Religion & IQ

By Razib Khan | December 16, 2008 8:15 am

A correspondent forward me this paper, The intelligence-religiosity nexus: A representative study of white adolescent Americans:

The present study examined whether IQ relates systematically to denomination and income within the framework of the g nexus, using representative data from the National Longitudinal Study of Youth (NLSY97). Atheists score 1.95 IQ points higher than Agnostics, 3.82 points higher than Liberal persuasions, and 5.89 IQ points higher than Dogmatic persuasions. Denominations differ significantly in IQ and income. Religiosity declines between ages 12 to 17. It is suggested that IQ makes an individual likely to gravitate toward a denomination and level of achievement that best fit his or hers particular level of cognitive complexity. Ontogenetically speaking this means that contemporary denominations are rank ordered by largely hereditary variations in brain efficiency (i.e. IQ). In terms of evolution, modern Atheists are reacting rationally to cognitive and emotional challenges, whereas Liberals and, in particular Dogmatics, still rely on ancient, pre-rational, supernatural and wishful thinking.

If you read this weblog you know I have touched upon this topic before. Here are the titles of some of the posts, Religious people are less intelligent, Heritability of religiosity, Biblical literalism or low IQ: which came first?, Educational levels & denomination, Pentecostals are stupid? Unitarians are smart? and Higher IQ ~ more atheism internationally. Obviously I’ve talked about this issue. I happen to be one of those people interested in religion, and, who believes in IQ. Most intelligent people don’t happen to actually believe in intelligence, so there’s a lot of interesting low hanging quantitative data there for anyone willing to poke around and cross-reference. As someone who has long conversations with people at Unitarian-Universalist churches and at InterVarsity Christian Fellowship meetings, these data aren’t particularly world-shaking.
So you’re wondering who is smart and who isn’t, right? (even if you don’t believe in IQ) Here’s the chart:


IQbyreligion.jpg
You’ll see a rough correspondence with the contentions I offered in my posts. The rank order shouldn’t shock you.
NsForEachGroup.jpgI don’t put that much stock in the standard deviation differences for all these groups. Look at the N’s (remember these were youth from the NLSY sample). This isn’t to say that you should discard these inferences as some of you will want to based on the N’s; look at my previous posts and you’ll see data which supports much of this rank order, and the differences between some classes are very large. I only mention the standard deviation issue because it is a point of discussion in the paper itself.
In any case, you might notice a few peculiarities. The spelling of “Muslem” for example; the author is Danish, so that’s a minor issue. But, the racial breakdown for “Muslem” is wrong, at least for the general population. The racial breakdown for the other groups looks correct, so I don’t know what happened here. The Pew Religious Survey has the details, but only about 30-40% of Muslims in the United States are “white” (which includes individuals of Middle Eastern origin), though this paper contends that 85% are. Additionally, the “Un. Church of Christ” is coded as “Dogmatic” in the paper. To me, “Un.” would imply “United,” as in United Church of Christ. This is in fact the most liberal Christian denomination in the United States. The Church of Christ on the other hand is moderately Fundamentalist. I suspect there was a confusion somewhere.
Some of you might not be aware of how IQ distributions look. I decided to assume that the standard deviation was 13, and graphed a few of these denominations and did a little editing in Adobe Illustrator. The opacity causes some issues on the “left half” of the bell curve, but just look at the overlaps on the “right half.”
religionIQdistrib.jpg
Finally, I thought I would address this:

…In terms of evolution, modern Atheists are reacting rationally to cognitive and emotional challenges, whereas Liberals and, in particular Dogmatics, still rely on ancient, pre-rational, supernatural and wishful thinking.

idiocracy.jpgThere’s some evolutionary talk in the paper, but I’m rather skeptical of it. I happen to think that religious cognition is the human norm, and that very high IQ individuals who have a naturalistic worldview are deviant. Those are just the numbers. Since intelligence is a normally distributed trait on a priori grounds you assume it has not been subject to strong unidirectional selection for any period of time. Perhaps there is a frequency dependent dynamic at work (that’s my suspicion). In any case, intelligent people are evolutionarily being selected against right now, so I’d rather avoid language which depicts the religious as older models doomed to extinction.

CATEGORIZED UNDER: Psychology
  • http://congenialtimes.blogspot.com Mark

    I’m surprised that the white norm is set at 106 in this study. Isn’t the white norm in the US usually set at 100? Why the discrepancy, do you think?

  • http://scienceblogs.com/gnxp razib

    I’m surprised that the white norm is set at 106 in this study. Isn’t the white norm in the US usually set at 100? Why the discrepancy, do you think?
    i don’t know, but i assumed it had something to do with the kids in the NLSY. the difference between the means is more important than the means to me.

