Is the rise in autism a sign of a human evolutionary process?

[Neonatal RRT]

AI Overview

Yes, there is scientific evidence suggesting a connection between autism and human brain evolution, particularly that the same genetic changes that made the human brain unique also increased the risk for neurodevelopmental conditions like autism, according to a Yahoo article. Studies show that human-specific genetic changes, which accelerated the development of certain brain cells and supported higher cognitive functions such as language, may also have created a greater susceptibility to autism. This suggests that the high prevalence of autism in humans could be a trade-off for unique human cognitive abilities.

Human-Specific Brain Evolution and Autism:

• Unique human brain cells:
  Researchers have found that a type of brain neuron, called L2/3 IT neurons, evolved unusually fast in the human lineage compared to other apes. These changes coincided with alterations in genes linked to autism.
  
  
• Genetic changes:
  Some genetic changes that were accelerated in the human genome after diverging from chimpanzees are associated with autism spectrum disorder (ASD).
  
  
• Natural selection:
  The theory proposes that natural selection favored these rapid brain changes, which were beneficial for developing complex human traits like language and sophisticated cognitive abilities.
  
  
• An evolutionary trade-off:
  In this evolutionary framework, autism may be a side effect of these beneficial adaptations, meaning that the genetic factors that enhance human intelligence and language also increase the risk for autism.
  

Why Autism is More Prevalent in Humans:

• Human-specific traits:
  The cognitive traits involved in autism, such as complex speech production and comprehension, are either unique to humans or far more sophisticated than in other animals.
  
  
• Unique genetic changes:
  Behaviors associated with disorders like autism and schizophrenia are not typically observed in non-human primates, suggesting these conditions are likely a uniquely human phenomenon.
  
  
• The "price" of being human:
  The high prevalence of autism in humans is potentially the price we paid for the unique cognitive abilities that define our species.
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  Human evolution may explain high autism rates
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• Autism’s High Prevalence Could Be an Evolutionary Trade-Off.
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• Highlight: The Intertwined Evolution of Human Cognition and Autism - PMC
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• https://academic.oup.com/mbe/article/42/9/msaf189/8245036

 

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Human-Specific Brain Evolution and Autism:

Just something else to consider at the same time. We have seen genetic alterations over time in modern humans as well.

One of these is the way in which people of European descent have a much higher tolerance for alcohol than people who's ancestry lies in other parts of the world. This is believed to be at least partly influenced by the high levels of pollution throughout Europe during the coal age. People couldn't drink water because it was too polluted. For many generations wealthy people drank wine and poorer folk drank ale.

There's another modern influence in humans that has also been going on for many generations now and that is the more common use of abstract thought - reading, writing and arithmetic. It was common amongst wealthier people for almost 1,000 years now but has also been common amongst the poorer people for the last 200 years to the point that these days it's rare to find illiterate people in modern societies.

These are skills that have become useful in terms of human success and survival to the point that people without these skills are at an extreme disadvantage. But it goes way beyond just simple skills to the way in which we live our lives and the way we think about everything around us.