Do liberals and conservatives really have different moral foundations?

The idea that political conservatives and liberals differ in fundamental ways — in their biology and neurology, personality and moral foundations — has received a good deal of attention.

However, cracks have begun to appear in this idea. In 2019, we covered new work finding that conservatives are not in fact more readily disgusted than liberals (disgust has a moral dimension, of course).

And the year before, Jesse Singal, a regular Digest guest blogger, covered evidence suggesting that claims about liberal-conservative personality differences have been overblown.

Now a major new review and meta-analysis of research into political orientation and moral foundations — essentially, how people view morality — calls into question some influential earlier conclusions. Writing in the Psychological Bulletin, J. Matias Kivikangas at Aalto University and colleagues report finding support for the idea of some basic moral differences between conservatives and liberals. However, they also conclude that the differences are less clear cut than had been thought, and the results are also less generalisable across regions, countries and political cultures than has been claimed.  

The team considered study data from 89 samples, with 605 effect sizes. In total, these studies included almost 44,000 participants who had been directly recruited as well as around 193,000 participants who had chosen to complete surveys on the YourMorals.org website (widely used as a data source in this field). In each case, participants had rated their own political orientation on "liberal to conservative" or "left to right" scales, or on social or economic dimensions.

They had also reported on their moral foundations using the Moral Foundations Questionnaire. This questionnaire assesses the degree to which people prioritise five domains in moral decision-making: harm/care, fairness/reciprocity, ingroup/loyalty, authority/respect and purity/sanctity. 

First, the researchers looked at evidence for the influential idea that, compared with liberals, conservatives endorse the moral foundations of care and fairness less, and loyalty, authority and sanctity more. They found that this claim was generally upheld by the data.

However, when they looked more closely, they found that conservative women were about as care-oriented as liberal women (it was conservative men who accounted for the link between conservatism and reduced endorsement of care as a moral foundation). Also, comparisons based on the YourMorals data produced around double the effect sizes of studies that used independent samples.

The team adds that "the consistency across the independent studies makes the estimates from the YourMorals dataset suspect". People who choose to fill in surveys on this website probably do so because they are especially interested in the topic, are more open to experience (a personality trait associated more with liberalism than conservatism) and espouse more extreme beliefs than average — a self-selection that means their attitudes are not representative of the general population.

The team also looked at the claim that moral differences between liberals and conservatives are universal, cutting across geography and culture. They found that this was not the case. In fact: "The association of moral foundations to political orientation varies culturally (between regions and countries) and subculturally (between White and Black respondents and in response to political interest)." For example, among subsamples of Black Americans taken from representative data sets, there was only a very weak association between conservatism and greater endorsement of sanctity and authority.

The researchers also note that while conservatism is often viewed as one-dimensional in the US, in Western Europe, for example, it is generally thought of as having two dimensions: economic and  social. The team found that liberal/conservative variations in endorsement of care and fairness were more related to economic conservatism — and sanctity less so.

Yet many studies use single "conservative-liberal" or "left-right" scales, which doesn't allow for such nuanced conclusions.

n fact, views on the meaning of "right-leaning" vary geographically, too; the team cites a study finding that in many countries conservatism is more commonly associated with the left and liberalism with the right (something that they note is very clearly the case in Latvia and other formerly communist nations, for example).

"In conclusion, the results of this meta-analysis both confirm and expand the relations of moral foundations and political orientation," the team writes. However, they "also raise some notable considerations for future studies regarding the methodology and theory".

Further reading

– Moral foundations and political orientation: Systematic review and meta-analysis.

About the author

Emma Young (@EmmaELYoung) is a staff writer at BPS Research Digest