Case studies of mental models in home heat control: searching for feedback, valve, timer and switch theories

An intergroup case study was undertaken to determine if: 1) There exist distinct mental models of home heating function, that differ significantly from the actual functioning of UK heating systems; and 2) Mental models of thermostat function can be categorized according to Kempton’s (1986) valve and feedback shared theories, and others from the literature. Distinct, inaccurate mental models of the heating system, as well as thermostat devices in isolation, were described. It was possible to categorise thermostat models by Kempton’s (1986) feedback shared theory, but other theories proved ambiguous. Alternate control devices could be categorized by Timer (Norman, 2002) and Switch (Peffer et al., 2011) theories. The need to consider the mental models of the heating system in terms of an integrated set of control devices, and to consider user’s goals and expectations of the system benefit, was highlighted. The value of discovering shared theories, and understanding user mental models, of home heating, are discussed with reference to their present day relevance for reducing energy consumption

Modelling Automation–Human Driver Handovers Using Operator Event Sequence Diagrams

This research aims to show the effectiveness of Operator Event Sequence Diagrams (OESDs) in the normative modelling of vehicle automation to human drivers’ handovers and validate the models with observations from a study in a driving simulator. The handover of control from automation to human operators has proved problematic, and in the most extreme circumstances catastrophic. This is currently a topic of much concern in the design of automated vehicles. OESDs were used to inform the design of the interaction, which was then tested in a driving simulator. This test provided, for the first time, the opportunity to validate OESDs with data gathered from videoing the handover processes. The findings show that the normative predictions of driver activity determined during the handover from vehicle automation in a driving simulator performed well, and similar to other Human Factors methods. It is concluded that OESDs provided a useful method for the human-centred automation design and, as the predictive validity shows, can continue to be used with some confidence. The research in this paper has shown that OESDs can be used to anticipate normative behaviour of drivers engaged in handover activities with vehicle automation in a driving simulator. Therefore, OESDs offer a useful modelling tool for the Human Factors profession and could be applied to a wide range of applications and domains.</jats:p

Case studies of mental models in home heat control: Searching for feedback, valve, timer and switch theories

An intergroup case study was undertaken to determine if: 1) There exist distinct mental models of home heating function, that differ significantly from the actual functioning of UK heating systems; and 2) Mental models of thermostat function can be categorized according to Kempton’s (1986) valve and feedback shared theories, and others from the literature. Distinct, inaccurate mental models of the heating system, as well as thermostat devices in isolation, were described. It was possible to categorise thermostat models by Kempton’s (1986) feedback shared theory, but other theories proved ambiguous. Alternate control devices could be categorized by Timer (Norman, 2002) and Switch (Peffer et al., 2011) theories. The need to consider the mental models of the heating system in terms of an integrated set of control devices, and to consider user’s goals and expectations of the system benefit, was highlighted. The value of discovering shared theories, and understanding user mental models, of home heating, are discussed with reference to their present day relevance for reducing energy consumption

Using the notion of mental models in design to encourage optimal behaviour in home heating use

Introduction: Understanding how to influence householder’s energy consuming behaviour, could inform far reaching strategies to combat climate change. A Mental Model (MM) approach to design, to encourage optimal behaviour was explored. Challenges exist in accessing, describing and analysing user MMs and associated behaviour.Method: A method that considered bias in interpretation was developed, involving a structured interview, concept maps and graphical self-reported behaviour. Using this method, 6 householders in matched accommodation, over winter 2011/2012, participated in a home heating case study. Thermostat set point data was also collected from participant’s households. A home heating expert was interviewed using the same method, for comparison.Results and discussion: Key variations in MMs of home heating were found. The differences in user MMs from each other, and an expert, were insightful in explaining non-optimal home heating operation. These suggest design solutions that could promote or compensate for user mental models to influence energy consumption

Mental models: understanding domestic energy systems and user behaviour

Energy consumption due to domestic heating is a major contributor to climate change. Kempton (1986) proposed that ‘Mental Models’ of thermostat controls could be linked to energy wasting behaviour. Mental models can be thought of as ‘pictures in the mind’ that help users understand and operate systems. This thesis explored if changes to the heating interface design could influence the mental model held, to promote appropriate behaviour with heating controls.Consideration of bias is essential when undertaking research into mental models. The ‘Tree-Rings’ framework was developed to address this, resulting in the creation of the ‘Quick Association Check’ (QuACK); a method for capturing and analysing mental models and behaviour related to heating controls. QuACk was initially applied to a case study of 6 householders. This revealed a ‘systems level’ approach was necessary to understand behaviour strategies, in contrast to Kempton’s single device focus.Differences in mental models explained differences in self-reported behaviour. Misunderstandings of how heating controls worked together and the influence of thermodynamics on boiler activation, explained variations in consumption between households. Norman’s (1983) ‘7 stages of activity’ was used to produce a design specification for a ‘control panel’ style heating interface. This focused on correcting key misunderstandings in householders’ mental models, that hindered appropriate behaviour. A home heating simulation was developed to allow the design to be compared with a typical presentation of heating controls. The new interface significantly improved the appropriateness of users’ mental models at the system and device levels. More appropriate behaviour was found with specific controls and the duration of goal achievement was significantly increased. These findings have implications for strategies to reduce domestic consumption through behaviour change, and provide insights that can be used to improve the design of home heating interfaces<br/

