Sensumotor transformation of input devices and the impact on practice and task difficulty

Age-related differences in processing visual device and task characteristics when using technical devices

With aging visual feedback becomes increasingly relevant in action control. Consequently, visual device and task characteristics should more and more affect tool use. Focussing on late working age, the present study aims to investigate age-related differences in processing task irrelevant (display size) and task relevant visual information (task difficulty). Young and middle-aged participants (20-35 and 36-64 years of age, respectively) sat in front of a touch screen with differently sized active touch areas (4″ to 12″) and performed pointing tasks with differing task difficulties (1.8-5 bits). Both display size and age affected pointing performance, but the two variables did not interact and aiming duration moderated both effects. Furthermore, task difficulty affected the pointing durations of middle-aged adults moreso than those of young adults. Again, aiming duration accounted for the variance in the data. The onset of an age-related decline in aiming duration can be clearly located in middle adulthood. Thus, the fine psychomotor ability "aiming" is a moderator and predictor for age-related differences in pointing tasks. The results support a user-specific design for small technical devices with touch interfaces.

Visual and skill effects on soccer passing performance, kinematics, and outcome estimations

The role of visual information and action representations in executing a motor task was examined from a mental representations approach. High-skill (n = 20) and low-skill (n = 20) soccer players performed a passing task to two targets at distances of 9.14 and 18.29 m, under three visual conditions: normal, occluded, and distorted vision (i.e., +4.0 corrective lenses, a visual acuity of approximately 6/75) without knowledge of results. Following each pass, participants estimated the relative horizontal distance from the target as the ball crossed the target plane. Kinematic data during each pass were also recorded for the shorter distance. Results revealed that performance on the motor task decreased as a function of visual information and task complexity (i.e., distance from target) regardless of skill level. High-skill players performed significantly better than low-skill players on both the actual passing and estimation tasks, at each target distance and visual condition. In addition, kinematic data indicated that high-skill participants were more consistent and had different kinematic movement patterns than low-skill participants. Findings contribute to the understanding of the underlying mechanisms required for successful performance in a self-paced, discrete and closed motor task.

Tactile stimulations and wheel rotation responses: toward augmented lane departure warning systems

When an on-board system detects a drift of a vehicle to the left or to the right, in what way should the information be delivered to the driver? Car manufacturers have so far neglected relevant results from Experimental Psychology and Cognitive Neuroscience. Here we show that this situation possibly led to the sub-optimal design of a lane departure warning system (AFIL, PSA Peugeot Citroën) implemented in commercially available automobile vehicles. Twenty participants performed a two-choice reaction time task in which they were to respond by clockwise or counter-clockwise wheel-rotations to tactile stimulations of their left or right wrist. They performed poorer when responding counter-clockwise to the right vibration and clockwise to the left vibration (incompatible mapping) than when responding according to the reverse (compatible) mapping. This suggests that AFIL implements the worse (incompatible) mapping for the operators. This effect depended on initial practice with the interface. The present research illustrates how basic approaches in Cognitive Science may benefit to Human Factors Engineering and ultimately improve man-machine interfaces and show how initial learning can affect interference effects.

Effects of angular shift transformations between movements and their visual feedback on coordination in unimanual circling

Tool actions are characterized by a transformation between movements and their resulting consequences in the environment. This transformation has to be taken into account when tool actions are planned and executed. We investigated how angular shift transformations between circling movements and their visual feedback affect the coordination of this feedback with visual events in the environment. We used a task that required participants to coordinate the visual feedback of a circular hand movement (presented on the right side of a screen) with a circling stimulus (presented on the left side of a screen). Four stimulus-visual feedback relations were instructed: same or different rotations of stimulus and visual feedback, either in same or different y-directions. Visual speed was varied in three levels (0.8, 1, and 1.2 Hz). The movement-visual feedback relation was manipulated using eight angular shifts: (-180, -135, -90, -45, 0, 45, 90, and 135°). Participants were not able to perform the different rotation/different y-direction pattern, but instead fell into the different rotation/same y-direction pattern. The different rotation/same y-direction pattern and the same rotation/same y-direction pattern were performed equally well, performance was worse in the same rotation/different y-direction pattern. Best performance was observed with angular shifts 0 and -45° and performance declined with larger angular shifts. Further, performance was better with negative angular shifts than with positive angular shifts. Participants did not fully take the angular shift transformation into account: when the angular shifts were negative the visual feedback was more in advance, and when angular shifts were positive the visual feedback was less in advance of the stimulus than in 0° angular shift. In conclusion, the presence and the magnitude of angular shift transformations affect performance. Internal models do not fully take the shift transformation into account.

