Bryan Caplan, the GMU economist and leading libertarian thinker, has posted his review of my book with Rob Kurzban, The Hidden Agenda of the Political Mind. Given that Kurzban and I, to use Caplan’s phrases, “frontally attack” a position that Caplan “strongly endorse[s],” it’s not surprising that Caplan’s review is negative. He playfully suggests it’s in his own “self-interest for the book to be widely read” given that the book says nice things about him personally, but that’s probably not the whole story – while no sane person who has followed Caplan’s work can doubt his tremendous intellect and energy, I nonetheless think he gets some central things wrong about public opinion, a point that many would find convincing if they read the book.

What are we arguing about?

There’s a real danger here of talking past each other. In his review, Caplan points to his lecture outline on self-interest in politics. In it, he says he interprets “‘people are self-interested’ as ‘on average, people are at least 95% selfish.'” This is an incredibly high bar.

Kurzban and I are in fact arguing against claims like the one in the first paragraph of Caplan’s review: “While self-interest occasionally plays a role, it poorly predicts both issue positions and voting behavior.” Our response isn’t that self-interest always or almost always matters to the exclusion of everything else, but instead that self-interest does a good deal better than “poorly” predicting.

This difference leads to some confusion. Caplan, for example, claims that we do not admit that “non-interest-based ideology” affects people’s views. This is contradicted by our explicit remarks on this topic. For instance, on page 206 we wrote: “When it comes to party identifications and ideological labels, we think they can exert substantial causal influence on a range of judgments.” This admission doesn’t compromise our central point, though, since we never said that ideology doesn’t matter at all or is entirely about self-interest. Instead, our project was to look at whether self-interest has substantial effects on public opinion, regardless of what else might matter.

Based on our analyses, my view is that lots of people have self-interested issue positions lots of the time. It’s not nearly 95%, but there is vast space between that bar and “poorly.” Kurzban and I are responding to claims that self-interest rarely matters much with a rebuttal that it often (but not always) matters quite a bit (more in some cases than others). Self-interest is one of the big pieces in a complex puzzle.

So, Caplan and I agree that people aren’t 95% selfish. But Caplan and I disagree over whether self-interest is a trivial factor in public opinion.

Making one’s case

Caplan says that we “trumpet a strong, incredible thesis, then ‘interpret’ virtually every fact to fit it” and that we “never clearly state what would count as evidence against their view.” I could say the same of Caplan’s book, The Myth of the Rational Voter.

Our agenda was not exclusively to try to falsify our own view, just as Caplan’s agenda was not exclusively to try to falsify his own. I look forward to Caplan’s future posts indicating where we have gone wrong as an empirical matter. However, a key question we wanted to address is whether the evidence supports the strong claims that have specifically been made with respect to whether self-interest is a poor predictor of political opinions.

Here are some examples. In Caplan’s lecture outline, he says: “Unemployment policy - The unemployed not much more in favor of relief measures.” It’s an empirical claim. When we checked the data in our book, we found that the unemployed were about 29 percentage points more supportive of unemployment benefits than those working full time. Similarly, Caplan says: “National health insurance - The rich and people in good health are about as in favor.” In our book, we found that wealthier people with health insurance were 19 percentage points less supportive than poorer people without health coverage when it comes to opinions on whether it ought to be the government’s responsibility to provide health coverage.

Are these effect sizes “poor” or are they “substantial”? This question depends on how one attaches numbers to words. Still, we feel very safe using Caplan’s own view of things. Indeed, later in his outline he refers to the 22 to 35 point gap in party affiliation by race as “massive” and the 6-point gender gap in party affiliation as “marked.” So, on Caplan’s metrics, the unemployment gap ought to be considered “massive” and the health insurance gap ought to be considered somewhere between “marked” and “massive.”

If these sorts of analyses do not count as evidence against Caplan’s view, it’s unclear what would.

Definitions and tautologies

Caplan spends much of his time criticizing our view of “inclusive interests.” Kurzban and I have a new post over at This View of Life (written before we saw Caplan’s review) that addresses much of this, so I’ll point the reader there and just give some brief thoughts here.

A problem in thinking about self-interest in politics is that the standard definitions of “self-interest” and “group interests” don’t make sense. In his lecture outline, for example, Caplan says: “Drawing on evolutionary psychology, I interpret altruism towards blood relatives in proportion to shared genes as self-interest.” We agree, as do most political scientists. But this puts a “group” squarely in the middle of “self” interest. So we use the biological term “inclusive” in part to signal this.

We also take evolutionary work seriously on the breadth of typical human motivations. These include not only short-term economic outcomes, but also social status fights (which also have obvious economic implications) and fights over sexual and reproductive lifestyles (which are mostly not directly economic).

In short, what are we to call it when individuals express opposition to discrimination against their own race, or when individuals express opposition to discrimination against their own sexual orientation, etc.? How are these cases importantly different from individuals expressing support for lots of people getting unemployment benefits based on their own unemployment? And what are we to call it when people who sleep around and want to delay having children oppose condemnation of promiscuity and limits on family planning? Maybe these examples aren’t “self-interest” on some definitions, but they’re surely closely related to self-interest. More to the point, they’re obviously not things that negate evidence of self-interest.

Relatedly, Caplan says we believe that one’s allies and social networks consist of “millions of people.” This is false. Our point (pp. 38-40) was that individuals often have a tangible stake in what happens with the actual circle of non-related people with whom they share benefits and burdens (mostly including romantic partners and close friends, but also leaking over into co-workers, fellow church members, etc.). This may be indirect self-interest, but it’s certainly not the absence of self-interest.

