Autism as Developmental Injury

Left untreated, people with phenylketonuria (PKU) can develop intellectual disabilities, seizures, and “other medical problems”.  But PKU does not cause any of those.  Phenylketonuria + a normal diet causes a build of of phenylalinine in the body, which causes those problems.  If PKU is caught at birth and the sufferer is kept on a phenylanlinine-light diet, they will never develop these problems.

Henry Markram suggests that something analogous is going on with autism.  He and his collaborators think that the actual problem is that autistic babies have extraordinary sensory sensitivity, and this sensitivity causes defenses that cause them to miss certain critical information during developmental periods.  What is challenging but achievable (the zone necessary for learning) for other people is overwhelming for them, so they don’t learn.  The developmental window closes and they’ve lost their chance to truly master that skill.  But if they were given stimulus in their zone of achievable challenge, they would learn those skills and maintain them for life.  They might continue to need accommodations, the way phenylketonurics need to stay on a phenylalinine-light diet their whole life, but with those accommodations they could function “normally”.  This is known as the intense world hypothesis.

The example they give is the critical period for learning language.  You *can* learn a new language after the critical period, but it will never be as easy, most people will never attain genuine fluency, and if you never learn any language it may be truly impossible to pick one up later.  If normal human speech is overwhelming to an autistic infant they will miss that period and their language will be impaired for life.  But if they’re given regular access to speech they are comfortable with (probably quieter and slower) they could learn it just fine, the same way hearing impaired children do fine with sign language.

I was also really impressed with the writing of this lay-press article.  I’ve been avoiding doing take downs, especially of popsci articles, because there are millions of wrong things every day and criticizing them is easy.  For a while I could justify them as case studies in critical reading, but now it just feels bad.  This had led to a lot of aborted blog entries, as I read something amazing and then realize it’s too flawed to pass on uncritically.   I don’t agree with everything the article says (insisting there’s only one cause of autism strikes me less as brave and more as idiotic), but it lays out its case in an informative and responsible manner.