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.     

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

In the present study, the usability of two laptop input devices, touchpad and trackpoint, is evaluated. The focus is set on the impact of sensumotor transformation of input devices on practice and task difficulty. Thirty novices and 14 experts operated either touchpad or trackpoint over a period of 1600 trials of a point-click task. As hypothesized, novices and experts operated the touchpad by 15% faster compared to the trackpoint. For novices, performance rose distinctly and levelled off after 960 trials. This consolidation occurred earlier than reported in literature (1400–1600 trials) and, contrary to the assumption, learning was similar for touchpad and trackpoint. The impact of task difficulty dropped remarkably by practice, which points at a more general than specific task learning. In conclusion, ergonomic guidelines can be derived for the user-specific optimization of the usage of touchpad and trackpoint. Actual and potential applications of this research include the user-specific optimization of laptop input devices. Within the theoretical framework of psychomotor models, a profound knowledge of user behaviour in human – computer interaction is provided. Ergonomic guidelines can be derived for the efficient usage of laptop input devices and an optimized hardware and software design.     

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

In the present study, the usability of two laptop input devices, touchpad and trackpoint, is evaluated. The focus is set on the impact of sensumotor transformation of input devices on practice and task difficulty. Thirty novices and 14 experts operated either touchpad or trackpoint over a period of 1600 trials of a point-click task. As hypothesized, novices and experts operated the touchpad by 15% faster compared to the trackpoint. For novices, performance rose distinctly and levelled off after 960 trials. This consolidation occurred earlier than reported in literature (1400-1600 trials) and, contrary to the assumption, learning was similar for touchpad and trackpoint. The impact of task difficulty dropped remarkably by practice, which points at a more general than specific task learning. In conclusion, ergonomic guidelines can be derived for the user-specific optimization of the usage of touchpad and trackpoint. Actual and potential applications of this research include the user-specific optimization of laptop input devices. Within the theoretical framework of psychomotor models, a profound knowledge of user behaviour in human-computer interaction is provided. Ergonomic guidelines can be derived for the efficient usage of laptop input devices and an optimized hardware and software design.     

Effects of sensorimotor transformations with graphical input devices

The impact of sensorimotor transformations with graphical input devices is surveyed with regard to action control. Recent evidence lets us assume that the distal action effect (the moving cursor) rather than the proximal action effect (the moving hand) determines the efficiency of tool use. In Experiment 1, different gains were explored with a touchpad and a mini-joystick. In correspondence with our assumptions the results revealed evidence that Fitts' law holds for distal action–effect movements, but less for proximal action–effect movements. Most importantly, this was not only true for the touchpad but also for the mini-joystick. We further found a more efficient use of the touchpad in comparison to the mini-joystick when a high gain was used. In Experiment 2, the dominance of the action effect on motor control was confirmed in an experiment with a digitiser tablet. The tablet amplitude was held constant, but again, movement times followed the perceived index of difficulty on the display. It is concluded that Fitts' law did not rely on the movements of the motor system, but on the distal action effects on the display (changes in visual space). Distal action–effect control plays an important role in understanding the constraints of the acquisition and application of tool transformations.     

Notebook input devices put to the age test: the usability of trackpoint and touchpad for middle-aged adults

In two experiments, the usability of input devices integrated into computer notebooks was under study. The most common input devices, touchpad (experiment 1) and trackpoint (experiment 2) were examined. So far, the evaluation of mobile input devices has been restricted to younger users. However, due to ongoing demographic change, the main target group of mobile devices will be older users. Therefore, the present study focused on ageing effects. A total of 14 middle-aged (40–65 years) and 20 younger (20–32 years) users were compared regarding speed and accuracy of cursor control in a point-click and a point-drag-drop task. Moreover, the effects of training were addressed by examining the performance increase over time. In total, 640 trials per task and input device were executed. The results show that ageing is a central factor to be considered in input device design. Middle-aged users were significantly slower than younger users when executing the different tasks. Over time, a significant training effect was observed for both devices and both age groups, although the benefit of training was greater for the middle-aged group. Generally, the touchpad performance was higher than the trackpoint performance in both age groups, but the age-related performance decrements were less distinct when using the touchpad.     

