Search Results (35)

This paper presents a mathematical formalization of human–computer interaction under a zero-distance constraint, introducing a degenerate formulation of Fitts’s Law. In classical models, movement time depends logarithmically on spatial distance and target size. By enforcing D → 0, the Index of Difficulty converges to zero, and movement time reduces to a constant equal to the physiological intercept, yielding a constant-time interaction model. A rigorous ε–δ limit analysis proves convergence, while an optimization formulation shows that zero-distance interaction achieves the global minimum of latency. From a control-theoretic perspective, the model eliminates nonlinear dependencies and produces a time-invariant system. The framework is empirically validated on a teleoperated mobile robotic platform using a haptic Touch–Release protocol. Experimental results show a reduction in total response latency from approximately 1040 ms to 450 ms (≈56%). Cryptographically secured telemetry (AES-256) ensures data integrity and reproducibility. The proposed model establishes a new paradigm of constant-time human–computer interaction, with implications for optimization and control in cyber–physical systems and safety-critical applications. Full article

Fitts’ law is a foundational model for predicting pointing performance and has been increasingly explored in immersive virtual reality (VR) environments. This paper presents a controlled experimental framework for deriving modality-specific Fitts’ law models in VR and evaluating their predictive transfer to applied interaction tasks. The framework comprises two scenarios. The first replicates a standardized ISO 9241 pointing task in a 3D virtual environment to derive predictive movement time models by systematically varying target distance (20–50 cm), target size (2.5–5 cm), and spatial configuration ($0^{\circ }$, ${45}^{\circ }$, ${90}^{\circ }$, ${135}^{\circ }$). The second simulates an applied warehouse-inspired task involving tool sorting and structured placement actions to evaluate the generalizability of the derived models in more ecologically valid VR interactions. Thirty-two participants completed all tasks using the Meta Quest 3 headset and two interaction modalities: a handheld controller and hand tracking with gesture recognition. Results show that Fitts’ law remains a strong predictor of movement time for 3D pointing in VR, with high linear fits for both the controller ($R^2=0.9615$) and hand tracking ($R^2=0.9668$). However, models derived from standardized pointing tasks showed limited transferability to applied object-manipulation scenarios, producing prediction errors of approximately 27–35% and systematically underestimating movement times. Additionally, both objective metrics and subjective evaluations indicated that controller-based interaction outperformed hand tracking in efficiency, accuracy, perceived workload, and usability. These findings highlight both the robustness and limitations of Fitts-based performance modeling in realistic VR interaction contexts. Full article

Novice drivers demonstrate inefficient visual scanning and elevated crash risk relative to experienced drivers. Different training programmes may influence gaze behaviour and performance in distinct ways. This study compared the impact of cognitive, simulator-based, and real-world training on visual attention and driving-related outcomes in novice drivers. Thirty novice drivers (18–27 years; ≤1 year driving experience) were randomized into three training groups (n = 10 each): cognitive training (PsyToolkit, Version 3.7.0), game-based simulator training, and supervised real-world driving. Baseline and post-training assessments included visuomotor performance (Fitts’ Law), attentional cueing (valid/invalid reaction time), simulator-based driving errors, and eye-tracking measures of gaze behaviour. Eye-tracking outcomes included dwell-time percentage and first-fixation order across predefined areas of interest (AOIs). Participants completed 10 consecutive days of modality-specific training. Cognitive training improved visuomotor performance and increased forward road monitoring. Game-based simulator training yielded the largest reductions in simulator driving errors, particularly lane deviations (Z = −2.89, p = 0.004). Real-world driving altered visual scanning patterns, with significant differences in rear-view mirror prioritization (p = 0.024). Across groups, gaze shifted from dashboard view toward safety-relevant AOIs. Training modifies novice drivers’ gaze behaviour in modality-specific ways, suggesting that a multimodal training approach may enhance visual attention and driving safety Full article

