Political ideology and environmentalism impair logical reasoning

Keller, L., Hazelaar, F., et al. (2024).

Thinking & Reasoning, 30(1), 79–108.

https://doi.org/10.1080/13546783.2023.2200976

Abstract

People are more likely to think statements are valid when they agree with them than when they do not. We conducted four studies analyzing the interference of self-reported ideologies with performance in a syllogistic reasoning task. Study 1 established the task paradigm and demonstrated that participants’ political ideology affects syllogistic reasoning for syllogisms with political content but not politically irrelevant syllogisms. The preregistered Study 2 replicated the effect and showed that incentivizing accuracy did not alleviate these differences. Study 3 revealed that syllogistic reasoning is affected by ideology in the presence and absence of such bonus payments for correctly judging the conclusions’ logical validity. In Study 4, we observed similar effects regarding a different ideological orientation: environmentalism. Again, monetary bonuses did not attenuate these effects. Taken together, the results of four studies highlight the harm of ideology regarding people’s logical reasoning.

Here is a summary:

This paper reports four studies investigating the influence of political ideology and environmentalism on logical reasoning performance using a syllogistic reasoning task. The key findings are:

1. People were more likely to judge the conclusion of a syllogism as valid when it aligned with their ideology (liberal, conservative, or environmentalist), even when the conclusion was logically invalid. Conversely, they were more likely to recognize flaws in conclusions that went against their ideology.
2. This ideological bias in reasoning occurred symmetrically across the political spectrum - both liberals and conservatives showed impaired logical reasoning for conclusions contradicting their ideology.
3. The bias persisted even when participants were offered monetary incentives for accurately judging the logical validity of conclusions, across online and lab studies in the US and Germany.
4. Political ideology and environmentalism did not impact logical reasoning for neutral, non-ideological syllogisms, suggesting the effect was specific to ideologically charged content.

The authors argue that ideological beliefs can negatively impact logical reasoning abilities in a systematic way when dealing with belief-consonant or belief-dissonant conclusions, even for abstract reasoning tasks devoid of real-world consequences. Monetary incentives failed to mitigate this ideological reasoning effect.