In our data, the actual variables are all about effects of personal characteristics on political opinions; we don’t include measures of the characteristics of one’s social networks. Though, obviously, one can make statistical assumptions. For example, it’s clear that African Americans are poorer on average. Importantly, then, even when individual African Americans are wealthier, they typically have family members and friends and neighbors who are poorer than the social networks of white Americans who are similarly wealthier. I believe it would be nutty to think that this doesn’t relate to individuals’ self-interest (including family members and indirect effects of friends).

This doesn’t lead to a tautology. We trace through the evolutionary background that focusses our attention on social status and sexual matters in addition to short-term economic matters. And we freely admit in the book that there’s a definitional looseness at work. But it’s a looseness that has always existed in the self-interest literature – we’re just calling attention to it. Again, e.g., if individuals who are religious minorities tend to oppose discrimination against religious minorities, it’s incoherent to say that that’s evidence of an absence of self-interest. If individuals who engage in casual sex don’t want others imposing social costs on people who engage in casual sex, it’s incoherent to say that that’s evidence of an absence of self-interest. And so on. Further, Caplan quotes a section where we ourselves discuss issues we think don’t fit with a self-interest account – how can a tautology produce such results?

Our book is about connecting real-life circumstances to the details of public opinion. We find lots of these connections. Call it whatever you’d like.

Now you see it, now you don’t (nerd alert: skip this section if you’re not interested in methodological discussions)

How have so many political scientists missed these points? Mainly, I think, because they load up their regression models with lots of variables that are large correlates of public opinion but really might not be big causes of public opinion. We talk about this in the text of the book in chapters 1, 2, and 10, and provide an academic demonstration of one of the main points in part B of the appendix to chapter 2.

In short: Of course you can always find ways to make demographic coefficients shrink in models of public opinion by “controlling” for ideology, party affiliation, and various explicitly political scales (like right-wing authoritarianism, etc.).

Let’s say that income, race, and gender combine to predict to a degree views on redistributive issues. And then let’s say that these coefficients are greatly reduced by “controlling” for ideology, party affiliation, and so on. Does that mean that income, race, and gender never mattered in the first place? Does being a conservative Republican turn poor, minority women into rich, white men? At best, this doesn’t mean that income, race, and gender don’t matter, but suggests something about the manner in which they matter.

But the “at best” case has problems that are rarely acknowledged. Things like ideology, party, and political scales are often big correlates of issue opinions, but there are reasons to be skeptical that they are commensurately big causes of issue opinions. If lots of people choose ideological labels and party preferences in large part because of their issue opinions, then it’s really quite dicey to just pop them in a multiple regression as predictors, something we explain at length in part B to the appendix to chapter 2 in the book.

Caplan says that the book doesn’t produce multiple regressions including “a simple measure of left-right ideology as an explanatory variable” and that it “never ‘races’ its thesis against any competing view.” But there were reasons we chose not to run these races. First, I have big doubts about whether such correlates are in fact primarily causes rather than effects or non-causal siblings. Here, Caplan’s focus on the “magnitudes” of these correlations is beside the point – there are plenty of really big but non-causal correlates of political attitudes, something multiple regressions will often fail spectacularly to reveal (again, see our appendix). Second, even if these do predict issue preferences, and even if they suppress demographic coefficients in multiple regression, they can’t actually erase the demographic facts, given that most of the features we look at (e.g., race, gender, sexual orientation, education, income, etc.) are surely plausibly viewed as coming very early in the causal chain. Third, we’re not arguing that self-interest is the only or even the largest correlate of public opinion; again, we’re arguing against the view that self-interest hardly ever matters much with our position that it often matters quite a bit – the argument isn’t over whether self-interest beats all rivals in correlation size, but whether it manages to finish the “race” with a decent time.

The Hidden Agenda of Bryan Caplan

There are lots of other specific claims in Caplan’s review that I take issue with. Perhaps I’ll address some at a later date, but I’ll close now in the service of (relative) brevity.

If you’ve followed Caplan’s work, you’ll know that he is deeply committed to advancing libertarian policy objectives. His argument in service of this objective is, basically: (1) People mostly just want what’s best for society as a whole. (2) Libertarian economists know better than others what’s best for society as a whole. (3) Therefore, people should follow the policy advice of libertarian economists.

Step 2 might well be true. But, if it turns out step 1 is wrong, and that political disagreement has a lot to do with competing constituencies’ self-interest, then it’s harder to get to step 3. If low-education native-born folks tend to oppose libertarian immigration policies because they’re often worse off under these policies, then that’s a problem for the argument. Or if low-income people with low-income social networks tend broadly to favor greater income redistribution because their own circumstances are advanced, then that’s also a problem.

So I understand the impulse here to undermine the book. It interferes with his attempts to advance libertarian policies. Apparently Caplan also thinks of me as a self-deluded activist, indeed, a conspiracy theorist – someone who seeks to “replace decades of careful and curious social science with near-tautologies and just-so stories,” and that “the only ‘important’ thing about this book is that it might destroy a valuable body of knowledge.”

It’s certainly true that I think that a big wing of political scientists are wrong about self-interest (though another wing of political scientists, those who more routinely interact with pollsters and political professionals, are often much more knowledgeable about demographic interests). But this is what scholarly debate is all about. We showed our work in the book, including over 100 pages of statistical appendixes, including specific data-based refutations of key points in Caplan’s work.

Interestingly, Caplan has strongly defended the psychological position that people often follow self-interest but then cover it up behind nice-sounding stories. Yet he thinks politics is one of the key exceptions to this general rule. I see lots in the data to suggest that politics is far from a special exception, and little in Caplan’s review of the book’s “conceptual flaws” that convinces me that we didn’t find what we in fact found.