Fig. 2: Information value grows with uncertainty in humans and monkeys.

a, The human population assigned greater value to information about uncertain rewards. Data are the same as in Fig. 1e but analyzed separately for trials where both offers had high or low reward uncertainty (dark or light red). The shaded area represents ±bootstrap s.e. b, Mean fitted GLM weights of offer attributes. Error bars represent ±s.e.; *P < 0.05; **P < 0.01; ***P < 0.001; signed-rank tests. c,d, Same as a and b, respectively, for animal R. e, Humans generally placed higher value on expected reward (left, E[r] versus Unc[r]) but increased the value of information more with uncertainty (right, Info × E[r] versus Info × Unc[r]). Data are fitted parameters ± s.e. from each individual. Colors indicate that neither coordinate (gray), the x coordinate (blue), the y coordinate (red), or both (purple) are significant (P < 0.05; t-tests). The text indicates the fraction of individuals above or below the identity line and its significance (binomial tests). For visual clarity, axes exclude one extreme outlier (error bar visible at the bottom of e and g); Sig., significant; Non-sig., non-significant. f, Same as e for all animals. The gray text indicates which data point came from which animal. The error bars are too small to see (all s.e. < 0.08). g, The value of information grows with uncertainty, as indicated by positive weights of Info × Unc[r] (y axis) for humans with negative, non-significant or positive weights of Unc[r] (x axis). The text indicates the fraction above y = 0 and its significance (binomial test). h, Histograms of fitted Info × Unc[r] weights for individuals classified as risk avoiders, non-significanters or seekers. The black histogram shows significant weights, and the text indicates the fraction of individuals with significant positive weights and the P value for whether this is greater than chance (one-tailed binomial tests). i, Same as g for all animals. Error bars are too small to see (all s.e. < 0.08). j, In animal P, the value of information grew with uncertainty (positive Info × Unc[r] weight; y axis), consistently in sessions when the animal tended to be risk averse, neutral or seeking (Unc[r] weight; x axis; n = 5,248, 5,102 and 4,766 trials, respectively). Data are shown as mean ± s.e. See Supplementary Table 6 for the details of all tests and P values.