(A) Unique variance explained by task engagement (r2 task-unique) in primary auditory cortex (A1; left) and inferior colliculus (IC; right) for each unit, grouped by animal. Mean variance explained did not differ significantly between animals in either area (A1 animal R: 0.025, T: 0.023, B: 0.017, F = 0.606, p = 0.547; IC animal R: 0.028, B: 0.021, L: 0.022, F = 0.221, p = 0.803, ANOVA). (B) Task performance (d’) for each behavior block, grouped by animal and recordings in A1 (left) and IC (right). Mean d’ differed between animals in both groups of experiments (A1 animal R: 1.55, T: 1.35, B: 0.93, F = 15.8, p < 0.0001; IC animal R: 1.52, B: 1.61, L: 2.48, F = 23.9, p < 0.0001, ANOVA). Interactions between animal and d’ on neural behavior state effects are reported in Figure 4 in the main text. (C) Unique variance explained by changes in pupil size (r2 pupil-unique), plotted as in A. Mean variance explained differed between animals in A1, but not in IC (A1 animal R: 0.011, T: 0.030, B: 0.012, F = 10.9, p < 0.0001; IC animal R: 0.018, B: 0.038, L: 0.022, F = 1.82, p = 0.170, ANOVA). (D) Scatter plots show r2 pupil-unique as a function of variance of pupil size during each experiment. This relationship is significant in both A1 (left, r = 0.341, p ≤ 10−5, hierarchical bootstrap) and IC (right, r = 0.409, p = 0.02). Dashed line shows regression fit. Multivariate regression shows that r2 pupil-unique depends significantly on both animal and pupil variance but not on d’ in A1 (animal: F = 11.5, p = 0.000021; pupil variance: F = 11.4, p = 0.00092; d’: F = 0.145, p = 0.703, ANOVA). In IC, r2 pupil-unique depends significantly only on pupil variance (animal: F = 2.23, p = 0.116; pupil variance: F = 16.2, p = 0.00016; d’: F = 0.032, p = 0.86, ANOVA).