We knew liberals were different, but just how different is revealed in a new study of the human brain indicating that not only do liberals and conservatives share different moral sentiments, but that markedly differing brain structures underlie those sentiments.
The study‚??s ‚??findings demonstrate that variation in moral sentiment corresponds to individual differences in brain structure and suggest that moral values possess deep-rooted biological bases distributed across distinct brain regions,‚?Ě say University of California, Santa Barbara, post-doctoral researcher Gary J. Lewis and three research collaborators in the August 2012 issue of the Journal of Cognitive Neuroscience (JCN).
‚??People differ in their sentiment for societally important moral and political values, and those differences are not simply observable in the voting booth, but can also be detected at the level of neuroanatomy,‚?Ě Lewis told Human Events in an August interview.
Building on studies that have found ‚??regional variation in brain volume is also linked to individual differences in psychological traits,‚?Ě the researchers used magnetic resonance imaging (MRI) to analyze the brain structures of 70 young adults and correlate them with differences in moral values‚??research that purports to be the first of its kind.
The researchers took as the basis for their study of moral values ‚??five core foundations‚?Ě‚??a desire to minimize harm to others, fairness, in-group loyalty, authority, and purity (a desire to avoid what is impure or disgusting). Measured with a 32-item Moral Foundations Questionnaire, previous studies have identified ‚??two higher moral factors‚?Ě‚??individualizing and binding, which in turn ‚??have been shown to account for significant variance in liberalism-conservatism [respectively] in both the United States and United Kingdom,‚?Ě Lewis and one of his collaborators, University of Edinburgh Psychology Prof. Timothy C. Bates, reported last year in the British Journal of Psychology.
In the more recent study, researchers discovered a greater volume of gray matter in two areas of the brain for subjects reporting conservative attitudes.
‚??Binding was positively and significantly correlated with gray matter volume‚?Ě in two areas, the bilateral subcallosal gyrus and the left anterior insula, ‚??for these moral domains,‚?Ě the researchers say in their JCN article, ‚??Moral Values Are Associated with Individual Differences in Regional Brain Volume.‚?Ě
‚??These brains regions‚?¶would likely show smaller gray matter volume in those with liberal attitudes, although work still needs to be done on this specific question,‚?Ě Lewis said. Generally, the researchers say, a greater volume of gray matter may reflect ‚??enhanced computational efficiency perhaps has a function of greater neuronal density.‚?Ě
Lewis and his collaborators are careful to point out that ‚??no common brain region was observed linking the moral domain and political orientation.‚?Ě The linkages come from self-report data from the Moral Foundations Questionnaire, and from a political orientation query asking respondents to rate themselves on a six-point scale from ‚?ĚVery liberal‚?Ě to ‚??Very conservative.‚?Ě
Nature vs. Nurture
It‚??s much too early to speculate how much moral values are a product of predisposition or environmental factors like language and culture.
‚??Where you‚??re born and raised, the culture and meanings you‚??re immersed in, these are larger effects in absolute terms than are the heritable predispositions we‚??re talking about,‚?Ě Jonathan Haidt, Thomas Cooley Professor of Ethical Leadership at the New York University-Stern School of Business told Human Events. ‚??The amazing thing is just that there‚??s any heritable predisposition‚??ideology is learned or imprinted onto a blank slate.‚?Ě Haidt (pronounced ‚??Hite‚?Ě) is a social psychologist whose book, The Righteous Mind: Why Good People are Divided by Politics and Religion, was published in March.
‚??I would not be at all surprised to learn that the brains of people who prize certain moral foundations behave differently in [functional] MRI‚??looking at the brain in action. But I am surprised to learn that the differences show up so clearly in structural MRI‚??in something as crude as the sheer size of various neural clusters,‚?Ě Haidt said. ‚??It‚??s as though phrenology was right, it‚??s just that the early phrenologists were wrong to look at bumps on the head, rather than clumps of neurons deeper down.‚?Ě
‚??The evidence is stacking up that there is an inherent component, but whether it is more powerful than the framing context of language I don‚??t think has been fully disentangled,‚?Ě University of Nebraska Psychology Prof. Kevin B. Smith told Human Events. ‚??Most likely these are not independent of each other, but interact in some way,‚?Ě said Smith, who also co-directs the Political Science Physiology Lab at University of Nebraska-Lincoln.
Smith last year co-published research demonstrating that political attitudes are sometimes represented by instances of ‚??involuntary physiological responses to facets of life far detached from the political issues of the day.‚?Ě He and his collaborators found that individuals with strong ‚??physiological responses to disgusting images‚?¶are more likely to self-identify as conservative…than are individuals with more muted physiological responses to the same images.‚?Ě
That evidence showing that political‚??and moral‚??differences ‚??have some sort of biological basis‚?¶helps explain why, as individuals, we have different belief systems and standards of conduct,‚?Ě Smith said.
‚??People differ in brain structure, and these brain structure differences can lead to differences in political behavior, but specific situations, such as war or resource scarcity, can lead to these underlying biological differences manifesting in differences in politics and values in even more powerful ways than might otherwise be observed,‚?Ě Lewis said.
‚??People who score high on binding and feel that authority is being challenged are more likely to have less latitude in how they might feel or respond to challenges.‚?Ě
For example, the arrest, prosecution, and August 17 conviction for hooliganism of three members of the Russian female rock band, Pussy Riot, might not be an expression of moral sentiment by President Vladimir Putin, because part of his motivation would be to expand and maintain political power. But members of the Russian Orthodox Church who support the conviction might score higher for binding, and exhibit greater volume of gray matter in the subcallossal gyrus and the frontal portion of the insula cortex.
‚??That would make an interesting test case,‚?Ě Lewis said, ‚??because you could predict and test whether the relationship was true or not.‚?Ě
The discovery of differing underlying brain structures for binding or individualizing ‚??should help us realize that the way we see things is not the only way,‚?Ě said Haidt. ‚??I don‚??t want us to retreat all the way to taste, as in musical taste, where we say that there‚??s no disputing tastes,‚?Ě but morality is complex, and we each bring to it a mind that is predisposed to pick out some features and be blind to others that other people care about.
‚??These are interesting results, and they fit with some other studies‚?¶indicating that differences in neural architecture correlate either directly with political attitudes or with traits such as moral values that certainly have implications for political temperaments,‚?Ě Smith said. He cautions, however that the sample sizes for these studies have been small and that there has not yet been much replication of the finding.
Because the research by Lewis and his collaborators focused on young adults and other studies have shown that regional brain volume changes throughout life, more study would be required ‚??to determine whether the associations detected here generalize to other ages or socio-demographic groups.‚?Ě Future research would attempt to clarify ‚??why individual differences in brain volume should correlate with psychological traits in general,‚?Ě and it would attempt to determine the ‚??causality underlying the observed relationships between brain structure and moral values,‚?Ě the researchers say.
Dr. Gary J. Lewis, who completed the research with colleagues Ryota Kanai, Timothy C. Bates, and Geraim Rees, was a post-doctoral research fellow at the University of California at Santa Barbara when the research was published. Lewis embarked for Scotland on August 23 to take a post as a lecturer (an assistant professor in U.S. parlance) in psychology at the University of Stirling in Scotland.