Our moral codes are rooted in preconscious feelings of disgust at people who hurt others, cheat, are disloyal, disobey authority, and violate social taboos. Some of these moral feelings support modern Enlightenment ideas of morality while others are in contradiction with modern values of individual rights and critical thought. By illuminating the ways that our value systems are shaped by prerational impulses we can make more conscious choices about how to build a fair society and practice the civic virtues of fairness and engaged citizenship. But we also can begin to experiment with ways to enhance our moral reasoning with drugs and devices to become even better citizens than previously possible.
In this series:
From Moral Intuition to Moral Reasoning
Just as we have ancient neural architectures for bonding with our fellow mammals, we also appear to have evolved deeply-wired neural intuitions about fairness and morality. One of our deeply ingrained moral intuitions is that it is wrong to cheat, and that cheaters need to be punished. This impulse can be demonstrated in a laboratory experiment called the ultimatum game. One participant is given some money and instructed to offer a portion of it to the other participant. They can offer any fraction of the amount, or none at all, but they don’t get to keep any of the money if the other person rejects the split. Three quarters of participants offer something between 40% and 50%. When the splitter offers less than half it triggers a disgust reaction in the amygdala of the person who needs to choose to accept or reject the split. When that disgust reaction is strong enough, which is usually when the offer is less than 40% , the person will reject the split even though it means they are giving up whatever they were offered. That self-sacrifice to spank the “cheater” at the cost to oneself is known as “altruistic punishment.”
These intuitions can be observed in our simian cousins and human children. When chimpanzees and human children are set up in ultimatum situations they also mostly offer fairish splits, and their willingness to sacrifice rewards to punish cheaters is the same as in adult humans.  Even human infants under two years old react negatively when they observe unequal rewards given to others. According to Paul Bloom, one of the leading researchers on the moral life of infants and the author of Just Babies , infants exhibit four moral sensibilities:
- moral judgment: some capacity to distinguish between kind and cruel actions.
- empathy: suffering at the pain of those around us and wishing to make this pain go away.
- fairness: a tendency to favor those who divide resources equally.
- justice: a desire to see good actions rewarded and bad actions punished.
We experience these biologically rooted moral intuitions differently than we do other kinds of values. A group at DePaul University in Chicago surveyed students about a variety of moral attitudes. Some had been ranked by previous researchers as biologically determined and heritable, such attitudes towards premarital sex, racism and the death penalty, and others as only weakly influenced by biology and genes, such as attitudes about privacy. They found that the stronger the likely genetic influence on the value the more deeply held the students beliefs were about that value.
Just as empathy has to be cultivated by intelligence to become a mature theory of mind and social intelligence, our moral intuitions can only take us so far. Is the affirmative action fair? Is collateral damage in a war morally justified? Should a poor man steal bread? In order to cultivate the virtue of fairness we need to move from innate moral intuitions to mature moral reasoning.
Liberal and Conservative Brains
The psychologist Jon Haidt adds to this picture by showing that we are not all equally sensitive to inherited moral intuitions. Haidt began his research on moral intuitions by studying reactions to topics like cannibalism and incest. By unraveling how people felt about these deeply emotive questions he eventually identified a set of core moral intuitions which he, and the other proponents of “Moral Foundations Theory,” believe have evolutionary and neurobiological roots:
- Care/harm: protecting others from harm
- Fairness/cheating: treating others in proportion to their actions
- Liberty/oppression: judgments about whether subjects are tyrannized.
- Ingroup Loyalty: to your race, group, family, nation
- Respect for Authority/Hierarchy
- Sanctity/Purity: sanctity/degradation, avoiding disgusting things, foods, actions.
Haidt found that conservatives, liberals and libertarians differ in their sensitivity to these innate, monkey-brain moral sentiments. Liberals are more sensitive to the first two, the impulses to protect others from harm and to fairness. Conservatives are less sensitive to these, and more sensitive to the impulses to protect the in-group, to defer to authority, and to have disgust for the profane. For instance, liberals are more likely to agree with the statements “I wish there were no nations or borders and we were all part of one big group” and conservatives are more likely to agree that “Respect for authority is something all children need to learn.” Libertarians are more sensitive to the liberty/oppression intuition, and less sensitive to the other five.
