Pupil dilations during target-pointing respect Fitts' Law (original) (raw)
Related papers
Pupil responses during discrete goal-directed movements
Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, 2014
Pupil size is known to correlate with the changes of cognitive task workloads, but how the pupil responds to requirements of basic goal-directed motor tasks involved in human-machine interactions is not yet clear. This work conducted a user study to investigate the pupil dilations during aiming in a tele-operation setting, with the purpose of better understanding how the changes in task requirements are reflected by the changes of pupil size. The task requirements, managed by Fitts' index of difficulty (ID), i.e. the size and distance apart of the targets, were varied between tasks, and pupil responses to different task IDs were recorded. The results showed that pupil diameter can be employed as an indicator of task requirements in goal-directed movements-higher task difficulty evoked higher valley to peak pupil dilation, and the peak pupil dilation occurred after a longer delay. These findings contribute to the foundation for developing methods to objectively evaluate interactive task requirements using pupil parameters during goal-directed movements in HCI.
Pupil responses to continuous aiming movements
International Journal of Human-Computer Studies, 2015
Pupillary response is associated with perceptual and cognitive loads in visual and cognitive tasks, but no quantitative link between pupil response and the task workload in visual À motor tasks has been confirmed. The objective of this study is to investigate how the changes of task requirement of a visual À motor task are reflected by the changes of pupil size. In the present study, a simple continuous aiming task is performed and the task requirement is manipulated and measured by Fitts' Index of Difficulty (ID), calculated for different combinations of the target size and movement distance. Pupil response is recorded using a remote eye-tracker. The results show that event-triggered pupil dilations in continuous aiming movements respect Fitts' Law, such that higher task difficulty evokes higher peak pupil dilation and longer peak duration. These findings suggest that pupil diameter can be employed as a physiological indicator to task workload evoked by the task requirement in visual Àmotor tasks.
Procedia Manufacturing, 2015
This study aimed at investigating the effects of the target shape, the movement distance, the target size, and the direction of target presentation on the pointing performance using an eye-gaze input system. The target shape, the target size, the movement distance, and the direction of target presentation were within-subject experimental variables. The target shape included: diamond, circle, rectangle, and square. The direction of target presentation included eight directions: upper, lower, left, right, upper left, upper right, lower left, and lower right. It has been explored what type of cursor shape is suitable for eye-gaze input interfaces. On the basis of the data for identifying the effects of the aspect ratio of a target and the movement direction on the pointing time, an attempt was made to develop a generalized and extended Fitts' model that took into account the movement direction and the shape of a target. As a result, the generalized and extended model was found to fit better to the experimental data.
Effects of Eye Measures on Human Controller Remnant and Control Behavior
2017
The aim of the current research was to investigate the possible relation between changes in eye activity parameters, variations in human remnant at the perceptual level and changes in human operator model parameters. Fourteen subjects performed a pitch tracking task, in which the display brightness was varied by changing the background color around a simplified primary flight display, in order to create a controlled, quasilinear change in the pupil diameter through the pupillary light reflex. Pupil diameter, blink, eye opening, and opening and closing amplitudes and speeds were recorded using an eye tracker. Participants controlled single integrator-like and double integrator-like dynamics. The variation in pupil diameter did not introduce significant differences in neither remnant characteristics nor the human operator model parameters. An interesting effect occurred in the human controller's time delay for the single integrator task, where the time delay was significantly higher for the darkest brightness compared to the other levels of brightness. This effect was not observed for the double integrator dynamics. Data suggested that the more difficult controlled dynamics induced a squinting effect, visible in smaller eye opening, and smaller eye opening and closing amplitudes. These results suggest that performance, and control behavior are invariant to the display brightness. Moreover, monitoring changes in the eye activity could represent a method of predicting variations in human remnant characteristics and human controller model parameters, introduced by task difficulty.
The aim of this study is to investigate how well eye movement times in visual target selection tasks by an eye input device follows the typical Fitts' Law and to compare vertical and horizontal eye movement times. Background: Typically manual pointing provides excellent fit to the Fitts' Law model. However, when an eye input device is used for the visual target selection tasks, there were some debates on whether the eye movement times in can be described by the Fitts' Law. More empirical studies should be added to resolve these debates. This study is an empirical study for resolving this debate. On the other hand, many researchers reported the direction of movement in typical manual pointing has some effects on the movement times. The other question in this study is whether the direction of eye movement also affects the eye movement times. Method: A cursor movement times in visual target selection tasks by both input devices were collected. The layout of visual targets was set up by two types. Cursor starting position for vertical movement times were in the top of the monitor and visual targets were located in the bottom, while cursor starting positions for horizontal movement times were in the right of the monitor and visual targets were located in the left. Results: Although eye movement time was described by the Fitts' Law, the error rate was high and correlation was relatively low (R 2 = 0.80 for horizontal movements and R 2 = 0.66 for vertical movements), compared to those of manual movement. According to the movement direction, manual movement times were not significantly different, but eye movement times were significantly different. Conclusion: Eye movement times in the selection of visual targets by an eye-gaze input device could be described and predicted by the Fitts' Law. Eye movement times were significantly different according to the direction of eye movement. Application: The results of this study might help to understand eye movement times in visual target selection tasks by the eye input devices.
