social influence and the spread of autism

You need to check out this new article in AJS, “Social influence and the autism epidemic” by Ka-Yuet Liu, Marissa King, and Peter Bearman.  The paper fits in the growing literature on social networks, interpersonal influence, and health outcomes (see Teppo’s take on the topic), but the conclusions are somewhat different than its predecessor studies. Obviously, it would be ridiculous to say that somebody can catch autism from a neighbor, but it’s not unreasonable to think that other social mechanisms might lead to a diffusion of the autism epidemic. The authors point to several possible mechanisms:  shared exposure to autism-causing toxicants or viruses (i.e., environmental effect), parents’ residential choices might cause them to sort themselves into neighborhoods where autism is prevalent (i.e., selection effect), or parents might learn about the symptoms of autism from other parents in their social networks and receive other helpful information that assists in autism diagnosis (i.e., social influence). In the latter case, social networks do not cause autism, but they do increase the likelihood that autism is diagnosed.

Through a careful analysis, Liu et al. are able to show that the social influence mechanism explains the correlation between autism diagnosis and living close to another child previously diagnosed with autism. Here’s a summary from the paper’s conclusion:

One does not “catch” autism from someone else, yet a social diffusion process contributes significantly to the increased prevalence of autism. We observe a strong positive effect of proximity to other children with autism on the subsequent chance of diagnosis, robust to a range of individual- and community-level controls in both urban and less urban areas. In addition, close proximity to a child with autism was inversely associated with the likelihood of subsequent sole MR diagnosis, while it correlated strongly with the chance of autism-MR diagnosis. Proximity also increases the chance of autism rather MR diagnosis given the same level of severity in autism symptoms. Social influence arises strongly for high-functioning cases of autism. The effect of proximity is also more prominent in younger children, when diagnosis is more difficult and parental resources are more important. Children who were diagnosed with autism have a similar mode of referral as that of their nearest neighbor with autism before their diagnosis. All of these findings are consistent with a mechanism of social diffusion of awareness of the symptoms and the benefits of treatment and are inconsistent with competing explanations.

The study supports a social influence model of diffusion.  But unlike most diffusion studies in organizational research, which usually conceive of social influence as mimesis, the study points to information exposure as a mechanism. Children are more likely to receive an autism diagnosis because their parents  learn more about the disease due to their increased exposure to other children with autism. They know which doctors to seek, which questions to ask, which programs to access, etc., all of which facilitate the diagnosis.  The process seems generalizable. The spread of many social and organizational phenomena, but especially those that involve complex systems of adoption or diagnosis, could be accounted for by increased exposure to information about the phenomenon in question.  The spread of iPhones, organizational policy fads, or the diffusion of automobiles may all have been facilitated by this sort of social influence.

Written by brayden king

April 16, 2010 at 4:28 pm

4 Responses

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  1. So, the bottom line is that there’s an overwhelming selection effect. I can see media construing this as network/influence-> autism effect — “social diffusion process contributes significantly to the increased prevalence of autism” — not recognizing that this has to do with incidence diagnosis/recognition rather than a causal argument about the origins of autism.



    April 16, 2010 at 4:55 pm

  2. Well, perhaps a useful take on this would be medicalization–especially with Asperger’s, people who used to just be nerds now have a disease…



    April 16, 2010 at 5:00 pm

  3. Elaine Showalter documented the same sort of thing for chronic fatigue syndrome (now apparently “fibromyalgia”), recovered memories, multipe personalities etc in “Hystories”.



    April 17, 2010 at 3:58 am

  4. Bearman’s colleague at Columbia, Gil Eyal, has a book coming out soon on autism, though more from a soc-of-science perspective:


    Jeff Sallaz

    April 26, 2010 at 8:40 am

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