Mike Weight and I have a draft of a manuscript about responses to personality tests by Amish and non-Amish young men from the same county in Indiana. We have mentioned this material before on the blog. The paper is getting ready to ship out: we are hoping to take advantage of our readers and solicit comments and criticisms and outrage and whatever. Drs. Charlton and Thompson may be especially knowledgeable about this approach along with many of our anonymous cowards.
Our approach is to use published data from a personality test from 1970 to construct an index of “Amishness” that we call the AQ that is analogous to the well-known IQ of cognitive testing. With that, the whole standard machinery of quantitative genetics is immediately available. Whether or not the genetic model is correct or near correct there is a clear and explicit baseline that alternate models should be able to match. For example the difference in mean AQ between young Amish men and their non-Amish neighbors is about 2.8 standard deviations. In the IQ world this would correspond to a group different of 42 points. In the stature world this would correspond to a height difference of about 8 inches.