GUI objects with impenetrable borders: Instruction (not practice) makes perfect

Walker and Smelcer (Proceedings of the CHI 90, ACM, New York, 1990, pp. 221–225) found that menus could be selected faster if they were placed against the edge of the screen. Doing so creates an impenetrable border between the menu and the edge of the screen that the mouse cursor cannot penetrate. This changes how users move the mouse, so that selection times quicken compared to menus with a penetrable border. Experiment 1 investigated the effect that practice has on the acquisition of objects with and without impenetrable borders. The findings suggest that excessive practice was not necessary to demonstrate border type differences; thus, the advantage of having impenetrable borders seems to be relatively instantaneous. However, it was not readily apparent whether or not participants would realize the advantages of impenetrable borders without instruction. Thus, the primary purpose of Experiment 2 was to assess whether or not users would discover the benefits of impenetrable borders spontaneously. Participants were assigned to either the penetrable or impenetrable border condition. Additionally, participants received either full instruction concerning the benefits of the target placement, or limited instruction that simply informed the participant about the nature of the task. The results demonstrated that participants receiving limited instruction selected targets with impenetrable borders faster than participants who selected objects with a penetrable border. However, an exploratory comparison suggests that only 50% of participants who received limited instruction actually detected the impenetrable border. An additional comparison suggests that with practice the participants who were successful at detecting the impenetrable border selected the targets as quickly as participants who received full instruction concerning the benefits of impenetrable borders. The findings suggest that with full instruction, all users will perform reduced selection times. Given that not all participants discovered the impenetrable border it suggests that, whenever possible, users should receive instruction pertaining to the benefits of the impenetrable borders.     

Width guidelines for rectangular objects with penetrable and impenetrable borders

Generally, selection times quicken when objects are placed against a display's edge. Experiment 1 investigated whether or not this continues to be true if the width of those objects, i.e. rectangular scrollbars, was manipulated. The results indicated that increasing width affected selection times for objects with penetrable borders, but not for those with impenetrable borders. A follow-up experiment examined whether or not selection times vary when participants selected very thin and wider scrollbars, each with impenetrable borders. The results indicated that width manipulations did not influence selection time, thus designers could use very thin objects with impenetrable borders without slowing selection time.     

Width guidelines for rectangular objects with penetrable and impenetrable borders

Generally, selection times quicken when objects are placed against a display's edge. Experiment 1 investigated whether or not this continues to be true if the width of those objects, i.e. rectangular scrollbars, was manipulated. The results indicated that increasing width affected selection times for objects with penetrable borders, but not for those with impenetrable borders. A follow-up experiment examined whether or not selection times vary when participants selected very thin and wider scrollbars, each with impenetrable borders. The results indicated that width manipulations did not influence selection time, thus designers could use very thin objects with impenetrable borders without slowing selection time.     

Improving cascading menu selections with adaptive activation areas

Cascading menus are the most commonly used hierarchical menus in graphical user interfaces (GUIs). These menus, however, tend to have elongated paths with corner steering, which can result in navigation difficulties. To resolve the corner steering problem, most current cascading menus implement an explicit time delay between the cursor entering or leaving a parent menu item and posting/unposting the associated menu. In this paper, we present adaptive activation-area menus (AAMUs), a technique to improve cascading menu performance by providing a localized triangular activation area between the menu and the child submenu. This triangular activation area aims to overcome the corner steering problem by permitting quick diagonal navigation without imposing a time delay.We describe four experiments designed to refine and validate the AAMU technique. Our first experiment shows that AAMUs improve item selection performance in comparison to traditional menus and a number of competing techniques, including gesture-based menus and enlarged activation-area menus (EMUs). Our second and third experiments reveal, however, that in a searching task, where the user has to look through multiple submenus to find the target, the basic AAMU design suffers from a “cursor trapping” problem, where the user has to move the cursor out of the activation area prior to exploring another submenu. An evaluation of an improved AAMU design shows that it is as fast as or faster than traditional menus and EMUs for both selection and searching tasks.     

Adapting menu layout to tasks

Menus are an increasingly popular style of user-system interface. Although many aspects of menu design can affect user performance (e.g. item names and selection methods), the organization of items in menus is a particularly salient aspect of their design. Unfortunately, empirical studies of menu layout have yet to resolve the basic question of how menus should be organized to produce optimal performance. Furthermore, a disturbingly common finding has been that any initial effects of menu layout disappear with practice. Thus it is tempting to conclude that menu organization is not important or that it only affects performance during learning. In this paper we present some reasons to doubt this conclusion. In particular, we have found persistent effects of layout with multiple-item selection tasks, in contrast with studies employing a single-item selection paradigm. The results of a controlled study comparing various menu designs (fast-food keyboards) show that the types of tasks to be performed by users must be considered in organizing items in menus and that there may be sustained effects of menu organization with some tasks. In addition, the results of this study support the use of a formal methodology based on user knowledge for menu design. By comparing the performance of subjects using menus designed using our methodology with the performance of subjects using “personalized” menus, we were able to demonstrate the general superiority of our method for designing menus, and for tailoring menus to meet task requirements as well.     