Notebook input devices put to the age test: the usability of trackpoint and touchpad for middle-aged adults

In two experiments, the usability of input devices integrated into computer notebooks was under study. The most common input devices, touchpad (experiment 1) and trackpoint (experiment 2) were examined. So far, the evaluation of mobile input devices has been restricted to younger users. However, due to ongoing demographic change, the main target group of mobile devices will be older users. Therefore, the present study focused on ageing effects. A total of 14 middle-aged (40-65 years) and 20 younger (20-32 years) users were compared regarding speed and accuracy of cursor control in a point-click and a point-drag-drop task. Moreover, the effects of training were addressed by examining the performance increase over time. In total, 640 trials per task and input device were executed. The results show that ageing is a central factor to be considered in input device design. Middle-aged users were significantly slower than younger users when executing the different tasks. Over time, a significant training effect was observed for both devices and both age groups, although the benefit of training was greater for the middle-aged group. Generally, the touchpad performance was higher than the trackpoint performance in both age groups, but the age-related performance decrements were less distinct when using the touchpad.     

Designing touchpad user-interfaces for vehicles: which tasks are most suitable?

Designers of in-vehicle computing systems must consider which input devices are most suitable for use in the safety-critical driving situation. This paper describes a study aiming to establish which tasks are best supported by an in-vehicle touchpad system. Eighteen participants (50:50 right/left handed) drove three routes in a right-hand drive simulator while following a lead vehicle at a perceived safe distance. At specific points, participants were asked to carry out seven tasks of varying qualities using a prototype touchpad system, a touchscreen or a rotary controller interface. Results indicated that participants were most negative (in terms of preferences and performance) with the rotary controller interface. Conversely, the results for the touchpad versus the touchscreen interfaces were clearly task dependent. For instance, with the touchpad, subjective opinions and objective performance were most positive for tasks in which simple commands enabled drivers to bypass the need for complex menu interactions (e.g. changing the interior temperature). In contrast, results for the touchscreen were evidently superior for simple menu selection tasks (e.g. selecting a preset radio station). Conclusions are drawn regarding the nature of tasks that are best suited to alternative input devices within vehicles and the potential for a touchpad/touchscreen solution.     

The influence of user expertise and prototype fidelity in usability tests

An empirical study examined the impact of user expertise and prototype fidelity on the outcomes of a usability test. User expertise (expert vs. novice) and prototype fidelity (paper prototype, 3D mock-up, and fully operational appliance) were manipulated as independent variables in a 2 × 3 between-subjects design. Employing a floor scrubber as a model product, 48 users carried out several cleaning tasks. Usability problems identified by participants were recorded. Furthermore, performance, system management strategies and perceived usability were measured. The results showed that experts reported more usability problems than novices but these were considered to be less severe than those reported by novices. Reduced fidelity prototypes were generally suitable to predict product usability of the real appliance. The implications for the running of usability tests are specific to the fidelity of the prototype.     

Interactions of perceptual and conceptual processing: Expertise in medical image diagnosis

In this study, we selected medical image diagnosis as a task to investigate how expertise influences the relations between perceptual and conceptual processing. In an experiment, participants, namely five novices and five experts, made diagnoses on 13 CT images. We obtained two types of data concerning verbal protocols and manipulating computational systems. The segments related to perceptual and conceptual processing were extracted from these data, and the interrelations of the two components were analyzed. Consequently, we confirmed three salient features in the experts: (1) the experts verbalized more types of findings and more types of hypotheses than novices; (2) the experts generated several hypotheses in the early phases of the task; and (3) they newly verbalized many perceptual features during conceptual activities, and verbalized conceptual words during perceptual activities. These results suggest that expertise in medical image diagnosis involves not only the development of both perceptual and conceptual processing, but also the development of an ability to connect the two components.     

