Stimulus complexity and dual tasking effects on sustained auditory attention in noise.
BACKGROUND
The effect on sustained auditory attention of a constellation of factors that characterize aviation, maritime, and land environments was investigated. The ability to detect infrequent spoken messages while performing an unrelated visual motor tracking task was studied in the presence of background noise.


METHODS
Six subjects each were assigned to four conditions defined by the presence/absence of 80-dBA pink noise and presence/absence of the secondary task. Subjects were given three detection tests in which the 75-dB SPL critical signal was comprised of one, two, or three components. A button press with the left hand signified detection of the critical signal. For each test there were six consecutive 20-min vigils comprised of 150 trials. The critical signal was presented in 10 of these. For the tracking task subjects used a computer mouse controlled by the right hand to follow the sinusoidal movement of a 3-cm vertical line across a computer monitor.


CONCLUSIONS
Background noise resulted in a significant decrease in hits, and significant increases in false alarms and response time. Since the signal and noise were both auditory, the noise was likely effective as a masker rather than a stressor. The secondary task did not impact performance, possibly because the auditory task was too easy and the event rate too slow. As in previous studies using alphanumeric events, there was no attention decrement over time. However, response time decreased as the number of components in the critical signal increased. Possible explanations are guided attention through priming or the provision of a temporal foreperiod.
Abel
Sharon M
SM
Individual Readiness Section, Defence Research and Development Canada--Toronto, Toronto, Ontario, Canada. sharon.abel@drdc-rddc.gc.ca
D001288:Attention; D001302:Audiometry, Speech; D006309:Hearing; D006801:Humans; D010470:Perceptual Masking; D011930:Reaction Time; D013647:Task Performance and Analysis