The<unk>  is an unsubstantiated hypothesis in evolutionary psychology regarding the causes of autism spectrum and schizophrenia spectrum disorders, first presented by Bernard Crespi and Christopher Badcock in 2008. It claims that certain autistic and schizotypal traits are opposites, and that this implies the etiology of the two conditions must be at odds. The<unk>  is based around genomic imprinting, an epigenetic process through which genes are expressed differently by way of one parent's contribution having more effect than the other. Specifically, proponents of the<unk>  propose that autism spectrum disorders are caused by paternal overimprinting, while schizophrenia spectrum disorders are caused by maternal overimprinting; they point to a number of supposed correlations and anticorrelations seen between the disorders and other traits to support the hypothesis. While the hypothesis has found some attention in popular science, it lacks scientific backing. It has also been attacked as unfalsifiable, exaggerated, and overly broad. Specific issues for the hypothesis include that the predictions it makes about genetic disorders are falsified, that the effects of the two disorders on empathy and mentalizing are contrary to Crespi and Badcock's model, and that many neuroimaging findings fail to support the hypothesis.
Imprinted brain hypothesis
Thrifty gene hypothesis
Drifty gene hypothesis
Germ theory of disease
Two-streams hypothesis
Refrigerator mother theory
Genomic imprinting
Kraepelinian dichotomy