Towards Pupil-Assisted Target Selection in Natural Settings: Introducing an On-Screen Keyboard
Human-Computer Interaction – INTERACT 2017, 2017
Preliminary reports have shown the possibility to assist input commands in HCI via pupil dilation. Applicability of these findings is however subject to further investigations, since the specificity of changes in diameter is low, e.g. through variations in brightness. Investigating employability and shape of pupil size dynamics outside a strictly controllccced laboratory, we implemented the emulation of selection via an integrated mechanism of pupil dilation and constriction that could speed up a dwell time of 1.5 s. During the operation of an on-screen keyboard, 21 subjects were able to type via this mechanism, needing 1 s on average per keystroke and producing only slightly more than 1% false positive selections. Hereby, pupil dynamics were assessed. More than 90% of keystrokes could be accelerated under assistance of pupil variations. As suggested from basic research, pupil dilated when fixating later selected keys and constricted shortly afterwards. This finding was consistent between all subjects, however, pupil dynamics were shifted in regard to temporal occurrence and amplitude of diameter changes. Pupil-Assisted Target Selection shows potential in non-strictly controlled environments for computer input and may be further improved on the basis of this data. This might culminate in an integrated gaze-based object selection mechanism that could go beyond the benchmarking dwell time performance.
Task and effector constraints on the kinematics of pointing movements
PsycEXTRA Dataset, 2000
Recent work has emphasized the distinction between task and effector constraints underlying performance in Fitts' type discrete pointing tasks. We explored the relative contributions of these constraints in a cursor-pointing task by manipulating the controldisplay scale, thereby dissociating movement scale at the level of the hand from movement scale at the level of the cursor. Using linear regressions to predict movement time, we found that effector constraints best predict the primary transport phase of the movement, bringing the hand near the target. Visual task constraints underlie the secondary target acquisition phase of the movement. We present a reformulation of Fitts' (1954) index of difficulty, capturing the relative contributions of effector and visual task constraints.
Effort and pupil behaviour in a visual search task
2010
Perceptual load is reflected in the size of the eye pupil. High perceptual load decreases processing of irrelevant information because attentional resources are employed in the experimental task. Large scale attentional zoom decreases processing efficiency due to a spread of attentional resources. The relationship between perceptual load, attentional zoom, and distractor processing was investigated with modified version of Beck and Lavie’s (2005) distractor processing paradigm. Both behavioural data (i.e. accuracy and response times) and a physiological measure (pupil change) were recorded concomitantly. Results indicated that pupils dilated more in the high load conditions than in the low load conditions, but failed to show differences due to display size manipulations. Moreover, while behavioural data indicated that distractor processing was reduced in the high load condition, pupil reactions to different distractors were just as strong in both the high and the low load condition....
Pupil size variations correlate with physical effort perception
It has long been established that the pupil diameter increases during mental activities in proportion to the difficulty of the task at hand. However, it is still unclear whether this relationship between the pupil size and effort applies also to physical effort. In order to address this issue, we asked healthy volunteers to perform a power grip task, at varied intensity, while evaluating their effort both implicitly and explicitly, and while concurrently monitoring their pupil size. Each trial started with a contraction of imposed intensity, under the control of a continuous visual feedback. Upon completion of the contraction, participants had to choose whether to replicate, without feedback, the first contraction for a variable monetary reward, or whether to skip this step and go directly to the next trial. The rate of acceptance of effort replication and the amount of force exerted during the replication were used as implicit measures of the perception of the effort exerted during the first contraction. In addition, the participants were asked to rate on an analog scale, their explicit perception of the effort for each intensity condition. We found that pupil diameter increased during physical effort and that the magnitude of this response reflected not only the actual intensity of the contraction but also the subjects’ perception of the effort. This finding indicates that the pupil size signals the level of effort invested in a task, irrespective of whether it is physical or mental. It also helps refining the potential brain circuits involved since the results of the current study imply a convergence of mental and physical effort information at some level along this pathway.