Philip Quinn

Dips and ceilings: understanding and supporting transitions to expertise in user interfaces

Interface guidelines encourage designers to include shortcut mechanisms that enable high levels of expert performance, but prior research has demonstrated that few users switch to using them. To help understand how interfaces can better support a transition to expert performance we develop a framework of the interface and human factors influencing expertise development. We then present a system called Blur that addresses three main problems in promoting the transition: prompting an initial switch to expert techniques, minimising the performance dip arising from the switch, and enabling a high performance ceiling. Blur observes the users interaction with unaltered desktop applications and uses calm notification to support learning and promote awareness of an alternative hot command interface. An empirical study validates Blurs design, showing that users make an early and sustained switch to hot commands, and that doing so improves their performance and satisfaction.

Zoofing!: faster list selections with pressure-zoom-flick-scrolling

The task of list selection is fundamental to many user interfaces, and the traditional scrollbar is a control that does not utilise the rich input features of many mobile devices. We describe the design and evaluation of zoofing---a list selection interface for touch/pen devices that combines pressure-based zooming and flick-based scrolling. While previous flick-based interfaces have performed similarly to traditional scrolling for short distances, and worse for long ones, zoofing outperforms (and is preferred to) traditional scrolling, flick-based scrolling, and OrthoZoom. We analyse experimental logs to understand how pressure was used and discuss directions for further work.

A Cost-Benefit Study of Text Entry Suggestion Interaction

Mobile keyboards often present error corrections and word completions (suggestions) as candidates for anticipated user input. However, these suggestions are not cognitively free: they require users to attend, evaluate, and act upon them. To understand this trade-off between suggestion savings and interaction costs, we conducted a text transcription experiment that controlled interface assertiveness: the tendency for an interface to present itself. Suggestions were either always present (extraverted), never present (introverted), or gated by a probability threshold (ambiverted). Results showed that although increasing the assertiveness of suggestions reduced the number of keyboard actions to enter text and was subjectively preferred, the costs of attending to and using the suggestions impaired average time performance.

The effects of interaction sequencing on user experience and preference

Presents results two studies into the influence of primacy and recency effects in interaction.Shows that recency effects significantly influence preferences.Primacy effects were not shown to influence preferences.Discusses factors influencing recency effects in interaction. Interactive computing tasks are composed of sequences of sub-interactions (or moments), each of which yields a slightly different user experience. Prior work, predominantly from the psychology literature, suggests that the order of these moments can affect peoples retrospective evaluation of experiences. Several kinds of sequencing effects have been examined, including primacy, recency, and peak-end effects. We review previous research on sequencing effects and their potential application in Human-Computer Interaction, of which prior work has found mixed results regarding the influence of interaction sequence on preference possibly because the magnitude of experiential changes caused by interactive tasks are weaker than those studied in psychological experiments. However, sequencing effects are still of great importance to interface design, because when they occur, they have the potential to substantially change user preferences for common interactions. To explore the subtlety of sequencing effects in HCI, we describe two experiments that examined user preferences for series of interactions with different orderings that created positive and negative recency and primacy effects. Positive and negative experiences were created with simulated system assistance that either worked well (aiding the user in drag-and-drop tasks) or worked poorly (hindering the user). In both experiments, the series differed only in the order of positive and negative momentary experiences. Results of Experiment 1 were mixed: the study provided some support for recency effects, but without strong evidence. Experiment 2 modified the experimental method to better accentuate the positive and negative experiences, and produced results showing strong effects of recency, but not of primacy. We discuss reasons for these results, consider overall explanations for the subtle nature of sequencing effects on HCI tasks, and provide an agenda for further research and design lessons regarding recency effects. Overall, we contribute new understanding of a phenomenon that can have a substantial impact on user experience, but that is currently underexplored in HCI.

The design, use, and performance of edge-scrolling techniques

Edge-scrolling techniques automatically scroll the viewport when the user points near its edge, enabling users to reach out-of-view targets during activities such as selection or drag-and-drop. Despite the prevalence of edge-scrolling techniques in desktop interfaces, there is little public research on their behaviour, use or performance. We present a conceptual framework of factors influencing their design. We then analyse 19 different desktop implementations of edge-scrolling by reverse-engineering their behaviour, and demonstrate substantial variance in their design approaches. Results of an interactive survey with 214 participants show that edge-scrolling is widely used and valued, but also that users encounter problems with control and with behavioural inconsistencies. Finally, we report results of a controlled experiment comparing four different implementations of edge-scrolling, which highlight factors from the design space that contribute to substantial differences in performance, overshooting, and perceived workload.

When Bad Feels Good: Assistance Failures and Interface Preferences

User interfaces often attempt to assist users by automating elements of interaction, but these attempts will periodically fail -- impeding user performance. To understand the design implications of correct and incorrect assistance, we conducted an experiment in which subjects selected their preferred of two interfaces (neutral and snapping) for a series of 10 drag-and-drop tasks. With neutral the dragged object moved pixel-by-pixel, and with snapping the object snapped to a grid. Snapping trials were engineered to provide controlled levels of objective performance gains and losses with respect to neutral: gains were achieved when the target was aligned with the grid, and losses were achieved through misalignment -- which required subjects to drop the object, hold a key, and complete the task using a finer movement resolution. Results showed a significant preference for the snapping interface, even when losses impaired performance.

An investigation of dynamic landmarking functions

It is easy for users to lose awareness of their location and orientation when navigating large information spaces. Providing landmarks is one common technique that helps users remain oriented, alleviating the mental workload and reducing the number of redundant interactions. But how many landmarks should be displayed? We conducted an empirical evaluation of several relationships between the number of potential landmarked items in the display and the number of landmarks rendered at any one time, with results strongly favouring a logarithmic relationship.

Loss Aversion and Preferences in Interaction

Many interfaces attempt to assist users by offering suggestions, predicting actions, or correcting user input. Although these attempts may often be beneficial, they will occasionally fail, and prior research from psychology and behavioral economics on loss aversion suggests that such failures may have an overweighted impact on subjective preferences. To better understand the relationship between interface outcomes and subjective preferences, we adapted to interaction a model from behavioral economics describing reference-dependent preferences. Two experiments examined our model’s predictions: both involved word-snapping interface assistance during text selection, with subjects choosing whether they preferred unassisted text selection (no snapping) or assisted text selection (snapping). In Experiment 1, the word-snapping feature could be disabled when it was unhelpful by backtracking the selection, which required progress losses in terms of target characters selected. In Experiment 2, word-snapping could be disabled by pressing a modifier key and waiting for an animation to complete, without need for the loss of target characters. Time and error performance with both experimental methods were comparable. The model predicts an aversion to progress losses in Experiment 1 that should be neutralized in Experiment 2, and the results of both experiments conformed to these predictions. We discuss the implications of the model as a platform for understanding user preferences more broadly, especially when considering interfaces that risk periodically failing to meet user expectations.