Behavioral performance and visual attention in communication multitasking: A comparison between instant messaging and online voice chat

Participants carried out a visual pattern-matching task on a computer while communicating with a confederate either via instant messaging (IM) or online voice chat. Communicating with a confederate led to a 50% drop in visual pattern-matching performance in the IM condition and a 30% drop in the voice condition. Visual fixations on pattern-matching were fewer and shorter during the communication task and a greater loss of fixations was found in the IM condition than the voice condition. The results, examined within a threaded cognition framework, suggest that distributing the work between the audio and visual channels reduces performance degradation. Implications for media literacy and distracted-driving are discussed.     

Effects of semi-rigid arch-support orthotics: an investigation with potential ergonomic implications

For many years, arch-support orthotics have been prescribed for individuals with discomfort and/or abnormal skeletal alignments in the structures of the lower extremity. Recently there has been an increased interest in promoting semi-rigid orthotics as an ergonomic aid for asymptomatic workers who must stand all day at their workplace. A laboratory study was performed to assess the biomechanical impact of prefabricated semi-rigid orthotics on asymptomatic individuals. Ten subjects wore semi-rigid arch-support orthotics (experimental condition) for two months and flexible polyurethane/Sorbothane shoe inserts (control condition) for two months. Throughout this 18-week testing period, the subjects returned to the lab to perform a battery of assessment tests at regularly scheduled intervals. These tests examined subject strength, standing posture, stability, fatigue effects, and body part discomfort. The results of this study showed no significant changes in the strength, posture, or stability as a function of insert type. The subjects reported a reduction in low-back discomfort along with an increase in foot discomfort during a fatiguing exertion task while wearing the semi-rigid orthotics as compared to the control condition.     

Noise and the performance of a four-choice psychomotor task

Noise can reduce the efficiency of an operator on a variety of different tasks. How noise produces a decrement in performance is the topic of considerable research and debate. Several authors have suggested that the effects of noise are mediated by the arousal system, high noise levels produce high arousal levels which are not conducive to the efficient performance of most tasks. The experiment reported here attempted to test directly the hypothesis that noise affects performance by increasing arousal. Twenty subjects were exposed to four noise conditions: teletype, intermittent, jet-cockpit and helicopter-cockpit noise at approximately l00dbA. The control or ‘quiet’ condition was white noise at 66dbA. The activity used was a four-choice psychomotor task which had previously been shown to be sensitive to the effects of noise. Heart rate, used as an indicator of arousal, was monitored in each 8-min trial session. No significant decrease in task performance was found in the four noise conditions. However, the intermittent noise condition produced a significantly higher total error score when compared with the jet and helicopter noise conditions. No significant increase in arousal level as indicated by heart rate was observed in the four noise conditions, but it was shown that as heart rate increased misses decreased. Knowledge of results was found to have a significant effect on arousal but not on performance. However, extroverts scored significantly more errors than introverts and subjects who scored highly on the neuroticism scale had significantly more misses than those subjects with a low score. Although this pattern of results is consistent with a recent report using the same task in similar noise conditions the fact that neither performance nor arousal was affected by noise presents apparent problems for the arousal hypothesis. It is suggested that the main factor that determines degradation of performance under noise is whether the task involves short term memory rehearsal processes and that arousal may increase, and so further affect performance, when subjects perceive that noise is interfering with the completion of an important task.     

Evaluating a user interface with ergonomic criteria

Subjects practiced drawing a figure on a computer screen by means of two interaction styles: Command codes and direct manipulation. These two interaction styles demanded different cognitive resources of the user and different times to perform the task. After practice, subjects performed multiple trials in three experimental conditions: in a time‐limit condition, with office noise, and in a neutral working condition. The drawing task was performed concurrently with one of three secondary tasks, each tapping different resources. In Experiment 1, subjects were divided into two equal size groups. Each group performed the task with only one of the two learned interaction styles. Secondary and primary task performance indicated no difference in workload between the two interaction styles. Only at the most demanding secondary task did the use of command codes result in higher workload. In Experiment 2, subjects performed the drawing task in each trial using their preferred interaction style. Consistent individual preferences for the interaction styles and a flexible use of the styles according to working conditions emerged with improved performance.     

