Figure 10. The effects of population size, meme invention rate, lifespan and migration rate on brain-culture coevolution. The results are compared with the ‘basic’ situation (complex culture: TrE, HE and Useless memes allowed; costly, evolvable LE; G=40; all other parameters as in fig. 8). Population x 3: the amount of resources available from the environment is multiplied by 3 (R=9000; this results in triple population size), other parameters as in the ‘basic’ situation. Creativity x 3: meme invention rate was 0.0004 (instead of 0.000133) per each meme category per year; other parameters as in the ‘basic’ situation. Lifespan x 2: probability of death per year is Age x 0.0005 (instead of Age x 0.002); this results in average lifespan 52 years instead of 27 years in the ‘basic’ situation. Migration rate 0: no migration between groups. Migration rate x 4: migration chance was 0.004 per individual per year instead of 0.001 in the ‘basic’ situation. Averages for years 50000 – 70000 from 10 model runs are shown.