Reactions, accuracy and response complexity of numerical typing on touch screens

Touch screens are popular nowadays as seen on public kiosks, industrial control panels and personal mobile devices. Numerical typing is one frequent task performed on touch screens, but this task on touch screen is subject to human errors and slow responses. This study aims to find innate differences of touch screens from standard physical keypads in the context of numerical typing by eliminating confounding issues. Effects of precise visual feedback and urgency of numerical typing were also investigated. The results showed that touch screens were as accurate as physical keyboards, but reactions were indeed executed slowly on touch screens as signified by both pre-motor reaction time and reaction time. Provision of precise visual feedback caused more errors, and the interaction between devices and urgency was not found on reaction time. To improve usability of touch screens, designers should focus more on reducing response complexity and be cautious about the use of visual feedback.

PRACTITIONER SUMMARY

The study revealed that slower responses on touch screens involved more complex human cognition to formulate motor responses. Attention should be given to designing precise visual feedback appropriately so that distractions or visual resource competitions can be avoided to improve human performance on touch screens.

Investigation of the performance of trackpoint and touchpads with varied right and left buttons function locations

This study investigates the relationships of the following 5 factors with commonly-used task patterns: 4 (2 existing and 2 newly-designed) built-in cursor input devices of notebook PCs, usage experiences, genders, sensitivity of cursor movements, and 5 tasks of input applications (including click, drag-drop, click-select, select-drag-drop, and type-select-click). This experiment reveals that there are significant differences among these factors in the operating times and/or error rates of particular tasks. Although somewhat influenced by the task patterns, the results show that the touchpad with the cursor-tracking pad located on the bottom-center and the right and left buttons on the bottom-left beneath the keyboard, which avoids ulnar and radial deviation and hindrance of text-entry-pointer-manipulation switching, leads to higher performance and preference, while the trackpoint leads to lower performance and preference. In addition, the touchpads with sensitivity values of 10 and 12 for cursor movement are preferred over those with the value of 8.

To twist, roll, stroke or poke? A study of input devices for menu navigation in the cockpit

Modern interfaces within the aircraft cockpit integrate many flight management system (FMS) functions into a single system. The success of a user's interaction with an interface depends upon the optimisation between the input device, tasks and environment within which the system is used. In this study, four input devices were evaluated using a range of Human Factors methods, in order to assess aspects of usability including task interaction times, error rates, workload, subjective usability and physical discomfort. The performance of the four input devices was compared using a holistic approach and the findings showed that no single input device produced consistently high performance scores across all of the variables evaluated. The touch screen produced the highest number of 'best' scores; however, discomfort ratings for this device were high, suggesting that it is not an ideal solution as both physical and cognitive aspects of performance must be accounted for in design.

PRACTITIONER SUMMARY

This study evaluated four input devices for control of a screen-based flight management system. A holistic approach was used to evaluate both cognitive and physical performance. Performance varied across the dependent variables and between the devices; however, the touch screen produced the largest number of 'best' scores.

