Summary: humans with ApoE4 variant living in Stone Age conditions with high exposure to parasites and pathogens, which cause their own damage to cognitive abili

Summary: humans with ApoE4 variant living in Stone Age conditions with high exposure to parasites and pathogens, which cause their own damage to cognitive abilities when untreated, had better cognitive performance than others in same condition without variant and than humans living in clean urban settings with variant (ApoE4 variant carriers face 4x risk of Alzheimers and other other age-related cognitive declines in clean environments).