highlights•Examines the influence of audio effects on perceived duration of interactive tasks.•Increasing-tempo beeps shortens perceived duration of interactive tasks.•Examines the influence of ...interface attentional demand on perceived duration.•Perceived duration is reduced with higher interface attentional demand.•Shows the effect of prospective versus retrospective methodology on time perception.
Users often need to wait for computer systems to perform some task, and these delays can have adverse effects on user experience. One way to ease the problem is to use stimuli that reduce perceived wait time. We conducted a study investigating how audio effects influence users perceived wait time across three interaction contexts — passive waiting with no visual feedback, passive waiting with visual feedback (watching a progress bar), and playing a simple game. We tested three different types of audio effects: a series of beeps that changed in tempo (increasing, decreasing, or constant tempo), a series of beeps that changed in pitch (rising, falling, or constant), and variants of a polyphonic Shepard tone (an auditory illusion that seems to rise or fall in pitch continuously); a silent condition was included as a baseline. In the first stage of the experiment, participants experienced a 10.1 second wait period, indicated with a progress bar, accompanied by an audio effect. They then estimated the duration of the wait, making a retrospective assessment of the experience. In the second stage, participants experienced a series of conditions that compared two 10.1 second wait periods accompanied by different effects and selected which one (if either) felt longer, making a prospective assessment (i.e., they were aware that the two durations would be compared before experiencing them). Results from the first stage showed that perceived duration differed across different audio conditions. Results from the second stage supported prior findings that increasing-tempo beeps can shorten perceived duration and generalised the findings to interactions that include visual feedback (e.g., watching a progress bar) and those involving direct interaction (e.g., playing a simple game).
•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 people's 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.
Supporting awareness of others is an idea that holds promise forimproving the usability of real-time distributed groupware.However, there is little principled information available aboutawareness ...that can be used by groupware designers. In thisarticle, we develop a descriptive theory of awareness for thepurpose of aiding groupware design, focusing on one kind of groupawareness called workspace awareness. We focus on how smallgroups perform generation and execution tasks in medium-sizedshared workspaces – tasks where group members frequently shiftbetween individual and shared activities during the work session.We have built a three-part framework that examines the concept ofworkspace awareness and that helps designers understand theconcept for purposes of designing awareness support in groupware.The framework sets out elements of knowledge that make upworkspace awareness, perceptual mechanisms used to maintainawareness, and the ways that people use workspace awareness incollaboration. The framework also organizes previous research onawareness and extends it to provide designers with a vocabularyand a set of ground rules for analysing work situations, forcomparing awareness devices, and for explaining evaluationresults. The basic structure of the theory can be used todescribe other kinds of awareness that are important to theusability of groupware.
Whereas a rightward bump is more likely than a leftward bump when walking through a doorway, investigations into potential similar asymmetries for drivers are limited. The research presented here ...aims to determine the influence of innate lateral spatial biases when driving. Data from the Strategic Highway Research Program Naturalistic Driving Study (SHRP 2 NDS) and a driving simulation were used to address our research questions. Data points from SHRP 2 were aggregated within relevant variables (e.g., left/right obstacles). In the simulation, participants drove in ways that were consistent with their everyday driving in urban and rural environments. Collision frequency, collision severity and average lateral lane position were analyzed with rightward biases throughout both analyzes. SHRP 2 data indicated greater likelihoods of collisions when vehicles crossed the right line/edge of the road and when making a right turn. There were more collisions with obstacles on the right side, which were also more severe, and greater rightward lane deviations in the driving simulation, contrasted with more severe collisions on the left side in SHRP 2 data, possibly because of the presence of traffic. These findings suggest that previously observed rightward biases in distant space when walking are also present when driving.
Phenotyping is considered a significant bottleneck impeding fast and efficient crop improvement. Similar to many crops,
, an internationally important oilseed crop, suffers from low genetic ...diversity, and will require exploitation of diverse genetic resources to develop locally adapted, high yielding and stress resistant cultivars. A pilot study was completed to assess the feasibility of using indoor high-throughput phenotyping (HTP), semi-automated image processing, and machine learning to capture the phenotypic diversity of agronomically important traits in a diverse
breeding population, SKBnNAM, introduced here for the first time. The experiment comprised 50 spring-type
lines, grown and phenotyped in six replicates under two treatment conditions (control and drought) over 38 days in a LemnaTec Scanalyzer 3D facility. Growth traits including plant height, width, projected leaf area, and estimated biovolume were extracted and derived through processing of RGB and NIR images. Anthesis was automatically and accurately scored (97% accuracy) and the number of flowers per plant and day was approximated alongside relevant canopy traits (width, angle). Further, supervised machine learning was used to predict the total number of raceme branches from flower attributes with 91% accuracy (linear regression and Huber regression algorithms) and to identify mild drought stress, a complex trait which typically has to be empirically scored (0.85 area under the receiver operating characteristic curve, random forest classifier algorithm). The study demonstrates the potential of HTP, image processing and computer vision for effective characterization of agronomic trait diversity in
, although limitations of the platform did create significant variation that limited the utility of the data. However, the results underscore the value of machine learning for phenotyping studies, particularly for complex traits such as drought stress resistance.
