Evolutionary Origins of Brain Disorders in Homo sapiens sapiens
Authors: Patricia A. Helvenston and Robert G. Bednarik
Abstract: This paper proposes a relatively recent advent of the brain disorders such as schizophrenia, obsessive compulsive disorder and bipolar illness, in anatomically modern humans. We will systematically demonstrate that the phylogenetically newest areas of the brain, including those containing von Economo neurons, are also the areas that are involved in these illnesses as well as other neurodegenerative brain disorders such as Alzheimerís, Parkinsonís and Huntingtonís disease. The evolutionary preservation of these disorders is imputed to conditions similar to those that gave rise to the recent neotenization of Homo sapiens; which is attributed to breeding mate selection becoming influenced by cultural constructs. We consider some recent failed models of biological natural selection and conclude that as hominin evolution became increasingly moderated by non-Darwinian criteria (i.e. niche construction and developmental systems theory possibly overriding the effects of natural selection) towards the end of the Pleistocene, disadvantageous features were tolerated, both of a somatic and neurological nature. Since anthropologists are concerned with human behavior, they should care deeply about the future directions of Homo sapiens sapiensí evolution, which is proceeding adversely with respect to the prevalence of serious brain illnesses.