title: Autism as the Low-Fitness Extreme of a Parentally Selected Fitness Indicator.
abstract: 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 for this fitness-advertising purpose. Could any human mental disorders be the equivalent of dull filaments in coot chicks-low-fitness extremes of mental abilities that evolved as fitness indicators? One possibility is autism. Suppose that the ability of very young children to charm their parents evolved as a parentally selected fitness indicator. Young children would vary greatly in their ability to charm parents, that variation would correlate with underlying fitness, and autism could be the low-fitness extreme of this variation. This view explains many seemingly disparate facts about autism and leads to some surprising and testable predictions.
authors.affiliation: Department of Psychiatry and Mental Health (116A), Veterans Affairs Healthcare System and the University of California Los Angeles, 11301 Wilshire Blvd, Los Angeles, CA, 90073, USA. AShaner@ucla.edu.
authors.forename: Andrew
authors.initials: A
authors.lastname: Shaner
authors.affiliation: Department of Psychology, University of New Mexico, Albuquerque, NM, 87131-1161, USA. gfmiller@unm.edu.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Miller
authors.affiliation: Departments of Psychiatry and Epidemiology/Biostatistics, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA. mintz@uthscsa.edu.
authors.forename: Jim
authors.initials: J
authors.lastname: Mintz
keywords: Autism; Fitness indicator; Parental selection; Sexual selection; Sibling rivalry