Figure 3. Effects of task dynamics on performance.

(a) STD of the subjects’ prediction errors (filled circles) as a function of the number of sounds after a change-point (SAC) in the generative mean azimuthal location, plotted separately for the two noise conditions (colors, as indicated; generative STDs are shown as dashed lines). For comparison, prediction-error STDs are shown for an approximately optimal predictive-inference model (open diamonds). Data from change-point trials (SAC=1) are not shown because locations were, by design, unpredictable on those trials. (b) Contrast values from a linear model describing individual subject (circles) and the approximately optimal model (each diamond represents analyses based on the same sound sequence experienced by the subject connected by a line) prediction-error STD in terms of (see inset in e): 1) the difference between change-point and non-change-point trials (CP), 2,3) the linear trend from SAC 2–6 for low-(Exp_low) or high-(Exp_high) noise trials, and 4) the difference between the two noise conditions (Noise). (c,d) Same conventions as in a,b but for perceptual errors on the dynamic task. Diamonds represent the theoretically predicted STD of perceptual errors computed from the optimal, precision-weighted combination of the subject- and condition-specific STDs of prior errors (circles in a, determined separately for each subject) and the subject-specific estimation-error STDs from the control task (the median value is shown as a horizontal dashed line; see Fig. 2g). (e,f) Same conventions as in a,b but for the frequency of high-confidence reports relative to overall frequency of high-confidence reports per subject. Diamonds represent the frequency of high-confidence reports corresponding to the theoretical perceptual errors in c, computed from the fraction of the theoretical posterior distribution within the confidence window. In a,c,e, circles and error bars are mean±sem of values measured from all 29 subjects. In b,d,f, points are data from individual subjects. Asterisks indicate sign-rank test for H₀: median value from the subject data=0, p<0.05. In each case, paired rank-sum test for H₀: median difference between subject data and theoretical prediction, p>0.087. In all panels, only data from sequences following noticeable change-points (changes in mean of at least twice the generative STD for SAC=1) were included.