Visual performance on detection tasks with double-targets of the same and different difficulty

This paper reports a study of measurement of horizontal visual sensitivity limits for 16 subjects in single-target and double-targets detection tasks. Two phases of tests were conducted in the double-targets task; targets of the same difficulty were tested in phase one while targets of different difficulty were tested in phase two. The range of sensitivity for the double-targets test was found to be smaller than that for single-target in both the same and different target difficulty cases. The presence of another target was found to affect performance to a marked degree. Interference effect of the difficult target on detection of the easy one was greater than that of the easy one on the detection of the difficult one. Performance decrement was noted when correct percentage detection was plotted against eccentricity of target in both the single-target and double-targets tests. Nevertheless, the non-significant correlation found between the performance for the two tasks demonstrated that it was impossible to predict quantitatively ability for detection of double targets from the data for single targets. This indicated probable problems in generalizing data for single target visual lobes to those for multiple targets. Also lobe area values obtained from measurements using a single-target task cannot be applied in a mathematical model for situations with multiple occurrences of targets.     

Visual performance on detection tasks with double-targets of the same and different difficulty

This paper reports a study of measurement of horizontal visual sensitivity limits for 16 subjects in single-target and double-targets detection tasks. Two phases of tests were conducted in the double-targets task; targets of the same difficulty were tested in phase one while targets of di^fferent difficulty were tested in phase two. The range of sensitivity for the double-targets test was found to be smaller than that for single-target in both the same and di^fferent target difficulty cases. The presence of another target was found to a^ffect performance to a marked degree. Interference e^ffect of the difficult target on detection of the easy one was greater than that of the easy one on the detection of the difficult one. Performance decrement was noted when correct percentage detection was plotted against eccentricity of target in both the single-target and double-targets tests. Nevertheless, the non-significant correlation found between the performance for the two tasks demonstrated that it was impossible to predict quantitatively ability for detection of double targets from the data for single targets. This indicated probable problems in generalizing data for single target visual lobes to those for multiple targets. Also lobe area values obtained from measurements using a single-target task cannot be applied in a mathematical model for situations with multiple occurrences of targets.     

The effects of feedback on performance and retention of skill for a natural language interface

This study investigated the effectiveness of different types of on-line feedback following user errors for informing users of the information and functions available in a system with a natural language interface. Twenty-four individuals performed a task based on an industry cost savings program, in which they were given general goals to pursue with regard to the task. Three feedback levels which differed according to the type and amount of feedback provided, along with two levels of system complexity, were examined. In addition, subjects performed the task again after one week to determine the effects of feedback on retention. Results indicated that the subjects in the second level of feedback generally performed better with respect to accessing system functions and information than those in the first level. Although there was some performance improvement from the second to third level, it was not significant. However, the third level of feedback did significantly improve the efficiency with which subjects used information to complete the task during the return condition. Overall, feedback did not affect the errors made, though at certain more limited stages of the tasks this effect was observed.     

