Figure 9. Evolution of social learning (LE, TE). A – genotypic and phenotypic values of LE and TE (phenotypic value = genotypic value + sum of the effects of the corresponding memes). The efficiency of ‘learning culture’ or ‘teaching culture’ is phenotype minus genotype. Note the extensive cultural evolution of teaching efficiency. B – memory loading; note that the TE memes occupy much larger proportion of memory than LE and TrE memes. Only HE memes are more successful, because they are strongly favoured by the cultural group selection. Averages from 10 model runs are shown. Parameters: G=40 (moderate between-group competition); 5 categories of memes are allowed (TrE, HE, Useless, LE and TE); parameters for LE and TE memes: mean efficiency 0.2, standard deviation of efficiency 0.3; C=5; R=2 (see Supplementary Table 1 for further explanations); genes for MC, LE and TE can mutate (for LE and TE genes: mutation rate 0.04, mean mutation effect 0, standard deviation 0.1); brain volume = 20 + MC + 30 x (genotypic value of LE + genotypic value of TE); initial values of LE and TE: 0.05, 0; other parameters were the same as previously described.