The Effects of Intermittent Noise on Human Serial Decoding Performance and Physiological Response

The effects of continuous, periodic, and aperiodic broad band noise on serial decoding performance and on three physiological response measures were investigated. Performance data were recorded from 16 undergraduate university students using an electronically programmed rapid serial decoding task. The task configuration chosen combined a basic serial reaction function with a mental coding and short-term memory function. To assess activation or arousal effects of noise, three physiological variables were also simultaneously recorded: finger photoplethysmographic blood volume pulse amplitude, pulse rate, and forearm eleetromyogram. In addition, responses to a noise annoyance sensitivity questionnaire were used in an attempt to assign subjects to experimental groups such that noise annoyance sensitivity across groups would be constant. Each subject was isolated in a soundproof chamber while performance data and physiological data were collected under four counterbalanced conditions: work in quiet, continuous noise, periodic noise, and aperiodic noise. A sound intensity level of 93 dBA broad band noise was used in all noise conditions. Finger vasoconstriction response was found to be significantly higher in all noise conditions than in quiet (p<0·03). Furthermore, vasoconstriction response was higher for persona found to be highly annoyed by noise than for persons less annoyed by noise (p<0·01). The results showing a significant relationship between a subjective measure of noise annoyance sensitivity and a measured physiological variable, photoplethysmographic blood volume pulse amplitude, do not appear to have been previously reported.