Humor as a Mental Fitness Indicator

Schizophrenia as one extreme of a sexually selected fitness indicator.

Schizophrenia remains an evolutionary paradox. Its delusions, hallucinations and other symptoms begin in adolescence or early adulthood and so devastate sexual relationships and reproductive success that selection should have eliminated the disorder long ago. Yet it persists as a moderately heritable disorder at a global 1% prevalence--too high for new mutations at a few genetic loci. We sugges...

Schizophrenia as one extreme of a sexually selected fitness indicator

Schizophrenia remains an evolutionary paradox. Its delusions, hallucinations and other symptoms begin in adolescence or early adulthood and so devastate sexual relationships and reproductive success that selection should have eliminated the disorder long ago. Yet it persists as a moderately heritable disorder at a global 1% prevalence—too high for new mutations at a few genetic loci. We suggest...

Handgrip Strength as a Darwinian Fitness Indicator in Men

Handgrip strength (HGS) is a robust measure of overall muscular strength and function, and has long been predictive of a multitude of health factors and physical outcomes for both men and women. The fact that HGS represents such a ubiquitous measure of health and vitality may reflect the significance of this trait during human evolution. This trait is also highly sexually dimorphic due to influ...

Humor and Mental Health

Autism as the Low-Fitness Extreme of a Parentally Selected Fitness Indicator.

Siblings compete for parental care and feeding, while parents must allocate scarce resources to those offspring most likely to survive and reproduce. This could cause offspring to evolve traits that advertise health, and thereby attract parental resources. For example, experimental evidence suggests that bright orange filaments covering the heads of North American coot chicks may have evolved f...