Effect of gazing at the camera during a video link on recall

The impact of looking into the camera during a presentation over a video link (resulting in the perception of mutual gaze) on information recall was investigated. In a face-to-face context mutual gaze has been shown to facilitate the encoding and subsequent recall of information [Fry, R., Smith, G.F., 1975. The effects of feedback and eye contact on performance of a digit-coding task. J. Soc. Psychol. 96, 145-146; Otteson, J.D., Otteson, C.R., 1980. Effect of teacher's gaze on children's story recall. Percept. Motor Skill. 50, 35-42; Sherwood, J.V., 1988. Facilitative effects of gaze upon learning. Percept. Motor Skill. 64 (3 Part 2), 1275-1278]. One explanation for these findings is that gaze acts as an arousal stimulus, which increases attentional focus and therefore enhances memory [Kelley, D.H., Gorham, J., 1988. Effects of immediacy on recall of information. Commun. Edu. 37(3), 198-207]. Two studies were conducted in order to test whether gazing at the camera during video-mediated presentations resulted in similar benefits as mutual gaze in a face-to-face context. In study 1 a confederate presented information about two fictitious soap products. In one condition, the confederate gazed at the camera for 30% of the presentation, therefore giving the participants the impression that he was gazing in their direction. In the other condition the confederate did not gaze at the camera. Participants viewed the sales presentations from both conditions. In the condition where gaze was directed at the camera, participants recalled significantly more information about the sales presentation. Study 2 employed the same pre-recorded sales presentations used in study 1, however they were delivered to the participants under audio-only conditions (therefore, the image was switched off). Results from study 2 indicated no recall differences between the two conditions. Findings from these studies would seem to indicate that the perception of gaze aversion over a video link (a consequence of the salesman not looking into the camera) has a negative impact on information recall. This has practical implications for video-mediated presentations. In a distance learning environment lecturers could be advised to look into the camera in order to promote more efficient learning in students.     

Microgravity simulation: physical and psychological workload evaluation tests in an underwater environment

As weightlessness is not completely reproducible on Earth, usability evaluation of space systems is often simulated through tests in an aquatic environment. A Neutral Buoyancy Facility test programme was organized in a special pool to simulate Extra-Vehicular Activities on the Columbus module of the future International Space Station with the aim of assessing various aspects of crew interface design.This study was designed to evaluate workload using visibility, accessibility and operability tests. Diving workload was determined through basic physiological measurements, such as pulmonary ventilation and heart rate during underwater operations.As anxiety can influence physiological processes, and consequently also the workload evaluation determined through these parameters, we developed an evaluation methodology to investigate the anxiety level based on a specific questionnaire submitted to all subjects before and after the dives.Heart rate increased in underwater work to a value approximately 50% larger than the value obtained in the resting condition while sitting outside the pool. This increase in heart rate was accompanied by an increase in pulmonary ventilation of 200% larger than the value recorded in the rest condition while sitting outside the water. The extent of these increases was notable in all the test subjects, who varied in age and stature.Recorded values of workload, heart rate and pulmonary ventilation were evaluated on the basis of Christensen's (Arbeitsphysiol. 14 (1950) 251) and Wells’ (J. Appl. Physiol. 10 (1957) 51) classifications. Through this analysis it was possible to determine that the workload, indicated by performance on our neutral buoyancy tests, corresponds to moderate physiological work.For test subjects, anxiety related to underwater performance was light. Among the causes of anxiety all the subjects indicated the lack of confidence with neutral buoyancy tests and a feeling of lack of safety, typical of aquatic environments.We can conclude that context did not produce considerable psychological effects, and consequently that the psychological load did not influence heart rate and pulmonary ventilation values that can therefore be directly related to task workload.     

The complex role of perceptual organization in visual display design theory

Two experiments were performed to test and extend the current ‘emergent features’ approach to display design for dynamic failure detection tasks. It was predicted that a display whose emergent features were well-mapped to goal-relevant task invariants would lead to better failure detection performance than either of two alternative displays. Contrary to prediction, Experiment 1 showed no differences in failure detection speed or accuracy across displays. The reason for this may have been that subjects did not discover the mapping between the mathematical properties of the task and the emergent feature, so in Experiment 2 subjects were explicitly instructed about the mapping and were advised on how to use the display geometry to help their performance. A significant difference in failure detection speed emerged, but the display supporting fastest performance was not the one with the well-mapped emergent feature. These results suggest that alternative perceptual organizational factors were at work which overpowered the intended effect. The results also underscore the difficulty of developing a theory of display design, and their impact on current theories is outlined.     

