On 8 Feb 2009 at 4:00, Allen Esterson wrote:

> In response to Joan Warmbold's suggestion that 
> >Henry Massie, M.D. was onto something with his research
> >in the 1970's in which he analyzed videos of the interactions
> >between parents and children BEFORE the onset of 'autistic-like'
> >behaviors.  His analysis determined that there was a distinct lack 
> >of appropriate response to the infants' signals...  
> <snip>> 
> To which question I would add:
> Did Massie do the same research with a corresponding number of (blind)
> controls to eliminate the possibility of confirmation bias in his
> analyses?
> 
> Judging by this:
> http://www.childdevelopmentmedia.com/intervention-prevention/91936p.html
> the answer is "No".

There is a major obstacle to claims that parental interaction is somehow 
responsible or predisposes the child to autism. This is that MZ-DZ twin 
studies of autism have consistently shown that the heritability of autism 
is very high, among the highest of behavioural disorders. These studies 
usually have shown as well that there is only a small unshared 
environmental component and no contribution of the shared environment. 
Claims that autism is caused by the parents would require substantial 
input from the shared environment.

For example, one of the more recent studies (Ronald et al, 2006) 
concludes that "extreme autistic-like traits show high heritability, no 
shared environment, and modest nonshared environment". Their estimates 
vary with the type of model fitting carried out, but ranged from 0.64 to 
0.92. 

Their summary Figure 1 shows MZ correlations around 0.8 with DZ around 
0.3. Using the conventional formula of h2 = (MZ-DZ) x2 gives heritability 
of 1.0, which surely doesn't leave much room for parental effects. 

As Allen noted, it seems more plausible that the parents in Massie's 
study are reacting to subtle signs of autism in their children rather 
than creating them.  It's also possible that it is genes that are 
responsible both for the autism of the children and the claimed 
unresponsive behaviour of the parents. Admittedly, Massie's proposal is 
kinder than Bettelheim's pernicious pseudoscience, but it still lays a 
heavy load on the parents. It's best to be careful with such claims.

Source (for the heritability data):

Ronald, A, Happe, F.,  Bolton, P., Butcher, L., Price, T., Wheelwright, 
S., Baron-Cohen, S., and Plomin, R. (2006). Genetic heterogeneity between 
the three components of the autism spectrum: a twin study. Journal of the 
American Academy of Child and Adolescent Psychiatry, 45, 691-699.

Available on-line at http://web.mit.edu/autism/ronald~1.pdf

Stephen

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Stephen L. Black, Ph.D.          
Professor of Psychology, Emeritus   
Bishop's University      e-mail:  [email protected]
2600 College St.
Sherbrooke QC  J1M 1Z7
Canada

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