Individual differences in response to automation: the five factor model of personality

This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness-whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five Factors relate to human response to automation. One-hundred-sixty-one college students experienced either 75% or 95% reliable automation provided with task loads of either two or four displays to be monitored. The task required threat detection in a simulated uninhabited ground vehicle (UGV) task. Task demand exerted the strongest influence on outcome variables. Automation characteristics did not directly impact workload or stress, but effects did emerge in the context of trait-task interactions that varied as a function of the dimension of workload and stress. The pattern of relationships of traits to dependent variables was generally moderated by at least one task factor. Neuroticism was related to poorer performance in some conditions, and all five traits were associated with at least one measure of workload and stress. Neuroticism generally predicted increased workload and stress and the other traits predicted decreased levels of these states. However, in the case of the relation of Extraversion and Agreeableness to Worry, Frustration, and avoidant coping, the direction of effects varied across task conditions. The results support incorporation of individual differences into automation design by identifying the relevant person characteristics and using the information to determine what functions to automate and the form and level of automation.     

The effect of gender and time-of-day on time perception and mental workload

Two experiments are reported which investigated how subject gender and time-of-day influenced the estimation of duration and the perception of task-related mental workload. In the first experiment, 24 subjects performed a filled time-estimation task in a constant blacked-out, noise-reduced environment at 0800h, 1200h, 1600h, and 2000h, respectively. In the second experiment, 12 different subjects performed an unfilled time estimation task in similar conditions at 0900h, 1400h, and 1900h. At the termination of all experimental sessions, participants completed the NASA Task Load Index workload assessment questionnaire as a measure of perceived mental workload. Results indicated that physiological response, reflected in body temperature change, followed an expected pattern of sequential increase with time-of-day. However, estimates of duration and the perception of mental workload showed no significant effects for time-of-day. In each of the experiments there were significant differences in time estimation and mental workload response contingent on the gender of the participant. These results are interpreted in light of the previous positive findings for circadian fluctuation in performance efficiency and the equivocal findings of a gender difference in time estimation. A unifying account of these collective results is given based on gender by time-of-day interactional effects. An earlier version of this paper was presented at the 32nd Annual Meeting of the Human Factors Society, Anaheim, CA, October, 1988.     

The effect of gender and time-of-day on time perception and mental workload

Two experiments are reported which investigated how subject gender and time-of-day influenced the estimation of duration and the perception of task-related mental workload. In the first experiment, 24 subjects performed a filled time-estimation task in a constant blacked-out, noise-reduced environment at 0800h, 1200h, 1600h, and 2000h, respectively. In the second experiment, 12 different subjects performed an unfilled time estimation task in similar conditions at 0900h, 1400h, and 1900h. At the termination of all experimental sessions, participants completed the NASA Task Load Index workload assessment questionnaire as a measure of perceived mental workload. Results indicated that physiological response, reflected in body temperature change, followed an expected pattern of sequential increase with time-of-day. However, estimates of duration and the perception of mental workload showed no significant effects for time-of-day. In each of the experiments there were significant differences in time estimation and mental workload response contingent on the gender of the participant. These results are interpreted in light of the previous positive findings for circadian fluctuation in performance efficiency and the equivocal findings of a gender difference in time estimation. A unifying account of these collective results is given based on gender by time-of-day interactional effects. An earlier version of this paper was presented at the 32nd Annual Meeting of the Human Factors Society, Anaheim, CA, October, 1988.     

Effects of the periodic administration of odor or vibration on a 3-hr. vigilance task

The present study examined performance during 3 hr. of simulated sentry duty with and without the intermittent administration of low-level sensory stimuli (odor or vibration). For odor and control conditions, target-detection latency increased steadily over the course of the 3-hr. session. Administration of a tactile stimulus reduced the increase in detection latency compared to that found in odor and control conditions. For all conditions, there were no significant differences in target-detection frequency, shot accuracy, or friend-foe discrimination. Across all conditions, restlessness (motor activity) increased significantly the first hour and remained elevated for the rest of the session. Subjective measures of workload (NASA-TLX) indicated that the 3-hr. task rated high on physical demand, mental demand, frustration, and overall workload. These findings suggest that the intermittent delivery of a clearly detectable tactile stimulus can reduce reaction-time decrements that occur as time on task increases.     