Age effects on controlling tools with sensorimotor transformations

Controlling tools in technical environments bears a lot of challenges for the human information processing system, as locations of tool manipulation and effect appearance are spatially separated, and distal action effects are often not generated in a 1:1 manner. In this study we investigated the susceptibility of older adults to distal action effects. Younger and older participants performed a Fitts' task on a digitizer tablet without seeing their hand and the tablet directly. Visual feedback was presented on a display in that way, that cursor amplitude and visual target size varied while the pre-determined hand amplitude remained constant. In accordance with distal action effects being predominant in controlling tool actions we found an increase in hand movement times and perceptual errors as a function of visual task characteristics. Middle-aged adults more intensely relied on visual feedback than younger adults. Age-related differences in speed-accuracy trade-off are not likely to account for this finding. However, it is well known that proprioceptive acuity declines with age. This might be one reason for middle-aged adults to stronger rely on the visual information instead of the proprioceptive information. Consequently, design and application of tools for elderly should account for this.

Crosstalk Between Proximal and Distal Action Effects During Tool Use

When using a tool, proximal action effects (e.g., the hand movement on a digitizer tablet) and distal action effects (e.g., the cursor movement on a display) often do not correspond to or are even in conflict with each other. In the experiments reported here, we examined the role of proximal and distal action effects in a closed loop task of sensorimotor control. Different gain factors perturbed the relation between hand movements on the digitizer tablet and cursor movements on a display. In the experiments, the covert hand movement was held constant, while the cursor amplitude on the display was shorter, equal, or longer, and vice versa in the other condition. When participants were asked to replicate the hand movement without visual feedback, hand amplitudes varied in accordance with the displayed amplitudes. Adding a second transformation (Experiment 1: 90°-rotation of visual feedback, Experiment 2: 180°-rotation of visual feedback) reduced these aftereffects only when the discrepancy between hand movement and displayed movement was obvious. In conclusion, distal action effects assimilated proximal action effects when the proprioceptive/tactile feedback showed a feature overlap with the visual feedback on the display.

Practice and carryover effects when using small interaction devices

The use of interaction devices in modern work often challenges the human motor system, especially when these devices introduce unfamiliar transformations to the user. In this paper we evaluated expert performance and skill differences between experts and novices when using small motion- and force-controlled interaction devices (touchpad and mini-joystick) in an applied text-editing task. Firstly, experts performed better with their familiar input device than with an unfamiliar one. Particularly touchpad experts operating the unfamiliar mini-joystick showed highly asymmetric carryover costs. Results showed that the efficient performance of experts depended on domain-specific skills, which were not transferable. Secondly, with considerable practice (more than observed for simple and short tasks) novices were brought up to higher levels of performance. The motion-transformation between hand and cursor action was easier in understanding and application than the force-transformation. Thus, the touchpad was used more efficiently than the mini-joystick. In conclusion, practice effects found so far are considerably underestimated when it comes to an applied task. The results give reason to develop and implement skill-sensitive training procedures, since the acquisition of domain-specific skills is critical for expert performance. As a consequence, training procedures might be essential for complex applications and/or unfamiliar device transformations.

Adjustment to a complex visuo-motor transformation at early and late working age

Age-related changes of adjustment to visuo-motor transformations were studied for a complex transformation modelled after those encountered in laparoscopic surgery. Movement times of aimed movements were initially almost identical for the two age groups and diverged in the course of practice. In test phases without visual feedback, no age-related variation of the adaptive shifts and after effects of amplitude and curvature of hand movements were observed, but only of their direction. Directional adaptive shifts were bimodally distributed, with one mode near to perfect adaptation ('adapters') and the other one near to absence of adaptation ('non-adapters'). Among the young participants, adapters were more frequent than among the old participants. These findings extend previous results on age-related changes of adjustment to simple transformations to complex transformations. They are consistent with the claim that age-related changes of adjustment to visuo-motor rotations come about primarily by impairments of strategic corrections. A link is established between basic-research findings and transformations encountered outside the laboratory: what suffers at higher working age is explicit knowledge of visuo-motor rotations and the strategic corrections based on it. This suggests the provision of opportunities for explicit-knowledge acquisition for those of a higher age.