The complex role of perceptual organization in visual display design theory.

Two experiments were performed to test and extend the current 'emergent features' approach to display design for dynamic failure detection tasks. It was predicted that a display whose emergent features were well-mapped to goal-relevant task invariants would lead to better failure detection performance than either of two alternative displays. Contrary to prediction. Experiment 1 showed no differences in failure detection speed or accuracy across displays. The reason for this may have been that subjects did not discover the mapping between the mathematical properties of the task and the emergent feature, so in Experiment 2 subjects were explicitly instructed about the mapping and were advised on how to use the display geometry to help their performance. A significant difference in failure detection speed emerged, but the display supporting fastest performance was not the one with the well-mapped emergent feature. These results suggest that alternative perceptual organizational factors were at work which overpowered the intended effect. The results also underscore the difficulty of developing a theory of display design, and their impact on current theories is outlined.     

Influence of 2D and 3D view on performance and time estimation in minimal invasive surgery

This study aimed to evaluate the impact of two-dimensional (2D) and three-dimensional (3D) images on time performance and time estimation during a surgical motor task. A total of 60 subjects without any surgical experience (nurses) and 20 expert surgeons performed a fine surgical task with a new laparoscopic technology (da Vinci robotic system). The 80 subjects were divided into two groups, one using 3D view option and the other using 2D view option. We measured time performance and asked subjects to verbally estimate their time performance. Our results showed faster performance in 3D than in 2D view for novice subjects while the performance in 2D and 3D was similar in the expert group. We obtained a significant interaction between time performance and time evaluation: in 2D condition, all subjects accurately estimated their time performance while they overestimated it in the 3D condition. Our results emphasise the role of 3D in improving performance and the contradictory feeling about time evaluation in 2D and 3D. This finding is discussed in regard with the retrospective paradigm and suggests that 2D and 3D images are differently processed and memorised.     

Competitively versus cooperatively? An analysis of the effect of game play on levels of stress

Many gamers report that playing video games, including those with violent content, helps them to reduce stress. However, few studies have examined competitive and cooperative video game play as they relate to stress reduction. The current study employed a design to acutely stress 100 participants before assigning them randomly to play a mildly violent game either competitively or cooperatively with a female confederate. Results indicated stress levels declined over time at equal levels during both competitive and cooperative game play. Participants in the competitive condition held a slightly less positive impression of the confederate following game play, although players held a generally positive impression of the confederate overall.     

Effects of respirators on performance of physical, psychomotor and cognitive tasks

Possible work decrements caused by respirator usage were examined. A battery of physical, psychomotor and cognitive tasks was used to investigate the effects of respirator wear on 12 subjects. A repeated measures experimental design was used to study the effects of three types of respirators: a disposable dust mask; an air purifying half-mask; and a full-face airline mask. Performance while wearing a mask was compared to the control condition without a respirator. The results from the physical work task of riding a bicycle ergometer indicated approximately a 10% increase in oxygen consumption when subjects wore half and full-face masks in comparison to when they performed the tasks without a mask. The results indicate that wearing the respirators did not have a significant effect on the performance of cognitive tasks but did affect significantly the performance of psychomotor tasks such as steadiness of work performance and movements requiring accurate control for positioning of objects.     

Prediction of the maximum acceptable weight of symmetrical and asymmetrical lift using direct estimation method

The objective of this research was to study the effectiveness and accuracy of using the direct estimation method to determine a worker's lifting capacity or MAWOL of symmetrical and asymmetrical lifting tasks. Sixteen lifting tasks involving four different lifting angles and lifting frequencies were studied. The influence of these independent variables on MA WOL was analysed. In the first session of the study, ten male subjects performed sixteen lifting tasks to predict the MA WOL for each task condition using the psychophysical method. In the second session of the study, the MAWOL for sixteen task conditions were estimated using the direct estimation method. The results of this study indicate that direct estimation is an accurate method to establish MAWOL quickly for a series of lifting tasks. Analysis of the MAWOLs determined by two different methods indicated no significant difference between these two values. However, a significant difference was found between the direct estimated MAWOL and the psychophysicaly predicted MAWOL at the frequency of I lift/min with 30° or 60° asymmetry. This finding shows the limitation of the direct estimation method in developing MAWOL which indicates as the interval between lifts increases, subjects have difficulty in making accurate estimates of the stress of the specific task.     