Expert versus novice use of the executive support systems: an empirical study

Expertise is essential in problem solving, particularly for executives. Much literature indicates that, in solving daily problems, executives may employ both analytical thinking and intuition. To develop skills and apply intuition, company executives require the use of support devices such as executive support systems (ESS), but their value may differ substantially between experts and novices.Previous research has failed to address the effects of expertise on ESS use. Therefore, this study examines how professionals use them to address business-oriented tasks. The professionals studied were divided into two groups, depending on whether they were experts or novices in the business represented by those tasks. The findings of the experiments show that computer self-efficacy strongly influenced the use of ESS. Moreover, experts felt that the ESS was of greater use when more powerful systems were employed, while the difference for novices between more and less powerful systems was insignificant. Finally, experts rated their user information satisfaction score significantly higher when employing more powerful systems. However, novices rated systems significantly higher only when they cognitively fit the performed task. Implications are discussed.     

Designing touchpad user-interfaces for right-hand drive vehicles: an investigation into where the touchpad should be located

Touchpads in vehicles offer a range of potential benefits over existing input devices, such as touchscreens. This article describes a study aiming to establish where a touchpad should be located within a right-hand drive vehicle. Sixteen participants (50:50 right/left handed) drove three routes in a right-hand drive simulator while following a lead vehicle at a perceived safe distance. At specific points, participants were asked to carry out three tasks of varying complexity using the touchpad. For each of the routes travelled, the touchpad was positioned in one of the three locations: in the centre console; in the door armrest and in the steering wheel. Differences in the performance and preferences of right-handed people vs. left-handed people were found. Right-handed people rated the door armrest location highly and made few glances towards this location while driving. In contrast, left-handed drivers were more positive towards the centre console location. The steering wheel location required a particularly high-visual demand. It is concluded that, for right-hand drive vehicles, a touchpad should be located in both the centre console and the door armrest to suit the diverse needs of the driver population.     

What does it mean to be good at using a mobile device? An investigation of three levels of experience and skill

An increasing number of computer users lack formal training in operating their devices. These daily users cannot be described as novices or experts within the predominant view of expertise. In order to describe and better understand this type of self-taught intermediate level of skill, 10 casual users of a high-end smartphone series were compared to 10 novices and 4 professionals (help desk personnel) in their learning histories, task performance, and cognitive outcomes. Our study suggests that this type of self-taught intermediate level of skill is device-specific. Experienced users (casual users and experts) exhibited superior performance for representative tasks. This is mainly attributable to faster navigation and better knowledge of interface terminology, not to deeper conceptual representation of the problems. Interviews suggest that this skill is the consequence of routine use and three recurring learning events: familiarization, following of media, and ad hoc problem-solving situations. We conclude by discussing why intermediate levels of skill deserve more attention in HCI research.     

Touch a screen or turn a knob: choosing the best device for the job

Input devices enable users to interact with systems. In two experiments, we assessed whether and how task demands and user age influenced task performance for a direct input device (touch screen) and an indirect input device (rotary encoder). In Experiment 1, 40 younger (18-28 years) and 40 middle-aged to older adults (51-65 years) performed tasks using controls such as sliders, up/down buttons, list boxes, and text boxes while using a system. The optimal input device to facilitate performance was dependent on the task being performed and the age of the user. In Experiment 2, touch screen use was assessed for 20 younger (19-23 years) and 20 older adults (51-70 years). Task demands were manipulated through button size, movement distance, direction, and type of movement. Performance was moderated by the age of the user and by task demands. Actual or potential applications of this research include guidance for the optimal selection of input devices for different user populations and task characteristics.     

Text Input on a Smartwatch QWERTY Keyboard: Tap vs. Trace

This study examines text input performance on a smartwatch using tap and trace input methods on a standard QWERTY keyboard (Swype^TM). Participants were either experts or novices to the tracing technique on their smartphone. No users had experience typing on a smartwatch. Participants were able to type at speeds comparable to, or exceeding, those reported in the literature for smartphones and small screen devices. Both novices and tracing experts typed faster overall using the trace input method than the tap method and experts typed the fastest using trace (37 WPM). Word error rates were also comparable to those reported for smartphone text input. These results suggest that using a standard QWERTY keyboard that allows both tap and trace for text input is a viable option on a smartwatch.     

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.     

