(This article was originally published at Statistical Modeling, Causal Inference, and Social Science, and syndicated at StatsBlogs.)
Pinker is clearly right to note that mass political opinions on seemingly diverse issues cohere, and Andrew, I think, is way too quick to challenge this
I [Kahan] could cite to billions of interesting papers, but I’ll just show you what I mean instead. A recent CCP data collection involving a nationally representative on-line sample of 1750 subjects included a module that asked the subjects to indicate on a six-point scale “how strongly . . . you support or oppose” a collection of policies:
policy_gun Stricter gun control laws in the United States.
policy_healthcare Universal health care.
policy_taxcut Raising income taxes for persons in the highest-income tax bracket.
policy_affirmative action Affirmative action for minorities.
policy_warming Stricter carbon emission standards to reduce global warming.
Positions clustered on these “diverse” items big time. The average inter-item correlation was 0.66. . . . Being able to form a scale like this with a general population sample is pretty good evidence in itself (and better than just picking two items out of GSS and seeing if they correlate) that people’s opinions on such matters cohere.
But just to make the case even stronger, let’s consider how much of the variance in liberal policy preferences can be explained by ideology. . . .
[Kahan's graph was pretty good, but I cropped it here to make it even better, by dumping an uninformative title, an uninformative y-axis, and a pointless footnote. Cool, huh? --- AG]
Pinker is clearly wrong—not just in his answer but in his style of reasoning—to connect this sort of coherence to “different conceptions of human nature” among people of opposing ideologies
Pinker, however, is indeed doing something very objectionable: he is engaged in rank story-telling.
He notes that political philosophers identify ideologies with different conceptions of “human nature,” a “conflict of visions so fundamental as to align opinions on dozens of issues.” Well, maybe political philosophers do do that. But the idea that “different conceptions of ‘human nature’ ” explains coherence and variance in mass political opinion is an empirical claim, and as far as I know there’s not any support for it.
I [Kahan] think it’s almost certainly false. . . .
Ironically, Andrew is making the sort of mistake he says Pinker made.
This last point follows from all the others. Andrew sees Pinker doing something irritating, and then treats a conjecture . . . as a general law that explains this particular instance, etc.
Wow—I love this sort of discussion! Here’s my reply:
In regard to the specifics, survey responses are noisy (presumably representing a lot of “nonattitudes” in the population). I think that many individual people feel there is a logic connecting all their political beliefs, but different people have different logics. Pinker gave an example of gay marriage and the military budget. There is a wide range of views on these two topics and the correlation is low, because these two issues can be placed in many different conceptual frameworks. What you have shown is that in your survey with those questions you get high correlations. GSS and NES show low correlations. I think it would be fair to say that some aspects of political attitudes can be predicted from other attitudes. In general, attitudes on different issues are more highly correlated with partisanship than with each other. I guess it would be ok to compromise and say that the correlations are moderate. I perhaps was overreacting to Pinker’s statement because I’m sensitive to this issue, of people not realizing the diversity of opinions among Americans, especially among those Americans who are not highly politically involved.
Regarding Kahan’s last point, where do I say anything about “a general law”? Here’s what I wrote:
Psychology is a universal science of human nature, whereas political science is centered on the study of particular historical events and trends. Perhaps it is unsurprising, then, that when a psychologist looks at politics, he presents ideas that are thought-provoking but are too general to quite work.
I think the first sentence is unobjectionable. I really do think psychology is more universal than political science. Sure, there are some aspects of political science that are universal, but my own work, for example, on Democrats and Republicans is unapologetically both time- and space-bound in a way that psychology certainly tries not to be.
My second sentence above is phased very carefully. I don’t think that “perhaps it is unsurprising” is anything like claiming “a general law”! But Kahan has a good point that I was oversimplifying a bit by downplaying the predictability of attitudes across issue domains.
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