Figure 5: Modelling the modulation of serial choice bias.
From: Pupil-linked arousal is driven by decision uncertainty and alters serial choice bias
(a) Schematic representation of the regression model with modulatory terms. (b) The contribution of history terms (past choices and stimuli) as a fraction of the total variance in the decision variable33, decreased with stronger sensory evidence. (c) Choice weights for the previous seven trials, obtained from the history model without modulatory terms. Each line corresponds to one observer. Purple, ‘repeaters’ with positive choice weight for lag 1. Orange, ‘alternators’ with negative choice weights for lag 1. Black line, group mean. Grey dashed line, group mean of absolute choice weight. (d) Choice weights at lag 1 plotted against the corresponding stimulus weights. Coloured dots and error bars indicate individual observers±68% confidence intervals obtained from a bootstrap. See Methods for an interpretation of this graph in terms of behavioural strategy. (e) Regression weights for the interaction between previous pupil response or RT and previous choices or stimuli. N=27, group mean±s.e.m. (f) Correlation between choice weights and their modulation by pupil dilation or RT. Colours indicate the choice weight as derived from the basic model in d. Error bars are 68% confidence intervals obtained from a bootstrap. The intercept of the least-squares regression line, corresponding to the mean beta weight across the group, is indicated with a triangle on the y axis. (g) Beta weights for interaction between previous pupil response or RT and previous choices. Group split based on the sign of individual choice weights. ***P<0.001, **P<0.01, *P<0.05, NS P>0.05, Pearson’s correlation coefficient or permutation test.