Information society and information technology

To investigate the characteristics of a computer touchpad as a pointing device, 14 participants used their right hand to manipulate the touchpad on a laptop computer. They were required to move a cursor over different distances (7.5 cm, 15 cm) from a home location to targets of different diameters (8 mm, 16 mm), situated to the upper left, middle, or right of a computer screen. A kinematic analysis of movement onsets and cursor trajectories indicated the nature of inefficiencies of the touchpad compared with other devices, primarily excessive submovements. Upper leftward movements were poorer, which can be explained by asymmetries in the finger-wrist system. This result implies that screen accessibility can vary as a function of users' interaction with cursor controllers and that the default placements of key icons might need to vary as a consequence.     

Automated speech recognition for spreadsheet tasks: Performance effects for experts and novices

The performance of spreadsheet users was compared for two modes of input to the computer, keyboard and automated speech recognition (ASR). Subjects from both an expert group and a novice group were also classified by decision style. Dependent measures were task completion time, accuracy, keystroke count, correction count, and user confidence. Results for a speaker‐dependent, discrete‐word recognizer showed that, for both simple data input and more complex analytical spreadsheet tasks, neither the experts nor the novices performed more effectively using ASR. However, both groups expressed the desirability of having speech input as an option for desktop computing.     

Impact of variable initiative on a natural language dialog system

Flexible spoken natural language dialog systems should permit variable initiative behaviour. This is behaviour where the task initiative can vary from strongly computer controlled to strongly user controlled or somewhere in between. Such behaviour allows a system to effectively communicate with both task novices and experts as well as with intermediate levels of expertise. The paper outlines a mechanism for obtaining variable initiative behaviour and presents experimental results on the performance of an implemented system capable of variable initiative behaviour.     

How Age Affects Pointing With Mouse and Touchpad: A Comparison of Young,Adult, and Elderly Users

Effects of age on pointing performance have become increasingly important as computers have become extensively used by still larger parts of the population. This study empirically investigates young (12–14 years), adult (25–33 years), and elderly (61–69 years) participants' performance when pointing with mouse and touchpad. The goal is to provide an integrated analysis of (a) how these three age groups differ in pointing performance, (b) how these differences are affected by the two pointing devices, and (c) how the submovement structure of cursor trajectories may explain performance differences. Results show that adult participants perform better than both young and elderly participants in that adult participants make fewer errors than young participants and complete trials quicker than elderly participants. Moreover, young participants are quicker than elderly participants, who make neither more nor less errors than young and adult participants. All three age groups were slower and made more errors with the touchpad than the mouse, but the touchpad slowed down elderly participants more than young participants, who in turn were slowed down more than adult participants. Adult participants made more efficient submovements than elderly participants; young participants had an intermediate position in that they were similar to adult participants for some submovement measures and similar to elderly participants for others.     

Determinants of conflict detection: a model of risk judgments in air traffic control

OBJECTIVE: A model of conflict judgments in air traffic control (ATC) is proposed. BACKGROUND: Three horizontal distances determine risk judgments about conflict between two aircraft: (a) Dt(o) is the distance between the crossing of the aircraft trajectories and the first aircraft to reach that point; (b) Dt(h) is the distance between the two aircraft when they are horizontally closest; and (c) Dt(v) is the horizontal distance between the two aircraft when their growing vertical distance reaches 1000 feet. METHODS: Two experiments tested whether the variables in the model reflect what controllers do. In Experiment 1, 125 certified controllers provided risk judgments about situations in which the model variables were manipulated. Experiment 2 investigated the relationship between the model and expertise by comparing a population of certified controllers with a population of ATC students. RESULTS: Across both experiments, the model accounted for 44% to 50% of the variance in risk judgments by certified controllers (N=161) but only 20% in judgments by ATC students (N=88). There were major individual differences in the predictive power of the model as well as in the contributions of the three variables. In Experiment 2, the model described experts better than novices. CONCLUSION: The model provided a satisfying account of the data, albeit with substantial individual differences. It is argued that an individual-differences approach is required when investigating the strategies involved in conflict judgment in ATC. APPLICATION: These findings should have implications for developing user-friendly interfaces with conflict detection devices and for devising ATC training programs.