Unstable Tracking Research Articles

Selective Auditory - Visual Interference Effects in a Dual Task Paradigm: Implications for Assessing Individual Differences

Three experiments are reported that tested predictions from a multiple resource framework for selective patterns of interference in a visual - auditory dual task paradigm. Subjects performed an auditory memory search task both alone and in conjunction with several visual information processing tasks. In Experiment 1 the level of speech intelligibility in the memory search task did not affect performance in an unstable tracking task. In Experiments 2 and 3 speech intelligibility did affect performance in a spatial processing task and a mathematical reasoning task. These results are discussed in terms of their relevance for designing a test battery to identify individuals likely to be affected by changes in speech intelligibility.

Rapid Communication Display Technology Efficiency in a Multi-Task Environment

The present study examined the advantage of Rapid Communication (RAP-COM) Display Technology over conventional spatially arrayed displays in the context of secondary task demands. This research represents an early step in assessing the use of RAP-COM display techniques in multi-task environments. Eight subjects were instructed to respond to briefly presented visual stimuli, while concurrently performing an unstable tracking task at two levels of difficulty. Duration thresholds, obtained using a moment-to-moment adaptive tracking performance procedure, were collected for RAP-COM and spatially arrayed displays while RMS error scores were collected from the unstable tracking task performance. Information transfer rates for the RAP-COM technique were faster than for the spatially distributed array under both the single and dual task conditions. Regardless of secondary tracking task difficulty, subjects were able to maintain primary task performance levels on RAP-COM and spatial display tasks, although a decrement in tracking performance was seen.

Gender Differences in Criterion Task Set Performance and Subjective Ratings

This paper summarizes gender differences in performing various elements of the Criterion Task Set. Performance data and Subjective Workload Assessment Technique ratings were analyzed for 28 men and 28 women who participated in a large-scale CTS validation study. In general, women tended to perform slightly better than men on the majority of tasks. In particular, performance by women was better on Grammatical Reasoning, Linguistic Processing, Mathematical Processing, and Memory Search. Response times on Probability Monitoring were faster for women but at the expense of a greater number of False Alarms. Men performed better only on the high level of Continuous Recall and the medium level of Unstable Tracking. Women tended to give lower subjective ratings than men to those tasks with a high memory component and gave higher ratings than men to those tasks involving input/output and spatial elements.

Development of the Criterion Task Set Performance Data Base

The initial phase of a large-scale experimental study was conducted involving the training and testing of fifty human subjects on the Criterion Task Set (Version 1.0). Testing was performed under baseline conditions and the stressors of noise and sleep loss. The resulting data base includes CTS performance data and subjective ratings obtained using the Subjective Workload Assessment Technique (SWAT) for each task, along with information on subject individual differences. This paper presents the methodology used for the data collection and analysis efforts and provides a summary of the performance and subjective assessment information. In general, no performance differences were found under the noise stress condition. Following sleep loss, response times for the central processing tasks deteriorated as did performance on the Unstable Tracking and Interval Production tasks.

A Technique for Trolley Arc Reduction

Arcing which occurs at the trolley shoe is one of the leading causes of electrical accidents in the coal mining industry. Arcs occur if trolley contact is made or broken under load. Some of these incidents are caused by improper vehicle operation and others occur as a result of unstable tracking conditions. The arcing can be reduced by detecting the disconnect condition and snubbing the arc by responsive control circuitry. Once the disconnect has been completed, reconnection under load can be controlled with the same circuitry. A system of accomplishing this arc reduction is presented along with the results of a simulation used to test the effectiveness of the technique. Guidelines are suggested for incorporating arc-reducing control circuitry into mine track vehicles.