Movement time to edge and non-edge targets

Time to capture a target at the edge of a screen is expected to be less than when the target is slightly away from the screen edge. This is due to the effective target width, in the direction of cursor movement, being large when the target is at the screen edge, allowing a user to control the movement only in a direction perpendicular to the direction of movement. An experiment with 71 participants and a range of Fitts’ Index of Difficulty (ID) showed a strong difference in the capture times of targets at the screen edge and targets placed one pixel from the screen edge. This advantage is typically 100 ms, independent of the ID of the movement.

Practitioner Summary: Movement time to icons placed at the screen edge (no space between icon and screen edge) is faster than when they are placed a short distance from the edge (as in Microsoft Windows).     

The effects of platform motion and target orientation on the performance of trackball manipulation

The trackball has been widely employed as a control/command input device on moving vehicles, but few studies have explored the effects of platform motion on its manipulation. Fewer still have considered this issue in designing the user interface and the arrangement of console location and orientation simultaneously. This work describes an experiment carried out to investigate the performance of trackball users on a simple point-and-click task in a motion simulator. By varying the orientation of onscreen targets, the effect of cursor movement direction on performance is investigated. The results indicate that the platform motion and target orientation both significantly affect the time required to point and click, but not the accuracy of target selection. The movement times were considerably longer under rolling and pitching motions and for targets located along the diagonal axes of the interface. Subjective evaluations carried out by the participants agree with these objective results. These findings could be used to optimise console and graphical menu design for use on maritime vessels. STATEMENT OF RELEVANCE: In military situations, matters of life or death may be decided in milliseconds. Any delay or error in classification and identification will thus affect the safety of the ship and its crew. This study demonstrates that performance of manipulating a trackball is affected by the platform motion and target orientation. The results of the present study can guide the arrangement of consoles and the design of trackball-based graphical user interfaces on maritime vessels.     

Two-mode target selection: Considering target layouts in small touch screen devices

A variety of studies have been conducted to improve methods of selecting a tiny virtual target on small touch screen interfaces of handheld devices such as mobile phones and PDAs. These studies, however, focused on a specific selection method, and did not consider various layouts resulting from different target sizes and densities on the screen. This study proposes a Two-Mode Target Selection (TMTS) method that automatically detects the target layout and changes to an appropriate mode using the concept of an activation area. The usability of TMTS was compared experimentally to those of other methods. TMTS changed to the appropriate mode successfully for a given target layout and showed the shortest task completion time and the fewest touch inputs. TMTS was also rated by the users as the easiest to use and the most preferred. TMTS could significantly increase the ease, accuracy, and efficiency of target selection, and thus enhance user satisfaction when the users select targets on small touch screen devices.

Relevance to Industry

The results of this study can be used to develop fast and accurate target selection methods in handheld devices with touch screen interfaces especially when the users use their thumb to activate the desired target.     

The effects of platform motion and target orientation on the performance of trackball manipulation

The trackball has been widely employed as a control/command input device on moving vehicles, but few studies have explored the effects of platform motion on its manipulation. Fewer still have considered this issue in designing the user interface and the arrangement of console location and orientation simultaneously. This work describes an experiment carried out to investigate the performance of trackball users on a simple point-and-click task in a motion simulator. By varying the orientation of onscreen targets, the effect of cursor movement direction on performance is investigated. The results indicate that the platform motion and target orientation both significantly affect the time required to point and click, but not the accuracy of target selection. The movement times were considerably longer under rolling and pitching motions and for targets located along the diagonal axes of the interface. Subjective evaluations carried out by the participants agree with these objective results. These findings could be used to optimise console and graphical menu design for use on maritime vessels.

Statement of Relevance: In military situations, matters of life or death may be decided in milliseconds. Any delay or error in classification and identification will thus affect the safety of the ship and its crew. This study demonstrates that performance of manipulating a trackball is affected by the platform motion and target orientation. The results of the present study can guide the arrangement of consoles and the design of trackball-based graphical user interfaces on maritime vessels.     

Correcting menu usability problems with sound

Future human-computer interfaces will use more than just graphical output to display information. In this paper we suggest that sound and graphics together can be used to improve interaction. We describe an experiment to improve the usability of standard graphical menus by the addition of sound. One common difficulty is slipping off a menu item by mistake when trying to select it. One of the causes of this is insufficient feedback. We designed and experimentally evaluated a new set of menus with much more salient audio feedback to solve this problem. The results from the experiment showed a significant reduction in the subjective effort required to use the new sonically-enhanced menus along with significantly reduced error recovery times. A significantly larger number of errors were also corrected with sound.     