The Quick Association Check (QuACk): a resource-light, ‘bias robust’ method for exploring the relationship between mental models and behaviour patterns with home heating systems

Easy-to-apply methods, allowing exploration of users’ mental models and behaviour with devices, are scarce. Existing methods can be resource-intensive, or fail to mitigate bias, threatening output validity. This paper describes the development of the Quick Association Check (QuACk) and highlights the methodological improvements following qualitative iterations. QuACk is a semi-structured interview with paper-based activities and templates, constructed with consideration of bias from the outset, offering a quick, resource light method to explore association between householders’ heating mental models and behaviour patterns. Through qualitative iterations of the method, key revisions identified the need to: (1) strongly emphasise positioning, guidance and structure; (2) re-categorise existing ‘shared models’ in the literature as ‘device generic’, rather than ‘thermostat specific’ during data interpretation and (3) consider an association at the system level, rather than the device level. The potential to apply the findings of QuACk to energy-reducing strategies is discussed, and generalisability considered

Do medical students with a disability experience adverse educational outcomes on UK medical courses?

Background International data demonstrate that medical students with disabilities experience differential awarding. One cross-sectional study finds lower graduation rates and scores in written exams, with no impact on clinical exams. Disabled students graduated with lower decile scores. This quantitative, retrospective, longitudinal study explored the impact of disability on exam performance, course performance and course discontinuation. Method Anonymised data were obtained for 1743 students on a UK graduate medical programme from 2011 to present. Statistical tests, including t-tests and one-way ANOVA were conducted for main effects of demographic variables on exam results and categorical outcomes. Regression models established the effects of variables and sub-categories of variables on results and categorical outcomes. Results Significant main effects of disability on exam scores were identified, as well as failure probability. Regressions showed significant differences in outcomes between different types of disability, with mental health conditions predicting course discontinuation. A significant amplifying effect was found for BAME students with disability. Conclusion Disability had a significant negative impact on all course outcomes, illustrating inequity in medical training and an area of focus for curriculum development. Intersectional data identified a key disadvantaged subgroup of medical student

Investigating the effect of train occupancy information

Reducing the negative effects of train crowding could improve passengers’ travel experience by moderating stress, and enhancing comfort. Although crowding seems unavoidable due to an increase in the number of passengers, it should be handled effectively. Thus, this study aims to help improve overcrowding issues by exploring the effects of occupancy information developed to encourage passenger behaviour change. This will be achieved by identifying factors affecting their decision making regarding selection of carriage, and measuring their intentions to board a less occupied carriage as a response to occupancy information. An online questionnaire was conducted, and 119 rail users participated in the study. The majority of them reported that the information was helpful (91%), and they were willing to move to board an emptier carriage if they had been informed (93%). Additionally, the occupancy information was a significant predictor of a passenger’s intention to move to board less busy carriages for proposed travel scenarios as verified in ordinal logistic regression models

The usability of F1 interfaces

The complexity of driver’s interfaces in Formula One has increased dramatically in the last 25 years. This has resulted in criticisms from drivers and has been blamed in several cases for accidents due to distraction or mode error. Technologies adopted by Formula One to improve performance have led to additional interface requirements and the resultant interface design adaptations. Specific regulatory changes have also been identified as significant factors in dictating the driver’s interface workload. Research is currently ongoing into the empirical analysis of the interfaces. Even minor design decisions can have a large effect on usability. These findings have confirmed the challenges facing human factors engineers tasked with designing interfaces featuring large amounts of functionality for use within high cognitive workload conditions

When energy saving advice leads to more, rather than less, consumption

Energy saving technology that relies on behaviour change fails to deliver on its promise. Energy saving advice also has limited effect. This paper examines and reveals how technology and energy saving advice interacts with householders’ thought processes to influence energy consumption. A case study of three households that held a ‘Feedback’ mental model of the home heating thermostat, as defined by Kempton [1986. ‘Two Theories of Home Heat Control’. Cognitive Science 10 (1): 75–90], was undertaken to understand the driver behind differences in their home heating strategies, and the effect on energy consumption. Analysis was undertaken from five different data sources comprising: (1) boiler on durations, (2) thermostat set point adjustments, (3) self-reported strategies with home heating controls, (4) user mental model descriptions of the home heating system, and (5) Interview transcripts. The authors found that differences in user mental models of home heating at the system level explained differences in the strategies chosen at the control device level. Differences in boiler on periods were found to relate to limitations of the ‘Feedback’ mental model; that is, the model fails to consider the effect of the movement of warm air within the home and the impact of internal/external temperature differentials on heat loss rates. The authors argue that technology and advice should be tailored to the thought processes adopted by householders in order to promote behaviour that would realise intended energy savings