This study quantitatively evaluates the performance of a non-invasive hybrid brain–computer interface (BCI) compared to a conventional mouse in pointing (point-and-click) tasks. A commercial wearable BCI (Brainfingers), based on electromyography (EMG) and electrooculography (EOG) signals with low-level electroencephalography (EEG) components, was assessed against a Microsoft Optical Mouse using ISO/TS 9241-411-based one-dimensional (1D) and two-dimensional (2D) target acquisition tasks. Pointer coordinates were recorded and analyzed using Fitts’ law metrics. A total of 48 non-disabled participants completed the experiments. The results reveal significant performance differences between the two input devices. The BCI device exhibits substantially lower performance than the mouse across the reported Fitts’ law measures. Mean throughput was 0.35 bits/s for the BCI and 6.03 bits/s for the mouse in the 1D tests and 0.43 bits/s for the BCI and 5.17 bits/s for the mouse in the 2D tests. Despite the BCI’s low performance and although the present experiments involved non-disabled participants, the findings, considered alongside the prior literature on Brainfingers and non-invasive BCIs for computer access, suggest that the device may still have assistive technology value for users with severe motor impairments. Full article

Background: Passing in lacrosse is a fundamental skill essential for both offense and defense, directly influencing game flow. Although the speed–accuracy trade-off is well recognized in motor control, its features in lacrosse passing—particularly regarding directional aspects and skill differences—remain unclear. This study quantified the relationship between pass speed, accuracy, bias, and consistency and examined directional effects and skill-level differences. Methods: Twenty-two female university players (skilled: n = 9; unskilled: n = 13) executed overhand passes to a 5 cm × 5 cm target from 11 m under three effort conditions: warm-up, game intensity, and full effort. Ball speed was derived from lateral video, and landing coordinates from posterior footage. Accuracy, bias, and consistency were assessed using radial error (RE), centroid error (CE), absolute CE (|CE|), and bivariate variable error (BVE). Directional patterns were analyzed through lateral and vertical components and the 95% confidence intervals of the major and minor axes of an error ellipse. A two-way analysis of variance was performed with condition as the within-subject factor and skill level as the between-subject factor. Results: Ball speed increased significantly across conditions. RE, |CE|, and BVE increased with speed, showing directional dependence: variability expanded mainly along the major axis, while the minor axis remained stable. Skilled players showed smaller RE and BVE, with differences most evident vertically and along the major axis. CE direction stayed consistent, indicating that reduced accuracy stemmed from greater bias magnitude and lower consistency rather than shifts in the mean landing point. Conclusions: Findings confirm a speed–accuracy trade-off in lacrosse passing, characterized by directional specificity and skill-related effects. Combining RE, CE, BVE, and ellipse-axis analyses clarified error structure, showing variability concentrated along the movement axis. These results support training focused on vertical control and timing and highlight the value of directional metrics for assessing lacrosse performance. Future research should include male athletes, advanced levels, and in-game scenarios to extend generalizability. Full article

Background: Humans interacting with virtual objects is becoming common due to the popularity of the devices adopting the mixed reality (MR) techniques. Assessing hand functions using these devices for medical purposes provides alternatives in addition to the traditional hand function assessment techniques. Objectives: The objectives were to compare the movement time (MT) of handing a real and a virtual object between post-surgery wrist fracture patients and healthy adults and to determine the correlation between the MT and commonly adopted hand function indicators. Methods: An experiment was performed. A total of 29 participants, including 17 patients and 12 healthy adults, joined. All the participants moved a real or a virtual tube from an origin to a destination. A set of MR device was adopted to generate the virtual object. The MTs were analyzed to compare differences between the patients and the healthy adults. Regression models were developed to predict the MT under experimental conditions. Results: The MT of the surgical hand was significantly longer than that of the nonsurgical hand of the patients and was significantly longer than that of the left hand of the healthy adults. The MT was negatively correlated with the commonly adopted hand function indicators, including grip strength, range of motion, hand dexterity score, and Modified Mayo Wrist Score. Conclusions: The anticipation that the MT of interacting with virtual objects for patients may reveal hand function characteristics for post-surgery patients was supported. The regression models developed could reveal the progression of hand function recovery for these patients. Having patients interact with virtual objects could be a supplemental approach in assessing their hand functions. Full article

