Conflicting Evolutionary Pressures on Human Cognition: A Case Study of Autism

The current dominant view is that the evolutionary pressures leading to our large brain sizes were predominantly social. This study investigates the effects of both technical and social pressures on our cognitive evolution, to determine whether the pressures were more complex than social theories allow. This is assessed both between hominin species and within our species. Between species effects are determined by evaluating the evolution of human cognition in 4 stages. Archaeological evidence of behaviour and changes in brain structure are presented for each stage. This allows specializations to be identified, and permits us to suggest whether specialization in each species was in response to social pressures, or a more complex pattern of both technical and social pressures. The results of this evaluation support a more complex pattern of evolutionary pressures. Within species effects are assessed, using Autism Spectrum Condition (ASC) as an example of an alternate, more technically focused, adaptive strategy. This condition accentuates technical behavioural traits which would be advantageous to a Palaeolithic population. The genetics of the condition show that it is highly heritable, was likely present prior to 200 ka, and under positive selection. Thus, these technical traits must have had an impact on past populations. A survey is conducted to assess whether characteristics and components of autism would influence individual’s engagement with material culture, in particular art. The results provide an example of how individuals with enhanced technical traits within our species may have affected our cultural evolution. Thus, the role of technical pressures in our evolution and how they relate to social pressures requires more attention.