ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_1

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

Our study examined pilot scheduling behavior in the context of simulated instrument flight. Over the course of the flight, pilots flew along specified routes while scheduling and performing several flight-related secondary tasks. The first phase of flight was flown under low-workload conditions, whereas the second phase of flight was flown under high-workload conditions in the form of increased turbulence and a disorganized instrument layout. Six pilots were randomly assigned to each of three workload preview groups. Subjects in the no-preview group were not given preview of he increased-workload conditions. Subjects in the declarative preview group were verbally informed of the nature of the flight workload manipulation but did not receive any practice under the high-workload conditions. Subjects in the procedural preview group received the same instructions as the declarative preview group but also flew half of the practice flight under the high-workload conditions. The results show that workload preview fostered efficient scheduling strategies. Specifically, those pilots with either declarative or procedural preview of future workload demands adopted an efficient strategy of scheduling more of the difficult secondary tasks during the low-workload phase of flight. However, those pilots given a procedural preview showed the greatest benefits in overall flight performance.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_2

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

Psychophysiological assessment of pilot mental workload using heart rate should be augmented with an autonomic space model of cardiovascular function. This model proposes that autonomic nervous system influences on the heart may change with psychological processing in ways that are not evident in heart rate. A method of mental-workload assessment was proposed that used multiple psychophysiological measures of cardiovascular responsivity to derive the underlying sympathetic and parasympathetic information needed to represent the autonomic space for heart rate. Principal-components analysis was used to extract Sympathetic and Parasympathetic components from heart period, residual heart period, respiratory sinus arrhythmia, and Traube-Hering-Mayer wave in three experiments that manipulated perceptuallcentral processing and physical task demands. This initial evaluation of the method concluded that the autonomic components were valid and that the components had greater diagnosticity, and for some manipulations greater sensitivity, than heart rate. These results support the contention that the Sympathetic and Parasympathetic components provided increased precision for mental-workload assessment.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_3

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

This study examined the effects of exposure to intermittent jet aircraft noise (70 dBA or 95 dBA maximum intensity) and knowledge of results concerning signal detections (hit-KR) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Perceptual sensitivity (d) was poorer in the context of noise than in quiet but only in the presence of hit-KR. The lack of noise-related performance differences in the absence of hit-KR most likely reflected a "floor effect" rather than some special relation between noise and feedback. When compared to subjects performing in quiet, those who operated in noise were less able to profit from hit-KR, a result that may reflect the effects of noise on information processing. In addition to its negative effects on signal detectability, noise elevated the perceived workload, as measured by the NASA-TLX. This effect was robust; it was independent of the presence of hit-KR, even though hit-KR generally lowered the overall level of perceived workload. The results provide the initial experimental demonstration that perceived workload is a sensitive measure of the effects of aircraft noise in monitoring tasks.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_4

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

Two experiments are reported that examined the influence of variation in task demand on performance and workload. The first experiment considered how the manipulation of prior level of task demand affected subsequent workload and performance. The second experiment examined the effects on performance and workload of increments in the level of task demand. Results from the first study indicated that prior level of imposed task difficulty did affect response in a manner consistent with a scaling of workload in relation to previous task conditions. The second study demonstrated the primacy of absolute demand level over increments in that demand as influencing operator response. Overall, our results indicate that workload and performance are sensitive to multiple characteristics of the task and not instantaneous demand level alone. These findings are important in explaining why association and dissociation occur between task demand, operator efficiency, and perceived workload in differing performance contexts. The importance of these findings for the aviation psychologist in assessing pilot and operator workload is articulated.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_5

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

Previous research with the NASA Task Load Index (TLX) and the Subjective Workload Assessment Technique (SWAT) has demonstrated their sensitivity to variations in workload under flight and other complex work conditions but has not addressed some important measurement and methodological issues regarding their application. This article reviews data that address several such issues including the effects of delayed workload ratings, the effects of previous workload levels on ratings, and procedures used to combine subscale ratings into one overall estimate of subjective workload.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_6

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor

摘要:

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.

ISSN:1050-8414    

DOI:10.1207/s15327108ijap0501_7

出版商:Lawrence Erlbaum Associates, Inc.    

年代:1995

数据来源: Taylor