Use of the RoboFlag synthetic task environment to investigate workload and stress responses in UAV operation

Use of unmanned aerial vehicles (UAVs) is an increasingly important element of military missions. However, controlling UAVs may impose high stress and workload on the operator. This study evaluated the use of the RoboFlag simulated environment as a means for profiling multiple dimensions of stress and workload response to a task requiring control of multiple vehicles (robots). It tested the effects of two workload manipulations, environmental uncertainty (i.e., UAV’s visual view area) and maneuverability, in 64 participants. The findings confirmed that the task produced substantial workload and elevated distress. Dissociations between the stress and performance effects of the manipulations confirmed the utility of a multivariate approach to assessment. Contrary to expectations, distress and some aspects of workload were highest in the low-uncertainty condition, suggesting that overload of information may be an issue for UAV interface designers. The strengths and limitations of RoboFlag as a methodology for investigating stress and workload responses are discussed.     

Adaptive Automation for Human Supervision of Multiple Uninhabited Vehicles: Effects on Change Detection,Situation Awareness,and Mental Workload

Human operators supervising multiple uninhabited air and ground vehicles (UAVs and UGVs) under high task load must be supported appropriately in context by automation. Two experiments examined the efficacy of such adaptive automation in a simulated high workload reconnaissance mission involving four subtasks: (a) UAV target identification; (b) UGV route planning; (c) communications, with embedded verbal situation awareness probes; and (d) change detection. The results of the first “baseline” experiment established the sensitivity of a change detection procedure to transient and nontransient events in a complex, multi-window, dynamic display. Experiment 1 also set appropriate levels of low and high task load for use in Experiment 2, in which three automation conditions were compared: manual; static automation, in which an automated target recognition (ATR) system was provided for the UAV task; and adaptive automation, in which individual operator change detection performance was assessed in real time and used to invoke the ATR if and only if change detection accuracy was below a threshold. Change detection accuracy and situation awareness were higher and workload was lower for both automation conditions compared to manual performance. In addition, these beneficial effects on change detection and workload were significantly greater for adaptive compared to static automation. The results point to the efficacy of adaptive automation for supporting the human operator tasked with supervision of multiple uninhabited vehicles under high workload conditions.     

Second choices in a visual span of apprehension task

Four Ss were run in a visual span of apprehension experiment to determine whether second choices made following incorrect first responses are at the chance level, as implied by various high threshold models proposed for this situation. The relationships between response biases on first and second choices, and between first choice biases on trials with two or three possible responses, were also examined in terms of Luce’s (1959) choice theory. The results were: (a) second choice performance in this task appears to be determined by response bias alone, i.e., second choices were at the chance level; (b)first and second choice response biases were not related according to Luce’s choice axiom; and (c) the choice axiom predicted with reasonable accuracy the relationships between first choice response biases corresponding to trials with different numbers of possible response alternatives.     

Spatial and temporal task characteristics as stress: a test of the dynamic adaptability theory of stress, workload, and performance

The goal for this study was to test assertions of the dynamic adaptability theory of stress, which proposes two fundamental task dimensions, information rate (temporal properties of a task) and information structure (spatial properties of a task). The theory predicts adaptive stability across stress magnitudes, with progressive and precipitous changes in adaptive response manifesting first as increases in perceived workload and stress and then as performance failure. Information structure was manipulated by varying the number of displays to be monitored (1, 2, 4 or 8 displays). Information rate was manipulated by varying stimulus presentation rate (8, 12, 16, or 20 events/min). A signal detection task was used in which critical signals were pairs of digits that differed by 0 or 1. Performance accuracy declined and workload and stress increased as a function of increased task demand, with a precipitous decline in accuracy at the highest demand levels. However, the form of performance change as well as the pattern of relationships between speed and accuracy and between performance and workload/stress indicates that some aspects of the theory need revision. Implications of the results for the theory and for future research are discussed.     

