Effect of oise Reduction on Reaction Time to Speech in oise

In moderate levels of noise, listeners report that noise reduction (NR) processing can improve the perceived quality of a speech signal as measured on a typical MOS rating scale. Most quantitative experiments of intelligibility, however, show that NR reduces the intelligibility of noisy speech signals, and so should be expected to increase the cognitive effort required to process utterances. To study cognitive effort we look at how NR affects reaction times to speech in noise, using material that is still highly intelligible. We show that adding noise increases reaction times and that NR does not restore reaction times back to the quiet condition. The implication is that NR does not make speech "easier" to process, at least as far as this task is concerned.