Listening effort: A consequence of continuous listening in noise?
Listening in noise is known to impact negatively on speech perception (Miller & Nicely, 1955). It also has consequences for cognitive abilities like short-term memory capacity (Rabbitt, 1968) possibly because of increased processing demands (i.e., listening effort) induced by the noise. This study aimed at understanding the role of listening in noise on ability to sustain attention. It was based on the hypothesis that listening in noise is resource-heavy and results increased lapsing of attention as processing resources are exhausted.
We tested this hypothesis in typically-developing children, aged 6 - 12 years, who completed a continuous listening task (Roebuck, Freigang, & Barry, in prep) presented in 4-speaker babble at +2dB SNR. The task involved listening to a story (16 mins) and pressing a button to intermittently occurring targets. The targets (n = 108) were either nonsense words (n = 36) or mispronunciations, which could be predicted (n = 36) or not predicted (n = 36) from the preceding context. Three noise conditions were used: (1) noise throughout (2) noise 1st half; (3) noise 2nd half.
Previous research (Roebuck et al., in prep) suggests a benefit when listening in quiet for predictable words compared with unpredictable or nonsense words. Reflecting increasing listening effort and consequent lapsing in attention, we predicted for Condition 1: A) an increase in errors due to the more difficult listening conditions, B) a decrease in benefit of context and, C) an increase in reaction time from the first to the second half of the task.
Predictions A and B were supported by the data for all age groups. Reaction times, however, decreased significantly from the first to the second half of the task. In addition to possible effects due to listening effort, the findings suggest influences from on-task learning, and possible adaptation to noise over time. Conditions 2 and 3 (in progress) explore these different possible contributions to continuous listening in noise.
Miller, G. A., & Nicely, P. E. (1955). An analysis of perceptual confusions among some English consonants. Journal of the Acoustical Society of America, 27(2), 323-352.
Rabbitt, P. M. (1968). Channel-capacity, intelligibility and immediate memory. The Quarterly Journal of Experimental Psychology, 20(3), 241-248.
Roebuck, H., Freigang, C., & Barry, J. G. (in prep). Listening to continuous speech: the role of sustained attention in children referred for listening difficulties without hearing loss.