Performance in the sentence recognition task.

Lists of twenty sentences presented at different SNRs in Exp.1 (left panel), in which 21 listeners sat in a normally-lit room (75 lux). Exp.2 measured performance in the same task (using different sentence lists than in Exp.1) at two SNRs in which 28 listeners sat in the same room under similar luminance settings (75 lux), or in close-to-darkness (0 lux), or in very bright luminance settings (220 lux). Luminance (although it has a huge impact on the pupil) had no effect on behavioral performance. Error bar represents 1 standard error from the mean.