Search PubMed⌕ Search

Biomedical subjects

G R Hockey

Publications and source records attributed to G R Hockey.

At least 19 recordsLinked to original sources
PubMed2000

Effects of time-pressure on decision-making under uncertainty: changes in affective state and information processing strategy.

An experiment is reported that investigated the extent to which affective state, information processing strategy and task structure determine the effects of time-pressure on decision-making. Research participants were presented with risk scenarios involving a choice between safe and risky actions. The scenarios were systematically varied in terms of outcome valence (positive or negative) and effort associated with taking the safe action (high or low). Half the participants were given unlimited time to make their decision, the other half were required to choose within a deadline. The findings showed that time-pressured participants were more anxious and energetic and used a number of different strategies to cope with the deadline. These effects, as well as changes in risk-taking, were shown to vary systematically with task structure, particularly the effort manipulation. The findings are discussed in terms of how they contribute to theories of time-pressure and the methodological implications they have for future research in this area.

Adaptation, Psychological↗
PubMed2000

A conceptual framework for designing micro-worlds for complex work domains: a case study of the Cabin Air Management System.

A conceptual framework for the design of micro-worlds is presented in this paper. This is illustrated by a micro-world, called Cabin Air Management System (CAMS), that has been used in a research program to investigate human behavior during work with complex systems. Although CAMS is based on the operational context of spaceflight, its underlying principles correspond to a process control task. The authors propose a theoretical framework for micro-world design, which was used to guide the development of the CAMS micro-world. This may provide a helpful guideline for researchers wishing to develop a micro-world by using a more structured approach. A detailed technical description of CAMS is given to demonstrate the kind of real-world scenarios that may be simulated with this task environment. Finally, general aspects of the utility of micro-world research are discussed.

Air Conditioning↗
PubMed2000

Effects of training on short- and long-term skill retention in a complex multiple-task environment.

The paper reports the results of an experiment on the performance and retention of a complex task. This was a computer-based simulation of the essential elements of a spacecraft's life support system. It allowed the authors to take a range of measures, including primary and secondary task performance, system intervention and information sampling strategies, mental model structure, and subjective operator state. The study compared the effectiveness of two methods of training, based on low level (procedure-based) and high level (system-based) understanding. Twenty-five participants were trained extensively on the task, then given a 1-h testing session. A second testing session was carried out 8 months after the first (with no intervening practice) with 17 of the original participants. While training had little effect on control performance, there were considerable effects on system management strategies, as well as in structure of operator's mental model. In the second testing session, the anticipated general performance decrement did not occur, though for complex faults there was an increase in selectivity towards the primary control task. The relevance of the findings for training and skill retention in real work environments is discussed in the context of a model of compensatory control.

Adult↗
PubMed1999

Multiple-task performance on a computer-simulated life support system during a space mission simulation.

This paper presents an experiment which examined the effects of isolation and confinement during a simulation of a short-term space mission. During the 7-day spaceflight simulation, four Canadian astronauts were tested daily on a 30-min performance task. The task, CAMS (Cabin Air Management System), represents a computer-based simulation of a generic life support system. As a multiple-task environment, it allows the measurement of a wide range of task management variables such as primary and secondary task performance, and system control activities. Measures of subjective state variables were also taken. The results did not show any evidence of serious performance decrements for any crew member. The analysis revealed different adjustment patterns with which crew members responded as a function of mission duration and variations in workload. Among the secondary tasks employed, prospective memory was found to be more sensitive than reaction time to increases in workload. The paper concludes with a discussion of the utility of spaceflight simulations and computer-based simulations of space work.

Adaptation, Psychological↗
PubMed1999

Performance evaluation in analogue space environments: adaptation during an 8-month Antarctic wintering-over expedition.

BACKGROUND: This paper reports a study which examined the impact of long-term isolation and confinement on multiple-task performance. METHODS: A group of 10 scientists and 6 technicians from a French wintering-over expedition in the Antarctic participated in the 8-mo study. The group was tested 8 times on a computerized simulation of a complex life support system. The task environment allowed the measurement of primary and secondary task performance, system control activities and subjective operator state. RESULTS: No signs of serious performance decrements were observed but a number of subtle indications of hidden decrements emerged. The data also revealed strong differences in performance between the professional groups. Finally, the paper discusses the implications of the work for extended spaceflight.

Adult↗
PubMed1999

Maintenance of complex performance during a 135-day spaceflight simulation.

BACKGROUND: The maintenance of crew performance during extended space missions has been a major concern because of the problems associated with prolonged isolation and confinement. Previous research has failed to address this problem by not using appropriate performance tests. METHOD: Three Russian cosmonauts were tested on a PC-based simulation of a spacecraft's life support system during a 135-d simulation of a MIR spaceflight. A complex multiple-task environment was used to examine a comprehensive range of task management variables, including both primary and secondary task performance, control activity and information sampling behavior. Subjective state variables were also measured. RESULTS: The data suggested an overall successful adjustment to isolation and confinement, though some indications of temporary disruptions of some performance indicators were observed. Information sources were sampled less frequently with increasing mission length while system control activities showed a tendency to increase. CONCLUSION: Suggestions are made to address the problem of continuous learning during repeated testing sessions. Using well-designed computer simulations of complex task environments appears to be a promising approach for the evaluation of crew member performance.

