Model-Based Reasoning in Humans Becomes Automatic with Training
Results of a logistic regression that considers model-free and model-based influences on choice in the current trial with respect to events that occurred up to 3 trials in the past. (A) Each regressor describes whether events on trial t-1, t-2 and t-3 increase (coded as +1) or decrease (coded as -1) the probability of choosing fractal A according to a model-free or a model-based system (6 total regressors). Model-free coefficients are plotted on the left-hand side of x-axis, and model-based coefficients on the right-hand side. Data from days 1 and day 3 are plotted in the top and bottom panels respectively. Coefficients corresponding to the single-task are shown in blue, and those corresponding to the dual-task are shown in orange. Vertical lines represent SEM. * denotes p < 0.05, ‡ denotes p = 0.09. (B) For each condition (single-task in blue, dual-task in orange), and separately for days 1 and 3, we summed (individually) the coefficients corresponding to trial t-1, t-2 and t-3, and derived single estimates of the degree to which model-free (plotted on the y-axis) and model-based (plotted on the x-axis) control were dominant in choice. Vertical lines represent 95% confidence intervals. A line through the origin represents points in which model-free and model-based valuations have an equal influence on choice.