• Introduction:
  • Investigates partisan bias in decision-making processes.
  • Compares biases based on partisanship and race.
• Study 1: Implicit Bias Measures:
  • Utilizes Implicit Association Test (IAT) to measure implicit biases.
  • Finds stronger implicit biases toward opposing partisans compared to racial outgroups.
• Study 2: Explicit and Implicit Partisan Affect:
  • Examines explicit and implicit biases using feeling thermometers.
  • Shows stronger affective polarization toward opposing partisans than racial outgroups.
• Study 3: Behavioral Evidence of Partisan Bias:
  • Uses trust and dictator games to assess tangible effects of bias.
  • Finds individuals more generous toward copartisans than opposing partisans, regardless of race.
• Study 4: Separating Ingroup Favoritism from Outgroup Animosity:
  • Further explores ingroup favoritism and outgroup animosity using dictator and trust games.
  • Confirms significant biases toward copartisans and against opposing partisans, with minimal effects based on racial cues.
• Discussion:
  • Compares strength and implications of partisan bias versus racial bias.
  • Highlights the significance of partisan identity and affective polarization in contemporary American politics.
  • Discusses implications for political processes and the evolving relationship between American voters and their parties.

The article "Fear and Loathing Across Party Lines: New Evidence on Group Polarization" by Shanto Iyengar and Sean J. Westwood offers a detailed exploration of affective polarization in American politics, comparing it to racial biases and examining its consequences on social and political behaviors. :

• Affective Polarization Defined: Affective polarization refers to the phenomenon where members of one political party view members of the opposing party with hostility and view their own party members more positively. This form of polarization is distinct from ideological polarization and is measured in terms of social identity and affect towards co-partisans versus opposing partisans.

• Key Findings on Affective Polarization:

  • Partisan identity has become a significant form of social identity, with hostility towards opposing partisans ingrained in voters’ minds. This hostility is just as strong as, if not stronger than, racial biases.
  • Political partisanship influences not only political decisions but also non-political judgments and behaviors, with partisans discriminating against opposing partisans in a manner that exceeds discrimination based on race.
  • Unlike social divides such as race or gender, where social norms constrain expressions of bias, there are fewer social norms to temper disapproval of political opponents, allowing partisans to freely express animus.

• Evidence of Affective Polarization:

  • The use of implicit measures reveals that hostile feelings towards the opposing party are automatic in voters' minds, demonstrating the deep embedment of partisan identity.
  • Experiments show that partisans preferentially discriminate against opposing partisans, even in non-political contexts, based more on outgroup animus than ingroup favoritism.

• Impact on Interpersonal Relations:

  • Preference for same-party marriage and social relationships is increasing, with actual marriages across party lines being rare. This trend towards homophily based on partisan identity indicates a growing relevance of partisan cues for interpersonal relations.
  • Partisan affiliation is openly displayed in various contexts, further entrenching party preference into personal and social domains.

• Implications for Political Behavior and Society:

  • The entrenched nature of affective polarization suggests that partisan bias is deeply rooted in the social identity of Americans, leading to discriminatory behaviors that prioritize partisan affiliation over other considerations, including merit.
  • The strength of partisan bias is demonstrated through behavioral experiments where participants display a strong preference for their own party members, highlighting the significant role of partisan identity in everyday decisions.

• Comparative Analysis of Partisan and Racial Bias:

  • The article provides a comparative analysis showing that partisan affect and discrimination based on partisanship are as significant as racial bias, challenging the common perception of race as the deepest divide in American society.
  • This comparison sheds light on the magnitude of affective polarization, with partisan animosity surpassing racial hostility in certain measures.

• Effects of Ingroup and Outgroup Membership: Partisans show a strong preference for allocating resources to copartisans over independents or opposing partisans in both dictator and trust games. This behavior persists even in non-political contexts, emphasizing the deep-seated nature of partisan bias, which is not restrained by social norms against discrimination like racial bias is.

• Explanation for Stronger Partisan Affect: The authors suggest that the stronger affective response to partisan cues over racial cues is due to the lack of social norms discouraging discrimination based on political affiliation. Furthermore, partisan identity is a chosen affiliation, which might lead to stronger feelings of responsibility and opposition, enhancing the sense of conflict and animosity towards out-party members.

• Comparisons of Implicit and Explicit Party Affect: The study finds that implicit and explicit measures of partisan affect reveal similar degrees of affective polarization. This suggests that partisan affect deeply influences both conscious and unconscious attitudes, underlining the affective, rather than ideological, basis of party identification in the U.S.

• Implications for Political Behavior: The pervasive affective polarization has significant implications for political cooperation and the legitimacy of political opponents. It encourages elected officials to adopt confrontational stances and undermines efforts at bipartisan cooperation, reflecting a shift in American politics towards more entrenched and affect-driven party identities.