Adult↗
PubMed1998

Task analysis for the investigation of human error in safety-critical software design: a convergent methods approach.

An investigation was conducted into sources of error within a safety-critical software design task. A number of convergent methods of task- and error-analysis were systematically applied: hierarchical task analysis (HTA), error log audit, error observation, work sample and laboratory experiment. HTA, which provided the framework for the deployment of subsequent methods, revealed possible weaknesses in the areas of task automation and job organization. Application of other methods within this more circumscribed context focused on the impact of task and job design issues. The use of a convergent methods approach draws attention to the benefits and shortcomings of individual analysis methods, and illustrates the advantages of combining techniques to analyse complex problems. The features that these techniques should possess are highlighted.

Ergonomics↗
PubMed1998

Effects of sleep deprivation and user interface on complex performance: a multilevel analysis of compensatory control.

This study was carried out to test the compensatory control model, which predicts performance maintenance under stress at the expense of effort and increased selectivity. It examined the effects of sleep deprivation on performance in an automated process control task based on a simplified life support system with two types of operator control panel interface: machine centered (M-C), in which access to the system was scheduled by the computer, and human-centered (H-C), in which access was ad-lib. The task environment also permitted the analysis of changes in strategy and in subsidiary activities (alarm reaction time, prospective memory). In a 2 x 2 repeated-measures design, 16 participants carried out the task with each interface after both normal sleep and one night of sleep deprivation (SD). No effects of SD were observed on primary task performance. As predicted, SD effects were confined to strategy changes and subsidiary task impairment and occurred only under the (low control) M-C interface. Subjective effort was increased under SD, with greater increases of effort associated with high levels of performance protection. The findings provide strong evidence in favor of the compensatory control model and argue for the use of complex, multilevel tasks in the analysis of performance under stress. Actual or potential applications include the development of more sensitive performance-testing systems based on multilevel analysis of decrement, and the design of interfaces for shift work and other suboptimal work conditions.

Adult↗
PubMed1997

Compensatory control in the regulation of human performance under stress and high workload; a cognitive-energetical framework.

This paper presents a cognitive-energetical framework for the analysis of effects of stress and high workload on human performance. Following Kahneman's (1973) model, regulation of goals and actions is assumed to require the operation of a compensatory control mechanism, which allocates resources dynamically. A two-level compensatory control model provides the basis for a mechanism of resource allocation through an effort monitor, sensitive to changes in the level of regulatory activity, coupled with a supervisory controller which can implement different modes of performance-cost trade-off. Performance may be protected under stress by the recruitment of further resources, but only at the expense of increased subjective effort, and behavioural and physiological costs. Alternatively, stability can be achieved by reducing performance goals, without further costs. Predictions about patterns of latent decrement under performance protection are evaluated in relation to the human performance literature. Even where no primary task decrements may be detected, performance may show disruption of subsidiary activities or the use of less efficient strategies, as well as increased psychophysiological activation, strain, and fatigue after-effects. Finally, the paper discusses implications of the model for the assessment of work strain, with a focus on individual-level patterns of regulatory activity and coping.

Adaptation, Psychological↗
PubMed1996

Skill maintenance in extended spaceflight: a human factors analysis of space and analogue work environments.

This paper discusses the implications of increasing mission lengths of manned spaceflight for the design of future space systems from a human factors point of view. It is argued that the increase in mission duration has brought about a number of new problems, which have not been sufficiently addressed in space research. Therefore, a review of analogue work environments is carried out to make up for the paucity of space research found in the area of human performance in long-duration spaceflight. This resulted in an evaluation of seven analogue environments concerning their similarity to space with industrial process control and nuclear submarines coming out as the closest match on the technical dimension. Finally, some recommendations are given from the lessons learned in spaceflight, simulation studies and appropriate analogue environments.

Aerospace Medicine↗
PubMed1996

Cognitive fatigue and complex decision making under prolonged isolation and confinement.

