Behavioural awakening and subjective reactions to indoor sonic booms

• Published in: Journal of sound and vibration Vol. 25; no. 3; pp. 479 - 495
• Main Authors: Ludlow, J.E., Morgan, P.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 08.12.1972
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/0022-460X(72)90195-2

Two experiments were conducted to investigate behavioural awakening (as measured by a button press) and subjective reactions to simulated sonic booms presented during sleep. In each experiment, eight young male subjects were used. In the first experiment, simulated booms, having intensities of 71·2, 74·2 and 77·6 dBA (fast), had no significant differential effects upon behavioural awakening frequencies. Of the subjective tests, only the fatigue test (FTCL) gave significantly adverse results for experimental (boom exposure) nights compared to control nights. However, for all such tests (a subjective stress scale, and simple subjective scales relating to the “depth” of sleep, sleep disturbance, and fatigue) there was a tendency for reported adverse effects following boom exposure nights. In the second experiment, simulated booms covered a wider range of intensities (69, 79, and 84·5 dBA (fast)), and significant differential behaviour awakening was found, with higher frequencies of awakening to higher intensity booms. In addition, all subjective tests revealed significantly more adverse effects, the higher the boom intensity. It is not unexpected that a certain minimum difference between stimulus intensities should be exceeded in order to obtain a range of behavioural and subjective effects. This is tentatively set at 6 dBA (fast) for indoor sonic booms. It is suggested that the subjective tests used in these experiments adequately reflected the behavioural responses resulting from sonic boom exposure during sleep, and that they are applicable to field work of a similar nature. In both experiments it was found that subjects awoke more frequently in the later part of the night (3–6.30 a.m.), and in Experiment 2, subjects also awoke in response to booms more often in the later part of the night. Again, in both experiments, there was a tendency towards a decline in the number of awakenings as the nights progressed. In Experiment 2, there was an additional waning of responses to the simulated booms, and a decrease in the number of times subjects were already awake when a boom occurred. No changes in the personality traits which were measured (extroversion, neuroticism, anxiety) were found as a result of the experimental program.