This article presents the Digital Thimble, an index-finger-wearable device designed for free-hand interactions in virtual reality (VR) by varying the touch contact force on a surface. It contains an optical mouse sensor for tracking and a pressure sensor for detecting contact force. A Fitts’ law study compared the Digital Thimble with a commercial finger mouse and a VR controller using both on-press and on-release selection methods. The results showed that the finger mouse provided higher throughput (3.11 bps) and faster speed (1258 ms) compared to the VR controller (2.89 bps; 1327 ms) and the Digital Thimble (2.61 bps; 1487 ms). Further evaluation in sorting and teleportation tasks demonstrated that the Digital Thimble delivered better accuracy and precision. Participants favored the Digital Thimble for its comfort and convenience, highlighting its potential as a user-friendly VR input device. Full article

Sea salt farms are the source of salt, an indispensable essential ingredient in various foods and products. Further, they act as frontlines to protect marine disasters from entering domestic residential areas. However, sea salt farming has decreased in popularity among recent-generation farmers in Samut Songkhram Province, Thailand. This paper presents the development of an affordable virtual learning (AVL) application for Thailand’s sea salt farming. Fitts’ law was applied to optimize user-interactive objects’ size and placement to reduce selection time. The sample consisted of 127 multigenerational users, namely those in Generation X, Generation Y, and Generation Z. This study found that the developed AVL applied Fitts’ law to be used harmoniously with VR economical equipment. A total of 90.55% of multigenerational users were satisfied with the developed AVL. The “Looking” and “Executing by eye focus” activities were enjoyed by 100% of participants. The following activities were “Walking” and “Listening”, with 82.68% and 77.95% enjoying them, respectively. Generation Z users responded more to the “Walking” activity than Generation X and Y users. In addition, the hypothesis testing result of learning outcomes through AVL was consistent among multigenerational users. Therefore, the developed AVL should be used as a medium to conserve sea salt farming in Thailand. Full article

Fitts’ law, a predictive model for motor task completion time, is widely utilized in human–computer interaction (HCI) research. While its formulas in two dimensions have achieved consensus over the decades, research diverges on its application in three dimensions. This paper synthesizes practical applications across touchscreens, virtual reality (VR), pedals, handheld devices, etc., with a specific emphasis on enhancing interaction experiences for vulnerable populations. This review studies Fitts’ law’s applicability in diverse interaction scenarios, highlighting design considerations for touchscreens and handheld/foot-held devices. This article underscores the need for future research to explore three-dimensional applications and consider user age, with potential expansions into medical and sports domains. This systematic review aims to empower designers in crafting more ergonomic products and improving HCI experiences. Full article

Working on a moving platform can significantly impede human performance. Previous studies on moving vehicles have often focused on the overall impact on general task performance, whereas our study’s emphasis is on precise hand movements, exploring the interaction between body motion and the escalation of task difficulty. We recruited 28 participants to engage in reciprocal aiming tasks, following Paul Fitts’s setting, under both in-motion and stationary conditions. The task index of difficulty (ID) was manipulated by varying the width of the targets and the distance between the targets. We measured participants’ movement time (MT), performance errors, and monitored their eye movements using an eye-tracking device, heart rate (HR), and respiration rate (RR) during the tasks. The measured parameters were compared across two experimental conditions and three ID levels. Compared to the stationary conditions, the in-motion conditions degraded human aiming performance, resulting in significantly prolonged MT, increased errors, and longer durations of eye fixations and saccades. Furthermore, HR and RR increased under the in-motion conditions. Linear relationships between MT and ID exhibited steeper slopes under the in-motion conditions compared to the stationary conditions. This study builds a foundation for us to explore the control mechanisms of individuals working in dynamic and demanding environments, such as pilots in airplanes and paramedics in ambulances. Full article

This research compares a Steam controller, a DualSense controller, two gestures on a prototype touchpad-implemented gamepad design, an iPad Pro, a Logitech G304 mouse with latency matching the iPad, and a Razer 8K gaming mouse using Fitts Task 2, 3D Aim Trainer for a performance and gameplay experience test in a Death Stranding firing range and gathers feedback on the devices. With the participants categorized by their gaming experience, the differences between the experienced groups are recorded in terms of performance and preference. The average result shows that the touch-based input has the potential of substituting a mouse when the latency condition is equal, and the players that already have touch-based FPS/TPS gaming experience tends to favor touch over a mouse input. However, the prototype controller designed to implement a larger touchpad did not meet the expectations in terms of performance and preference, but the knowledge, data and feedback gathered in this study will aid future touch-based gamepad designs in the emerging handheld console market. Full article

