Cauvin's central point... is that.. the development of domestication was not a sudden event owing to penury, or some other economic threat. Instead, sedentism long preceded domestication, houses had already changed from the primitive round structures, half underground, to rectangular buildings above ground, and that bricks and symbolic artefacts were already being produced. From this, he says, we may infer that early man, roughly 12,000-10,000 years ago, underwent a profound psychological change, essitially a religious revolution, and that this precided domestication of animals and plants. Ibid. p 60-61.