Distinct roles of dopamine and noradrenaline in human exploration-exploitation
REGRESSION
In order to analyze the individual tendency to explore or exploit, we performed a mixed-effects logistic regression. This allowed us to (i) identify factors that influence choice behavior and (ii) examine whether these influences differ between groups. Choice was explained as a function of previous return, traveltime, depletion rate, number of previous stays, group, and the interaction of the four main factors with group. We selected this model by incrementally adding a factor and tested whether it improved the model fit, compared to the reduced version.Separate model comparisons using likelihood ratio tests confirmed that the full model including all four main factors and their interaction with the experimental group was most appropriate. This was further reflected by the lowest (i.e., best) AIC value (Table Model comparison by the Akaike Information Criterion (AIC).The full model fitted participants’ choices best in a model comparison that considers differences in model complexity. Model performance is indicated by the Akaike Information Criterion (AIC). Lower values represent a better fit. The full model contains the factors previous return, travel time, depletion rate, number of previous stay decisions for the current tree, group, and the interaction of the first four factors with the experimental group.The mixed-effect logistic regression indicated that previous reward and travel time had significant effects on choice behavior. Participants in all three groups switched less when previous returns were high (main effect of previous reward, β = −0.749, 