Extended Data Fig. 3: Study 2b, Monetary Versus Individual Non-Monetary Conditions in the US and Mexico.

Effects of the three individual conditions: monetary (green), social norm (dark blue) and flat fee (light blue) in Mexico (N = 1,053 recruited on Prolific) and two samples in the US: one with the same nominal pay (N = 1,098 recruited on Prolific) as in Mexico and the other with the same subjective¹⁰⁷ pay (N = 1,122 recruited on Prolific) as in Mexico. Panel A shows the central tendency and distribution of effort by incentive type and country. The black line within each box represents a median, and the red dot shows a mean. Upper and lower bounds show the third and the first quartile, respectively. The whiskers represent the 1.5 times the interquartile range, with black points showing observations outside of this range. The width of each violin corresponds to the frequency of observations at any given number of images rated on the y-axis. Panel B shows the money advantage—that is, how much more effective money is than each of the two non-monetary treatments in each sample. Panel C shows the central tendency and distribution of the cost-effectiveness (effort per dollar spent) by incentive type and country. Graph elements are analogous to those in Panel A, with the width of each violin corresponding to the frequency of observations at any given level of cost-effectiveness (effort per dollar spent) rated on the y-axis. The results for cost-effectiveness are summarized in the main text. In Panel B, error bars are bootstrapped 95% CIs for the mean relative difference in the number of images in the monetary and each of the non-monetary conditions.