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EFFECT OF SENSORY MODALITY ON PERFORMANCE, WORKLOAD, AND FRONTAL
LOBE OXYGENATION IN A STANDARD VIGILANCE TASK
Veronica E. Scerra
Advisor: J. Christopher Brill
Human Factors Psychology
Old Dominion University
Abstract
The purpose of this research was to compare vigilance performance over time for visual,
auditory, and vibrotactile tasks, while simultaneously recording oxygenation in the frontal lobe
to assess physiological resource utilization. Subjective workload was assessed in each condition
using the NASA Task Load Index (NASA-TLX). The data indicate a significant effect of timeon-task in all experimental conditions, with the vigilance decrement asserting in each modality
condition within the first twenty minutes of the task. Significant differences in overall hit rates
and nonparametric sensitivity (A′) were found between the loosely coupled visual modality and
the closely coupled tactile and auditory modalities. Conversely, frontal lobe oxygenation
increased with time-on-task, possibly reflecting increased processing demands as cognitive
resources wane. The results suggest that although the vigilance decrement exists for all modality
conditions, tactile vigilance tasks may be performed as efficiently as auditory vigils, with no
significant differences in workload or physiological resource utilization
Scerra
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