ABSTRACT
Of considerable significance to the origins of ‘modern’ humans is the nexus between recent human evolution and pathologies. This is because, in contrast to earlier humans, our more immediate ancestors have been burdened with thousands of neurological and other detrimental conditions. This raises the paradox of why natural selection failed to expunge the alleles responsible for this bane of our species from the genome, as evolutionary forces would be expected to do. A related issue is that the many human brain illnesses seem to involve precisely those areas of the brain that are the phylogenetically most recent, which is hardly a coincidence. In reviewing the differences between the brains of humans and other primates, we discover the roles of exograms, memory traces stored outside the brain. They appear to be the factor most clearly defining the way the human brain operates differently from that of other animals. In considering human evolution, developmental systems theory, niche construction theory, the gene-culture co-evolutionary model, sexual selection and other aspects also need to be included.