“Beating” Fitts’ law: virtual enhancements for pointing facilitation

We survey recent research into new techniques for artificially facilitating pointing at targets in graphical user interfaces. While pointing in the physical world is governed by Fitts’ law and constrained by physical laws, pointing in the virtual world does not necessarily have to abide by the same constraints, opening the possibility for “beating” Fitts’ law with the aid of the computer by artificially reducing the target distance, increasing the target width, or both. The survey suggests that while the techniques developed to date are promising, particularly when applied to the selection of single isolated targets, many of them do not scale well to the common situation in graphical user interfaces where multiple targets are located in close proximity.     

Graphical versus character-based word processors: an analysis of user performance

The study investigates how experienced computer users take advantage of the availability of graphic user interfaces in a word processing task. Performance time and actions were compared in three groups of subjects working respectively with WordPerfect 5.1, WordPerfect for Windows, or WordPerfect V2.00 for the Macintosh. The three groups did not differ in efficiency: they performed the word processing task at the same speed. Very few WordPerfect 5.1 users worked with the pull-down menus; the great majority preferred using the function key shortcuts. No significant difference in menu use was noted between the two graphical user interface word processors (Windows and Macintosh). Windows users did not apply shortcuts to move text, but used menus or the button bar instead. There was no difference in the use of the mouse between the Windows and Macintosh groups. While better task satisfaction is often reported with the availability of graphical user interfaces, our findings are in agreement with other studies suggesting that experienced users don't perform more efficiently with such a computer environment.     

Complementary menus: Combining adaptable and adaptive approaches for menu interface

This study proposes a method of coupling adaptable and adaptive approaches to the design of menus. The proposed complementary menu types incorporate both adaptability and adaptivity by dividing and allocating menu adaptation roles to the user and the system. Four different types of interface adaptation (i.e., adaptable with/without system support and adaptive with/without user control) were defined. They were implemented in a hypothetical prototype mobile phone via a hotlist (an additional collection of quickly accessible items). A controlled lab experiment was conducted to compare the menu types and investigate the effects of the system support in the adaptable menus and the user control in the adaptive menus. Twenty subjects participated in the experiment and performed menu selection tasks. Both performance and user satisfaction measures were collected. The results showed that adaptable and adaptive menus were superior to the traditional one in terms of both performance and user satisfaction. Providing system support to the adaptable menu not only increased the users’ perception of the efficiency of selection, but also reduced the menu adaptation time. Important implications for the design of menus are described and valuable insights into the menu interface adaptation were gained from the quantitative and qualitative analyses of the experimental results.

Relevance to industry

The evaluation experiment conducted in this study may provide valuable information to designers of adaptive or adaptable menus. Adding system support to adaptable menu would be an attractive option to consider. Also, the results of a user survey provide useful information to the practitioners in mobile phone industry on the features users accessed most frequently.     

Motion marking menus: An eyes-free approach to motion input for handheld devices

The increasing complexity of applications on handheld devices requires the development of rich new interaction methods specifically designed for resource-limited mobile use contexts. One appealingly convenient approach to this problem is to use device motions as input, a paradigm in which the currently dominant interaction metaphors are gesture recognition and visually mediated scrolling. However, neither is ideal. The former suffers from fundamental problems in the learning and communication of gestural patterns, while the latter requires continual visual monitoring of the mobile device, a task that is undesirable in many mobile contexts and also inherently in conflict with the act of moving a device to control it. This paper proposes an alternate approach: a gestural menu technique inspired by marking menus and designed specifically for the characteristics of motion input. It uses rotations between targets occupying large portions of angular space and emphasizes kinesthetic, eyes-free interaction. Three evaluations are presented, two featuring an abstract user interface (UI) and focusing on how user performance changes when the basic system parameters of number, size and depth of targets are manipulated. These studies show that a version of the menu system containing 19 commands yields optimal performance, compares well against data from the previous literature and can be used effectively eyes free (without graphical feedback). The final study uses a full graphical UI and untrained users to demonstrate that the system can be rapidly learnt. Together, these three studies rigorously validate the system design and suggest promising new directions for handheld motion-based UIs.     

Designing to Facilitate Browsing: A Look Back at the Hyperties Workstation Browser

Since browsing hypertext can present a formidable cognitive challenge, user interface design plays a major role in determining acceptability. In the Unix workstation version of Hyperties, a research-oriented prototype, we focussed on design features that facilitate browsing. We first give a general overview of Hyperties and its markup language. Customizable documents can be generated by the conditional text feature that enables dynamic and selective display of text and graphics. In addition we present: — an innovative solution to link identification: pop-out graphical buttons of arbitrary shape.