Cognitive fatigue and subjective state were assessed in four healthy subject (three males and one female), confined for a period of 60 days in a hyperbaric chamber stimulating a space station environment. They were required to carry out daily a working memory/decision-making test, simulating the management of the levels of contaminants present in a spacecraft atmosphere. Information about a set of contaminants is presented on a 'reference screen.' This has to be memorized, then used to make decisions about the need for corrective action across a sequence of four 'status screens.' Subjects may check back to the reference information at any time. A low error rate was emphasized in the instructions and training. In addition to error rate, performance was also measured in terms of the time taken to make decisions and checks of reference screens (decision time and check time). Subjective measures were also made of workload and environmental resources (personal control and support), levels of anxiety and fatigue before the task, and cognitive effort expended during the task. The search for decrements during the second half of the isolation period was complicated by evidence of a continued learning process during the first half, probably because of insufficient practice before isolation. Learning curves (negative exponential functions) were fitted to the data points for the first half of the isolation period, and residuals between predicted and observed data for the second four weeks were analyzed. All subjects showed increases in decision time and check time during the last weeks of isolation, with one subject also showing an increase in errors. Workload levels were reported as moderate, but varied across the four subjects, The same was true for resources. Anxiety was low and relatively stable over the entire 60-day period, but fatigue levels were elevated during the second half. This was particularly true for the two subjects who maintained the required low error rate. Effort was also quite stable, through it tended to follow changes in work demands and fatigue. Individual subjects are seen to adapt to the stress of prolonged isolation in different ways. Two subjects maintained low error rates under increasing subjective demands by additional cognitive effort and slowing of performance. The other two subjects exhibit more widespread decrement, including high error rates, without increase in subjective demands. The analysis of individual patterns of adaptation is recommended as a way of understanding and predicting the impact of isolation and confinement during spaceflights.

Adaptation, Psychological↗
PubMed1995

Level of operator control and changes in heart rate variability during simulated flight maintenance.

The demands of dynamic monitoring and fault diagnosis for flight engineer trainees were examined in relation to changes in heart rate (HR) and two spectral analysis measures (midfrequency: 0.07-0.14 Hz; high frequency: 0.15-0.40 Hz) of heart rate variability (HRV). Eleven trainee flight engineers were studied, as part of their training and assessment, over three 3-h sessions in a cockpit simulator. During each session, faults and incidents programmed into the system had to be detected, diagnosed, and corrected. Electrocardiograms were taken, and each session was recorded on videotape. Work phases were classified from video analysis of flight maintenance activities, using Rasmussen's cognitive control taxonomy, into monitoring, routine (rule-based), and problem-solving (knowledge-based) phases. HR and HRV were found to be sensitive to different phases of the work environment. HRV was suppressed during the mentally demanding problem-solving mode of the level flight phase, but only for the midfrequency component. Elevated heart rate, in contrast, was associated with the more generally stressful takeoff and landing phases. The findings support both the use of HRV as a physiological index of mental effort and its value in operational contexts, and the value of ecologically derived methods of evaluating differences in work demands in complex systems.

Adult↗
PubMed1993

European isolation and confinement study. Cognitive fatigue in complex decision-making.

In six healthy males, confined in a hyperbaric chamber complex for 4 weeks, mental fatigue was assessed by means of a Working Memory Test. This test involved a decision-making task, which concerned the management of the chemical environment of a spacecraft affected by the presence of contaminants. Five items of reference information were shown on a screen and had to be memorized, then five "status" cards were given, upon which the need for corrective action had to be decided. Checking back to the reference information was permitted. The following parameters of the decision-making process were recorded: memorizing time (MT), decision-making time (DT), checking-back time (CT), total time per card (TT), and percent false decision (%E). Data analysis had to compensate for continued learning during the isolation period, because the pre-isolation training period had been too short. For this reason, only the last 3 weeks of isolation were considered. Only data from correct trials were used in data analysis. The group average performance measures were fairly constant over the 3-week period, indicating that there are no strong overall effects of isolation on mental functioning. There is a tendency towards increasing MT and CT and decreasing DT, but these changes are not statistically significant. There was also a tendency for increased mental fatigue on weekends (only the increase in CT was statistically significant). Analysis of the data for the one subject without missing days and with low and constant error rates over the three weeks shows that his behavior became more variable over time (particularly in DT), and that a breakdown of normal cognitive processes occurred on two days during the fourth week of isolation. Further experiments with a longer pre-isolation training period and a longer isolation period are needed to determine whether this is a general or an exceptional phenomenon.

Cognition↗
PubMed1989

Assessing the impact of computer workload on operator stress: the role of system controllability.

This paper considers the impact of working with computer-based systems in terms of mental workload and the well-being of operators. In particular, the paper focuses on issues of controllability in human-computer systems as they relate to operator stress. Through the adoption of a state control model of stress regulation, it becomes apparent that while general usability criteria are necessary for the design of controllable systems, they may not be sufficient to guarantee controllability. The implications for research and system design are discussed, with reference to the assessment of operator workload, controllability and stress. A methodology for assessing computer stress is described, based on the analysis of stressful computer-related episodes and their accompanying affective and cognitive states. This technique allows the relationship between workload and controllability to be studied in particular computer work environments, in relation to individual work goals and coping strategies.

Attitude to Computers↗
PubMed1977

Effects of cigarette smoking on incidental memory.

The effects of cigarette-smoking in an immediate memory task were studied in two groups of 25 female students (habitual smokers) tested either under a control (no smoking) condition or after smoking one cigarette. The memory task, requiring immediate serial recall of eight words, showed no differences between the two groups. Subjects were, however, also tested on recall of the position of words on the screen (each word could appear in any of the four corners). On this measure of incidental recall, the non-smoking group was far superior to the smoking group. This finding is in agreement with results obtained with noise-induced arousal and with the view that attentional selectivity is greater during increased arousal.

Adult↗