Eye movement indices of mental workload

Four investigations were carried out to assess the feasibility of using eye movement measures as indices of mental workload. In the first experiment, saccadic extent was measured during free viewing while subjects performed low, moderate and high complexity, auditory tone counting as the workload tasks. The range of saccadic extent decreased significantly as tone counting complexity (workload) was increased. In the second experiment the range of spontaneous saccades was measured under three levels of counting complexity with a visual task that did not require fixation or tracking. The results indicated that the extent of saccadic eye movements was significantly restricted as counting complexity increased. In the third experiment, the effects of practice were examined and decreased saccadic range under high tone counting complexity was observed even when significant increases in performance occurred with practice. Finally, in experiment 4, the first experiment was repeated with additional optokinetic stimulation and the saccadic range was again observed to decrease with tone counting complexity. The results indicated that the extent of spontaneous and elicited eye movements was significantly restricted as counting complexity increased. We conclude that this measure may provide a valuable index of mental workload.     

Concurrent Performance of Gunner's and Robotics Operator's Tasks in a Multitasking Environment

In this study, we simulated a generic mounted crew station environment and conducted an experiment to examine the workload and performance of the combined position of gunner and robotics operator. Results showed that participants' gunnery task performances degraded significantly when he had to concurrently monitor, manage, or teleoperate an unmanned ground vehicle compared to the gunnery single task condition. For the robotics tasks, participants had the lowest performance when using the semi-autonomous robot, indicating overreliance on the aided target recognition capabilities available when task load was heavy (i.e., concurrent performance of the gunnery task). Participants' perceived workload increased consistently as the concurrent task conditions became more challenging. Individual difference factors such as spatial ability and perceived attentional control were found to correlate significantly with some of the performance measures. Implications for military personnel selection were discussed.     

Task complexity,student perceptions of vocabulary learning in EFL,and task performance

Background. The study deepened our understanding of how students’ self‐efficacy beliefs contribute to the context of teaching English as a foreign language in the framework of cognitive mediational paradigm at a fine‐tuned task‐specific level. Aim. The aim was to examine the relationship among task complexity, self‐efficacy beliefs, domain‐related prior knowledge, learning strategy use, and task performance as they were applied to English vocabulary learning from reading tasks. Sample. Participants were 120 second‐year university students (mean age 21) from a Chinese university. Method. This experiment had two conditions (simple/complex). A vocabulary level test was first conducted to measure participants’ prior knowledge of English vocabulary. Participants were then randomly assigned to one of the learning tasks. Participants were administered task booklets together with the self‐efficacy scales, measures of learning strategy use, and post‐tests. Data obtained were submitted to multivariate analysis of variance (MANOVA) and path analysis. Results. Results from the MANOVA model showed a significant effect of vocabulary level on self‐efficacy beliefs, learning strategy use, and task performance. Task complexity showed no significant effect; however, an interaction effect between vocabulary level and task complexity emerged. Results from the path analysis showed self‐efficacy beliefs had an indirect effect on performance. Our results highlighted the mediating role of self‐efficacy beliefs and learning strategy use. Conclusions. Our findings indicate that students’ prior knowledge plays a crucial role on both self‐efficacy beliefs and task performance, and the predictive power of self‐efficacy on task performance may lie in its association with learning strategy use.     

Perfectionism and performance in a new basketball training task: Does striving for perfection enhance or undermine performance?

ObjectivesIn the psychology of sport and exercise, the question of how perfectionism affects performance is highly debated. While some researchers have identified perfectionism as a hallmark quality of elite athletes, others see perfectionism as a maladaptive characteristic that undermines, rather than helps, athletic performance. Against this background, the purpose of the present study was to investigate how different aspects of perfectionism predict performance and performance increments.MethodA study was conducted with 122 undergraduate athletes to investigate how perfectionism during training affects performance and performance increments in a series of trials with a new basketball training task. Two aspects of perfectionism were examined: striving for perfection and negative reactions to imperfection.DesignThe design was a correlational prospective design.ResultsResults showed that striving for perfection during training predicted higher performance in the new task. In contrast, negative reactions to imperfection predicted lower performance when athletes attempted the task for the first time, once the positive influence of striving for perfection on task performance was partialled out. However, negative reactions to imperfection did not undermine performance in the consecutive trials. On the contrary, athletes with both high levels of striving for perfection and high levels of negative reactions to imperfection showed the greatest performance increments over the series of trials.ConclusionThe findings suggest that perfectionism is not necessarily a maladaptive characteristic that generally undermines sport performance. Instead, when learning a new training task, perfectionism may enhance performance and lead to performance increments over repeated trials.     