An experiment was performed to investigate the movement time (MT) and subjective rating of difficulty for real and virtual pipe transferring tasks. Thirty adults joined as human participants. The HoloPipes app in a Microsoft^® Hololens 2 augmented reality (AR) device was adopted to generate virtual pipes. The participants performed pipe transferring trials, from one location to another on a workbench, in both lateral and anterior–posterior directions. For the lateral transferring tasks, pipes in three diameters with three transferring distances and two origins were tested. For the anterior–posterior transferring tasks, pipes with a diameter of 2.2 cm with three transferring distances and two origins were tested. It was found that the MT of transferring a virtual pipe was significantly (p < 0.0001) shorter than that of transferring a real pipe. Moreover, male participants transferred the pipe significantly (p < 0.0001) faster than their female counterparts. Thus, the hypothesis that transferring a virtual pipe is less efficient than transferring a real pipe was rejected. It was also found that the MT of transferring both a real and a virtual object was dependent upon gender, handedness, and the transferring direction. In addition, the subjective rating of difficulty in pipe transferring is positively correlated (r = 0.48, p < 0.0001) with the MT. Based on Fitts’ law, additive MT models were proposed. These models could be used to predict the MT between handling real and virtual pipes under gender, handedness, and transferring direction conditions. Full article

Previous studies have shown that people with limited motor capabilities may rely on previous motor experience when making action possibility judgments for others. In the present study, we examined if having limited previous motor experience, as a consequence of spinal muscle atrophy (SMA), alters action possibility judgments. Participants with SMA and neurologically healthy (NH) sex- and age-matched controls performed a perceptual-motor judgment task using the Fitts’s law paradigm. Participants observed apparent motion videos of reciprocal aiming movements with varying levels of difficulty. For each movement, participants predicted the shortest movement time (MT) at which a neurologically healthy young adult could accurately perform the task. Participants with SMA predicted significantly longer MTs compared to controls; however, the predicted MTs of both SMA and NH participants exhibited a Fitts’s law relationship (i.e., the predicted MTs significantly increased as movement difficulty increased). Overall, these results provide evidence that participants with SMA who have limited, or no motor experience may make more conservative action possibility judgments for others. Critically, our finding that the pattern of action possibility judgments was not different between SMA and NH groups suggests that limited previous motor experience may not completely impair action possibility judgments. Full article

The principle of Fitts’ law explains that the difficulty of movement increases when targets are farther away and narrower in width, particularly when touching two parallel targets as quickly as possible. Understanding the differences in motor and gaze behaviors between extroverts and introverts when performing tasks that require speed and accuracy is crucial for the development of sensor-based interfaces for games and rehabilitation. This study aimed to investigate such differences in a computer task that assesses the speed–accuracy trade-off (Fitts’ task). Twenty introverts and seventeen extroverts wore an eye tracker and an accelerometer attached to their hand while performing 12 trials through six levels of difficulty presented on a computer screen. The results showed that introverts had longer visual fixations at the higher difficulty levels and reduced pupil diameter variability when difficulty was intermediate, suggesting that their gaze behavior may be different from that of extroverts. However, no significant differences were found in the speed and accuracy performance or kinematic variables between extroverts and introverts. These findings have important implications for the design of interventions that require both speed and accuracy in movement, such as in the development of virtual reality/games for rehabilitation purposes. It is important to consider individual differences in motor and gaze behaviors, particularly in those who may struggle with longer visual fixations, for the design of sensor-based applications and to promote successful interventions and recovery. Full article

Projected walk-through fogscreens have been created, but there is little research on the evaluation of the interaction performance with fogscreens. The present study investigated mid-air hand gestures for interaction with a large fogscreen. Participants (N = 20) selected objects from a fogscreen using tapping and dwell-based gestural techniques, with and without vibrotactile/haptic feedback. In terms of Fitts’ law, the throughput was about 1.4 bps to 2.6 bps, suggesting that gestural interaction with a large fogscreen is a suitable and effective input method. Our results also suggest that tapping without haptic feedback has good performance and potential for interaction with a fogscreen, and that tactile feedback is not necessary for effective mid-air interaction. These findings have implications for the design of gestural interfaces suitable for interaction with fogscreens. Full article