and prevalence of errors and discrepancies varied widely among trusts, as did local policies. Deviations from medication orders and local policies were sometimes made for efficiency or patient need. Smart pumps, as currently implemented, had little effect, with similar error rates observed in infusions delivered with and without a smart pump (10.3% vs 10.8%, p=0.8).ConclusionErrors and discrepancies are relatively common in everyday infusion administrations but most have low potential for patient harm. Better understanding of performance variability to strategically manage risk may be a more helpful tactic than striving to eliminate all deviations.

Background Procedural and documentation deviations relating to intravenous (IV) infusion administration can have important safety consequences. However, research on such deviations is limited. To address this we investigated the prevalence of procedural and documentation deviations in IV infusion administration and explored variability in policy and practice across different hospital trusts. Methods We conducted a mixed methods study. This involved observations of deviations from local policy including quantitative and qualitative data, and focus groups with clinical staff to explore the causes and contexts of deviations. The observations were conducted across five clinical areas (general medicine, general surgery, critical care, paediatrics and oncology day care) in 16 National Health Service (NHS) trusts in England. All infusions being administered at the time of data collection were included. Deviation rates for procedural and documentation requirements were compared between trusts. Local data collectors and other relevant stakeholders attended focus groups at each trust. Policy details and reasons for deviations were discussed. Results At least one procedural or documentation deviation was observed in 961 of 2008 IV infusions (deviation rate 47.9%; 95% confidence interval 45.5–49.8%). Deviation rates at individual trusts ranged from 9.9 to 100% of infusions, with considerable variation in the prevalence of different types of deviation. Focus groups revealed lack of policy awareness, ambiguous policies, safety and practicality concerns, different organisational priorities, and wide variation in policies and practice relating to prescribing and administration of IV flushes and double-checking. Conclusions Deviation rates and procedural and documentation requirements varied considerably between hospital trusts. Our findings reveal areas where local policy and practice do not align. Some policies may be impractical and lack utility. We suggest clearer evidence-based standardisation and local procedures that are contextually practical to address these issues. Electronic supplementary material The online version of this article (10.1186/s12913-018-3025-x) contains supplementary material, which is available to authorized users.

When running experiments within the field of Human Computer Interaction (HCI) it is common practice to ask participants to come to a specified lab location, and reimburse them monetarily for their time and travel costs. This, however, is not the only means by which to encourage participation in scientific study. Citizen science projects, which encourage the public to become involved in scientific research, have had great success in getting people to act as sensors to collect data or to volunteer their idling computer or brain power to classify large data sets across a broad range of fields including biology, cosmology and physical and environmental science. This is often done without the expectation of payment. Additionally, data collection need not be done on behalf of an external researcher; the Quantified Self (QS) movement allows people to reflect on data they have collected about themselves. This too, then, is a form of non-reimbursed data collection. Here we investigate whether citizen HCI scientists and those interested in personal data produce reliable results compared to participants in more traditional lab-based studies. Through six studies, we explore how participation rates and data quality are affected by recruiting participants without monetary reimbursement: either by providing participants with data about themselves as reward (a QS approach), or by simply requesting help with no extrinsic reward (as in citizen science projects). We show that people are indeed willing to take part in online HCI research in the absence of extrinsic monetary reward, and that the data generated by participants who take part for selfless reasons, rather than for monetary reward, can be as high quality as data gathered in the lab and in addition may be of higher quality than data generated by participants given monetary reimbursement online. This suggests that large HCI experiments could be run online in the future, without having to incur the equally large reimbursement costs alongside the possibility of running experiments in environments outside of the lab.

Human error can have potentially devastating consequences in contexts such as healthcare, but there is a rarely a simple dichotomy between errors and correct behaviour. Furthermore, there has been little consideration of how the activities of users (erroneous and otherwise) relate to the conceptual fit between user and device, despite the fact that healthcare technologies are becoming increasingly prevalent and complex. In this article, we present a study in which nurses’ conceptions of infusion device practice were elicited to identify misfits. By focusing on key concepts that users work with when setting up infusions and the extent to which the system supports them, our analysis highlights how actions are influenced by the different resources available to users including: the device itself; supporting artefacts; the conceptual understanding of the user; and the community of practice the user is part of. The findings reveal the ways in which users are resourceful in their day-to-day activities and also suggest potential vulnerabilities within the wider system that could threaten patient safety. Our approach is able to make previously under-explored aspects of practice visible, thus enabling insight into how users act and why.

