The story so far: Rich Lowry posted a Father’s Day column based on this report from the Institute for American Values. I questioned some of the report’s reasoning, as related by Rich in his column. Jonah rose from his couch and took up his pugil stick. Jonah and I eventually got tired and returned to our respective couches. Rich came back with some rebuttals of points I made. I promised to read the report and pass an opinion.

Prof. Wilcox of the University of Virginia, one of the report’s begetters, very kindly sent me a PDF of it. I read it with close attention. Conclusions, such as they are, follow.

First, this is a report, not a study. It actually summarizes conclusions from many studies, listed in 157 footnotes. (That doesn’t mean there are 157 studies referenced; some are referenced more than once, some footnotes cite more than one reference. On a quick sampling, the number of studies, books, and articles cited is around 200, with a median date around 1998.) That’s fine, and reports of this kind are bread and butter for journalistic commentators. I use them all the time, and so does everyone else around here. In the field of developmental psychology, though, it raises two questions.

Q1: This is a very b-i-g field, with thousands of studies coming out every year. Did the report’s authors cherry-pick just those studies likely to bolster pre-set conclusions?

Q2: This is a field severely afflicted by the gene panic of the later 20th century–what Steven Pinker has called the “see no genes, hear no genes, speak no genes” cast of mind that dominated the human sciences up to the late 1990s, and still has very strong, though now steadily weakening, influence. One therefore has to ask: Do the studies–whether cherry-picked or not–make careful efforts to separate out genetic factors, by comparing effects on twins raised together, twins raised separately, nontwin siblings raised together or separately, and so on? A study that doesn’t do this isn’t worth much, but there are a *lot* of such studies around.

A1: To answer Q1, you would need to be a person who’s been elbow-deep in the dev-psy literature for years, who knows the players and their “tendencies,” who has a birds-eye view of the whole scene. I’m not that person, so my honest answer must be “I don’t know.”

That–the elbow-deep stuff–is a good description of Judith Rich Harris, though, with whom I have been corresponding the past few days, so I passed Rich’s comments by her. She: “I see he cites Brian D’Onofrio’s studies of divorce (two papers by D’Onofrio, Turkheimer, Emery, Slutske, Heath, Madden, & Martin), but he fails to cite a study by Mendle, Turkheimer, D’Onofrio, Lynch, Emery, Slutske, & Martin, titled ‘Family Structure and Age at Menarche: A Children-of-Twins Approach.’ This study showed that there was no causal relationship between stepfather rearing and age of puberty in girls.” I leave this to properly qualified people to thrash out, if they feel like it.

A2: Again, without reading all the cited studies, which nobody is going to pay me to do, the only honest answer is “I don’t know.” Only two of the cited studies (both by Brian D’Onofrio et al. again) declare themselves in their titles to be genetically informed. As best I can judge from the footnoting, those are the Australian studies Rich cited.

Having given two “don’t knows,” I suppose I could be accused of copping out here. There’s a Q3 that sort of follows from my A2 though.

Q3: All right, I don’t know, without reading them, whether the cited studies take the proper pains to subtract out genetic effects. I have read the report, though. Does the report’s text suggest that its authors are aware of the importance of those proper pains in dev-psych work?

A3: Hmmm. The word “genetic” turns up six times in their text, but every one of those times the reference is to those two D’Onofrio et al. reports I just mentioned, the ones–the only ones–with genetic references in their titles. I’m going to declare myself agnostic again, but with a suspicion–a reasonable one, I do believe–that the answer to Q3 is “not as much as they should be.”