— application of pie menus to permit low cognitive load actions that reduce the distraction of common actions, such as page turning or window selection.

— multiple window selection strategies that reduce clutter and housekeeping effort. We preferred piles-of-tiles, in which standard-sized windows were arranged in a consistent pattern on the display and actions could be done rapidly, allowing users to concentrate on the contents.

     

Adaptively shortened pull down menus: location knowledge and selection efficiency

Adaptively shortened pull down menus, as introduced by Microsoft with the ‘personalized menus’ in Office 2000? and assumed to speed up menu selection, are examined. Displacement of items in this adaptively changing menu is argued to conflict with the user's location knowledge, leading to increased selection times and error rates. In a controlled experiment with 31 subjects, a standard menu was compared with a shortened and a gapped menu variant. The gapped menu variant served to distinguish effects from displacement and effects resulting from reduced item number. Selection times and error rates were smaller for the standard menu than for the shortened variant. The gapped menu, whilst it has longer distances, was faster than the shortened menu, but slower than the standard menu. According to our findings, the assumption that adaptively shortened pull down menus facilitate menu selection is weakened.     

Multimodal Intelligent Eye-Gaze Tracking System

This article presents a series of user studies to develop a new eye-gaze tracking–based pointing system. We developed a new target prediction model that works for different input modalities and combined the eye-gaze tracking–based pointing with a joystick controller that can reduce pointing and selection times. The system finds important applications in cockpit of combat aircraft and for computer novice users. User studies confirmed that users can perform significantly faster using this new eye-gaze tracking–based system for both military and everyday computing tasks compared to existing input devices. As part of the study it was also found that the amplitude of maximum power component obtained through Fourier Transform of pupil signal significantly correlates with selection times and perceived cognitive load of users in terms of Task Load Index scores.     

Adaptive sliding menubars make existing software more accessible to people with severe motion impairments

The graphical user interfaces of popular software are often inaccessible to people with severe motion impairments, who cannot use the traditional keyboard and mouse, and require an alternative input device. Reaching for buttons and selecting menu items, in particular, can be difficult for nonverbal individuals with quadriplegia, who control the mousepointer with head motion via a mouse-replacement system. This paper proposes interaction techniques that can be used with mouse-replacement systems and enable the creation of accessible graphical user interfaces. To illustrate these techniques, the paper presents an image editing application, named Camera Canvas, that uses a sliding toolbar as its universal menu controller. The parameters of the toolbar automatically adapt to the movement abilities of the specific user. Individuals with and without disabilities and of a variety of ages were observed using Camera Canvas. It was found that the developed techniques worked across many different movement abilities and experience levels. Then, it was investigated how such techniques could be used to “retrofit” existing Windows applications with new graphical user interfaces. A tool called Menu Controller was created that can automatically re-render the menus of some existing applications into adaptive sliding toolbars. Menu Controller enables users of mouse-replacement systems to select menu entries that were otherwise inaccessible to them.     

1D selection of 2D objects in head-worn displays

In current desktop user interfaces, selection is usually accomplished easily with a mouse or a similar two-dimensional locator. In wearable computing, however, controlling two dimensions simultaneously gets significantly harder: a change in one dimension results easily in an undesired change in the other dimension as well when the user is occupied with a parallel task – such as walking. We present a way to overcome this problem by applying one-dimensional selection for graphical user interfaces in head-worn displays. Our new interaction technique allows a wearable computer user to perform object selection tasks easily and accurately. The technique is based on a visible circle on the screen. The user controls the circle, altering its radius with a one-dimensional valuator. The midpoint of the circle is in the middle of the screen. The object currently on the perimeter of the circle is highlighted and can be selected. Our preliminary usability evaluation, applying our custom evaluation method designed especially for walking users, indicates that the proposed technique is usable also when walking.     

Distance estimation of near‐field visual objects in stereoscopic displays

Stereoscopic displays have a promising future because of recent advancements and popularity of handheld devices and maturing head mounted displays. Gesture interaction such as pointing, selection, pinching, and manipulation are now possible in the current virtual environments, where accurate distance judgment is required. In this paper, we address the perception of exocentric distance in stereoscopic displays under two target orientations: horizontal and vertical. Three parallax conditions (on screen, 5 cm from screen, and 10 cm from screen) were considered, where the screen was fixed at a distance of 100 cm from the observer. Four levels of center‐to‐center distance between 10 and 50 cm were employed. The perceptual matching task revealed underestimation in all conditions. The overall judgment of exocentric distance was only about 80% of the actual. We also found a main effect of distance and interaction between layout and distance to be significant. The two important findings of this study are that underestimation of exocentric distance increases as the separation between virtual targets increases and that in vertical orientation, accuracy increases with closer targets. However, the main effects of layout and parallax on accuracy of judgment were not significant. Engineering implications of the results are also discussed in this paper.