Visualization of our interpretation of the fitted model for a single society.

The leftmost panel (a) shows the posterior distributions for the four separate model parameters, neither of which bares directly on our hypothesis. Each pair of posteriors for the a and b parameters determines a posterior distribution for the age at which acquisition of a particular norm is completed, as shown in the centre panel (b). This pair of distributions in turn defines a posterior distribution over the difference in completion ages. This distribution is shown in the rightmost panel (c), computed by subtracting the inter-ethnic completion age from the intra-ethnic completion age, such that positive values are consistent with our hypothesis that intra-ethnic norms are acquired earlier. The red-shaded area in panel (c) represents the posterior probability that our hypothesis is correct.