Using survey responses from 25,000 people that allowed them to be assessed for their response to these moral intuitions and their views on political issues, Haidt and his team found that these moral intuitions predicted positions on issues ranging from gay marriage and immigration to global warming and defense spending. These innate moral sentiments help explain why our political debates are so often like we are talking different languages. We simply can’t understand how the other side can take certain kinds of arguments or sentiments seriously, and not see the importance of our views. As Haidt and his collaborators recently framed it, liberals and conservatives are as different as people from entirely different cultures.
These political differences are deeply rooted in neurobiological differences. The idea that political ideology has biological roots seems counterintuitive, since political views seem so determined by the time and place we find ourselves in. Also, what evolutionary advantage could there have been for humans to develop such divergent moral and political views? But a recent study by researchers from Harvard University, Brown University and Penn State University dramatically illustrates how deeply biological political ideology appears to be. They recruited twenty one adults, ten strongly liberal and eleven strongly conservative. The participants were asked to bathe in scent-free soap, refrain from smoking, drinking, deodorants, perfumes, sex or sleeping with humans or pets. They then taped a gauze pad under their arms for twenty four hours. The pads were frozen in vials, and thawed out later to be smelled by 125 participants whose politics had also been ascertained to be either strongly liberal or strongly conservative. The smellers rated each vial on a scale of 1 to 5 on attractiveness of the body odor. Controlling for gender, conservatives found the smell of other conservatives more attractive, and liberals liked how liberals smelled better. Somehow the biological bases of ideological preferences were being communicated through body odor. 
The evidence that these biological determinants of ideology are genetically inheritable is now quite strong. A 2014 meta-analysis of the effects of genes on politics looked at nineteen studies of 12,000 twins in five countries spanning three decades. As in studies of genetic influences on intelligence they did not find any single gene that explained a significant amount about the twins’ political views. But they did find a significant and substantial genetic influence on political views across a wide range of issues in every country and time period. Attitudes towards things as diverse as school prayer, death penalty, gay rights, foreign aid, feminism, taxation and global warming were all genetically linked.
PFC vs. Amygdala One of the most popular scenarios used in the emerging experimental philosophy field is the trolley dilemma. In the first trolley scenario the participant is told to imagine standing beside a train track and seeing a runaway trolley about to hit five men down the track. The participant is standing next to a lever which can switch the trolley to a track on which only one man is standing. Will the participant switch the train to the track to kill just one man instead of five? This is a classic utilitarian choice; the greater good for five outweighs the harm imposed on one. Most people choose to pull the lever.
In the second scenario, the “footbridge dilemma,” the participant is standing next to a very fat man on a bridge over the track. The participant is told that (however implausibly) the only way to stop the trolley hitting the five men is to push the fat man on the track. Most people say they wouldn’t or couldn’t push the fat man, even though the result would be the same as the first scenario; one man dies, five live.
Since neuroscientist Josh Greene and colleagues first used fMRI to watch the brains of people making these trolley decisions, more than decade of experiments has shown that the utilitarian decision in the first scenario is largely handled by the rational, prefrontal cortex, while the second “footbridge dilemma” strongly stirs up the emotional centers of the brain, overriding rational utilitarian calculation.  Passive moral judgments based on intuitions such as “its never OK to push someone to their death” are based in the amygdala, while active moral reasoning, such as the reasoning necessary to rationalize pushing the fat man on the track, relies on parts of the prefrontal cortex. People with larger, more active and better connected prefrontal cortices are better able to filter and channel the hot moral intuitions - including the desire to protect others and punish others, but also disgust, loyalty, and submission to authority - bubbling up from our amygdalas. On the other hand when people are sleepy, distracted, pressed for time or under stress they are less likely to make rational, utilitarian judgments.    
Another way of understanding the genetic influences on moral and political thought is that our genes partly determine the relative influence of the prefrontal cortex versus the more emotional parts of the brain like the amygdala on our moral and political decision-making. Conservatives have larger and twitchier amygdalas than liberals and libertarians, startle more easily, and react more strongly to bad smells and unpleasant images.      Conservatives are therefore more sensitive to the discomfort of uncertainty and cognitive dissonance, and work harder to avoid it. Sensitivity to the two liberal moral intuitions, care and fairness, is correlated with larger volumes in the PFC, while sensitivity to conservative moral intuitions, deference to authority, ingroup loyalty and purity/sanctity, is correlated with larger volumes in the emotive limbic system. When the influence of the PFC over the amygdala is reduced by alcohol or other cognitive burdens people express more racial bias and conservative opinions, and people become more conservative and morally judgmental when the amygdala’s disgust response is triggered by bad odors or the feeling of stickiness.  
