A bunch of my favorite social scientists, including Philip Tetlock, Jonathan Haidt, Lee Jussim, and Charlotta Stern, have co-authored an amazing article on the scarcity and value of political diversity in social psychology*, forthcoming in Behavioral and Brain Sciences.  Full pre-print version here.  Highlights:

1. Ideological imbalance is massive.

Inbar and Lammers (2012)… set out to test Haidt’s claim that there were hardly any conservatives in social psychology. They sent an email invitation to the entire SPSP [Society for Personality and Social Psychology] discussion list, from which 2923 individuals participated. Inbar & Lammers found that 85 percent of these respondents declared themselves liberal, 9 percent moderate, and only 6 percent conservative (a ratio of 14:1). Furthermore, the trend toward political homogeneity seems to be continuing: whereas 10% of faculty respondents self-identified as conservative, only 2% of graduate students and postdocs did so.

2. Ideological diversity has a more scientific benefits than mere demographic diversity:

Research in organizational psychology suggest that: a) the benefits of viewpoint diversity are more consistent and pronounced than those of demographic diversity (Menz, 2012; Williams & O’Reilly, 1998); and b) the benefits of viewpoint diversity are most pronounced when organizations are pursuing open-ended exploratory goals (e.g., scientific discovery) as opposed to exploitative goals (e.g., applying well-established routines to well-defined problems; Cannella, Park & Hu, 2008).

Seeking demographic diversity has many benefits (Crisp & Turner, 2011), including combating effects of past and present discrimination, increasing tolerance, and, in academic contexts, creating bodies of faculty who will be more demographically appealing to students from diverse demographic backgrounds. However socially beneficial such effects may be, they have little direct relation to the conduct or validity of science. Viewpoint diversity may therefore be more valuable than demographic diversity if social psychology’s core goal is to produce broadly valid and generalizable conclusions. (Of course, demographic diversity can bring viewpoint diversity, but if it is viewpoint diversity that is wanted, then it may be more effective to pursue it directly.) It is the lack of political viewpoint diversity that makes social psychology vulnerable to the three risks described in the previous section. Political diversity is likely to have a variety of positive effects by reducing the impact of two familiar mechanisms that we explore below: confirmation bias and groupthink/majority consensus.

3. Ideological diversity helps defuse confirmation bias:

Confirmation bias can become even stronger when people confront questions that trigger moral emotions and concerns about group identity (Haidt, 2001; 2012). Further, group polarization often exacerbates extremism in echo chambers (Lamm & Myers, 1978). Indeed, people are far better at identifying the flaws in other people’s evidence-gathering than in their own, especially if those other people have dissimilar beliefs (e.g., Mercier & Sperber, 2011; Sperber et al., 2010). Although such processes may be beneficial for communities whose goal is social cohesion (e.g., a religious or activist movement), they can be devastating for scientific communities by leading to widely-accepted claims that reflect the scientific community’s blind spots more than they reflect justified scientific conclusions (see, e.g., the three risk points discussed previously).

4. Why do liberals predominate?  The paper considers all the main hypotheses.  Results: Homophily and differences in interests are big parts of the story; differences in intellectual ability are not.  But there is also strong evidence that (a) hostile climate and (b) conscious discrimination play big roles too.  The evidence on conscious discrimination shocks even me:

Inbar and Lammers (2012) found that most social psychologists who responded to their survey were willing to explicitly state that they would discriminate against conservatives. Their survey posed the question: “If two job candidates (with equal qualifications) were to apply for an opening in your department, and you knew that one was politically quite conservative, do you think you would be inclined to vote for the more liberal one?” Of the 237 liberals, only 42 (18%) chose the lowest scale point, “not at all.” In other words, 82% admitted that they would be at least a little bit prejudiced against a conservative candidate, and 43% chose the midpoint (“somewhat”) or above. In contrast, the majority of moderates (67%) and conservatives (83%) chose the lowest scale point (“not at all”).

Inbar and Lammers (2012) assessed explicit willingness to discriminate in other ways as well, all of which told the same story: when reviewing a grant, 82% of liberals admitted at least a trace of bias, and 27% chose “somewhat” or above; when reviewing a paper, 78% admitted at least a trace of bias, and 21% chose “somewhat” or above; and when inviting participants to a symposium, 56% of liberals admitted at least a trace of bias, and 15% chose “somewhat” or above. The combination of basic research demonstrating high degrees of hostility towards opposing partisans, the field studies demonstrating discrimination against research projects that are unflattering to liberals and their views, and survey results of self-reported willingness to engage in political discrimination all point to the same conclusion: political discrimination is a reality in social psychology.

If you’re already telling yourself, “Discrimination can’t be a serious problem if people are so quick to admit their own failings,” you have entered Monty Python territory.

The piece ends with some wonderfully quixotic proposals to fix social psychology.  If anyone thinks any of these proposals will be seriously adopted, I’m ready to bet against you.

* Including personality psychology.