Qualitative changes in recall memory during day and night shifts

The effect of time of day on recall of words and drawings was studied in 29 French shiftworkers. Tests were carried out at 18:00, 22:00, 02:00 and 06:00. The task involved memorizing a list of 18 drawings for one half of the group, and 18 words (designating the corresponding figures) for the other half. At each time of day, the lists were presented both with and without an interpolated task. In the interpolated task condition, the first 9 items were followed by an interpolated imagery task and the last 9 by a spelling task, or vice versa. The results indicated an overall effect of time of day on the recall test, especially when memorizing drawings. At 18:00 in both the control and the interference condition, subjects recalled more words and drawings from the beginning of the list. Conversely, at 02:00, subjects recalled more words and drawings from the end of the list. The time spent in the interpolated comparison task varied with the time of day and was longer when memorizing drawings. The same time of day pattern of performance was found for spelling times. The implications upon issues concerning shiftwork and job demands are also discussed.     

Assessing the influence of repeated exposures and mental stress on human wayfinding performance in indoor environments using virtual reality technology

This study aimed to examine the effect of repeated exposures to indoor environments on people’s indoor wayfinding performance, both under normal condition and during fire emergency which could induce significant mental stress. Indoor wayfinding experiments were conducted in an immersive virtual museum developed using virtual reality technologies. Participants of the experiments were divided into three groups, who participated in one, two and three trials, respectively. Those who participated in more than one trial were given an interval of two weeks between two consecutive trials. Each trial of the experiment included a treasure hunting task and an egress task. Participants were presented with a virtual fire emergency during the egress task of their last trial. Data of wayfinding performance measures of the participants, as well as their physiological and emotional responses, sense of direction, wayfinding anxiety and simulator sickness were collected and analyzed. The results revealed significant positive impact of repeated exposure on participants’ wayfinding performance, which resulted in a decrease in the time needed to complete the treasure hunting task. The results also revealed significant negative impact of mental stressed caused by the fire emergency on participants’ wayfinding performance, which led to increased travel time and distance during egress. Such negative impact of stress, however, could be noticeably diminished by the repeated exposures, showing significant interaction effect between these two factors.     

The influence of performance standards and feedback on speed and accuracy in an electronically monitored data‐entry task

This study examined performance effects of using electronic performance monitoring (EPM) and feedback to induce compliance with speed and accuracy standards in a data entry task. The study focused on subjects who had difficulty meeting a preestablished data entry speed standard. Subjects performed a data‐entry task for 3 days. On the 1st (baseline) day, no performance standards were imposed, and all subjects were instructed to work at their normal speed and accuracy levels. For the 2nd and 3rd days of the experiment, subjects were assigned at random to one of two groups. In an experimental group, EPM and feedback were used to induce compliance with preestablished speed and accuracy standards. In a control group, subjects were unaware of EPM and received no feedback; they were instructed to continue working at their normal speed and accuracy levels. The introduction of EPM work management in the experimental group led to significant increases in data‐entry speed that were accompanied by significant increases in data‐entry errors. In addition, data‐entry errors produced by experimental subjects increased significantly over time during the workdays in which EPM work management was employed. These effects are discussed in terms of relevant research on goal setting and feedback utilization. The results suggest that when performance standards and feedback that emphasize speed more than accuracy are applied in EPM‐managed work settings, speed increments may be offset by decrements in work quality.