We need collective action to tackle global warming. However, research shows that people switch off from being concerned about the environment because they are often too busy, or fail to appreciate their ability to make a difference. An alternative approach is to run campaigns that are able to engage large numbers of people and engender feelings of concern and empowerment. This could then kick-start a range of pro-environmental habits. We present the development and evaluation of a playful installation that aimed to attract attention, and stimulate discussion about environmental issues amongst university staff and students. The first prototype was shown to successfully attract people to engage and interact with the installation. The second prototype was deployed in-the-wild, over the course of a week. We evaluated the extent to which the installation was successful at attracting attention, and in encouraging people to interact with it, to reflect on their habits and to discuss environmental issues with others. We found the Green Ball Kiosk was a fun way to raise discussions about green issues, to encourage the adoption of new environmentally friendly behaviours and to prompt people to maintain existing ones. We suggest that interactive installations such as this can be effective at promoting awareness and generating a "social buzz" about environmental topics when exhibited as a temporary installation.

Habit formation apps are intended to help instigate and maintain new behaviors. Prior research has established that these apps mostly do not support the theoretical 'habit' construct defined in psychology, yet are generally popular and well reviewed in app stores. This apparent mismatch between theory and 'in-the-wild' usage has not been investigated to date. Through an in-depth qualitative study of a popular application Lift, this research establishes that common techniques such as reminders and streaks are effective at supporting repetition of new behaviors, but at the same time create a dependency: on-going app use is often required to achieve lasting change. This dependency introduces fragility in users' attempts to change their behavior, as they often abandon the app and subsequently disengage with their new behaviors.

Objective Forgetfulness is one of the main reasons of unintentional medication non-adherence. Adherence technologies that help people remember to take their medications on time often do not take into account the context of people’s everyday lives. Existing evidence that highlights the effectiveness of remembering strategies that rely on contextual cues is largely based on research with older adults, and thus it is not clear whether it can be generalized to other populations or used to inform the design of wider adherence technologies that support medication self-management. Understanding how younger populations currently remember medications can inform the design of future adherence technologies that take advantage of existing contextual cues to support remembering. Methods We conducted three surveys with a total of over a thousand participants to investigate remembering strategies used by different populations: women who take oral contraception, parents and carers who give antibiotics to their children, and older adults who take medications for chronic conditions. Results Regardless of the population or the type of regimen, relying on contextual cues—routine events, locations, and meaningful objects—is a common and often effective strategy; combinations of two or more types of cues are more effective than relying on a single cue. Conclusions To effectively support remembering, adherence technologies should help users recognize contextual cues they already have at their disposal and reinforce relevant cues available in their environment. We show that, given the latest developments in technology, such support is already feasible.

Game developers have to ensure their games are appealing to, and playable by, a range of people. However, although there has been interest in the game-play experience, we know little about how learning relates to player involvement. This is despite challenge being an integral part of game-play, providing players with potential opportunities to learn. This article reports on a multiple case-study approach that explored how learning and involvement come together in practice. Participants consisted of a mix of gamers and casual players. Data included interviews, multiple observations of game-play, postplay cued interviews, and diary entries. A set of theoretical claims representing suggested relationships between involvement and learning were developed on the basis of previous literature; these were then assessed through a critical examination of the data set. The resulting theory is presented as 14 refined claims that relate to micro and macro involvement; breakdowns and breakthroughs in action, understanding, and involvement; progress; and agency, meaning and compelling game-play. The claims emphasize how players experience learning via breakthroughs in understanding, where involvement is increased when the player feels responsible for progress. Supporting the relationship between learning and involvement is important for ensuring the success of commercial and educational games.

Wearable computers are expected to become the next big thing but popular press is divided on whether they will be successful. In this paper we review the existing literature on one type of wearable -- smartwatches -- and extend their definition, in addition to highlighting the need to understand users' everyday appropriation of these technologies. We present initial findings from an on going interview study with ten early adopters that is, to the best of our knowledge, the first to investigate why and how people use smartwatches in real life. We describe everyday use of smartwatches, highlight the added value seen by users, and identify the limitations to mass adoption as expressed by current users.

Games are normally considered to be "fun", though recently there is growing interest in how gameplay can promote empathy and encourage reflection through "serious experience". However, when looking beyond enjoyment, it is not clear how to actually evaluate serious experience. We present an evaluation of four games that were submitted to a student game design competition; the competition challenged teams to design a game that inspired curiosity around human error and blame culture within the context of healthcare. The entries were judged by a panel of six experts and subjected to a round of play testing by twelve participants. Methods included gameplay observation, questionnaires, post-play interviews and follow-up email questions. We discuss the utility of these methods, with particular emphasis on how they enabled a consideration of the immediate and longer term impact of serious experience on players.

