Results of the 2AFC test in Experiment 1 (Exp1-Noise) and Experiment 2 (Exp2-Speech). The left plot shows the determined individual percentages of correct answers p_2AFC as points (horizontal offset for better readability). The boxes show the mean (box notch) and the 95% between-subject CI. The gray dashed line denotes 50% chance level. The right plot shows the interindividual variation in the determined p_2AFC values in the form of a box plot with the median (box line), the mean (cross), and the (across participants) interquartile range (IQR); whiskers display 1.5 × IQR below the 25th or above the 75th percentile and outliers beyond that range are indicated by asterisks.