Liberal Virtues How then can we understand liberal versus conservative ideas of virtue? As Jon Haidt and colleagues recently observed, the intuitive style of thought favored by conservatives is the human default style, while the analytical style of thought more common among liberals has to be learned. Liberals and conservatives don’t actually differ in their moral intuitions about authority, ingroup loyalty and sacred values. Both liberals and conservatives have prefrontal cortices that have been taught Enlightenment values, and amygdalas pinging them with disgust and alarm reactions. Rather their differences emerge because the prefrontal cortices of liberals are capable of filtering out the signals from the amygdala more successfully than in the brains of conservatives. When liberals feel impulses for deference to authority and hierarchy they are checked by reminders of the importance of equality and the questioning of authority. When liberals feel uneasy about outgroups, or impulses to favor their own kind, they are checked by reminders of the importance of tolerance and universalism. When liberals feel revulsion about the breaking of taboos, such as seeing two men kiss, the feelings are checked by reminders that “They aren’t hurting anyone...”
The real difference between liberal virtue and conservative virtue then is why and how the two tribes come to moral conclusions. Conservatives believe that moral intuitions are self-justifying. Liberals believe that reason needs to interrogate our intuitions. This leads liberals to be more tolerant and humble in their moral and political claims, a cautiousness and diffidence that conservatives interpret as weakness and uncertainty.
Intelligence, Personality and Ideology In 2010 the evolutionary psychologist Satoshi Kanazawa published an article provocatively titled “Why liberals and atheists are more intelligent.” Kanazawa reviewed the large body of evidence that correlates intelligence with atheism  and political liberalism , and proposed the “Savanna-IQ Interaction Hypothesis.”  The theory starts with the observation that human brains first evolved in the African savanna between 2.5 million and 130,000 years ago. Then, as we faced environmental challenges and started migrating around the globe, we had to evolve new cognitive abilities to deal with novel situations. This flexible form of learning and problem-solving is the basis of general intelligence, which then allowed us to invent tools, agriculture, and civilization. Individuals and groups with more of this ability are more open to novel experiences, more tolerant of ambiguity and complexity, and more open to novel ways of thinking such as atheism and liberalism.
Earlier I reviewed how the personality trait of openness to novelty is partly genetic and correlated with intelligence, and it is also correlated with political liberalism.  Across more than 70 studies of personality and politics reviewed by Sibley and Duckitt people who scored higher on openness to experience were less right wing, racially prejudiced and authoritarian. Just as the variations in serotonin genes may partly explain why some populations are happier, geographic variations in the genetic settings for personality may be influencing the politics of countries and American states. Using personality data for 600,000 Americans a group at the University of Illinois found that the liberalism of a state was strongly related to its citizens’ level of openness to experience.
Liberals are not without their own cognitive biases of course, and there are intelligent conservatives and stupid liberals. Both liberals and conservatives are prone to tune out information that doesn’t fit with their worldview. But the biases of liberals and conservatives are not symmetrical. The psychological factors that tend toward liberalism undercut cognitive bias in ways that conservative psychology does not. Liberals are far more invested in the project of a deliberative democracy guided by science and rational discussion.
Jon Haidt has drawn a very different conclusion from the differences between liberals and conservatives however. To Haidt liberals are deaf to important conservative moral intuitions that they should work harder to appreciate. This is a version of the “naturalistic fallacy,” the idea that something is right because it exists. The root of liberal deafness to conservative moral intuitions is not because liberals lack a cognitive faculty, but because, in general, they are better at exercising their cognitive faculties.
The enhancement of fairness, moral reasoning and the “liberal virtues” is therefore part of the larger project of cognitive enhancement, focused on becoming increasingly aware of and independent of one’s own cognitive biases.
Political IQ: https://www.psychologytoday.com/blog/the-scientific-fundamentalist/201003/why-liberals-are-more-intelligent-conservatives
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