Many novices struggle with navigation in 3D virtual environments — they frequently get lost and are unable to find objects and locations. In some virtual environments, novices are provided with ...navigation assistance (e.g., mini-maps, directional markers, or glowing trails) that help them move around in the world. However, it is possible that providing navigation assistance could lead to over-reliance, where the novice’s dependence on the assist means that they never develop a mental model of the environment that would allow them to navigate on their own. To investigate both the benefits and potential risks of navigation assistance in virtual environments, we carried out two online studies in which participants carried out route-finding tasks with different types of navigation assistance. Participants completed training trials, in which they practised a set of routes with the assist, and transfer trials, in which they had to navigate without the assist. The studies focus on two questions: whether assistance improves performance and user experience when it is present, and whether assistance leads to over-reliance and a drop in performance when the assist is removed. For the first question, both studies found that navigation assistance substantially improved performance and subjective experience while it was present — clearly showing that assistance can improve virtual environments for novices. For the second question, we found mixed evidence regarding the problem of over-reliance: the first study showed no performance differences between the highest and lowest levels of navigation assistance when the assist was turned off; the second study showed that there was a performance reduction when the assist was removed, but that the size of the reduction was much smaller than the improvement provided during training. We found that even when the navigation assist was extreme (e.g., pressing a button to be automatically taken in the correct direction), participants were still able to navigate the trained routes, suggesting that incidental learning does successfully occur in virtual environments. Our studies suggest that designers of virtual environments should strongly consider providing navigation assistance: assists can improve a novice user’s performance and experience by reducing navigation problems, and the risks of over-reliance appear to be small in comparison to the benefits for inexperienced users.
•Navigation assistance significantly improves performance and experience.•The amount of effort did not accurately predict spatial learning.•There is little risk of a user becoming over-reliant on navigation assistance.•Navigation learning occurs even in the presence of extreme navigation assistance.•The time benefits of navigating with assistance strongly outweigh the drawbacks.
Interface design guidelines encourage designers to provide high-performance mechanisms for expert users. However, research shows that many expert interface components are seldom used and that there ...is a tendency for users to persistently fail to adopt faster methods for completing their work. This article summarizes and organizes research relevant to supporting users in making successful transitions to expert levels of performance. First, we provide a brief introduction to the underlying human factors of skill acquisition relevant to interaction with computer systems. We then present our focus, which is a review of the state of the art in user interfaces that promote expertise development. The review of interface research is based around four domains of performance improvement: intramodal improvement that occurs as a factor of repetition and practice with a single method of interaction; intermodal improvement that occurs when users switch from one method to another that has a higher performance ceiling; vocabulary extension, in which the user broadens his or her knowledge of the range of functions available; and task mapping, which examines the ways in which users perform their tasks. The review emphasizes the relationship between interface techniques and the human factors that explain their relative success.
We-awareness is the socially recursive inferences that let collaborators know that all are mutually aware of each other’s awareness. While we-awareness is easy afforded in face to face collocated ...collaboration, it is much more difficult to design distributed groupware tools to provide equivalent capabilities: there can be no awareness unless it is programmed in via system features. We identify a series of questions that must be considered if we-awareness is to be supported. What types of awareness information is crucial and should thus be added to the ‘blank slate’ of a screen sharing system? How can that awareness information be captured through technology, and what information will be lost during this capture process? How should that information be translated, transformed and encoded into a digital form, and—as part of that—what information will be altered as part of that translation process? How will that information be transmitted, and what are the network effects in terms of that information being received in a timely manner? How will that information be represented to other participants in order to enable the rich and subtle interactions that occur in the face-to-face setting? We illustrate the nuances of these questions and why they are difficult to answer by revisiting several prior technical solutions to we-awareness.
Leadership is considered critical to virtual community success. Leaders engage in important community activities such as encouraging members and building social structure. These potential benefits, ...however, have rarely been empirically tested. We were presented with an opportunity to explore this issue while studying an online board-and-card-game community. During our study, the community experienced a major change in leadership when the founder – and formal leader – decided to substantially reduce his involvement in the site. This provided us with the rare opportunity to carry out a case study of leadership reduction in a real-world community. To look at the effects of leadership on community behaviour, we analysed 16 months of activity logs, supported by interviews, to compare the community before, during, and after the founder’s withdrawal. We observed strong variability in the effects of a leadership reduction – some results were in line with the “leadership hypothesis,” but others were unexpected. In some cases, we found evidence that reducing formal leadership can have negative effects on the success of the community; but in other cases, we found surprising sources of resilience to the reduction in leadership activities. Our study is the first to look at the details of how leadership (and a reduction in this role) affects several types of sub-community within a board-and-card game site, and the first to consider some of the factors that lead to differences in the effects of leadership reduction. Overall, we found that negative effects on sub-communities were closely tied to the specific activities that the leader provided, and the degree to which he was the only person able to provide those roles. The broad strokes of this finding agree with the leadership hypothesis, but there are several unexpected elements within the main story: the negative effects were less drastic than we anticipated, and all of the sub-communities (even the most dependent) survived the transition. The strong resilience of some of the sub-communities seems to be connected to their ability to “fall back” to a foundation of shared activity (i.e., game play) – an idea that has been introduced in earlier work but never studied empirically. This research helps designers to understand the complexities of leadership in online communities, providing an important foundation for developing and supporting online groups.
PDF
