As Tom Rees notes over at Epiphenom: “There’s a new paper out by Satoshi Kanazawa which is causing a bit of a stir.” Indeed. I saw the paper when it came out and decided almost immediately not to touch it in this forum. Why? Several reasons.
First, the title itself (“Why Liberals and Atheists are more Intelligent”) is sure to stir emotions and outrage. I have no interest in stirring either.
Second, it relies on various measures of “general intelligence” or g. Unlike Rees (who covers the study in some detail in his blog post), I have serious theoretical and methodological problems with g.
Third, Kanazawa’s study purports to measure neat dichotomies like conservative/liberal and religious/atheist. These are nearly always false dichotomies and pigeon-holing people into them is often specious.
Finally, I have to comment on Kanazawa’s use of what he calls the “Savanna Principle.”
What we call the “savanna hypothesis” in anthropology is primarily an ecological idea that had anatomical and dietary consequences. The hypothesis basically states that Africa was forested until around 8 million years ago, and that cooler and drier conditions approximately 5-7 million years ago resulted in the break-up of forest habitats and appearance of savanna-like environments. These new environments, in turn, opened up a new niche for at least one (and perhaps several) lineages of apes who became bipedal. We call this lineage “hominids.”
The hypothesis does not necessarily require or entail greater “intelligence.” Several lineages of felids and bovids also took advantage of this savanna niche, all without growing exceedingly large brains and becoming vastly more “intelligent.” The fact that some hominids may have subsequently become more intelligent is correlation, not causation.
It requires several leaps, in other words, to go from the savanna hypothesis to intelligence to religion to unbelief. These leaps are akin to a kind of faith in evolutionary psychology.