Biomedical subjects

L J Prinzel

Publications and source records attributed to L J Prinzel.

5 recordsLinked to original sources

PubMed2000

Evaluation of a psychophysiologically controlled adaptive automation system, using performance on a tracking task.

Three experiments were conducted to evaluate the performance of a psychophysiologically controlled adaptive automation system. Subjects were asked to perform a compensatory tracking task while their electroencephalogram (EEG) was recorded and an engagement index was derived from the EEG, using the alpha, beta, and theta bandwidths: beta/(alpha + theta) and beta/theta. In Experiment I, EEG was recorded from three different sites: frontal, parietal, and temporal. Although tracking performance did not differ as a function of site, the number of task mode allocations was greater under a negative feedback contingency than under a positive feedback contingency. This effect was seen primarily from frontal sites. Experiments II and III evaluated the adaptive automation system, using extended runs under positive and negative feedback with either a slope (Experiment II) or absolute (Experiment III) criterion used to drive the system. Using either criterion, performance was found to be significantly better under negative feedback. Future evaluation and use of psychophysiologically controlled adaptive automation systems are discussed.

Adaptation, Physiological↗

PubMed2000

A closed-loop system for examining psychophysiological measures for adaptive task allocation.

A closed-loop system was evaluated for its efficacy in using psychophysiological indexes to moderate workload. Participants were asked to perform either 1 or 3 tasks from the Multiattribute Task Battery and complete the NASA Task Load Index after each trial. An electroencephalogram (EEG) was sampled continuously while they performed the tasks, and an EEG index (beta/alpha plus theta) was derived. The system made allocation decisions as a function of the level of operator engagement based on the value of the EEG index. The results of the study demonstrated that it was possible to moderate an operator's level of engagement through a closed-loop system driven by the operator's own EEG. In addition, the system had a significant impact on behavioral, subjective, and psychophysiological correlates of workload as task load increased. The theoretical and practical implications of these results for adaptive automation are discussed.

Adaptation, Psychological↗

PubMed1999

Evaluation of an adaptive automation system using three EEG indices with a visual tracking task.

A system was evaluated for use in adaptive automation using two experiments with electroencephalogram (EEG) indices based on the beta, alpha, and theta bandwidths. Subjects performed a compensatory tracking task while their EEG was recorded and converted to one of three engagement indices: beta/(alpha + theta), beta/alpha, or 1/alpha. In experiment one, the tracking task was switched between manual and automatic modes depending on whether the subject's engagement index was increasing or decreasing under a positive or negative feedback condition. Subjects were run for three consecutive 16-min trials. In experiment two, the task was switched depending on whether the absolute level of the engagement index for the subject was above or below baseline levels. It was hypothesized that negative feedback would produce more switches between manual and automatic modes, and that the beta/(alpha + theta) index would be most effective. The results confirmed these hypotheses. Tracking performance was better under negative feedback in both experiments; also, the use of absolute levels of engagement in experiment two resulted in better performance. There were no systematic changes in these effects over three 16-min trials. The implications for the use of such systems for adaptive automation are discussed.

Adaptation, Biological↗

PubMed1997

Task-specific sex differences in vigilance performance: subjective workload and boredom.

Participants (24 men, 24 women) were asked to perform either a spatial or temporal vigilance task. Task-related Boredom and NASA-Task Load Index scores were collected. The results replicate Dittmar, Warm, Dember, and Ricks' 1993 finding of task-specific sex differences in vigilance performance and subjective workload. The present study also showed task-specific sex differences for boredom ratings. These results suggest that two explanations may account for the sex differences. More accurate perceptual discriminations may account for some of the differences in performance; however, sex differences in perceived boredom may more likely be responsible for the task-specific sex differences in vigilance performance and subjective workload.

Adolescent↗

PubMed1995

Sex differences in visuo-spatial ability: task difficulty, speed-accuracy tradeoff, and other performance factors.

Males have consistently been found to perform better than females on a task that requires the subject to mentally rotate a figure. Recently, Goldstein. Haldane, and Mitchell (1990) suggested that performance factors are operative in explaining sex differences in spatial ability. However, Stumpf (1993) was unable to replicate all of Goldstein et al.'s (1990) findings and to generalize them to other measures of spatial ability. In this study, it was hypothesized (1) that females would take longer to respond and would get fewer correct items than males on a spatial rotation task, and (2) that only females would show a speed-accuracy tradeoff as the difficulty of the spatial task increased from the 90 degrees to 180 degrees rotated conditions. The results confirmed each of these hypotheses. Furthermore, as Stumpf (1993) found, when ratio scores from the number of items correct to number attempted were computed for both males and females, differences in spatial ability were reduced, though still evident.

Adolescent↗