Self-observation and learning: the effect of watching oneself on problem solving performance

Two experiments examined the effects of videotape feedback and self-observation on children’s problem solving. The first experiment examined children’s performance on the Tower of Hanoi problem, and demonstrated that video self-observation promotes the acquisition and transfer of procedural knowledge necessary for problem solving. The study also found that specific information presented during the video presentation was not as important as the children seeing their actual prior performance on the problem. The second experiment examined the type of information that may be operative during self-observation. These findings narrow the range of possible explanations for learning through self-observation and, in general, suggest that the positive effect of self-observation is due to active observation of one’s own actual performance.     

Stimulus and response chunking in the Hebb Digits task

Using the Hebb Digits task, an incidental sequential learning paradigm, the effects of chunking of both the presentation and response phases of performance were examined. In the first experiment, consistent stimulus chunking increased learning, and performance was at an equivalent level to this when consistent chunking of both stimuli and responses was present. Consistent chunking of the responses alone did not significantly improve learning over a baseline condition where neither stimuli nor responses were chunked. The disruption of response organization in a second experiment, through a random response condition, failed to impact learning in non-chunked and stimulus chunked conditions. A third experiment found that response chunking did benefit learning in a condition where stimuli were presented in random chunks. A final experiment suggested extended processing of the digits could not account for performance gains in the stimulus chunking condition. Overall, the results suggest that the enhanced effects of chunking on learning were stimulus-driven rather than response-driven, except under conditions that constrained a consistent pattern of stimulus organization.     

The role of the Big Five personality factors in vigilance performance and workload

Using the five‐factor personality model, the present study explored the influence of personality factors on sustained attention and perceived workload. Ninety‐six college‐aged participants were administered a 12 minute vigilance fast event rate task. Following the vigil, participants were asked to first, rate their perceived workload of the task using the NASA‐TLX, and then second, complete the NEO‐PI‐R personality inventory. Traditional measures of hits, false alarms, and reaction times were examined as well as the signal detection indices of perceptual sensitivity and response bias. Extraversion correlated with false alarms (r = 0.181; eta² = 0.055) and conscientiousness correlated with both false alarms (r = ?0.275, eta² = 0.097) and perceptual sensitivity (r = 0.227, eta² = 0.052). With regard to perceived workload, neuroticism was related to perceived frustration (r = 0.238, eta² = 0.057). The findings are discussed in terms of theoretical implications, impact of task parameters, and practical applications. Copyright © 2002 John Wiley & Sons, Ltd.     

LEARNED HELPLESSNESS ATTRIBUTIONAL STYLE AND EXAMINATION PERFORMANCE: ENHANCEMENT EFFECTS ARE NOT NECESSARILY MODERATED BY PRIOR FAILURE

Studies have replicated both negative and positive associations between helpless attributional style and academic performance. Laboratory studies indicate that when enhancement effects occur, they may be moderated by the degree of failure individuals experience prior to task performance. In a longitudinal study of 96 college students who completed four examinations in two introductory psychology courses, we examined the relationship between helpless attributional style and examination performance across the semester, and whether prior examination failure moderated this association. Correlational analyses revealed that helpless attributional style was unrelated to exam performance in the first half of the semester and was positively related to improvements in performance in the second half. Regression analyses indicated that these enhancement effects were not moderated by previous performance on examinations in the course. The present findings underscore the need for longitudinal studies that investigate the pattern of associations between helpless attributional style and performance across time in real-life contexts.     

Conscious error perception: The impact of response interference from a secondary task

An erroneous response is not always accompanied by the conscious perception of the error being made. We examined whether increased response interference on a manual task improved the conscious perception of erroneous eye movements on a concurrent oculomotor task. In the first experiment, we examined whether a correlate of response interference, increased task difficulty alone, could improve perception of errors. We found no effect of task difficulty on self-monitoring. Results from a second experiment suggested that participants’ ability to monitor their eye movements improved with increased response interference, but post hoc analyses indicated that this was due to a decrease in corrective behaviors. Experiment 3 required participants to report directly on whether they had made an eye movement error, and we found that response interference perturbed, rather than improved, participants’ ability to report on their errors. Together, these findings contribute to models of error monitoring, revealing little support for the view that general increases in response interference or task difficulty are signals that contribute to the conscious detection of errors.     

