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.

Gender Differences in Core Symptomatology in Autism Spectrum Disorders across the Lifespan

“…Bishop, et al, 2000), ADHD (Russell, et al, 2006), physical/medical variables and academic achievement (Sagi, et al, 2007), and mouse models (see Lynn & Davies, 2007). Shaner, Miller, and Mintz (2008) proposed an explanation as to why this counterintuitive mechanism (i.e., a maternal imprint that impairs social communication skills in sons, as Skuse has suggested) may have evolved. Parents have to identify offspring most likely to survive and reproduce in order to successfully allocate their resources, whereas offspring have to advertise health to attract parental resources.…”

“…Parents have to identify offspring most likely to survive and reproduce in order to successfully allocate their resources, whereas offspring have to advertise health to attract parental resources. Infants and toddlers who are more articulate, expressive, playful, and socially engaged are more successful at attracting parental attention, protection, resources, and so forth (Shaner, Miller, & Mintz, 2008). Skills in language, facial expression, creative play, and coordinated social interaction may have been selected by parents as an indicator of fitness to aid them in determining investment (Shaner, et al, 2008).…”

“…Infants and toddlers who are more articulate, expressive, playful, and socially engaged are more successful at attracting parental attention, protection, resources, and so forth (Shaner, Miller, & Mintz, 2008). Skills in language, facial expression, creative play, and coordinated social interaction may have been selected by parents as an indicator of fitness to aid them in determining investment (Shaner, et al, 2008). Shaner and colleagues (2008) purported that offspring vary significantly in these skills, these skills correlate with underlying fitness, and autism may be the low-fitness extreme of this variation.…”

“…Shaner and colleagues (2008) purported that offspring vary significantly in these skills, these skills correlate with underlying fitness, and autism may be the low-fitness extreme of this variation. Regarding sex differences, mothers must be more selective in resource allocation to sons, as sons require more resources, increase the time frame until the mother can have another child, and have variable reproductive success compared to females (Shaner, et al, 2008). Therefore, in males, the development of fitness indicator skills (i.e., early social/communicative behaviors) must be even more complex, demanding, and sensitive to genetic quality and environmental hazards to ensure they are reliable and valid indicators.…”

Are there alternative adaptive strategies to human pro-sociality? The role of collaborative morality in the emergence of personality variation and autistic traits

“…However, identifying the evolutionary dynamics of AS has been hampered by the conflation of AS and autism with other impairments including intellectual disability. Evolutionary approaches thus attempt to explain autism as a broad category and as an asocial extreme of normal behaviour, with low fitness (Ploeger and Galis 2011;Crespi and Badcock 2008;Shaner, Miller, and Mintz 2008). The logic-based theory of mind seen in AS, however, remains to be explored as a pro-social strategy integrated within communities and arising from, and influencing, wider cognitive, emotional and social factors.…”