Technology not only brings benefits such as flexible working practices but can also have negative stressful consequences such as increasing email overload and the blurring of work-home boundaries. We report on an exploratory study that extends the current understanding of email usage by investigating how different professions at a university manage work and personal emails using different devices and how this impacts their work-home boundary management. Our findings lead us to identify two user groups: those with permeable boundaries (primarily academics) and those who have more rigid ones (primarily professional services employees) and that there are differences in when, where and how they manage their work and personal emails. In particular we find that some participants use micro-boundary strategies to manage transitions between work and personal life. Based on these novel findings we propose improvements of email software design to facilitate effective email, work-home boundary management, and support micro-boundary practices.

Challenge is considered to be one of the key components of game-play, where game designers face the tricky task of getting the balance right so that game-play is neither too easy nor too difficult. Through attempting in-game challenges, players experience cycles of breakdown and breakthrough, where breakthroughs involve moments of insight in which learning occurs. However, little attention has been given to how players actually overcome challenges to progress during game-play. Across two studies, we explore the ways in which players attempt to achieve breakthroughs in relation to single-player and co-located multiplayer games. We identified a number of strategies that are used by players, which illustrate how learning occurs during play. For instance, while "Experiment" involves forming an informal hypothesis, "Trial & error" occurs when the player tries to find out what, if anything, will happen when they carry out an action. These strategies are considered in relation to supporting player progress and engaging game-play when designing commercial and educational games.

Recent advances in mobile technology have had many positive effects on the ways in which people can combine work and home life. For example, having remote access enables people to work from home, or work flexible hours that fit around caring responsibilities. They also support communication with colleagues and family members, and enable digital hobbies. However, the resulting 'always-online' culture can undermine work-home boundaries and cause stress to those who feel under pressure to respond immediately to digital notifications. This workshop will explore how a socio-technical perspective, which views boundaries as being constituted by everyday socio-technical practices, can inform the design of technologies that help maintain boundaries between work and home life.

Within the CHI community there has been sustained interest in interruptions and multitasking behaviour. Research in the area falls into two broad categories: the micro world of perception and cognition; and the macro world of organisations, systems and long-term planning. Although both kinds of research have generated insights into behaviour, the data generated by the two kinds of research have been effectively incommensurable. Designing safer and more efficient interactions in interrupted and multitasking environments requires that researchers in the area attempt to bridge the gap between these worlds. This SIG aims to stimulate discussion of the tools and methods we need as a community in order to further our understanding of interruptions and multitasking.

Information behavior (IB) research involves examining how people look for and use information, often with the sole purpose of gaining insights into the behavior displayed. However, it is also possible to examine IB with the purpose of using the insights gained to design new tools or improve the design of existing tools to support information seeking and use. This approach is advocated by David Ellis who, over two decades ago, presented a model of information seeking behaviors and made suggestions for how electronic tools might be designed to support these behaviors. Ellis also recognized that IBs might be used as the basis for evaluating as well as designing electronic resources. In this article, we present the IB evaluation methods. These two novel methods, based on an extension of Ellis's model, use the empirically observed IBs of lawyers as a framework for structuring user-centered evaluations of the functionality and usability of electronic resources. In this article, we present the IB methods and illustrate their use through the discussion of two examples. We also discuss benefits and limitations, grounded in specific features of the methods.

Overview Over the last 30 years or so, computers have evolved rapidly into powerful and complex systems that underlie virtually every aspect of modern life and, if current trends continue, it is likely that they will be even more pervasive in the future. With the increased embeddedness of computer technology into our society, the characteristics of users have diversified rapidly from a situation where the average user was often a white, middle-aged male with a particular educational and socio-economic background to one in which users of all ages, sexes, social and ethnic backgrounds, levels of education and computer knowledge are interacting with complex interfaces to computer systems. The range and complexity of people's interactions with computers have also grown rapidly over recent years, so that we now do many things via a computer (e.g., managing a bank account, paying household bills, shopping, organising a holiday) that would have been done in the high street just a few years ago. These rapid developments present significant challenges to interface designers. As the range and sophistication of computer-based tasks have increased so have the interfaces that people are required to use, and so the issue of how people perceive and process complex displays of information when carrying out tasks becomes ever more important. In order to understand these processes more closely, analysts have utilised the theories and methods of cognitive psychology – the study of human perception and information processing – to construct cognitive models : specifications of the mental representations, operations and problem-solving strategies that occur during the execution of computer-based tasks.