Mindset matters: the role of employees’ stress mindset for day-specific reactions to workload anticipation

In this diary study, we extended knowledge on the role of employees’ stress mindset in the anticipatory phase of the stress process. We examined how workload anticipation is related to approach-coping efforts throughout the workday and how employees’ stress mindset moderates this relationship. Moreover, we investigated how approach-coping efforts are related to vigour and task performance at the end of the workday. Finally, we proposed conditional indirect effects of workload anticipation on vigour and task performance that are moderated by employees’ stress mindset. We conducted a daily diary study over five workdays with 171 employees. Results of multilevel path analysis showed that employees with a more positive stress mindset made more approach-coping efforts when anticipating high workload. Approach-coping efforts were positively related to vigour and task performance. For employees with a more positive stress mindset, workload anticipation had a positive conditional indirect effect on vigour and task performance. Our results suggest that employees react differently to workload anticipation depending on their stress mindset. Moreover, approach-coping efforts may be a cognitive-behavioural mechanism that explains how workload relates to vigour and task performance for employees with a more positive stress mindset.     

Role of multiple resources in predicting time-sharing efficiency: evaluation of three workload models in a multiple-task setting

The goal of our study was to assess the validity of the assumptions underlying three prominent workload models: the Time-Line Analysis and Prediction workload model (Parks & Boucek, 1989), the VACP workload model (Aldrich, Szabo, & Bierbaum, 1989), and the W/INDEX model (North & Riley, 1989). Sixteen subjects flew a low-fidelity flight simulation. Subjects were required to perform a two-axis tracking task, a concurrent visual-monitoring task, and a discrete decision task. The decision task had 16 variations defined by two levels on each of the following dimensions: input modality (visual vs. auditory), processing code (spatial vs. verbal), difficulty (easy vs. hard), and response modality (manual vs. voice). Dual-task costs were found only for the tracking task. The tracking data were then analyzed using two approaches: a traditional analysis of variance (ANOVA) and a correlational analysis of tracking performance versus model predictions. The ANOVA revealed that performance on the tracking task was better when the concurrent decision task was responded to vocally and was easy. Input modality and processing code of the concurrent decision task had no significant effect on tracking performance. The correlational analysis was used to evaluate each of the three models, to determine what features were responsible for improving the models' fit, and to compare their performance with a pure time-line model that makes no multiple-resource assumptions. All three models did a good job of predicting variance between experimental conditions, accounting for between 56% and 84% of the variance in our data and between 10% and 40% of an earlier data set. Different features of each model that affect the fit are then discussed. We conclude that it is important for models to retain a multiple-resource coding, although the best features of that coding remain to be determined. Coding tasks by their demand level appears to be less critical.     

Selective attention and rehearsal in the auditory short-term memory task performance of poor and normal readers

The performance of poor and normal sixth-grade readers was compared on an auditory short-term memory task in two studies. In the first study, the effects of distraction, list length, and speed of stimulus presentation were investigated to test the hypothesis that the performance of the poor readers is affected by deficits in selective attention. Group differences in performance, however, were obtained for both distraction and no-distraction conditions. The second experiment examined the hypothesis that group differences may reflect differences in the use of rehearsal. In the second experiment, half the reading-disabled children and half the controls were provided with rehearsal training prior to completing the same short-term memory task a second time. Rehearsal training resulted in improved performance relative to children who were not trained; however, there was no rehearsal training x reading group interaction. The poor readers continued to show deficits in performance relative to the performance of control children. The results of these two studies suggest that deficits observed for poor readers on short-term memory tasks may reflect processing difficulties in some area that precedes rehearsal and affects performance under both distraction and no-distraction conditions.The authors wish to express their thanks to the Sachem School District and Betty Gould, Nicholas Opinanate, and Guy Barber for their unlimited cooperation, and to John Neale for very helpful discussions of a number of issues in this paper.