In the most recent issue of AJPS, Nie and his colleagues have an article that makes those two claims. The claims seem perfectly plausible. And they present well-executed research backing them up. Their findings are consistent with a string of previous work making the same argument and coming to the same conclusion (they list several such studies along the way). The main difference: Previous studies have operationalized “small-circulation outlets” as talk radio or cable television, but Nie et al look at internet news sites. They find that more ideologically extreme folks are more likely to visit online news sites.

At the risk of sounding ungenerous, my reaction was “well, duh.” I suppose it’s important to have precise measurement, so it’s worth looking specifically at who is viewing online news sites even though we would expect to find that the same people who consume other niche media would also consume online news. And I suppose that’s a purpose of journals–to look carefully at specific questions. I’m not criticizing them for writing the article by any means. In fact, a “well duh” reaction means they thought to test something that the rest of us assumed was true without bothering to check for sure. Good for them.

So, in sum: People who visit online news and political sites are more politically extreme. Well, duh.

Together, these two articles are a must-read. They help explain why genes and other biological factors might influence our political leanings. Biological factors (especially genetics) are the dominant cause of these Big Five personality traits, which then remain stable throughout life. In turn, these Big Five traits influence our political leanings (Gerber et al.) and our political activity (Mondak et al.).

The Big Five personality traits

Both articles adopt the “Big Five” approach that, they claim, has become widely accepted among psychologists. Quoting two psychologists, Gerber et al. sum up these big five traits as follows:

The Big Five - Gerber et al., pg 113

As Mondak et al. note, these Big Five traits are often summed up as OCEAN: Openness, Conscientiousness, Extroversion, Agreeableness, Neuroticism (where neurotic is the opposite of emotionally stable).

Effects of personality on ideology

Gerber et al. argue that these Big Five personality traits influence our political leanings. Each trait may have different effects on our economic ideology (free market vs interventionist) as well as on our social ideology (pro-choice/pro-equality vs pro-life/pro-tradition). They expect four of the five traits to influence ideology. The only exception is extroversion, which they expect to influence political participation (as Mondak et al. show) but not ideology. Their predictions:

Using a very large sample drawn from the Cooperative Campaign Analysis Project (CCAP), the authors confirm most of these predictions. I’ve pasted below their Figure 1. All hypotheses are confirmed. Their only error was in predicting that emotional stability would cause folks to lean left on social issues. As it turns out, emotionally stable folks lean right on both dimensions and neurotic folks lean left on both dimensions. So we learn that Conservatives are hard-working, organized, closed-minded, and emotionally stable. Liberals are lazy, disorganized, open-minded, and neurotic. Let’s see how the punditocracy spins that one. The effects of personality rival the effects of education and income.

Figure 1 from Gerber et al. 2010

Contextual effects

Gerber et al. also argue that these effects can be contextual, although they seem less committed to this possibility than Mondak et al, for whom environmental interactions were a critical part of the story. In particular, they argue that race might matter. For example, blacks tend to view poverty as caused by systematic forces rather than by laziness; as such, conscientiousness may have a weaker pull among blacks toward economic liberalism. Likewise, blacks tend to be surrounded by liberalism; thus, “openness” might actually lead blacks to question the liberalism that surrounds them rather than pulling them toward the left. Gerber et al. find support for these contextual interactions with a series of figures like the one below. When I look at these figures, though, it doesn’t look so much like an interaction to me–rather, it looks like it’s just harder to predict ideology using personality among blacks than it is among whites.

Figure 2a from Gerber et al 2010

Comment and Criticism

This article, together with the similar one by Mondak et al., is a must-read. I’m not sure whether I’m persuaded yet that I need to demand a personality index on every poll I work with. But these two articles introduce us to a new psychological approach that I’m sure we’ll see much more of.

Theories

Proximity theory is the best-known of these three theories. It makes a basic claim: If you line up all the candidates from most liberal to most conservative, voters will pick the candidate whose ideology is most similar to their own. This theory serves as a basic assumption of the median voter theorem and other spatial models.

Discounting theory is similar to proximity voting, but with a recognition that winning candidates will have to battle other elected officials to get anything done. Imagine a genuinely moderate voter who desires middle-of-the-road policies. If the president is a staunch conservative, then that voter might prefer an extremely liberal Congress over a moderate Congress, given that actual policy outcomes will lie somewhere between what Congress and the president wants. Thus, a discounting voter weights candidate proximity based on the status quo.

The third theory, directional theory, argues that voters view the world in black and white. They want to vote for whichever candidate is on their side of the issues. For example, a moderate Republican would rather vote for an extremely conservative Republican than for a moderate Democrat, because the Republican is on the same side of the issues as the voter is–even if the moderate Democrat is closer to the voter ideologically.

Test

Previous attempts to test these three theories against one another empirically have run into several problems. For one thing, candidate positioning is endogenous–candidates try to place themselves ideologically in a winning position. There have also been a variety of measurement problems.

The main problem, though, has been a lack of critical tests. Previous research has not spelled out the exact circumstances under which these three theories yield different empirical results. The authors begin by filling that gap with a formal model. They show that only for voters within a narrow ideological range do the proximity and discounting rules produce divergent predictions; likewise, the proximity and directional rules produce divergent predictions only within another narrow ideological range. (See Figure 1, Table 1, and Figure 2 in the article for summaries of these scenarios.)

Knowledge of these ranges enables the authors to design critical tests of the theories with a simple experimental survey. Three survey questions provide most of the necessary data. First, they ask voters to place themselves on an 11-point ideological scale dealing with health care reform. Second, they ask them to choose one of two hypothetical candidates based only on each candidate’s position on this 11-point scale. And third, they ask voters to place current government policy along this 11-point scale.

Results

Using sophisticated statistical analysis of these data, the authors find that proximity voting is by far most common, followed by discounting and (distantly) directional voting. There is considerable heterogeneity within the sample; 57.7% are proximity voters, 27.6% are discounters, and only 14.7% are directional voters.

Demographic factors help explain some of this heterogeneity. For example, directional voter was twice as common among less educated respondents as among more educated ones. Most interestingly, discounting was much more common among moderates and independents,¹ a finding that may help explain why candidates polarize rather than converging to the ideological center.²

Critique

The authors provide a rigorous answer to a long-unanswered question. Their formal model is thoroughly persuasive, and it shows exactly where the three theories diverge. Thanks in large measure to this formal model, the authors have a compelling paper.

The empirical work is interesting, but I question whether they have underestimated discounting (and overestimated proximity voting). They do acknowledge a potential bias in this direction (p 310), but only in passing. My concern: When voters choose a hypothetical candidate in step two of the questionnaire, how do we know they are not taking account of the status quo? If they are, then they are making a discounted decision–not a proximity decision.

The authors attempt to control for this through question ordering–that is, by placing the status quo question last, not first, so as not to prime respondents toward discounting. But even if the status quo question were absent altogether, you still might have respondents considering the status quo when choosing a candidate. After all, when voters show up on election day, there is not a question on the ballot asking them to place status quo policies on an ideological scale–yet it appears that at least 27.6% of voters do so.

This article did set up a critical test between directional voting and the other two theories, but it did not set up a critical test between proximity and discounting. Granted, it showed that discounting is more common among moderate/independent voters than among others, but that’s only a marginal effect–a worthwhile finding, but not an answer to the puzzle.

Punchline: A significant contribution to this literature, but not a final answer.