Analyzing the Impact of Cognitive Load in Evaluating Gaze-based Typing

Gaze-based virtual keyboards provide an effective interface for text entry by eye movements. The efficiency and usability of these keyboards have traditionally been evaluated with conventional text entry performance measures such as words per minute, keystrokes per character, backspace usage, etc. However, in comparison to the traditional text entry approaches, gaze-based typing involves natural eye movements that are highly correlated with human brain cognition. Employing eye gaze as an input could lead to excessive mental demand, and in this work we argue the need to include cognitive load as an eye typing evaluation measure. We evaluate three variations of gaze-based virtual keyboards, which implement variable designs in terms of word suggestion positioning. The conventional text entry metrics indicate no significant difference in the performance of the different keyboard designs. However, STFT (Short-time Fourier Transform) based analysis of EEG signals indicate variances in the mental workload of participants while interacting with these designs. Moreover, the EEG analysis provides insights into the user's cognition variation for different typing phases and intervals, which should be considered in order to improve eye typing usability.Comment: 6 pages, 4 figures, IEEE CBMS 201

Haptic feedback in eye typing

Proper feedback is essential in gaze based interfaces, where the same modality is used for both perception and control. We measured how vibrotactile feedback, a form of haptic feedback, compares with the commonly used visual and auditory feedback in eye typing. Haptic feedback was found to produce results that are close to those of auditory feedback; both were easy to perceive and participants liked both the auditory ”click” and the tactile “tap” of the selected key. Implementation details (such as the placement of the haptic actuator) were also found important

Influences of dwell time and cursor control on the performance in gaze driven typing

In gaze controlled computer interfaces the dwell time is often used as selection criterion. But this solution comes along with several problems, especially in the temporal domain: Eye movement studies on scene perception could demonstrate that fixations of different durations serve different purposes and should therefore be differentiated. The use of dwell time for selection implies the need to distinguish intentional selections from merely per-ceptual processes, described as the Midas touch problem. Moreover, the feedback of the actual own eye position has not yet been addressed to systematic studies in the context of usability in gaze based computer interaction. We present research on the usability of a simple eye typing set up. Different dwell time and eye position feedback configurations were tested. Our results indicate that smoothing raw eye position and temporal delays in visual feedback enhance the system's functionality and usability. Best overall performance was obtained with a dwell time of 500 ms

Dwell-free input methods for people with motor impairments

Millions of individuals affected by disorders or injuries that cause severe motor impairments have difficulty performing compound manipulations using traditional input devices. This thesis first explores how effective various assistive technologies are for people with motor impairments. The following questions are studied: (1) What activities are performed? (2) What tools are used to support these activities? (3) What are the advantages and limitations of these tools? (4) How do users learn about and choose assistive technologies? (5) Why do users adopt or abandon certain tools? A qualitative study of fifteen people with motor impairments indicates that users have strong needs for efficient text entry and communication tools that are not met by existing technologies. To address these needs, this thesis proposes three dwell-free input methods, designed to improve the efficacy of target selection and text entry based on eye-tracking and head-tracking systems. They yield: (1) the Target Reverse Crossing selection mechanism, (2) the EyeSwipe eye-typing interface, and (3) the HGaze Typing interface. With Target Reverse Crossing, a user moves the cursor into a target and reverses over a goal to select it. This mechanism is significantly more efficient than dwell-time selection. Target Reverse Crossing is then adapted in EyeSwipe to delineate the start and end of a word that is eye-typed with a gaze path connecting the intermediate characters (as with traditional gesture typing). When compared with a dwell-based virtual keyboard, EyeSwipe affords higher text entry rates and a more comfortable interaction. Finally, HGaze Typing adds head gestures to gaze-path-based text entry to enable simple and explicit command activations. Results from a user study demonstrate that HGaze Typing has better performance and user satisfaction than a dwell-time method

Answering a Questionnaire Using Eyetracking

The beginning of eye tracking research lies far back in the past. Since eye tracking costs decreased over the past years, the usage of an eye tracker for everyday matters, like the interaction with a personal device, becomes more and more attractive. In the present work, the realization of interacting with a computer interface with only the help of an eye tracker is illustrated. The conducted study examines the acceptance and usability of such a system. Therefore, three different interaction methods have been implemented. In a study, the participants had to complete a questionnaire with those interaction methods using a Windows application and a low-cost eye tracking device. All in all, the study results imply that the number of negative aspects about this system outweigh the positive ones. The biggest issue was the restriction of mobility during the usage of the tracking device. In addition, the usage of the system turned out to be rather exhausting for the eyes. Generally speaking, among the three implemented interaction methods, the interaction method that combines gaze with a second input modality (a keyboard) scored best in terms of interaction speed and usefulness considering the completion of a questionnaire

Gaze interaction enhances problem solving: Effects of dwell-time based, gaze-augmented, and mouse interaction on problem-solving strategies and user experience

It is still unknown whether the very application of gaze for interaction has effects on cognitive strategies users employ and how these effects materialize. We conducted a between-subject experiment in which thirty-six participants interacted with a computerized problem-solving game using one of three interaction modalities: dwell-time, gaze-augmented interaction, and the conventional mouse. We observed how using each of the modalities affected performance, problem solving strategies, and user experience. Users with gaze-augmented interaction outperformed the other groups on several problem-solving measures, committed fewer errors, were more immersed, and had a better user experience. The results give insights to the cognitive processes during interaction using gaze and have implications on the design of eye-tracking interfaces

On object selection in gaze controlled environments

In the past twenty years, gaze control has become a reliable alternative input method not only for handicapped users. The selection of objects, however, which is of highest importance and of highest frequency in computer control, requires explicit control not inherent in eye movements. Objects have been therefore usually selected via prolonged fixations (dwell times). Dwell times seemed to be for many years the unique reliable method for selection. In this paper, we review pros and cons of classical selection methods and novel metaphors, which are based on pies and gestures. The focus is on the effectiveness and efficiency of selections. In order to estimate the potential of current suggestions for selection, a basic empirical comparison is recommended