How Deeply Ingrained in our Heads is Partisan Affect?

Polarization of American partisans continues to increase.  Liberals and conservatives alike have obvious contempt for opposing partisans — this is universally demonstrated by implicit, explicit and behavioral indicators.  Shanto Iyengar and Sean Westood of Stanford University and Princeton University, respectively, designed a set of four studies — titled “Fear and Loathing Across Party Lines: New Evidence on Group Polarization” to further investigate political dichotomy in America.

1. What They Did – Intervention Summary:

Study 1 assessed implicit partisan affect and anchored it to implicit racial affect. used two different brief versions of the Implicit Association Test (IAT) to measure implicit racial affect and implicit partisan affect.

Participants first completed four rounds of a BIAT created by the researchers to measure their implicit attitudes.  Their “D-scores” were calculated by subtracting their mean response times when pairing a Democratic mascot with “good”.  Positive D-scores (between 0 and 2) indicated greater positive affect for Republicans and inverse responses times indicated greater positive affect for Democrats.

To further validate the tests, the relationship between partisan D-score and a difference in feeling (regarding Democrats and Republicans) thermometer test was examined.

Finally, participants’ scores on the partisan BIAT and the race BIAT were compared.

2. What They Found – Results:

As was expected, they found that partisan D-scores corresponded closely with which party a participant self-identified with.  ”Strong Republicans”, for example, produced the most bias in favor of Republicans.

The thermometer test validation, despite a small amount of divergence, correlated strongly (r=.418) with the D-scores.

Racial affect BIATs showed a substantial black-white implicit bias, but the race effect size was not nearly as strong as the party effect size.  When compared to party BIATs, it was discovered that negative associations of opposing parties are faster which, in this case, means more automatic and/or stronger, than negative associations of African Americans.

This tells us that, since racial identity is, obviously, acquired at or before birth and racial attitudes are deeply ingrained, for partisanship to exceed race, its underlying hostility must be immense.

3. Who Was Studied – Sample:


*In order to capture racial affect among non-whites, African Americans were oversampled.

4. Study Name:

Iyenger and Westwood et al. 2014, Study 1

5. Citation:

Iyengar, Shanto & Westwood, Sean J. (2014).  Fear and loathing across party lines: New evidence on group polarization.

6. Link:

7. Intervention Categories:


8. Sample Size:


9. Central Reported Statistic:

“The spread between Democrats and Republicans on the partisan D-score was massive… (p<.001).”

10. Effect Size

D(Republican) = .27, D(Democrat) = -.23