Fig. 7.

Optimal response functions. a One good offered in fixed quantity (ρ = 2). Gray dots represent offer types presented in the session and the dotted line represents the indifference line. Good A is always offered in quantity 1 while good B varies in the range [0 5]. Optimal response functions are shown in the lower panels. b Idealized experimental session (ρ = 2). For each good, quantities vary in the range [0 5], but in each offer type at least one good is offered in quantity 1. Lower panels show the optimal response functions (ORF, step functions). c Idealized experimental session (ρ = 3). d Optimal mean response functions. The histogram represents the distribution of ρ/Q _B, where ρ is the relative value and Q _B is the maximum quantity of juice B offered. Lower panels show the mean optimal response functions, mean(ORF). For offer value B, the response function is computed as the cumulative distribution function for ρ/Q _B. e Idealized session with uniform distribution and equal value ranges (a.u.). Lower panels show the corresponding optimal response functions (ORF_uniform). Note that the curvature of ORF_uniform is in the same direction as that observed on average in the neuronal population (Fig. 2a, histogram)