  • http://congenialtimes.blogspot.com Mark

    I was curious because I’m working on a series of posts about intelligence among the Amish (the first of which I just posted in response to this post) and they generally score a few points above 100 on non-verbal tests of intelligence. (I don’t think that verbal tests are fair measures for Amish schoolchildren given that English isn’t their first language.) I couldn’t resist trying to insert them into the little hierarchy you got going here…

  • http://missivesfromthefrontallobe.blogspot.com Katharine

    Since you say intelligence is being inadvertently selected against by the use of contraception, what do you think would happen if contraception and education were available to everyone in the experimental sample ?

  • catgirl

    Mark, Amish people in the United States (at least in Pennsylvania) learn English as a first language. They have a distinct dialect due to their relative isolation, but it’s still English. What language do you think they speak?

  • http://scienceblogs.com/gnxp razib

    i’ve run into amish in pennsylvania. yeah, they speak english fluently. but i’ve heard them speak in german too.

  • Memphis Aggie

    Just 1 SD from highest mean to lowest mean, very unbalanced design. Comparatively low variance among “Muslems” is due to probably low sample size in cohort. It looks like to me like Protestant denominations are over-specified and other religions are under represented.
    What do you mean though about “believing in IQ”? Does that mean believing IQ is genetic? I believe the IQ phenotype is a mix of genetic and environmental factors. I’d be curious if level of education was tracked as well as level of religious devotion. One could argue that education caused an increase of Atheism and that the degree of religious observance might be a better method of splitting the population. I’m not sure what the finer distinctions between closely related Christian faiths are intended to prove.

  • http://scienceblogs.com/gnxp razib

    One could argue that education caused an increase of Atheism and that the degree of religious observance might be a better method of splitting the population
    this has come up in several comments (some which i’ve not let through because of their abusive nature). remember, this was an NLSY based study, they were focusing on 12-17 year olds from what i know.
    in any case, let me reiterate: this rank order can be find using other methodologies (education, vocabulary tests, conventional folk wisdom on the south).

  • Memphis Aggie

    I’d argue that the religious affiliation of 12-17 years is really about the parents and may be a poor marker for later in life. People change, I did. I’ve been in 4 of the listed categories at various times in my life depending on the strictness of the definitions.

  • Memphis Aggie

    ” this rank order can be find using other methodologies (education, vocabulary tests, conventional folk wisdom on the south).”
    So the data is somewhat confounded and interpretation is more difficult. Still it’s a very large survey.

  • http://scienceblogs.com/gnxp razib

    I’d argue that the religious affiliation of 12-17 years is really about the parents and may be a poor marker for later in life. People change, I did. I’ve been in 4 of the listed categories at various times in my life depending on the strictness of the definitions.
    yes. i didn’t emphasize this because i wasn’t interested, but the paper was especially curious as to who “defected” over the 12-17 period. that is, kids who became atheists or skeptics. smarter kids did. the tendency was especially pronounced in males.

  • Memphis Aggie

    Makes sense – smarter kids are more likely go away to college where social pressure is often hostile to religion, while others might get married younger and have families, which is conducive to faith. I’m sure there are studies have shown that effect.

  • http://www.halfsigma.com Half Sigma

    Sarah Palin’s association with a low-IQ religion was one of my factors in evaluating her.

  • mlk

    “Makes sense – smarter kids are more likely go away to college where social pressure is often hostile to religion, while others might get married younger and have families, which is conducive to faith.”
    The vast majority of kids between ages 12-17 are not in college.

  • HP

    very high IQ individuals who have a naturalistic worldview are deviant
    I don’t see how my sex life is at all relevant. :)

  • http://congenialtimes.blogspot.com Mark

    Catgirl,
    Amish typically speak a dialect of German (usually Pennsylvania Dutch) at home and learn English when they enter school as a second language. By the time they become adults, most are fluent in English, but it’s not their first language.
    Great blog for Amish stuff on the web by a guy who has lived with numerous Amish families:
    http://amishamerica.typepad.com/
    Here’s some posts on Amish language:
    http://amishamerica.typepad.com/amish_america/amish_language/

  • http://congenialtimes.blogspot.com Mark

    “Since you say intelligence is being inadvertently selected against by the use of contraception, what do you think would happen if contraception and education were available to everyone in the experimental sample?”
    This wasn’t addressed to me, but fwiw I doubt it would close the gap. Intelligent people simply are more interested in and place a higher value on learning. They have more *reason* to postpone childbearing because getting a higher education is more important to them, and in postponing childbearing they inevitably decrease fertility.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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