A lot of different cultures claim to have the monopoly on feeling guilt; I've personally been to dinner parties where Jewish and Catholic guests argued for hours about their religion's supreme handle on the emotion. But when it comes to understanding why we feel guilt, things get more complicated. Guilt, it turns out, is a complicated emotion with intriguing ramifications for how we interact with others and interpret moral codes — and that's led to several competing ideas about why it has developed and what purpose it really serves in human psychology.
When it comes to defining guilt, it needs to be disentangled from another similar emotional experience: shame. According to a 2014 review of neurobiology in the brain, the common way of distinguishing these two emotions is through their social ties: "While the feeling of shame implicates the presence of other people, guilt can arise and persist without others." Guilt, in other words, can be a private emotion about transgressing or doing something wrong, while shame is about our concern at the opinions and disapproval of others when we've done something wrong.
Guilt is also a hugely powerful emotion, one that we actually feel physically; Princeton scientists found in 2013 that we do genuinely feel "heavy" with the weight of our deeds when we're experiencing guilt.
So why on earth does guilt exist (beyond giving our parents an emotional superpower that helps them manipulate us into coming home for Thanksgiving)? Researchers have some ideas.
Is It To Stop Us From Destroying One Another?
One theory on the evolution of guilt is that it may have developed because of our tendency to live in socially connected, mutually supportive groups. A lot of human behaviors are traced back by evolutionary scientists to our social past; to survive as a species, we've often had to band together, and anything that helped that cooperation may have provided an evolutionary advantage.
So what good does guilt do in group situations? The famous American psychotherapist Peter Breggin explained the theory of social cooperation and guilt in 2015:
"The existence of violent impulses would have made it difficult or impossible for humans to live in close-knit families and clans without destroying each other. Nature's answer was the development of guilt, shame and anxiety—internal emotional inhibitions or restraints specifically against aggressive self-assertion within the family and other close relationships."
The idea is that humans are innately prone to clashing, particularly when they're living in close quarters. If we feel guilt whenever we fight or betray one another, we're less likely to keep doing it, meaning that the social infrastructure stays intact instead of gradually fracturing with a lot of infighting. Human social groups, like all social collectives, have to have reciprocity, where you trust that other people will help you when you help them; guilt, according to this theory, makes us feel bad when we violate reciprocity, and makes it more likely that we won't screw others over.
It's a way of thinking that was raised by both Freud and Darwin, and has been bolstered by various scientific discoveries. One is that crying — a behavior that appears to have evolved to bond social groups together through sympathy and vulnerability — appears to inspire guilt in others. From this perspective, it's evolved as part of a pantheon of emotional responses that are designed to keep us together when risky or problematic situations threaten to tear the group apart.
Another is the recent discovery that guilt and cooperation are highly linked in the brain; when we're tempted to do something that would make us betray or hurt others, our sense of bonding and loyalty to others kicks in. It's not just about wanting not to hurt others, either; it's a "fear of the loss of support," in the words of one emotional science expert. Guilt, at least interpersonal guilt, is meant to keep us from f*cking up all our relationships with others.
Is It Designed To Stop Us From Breaking The Rules?
A different angle on guilt's purpose posits that the emotion's function is keeping people in line. We often feel guilt when we break rules, not necessarily because they hurt others, but because we've been told explicitly not to do something. Some theorists think this is at the core of guilt's purpose: it's evolutionarily helpful because it keeps us "moral," obeying the codes of behavior set by those around us, rather than rebelling and causing potential problems.
According to 2007 research conducted by the American Psychological Association, guilt is such a powerfully unpleasant emotion for many of us that it acts as an effective deterrent; when we feel guilty about something, we're unlikely to do it again. Studies of the brain as it experiences guilt also indicate that there's a strong moral component, because it tends to show up in the prefrontal regions of the brain that indicate demands on our behavior. (The demand, in this case, is "stop that".)
Guilt, according to this theory, is a bit like a punishment for stepping out of line, imposed by the brain to reinforce societal punishments, like ostracism or your best friend not talking to you because you made out with her boyfriend. And a fascinating 2012 study found that the more guilt-prone people are, the more likely they are to behave morally: guilt-prone people don't need extra motivation to follow the rules or value doing the right thing, because the sheer unpleasantness of the emotion is strong enough.
It's a region of our personalities known as self-punishment. Shame, the social component of guilt, also features high amounts of self-punishment; a 2015 study of undergraduates found that the more ashamed they were of a potentially dodgy financial interaction, the more likely they were to give up their winnings afterwards and deprive themselves. Shame, according to the scientists behind the study, seems to help us maintain our reputations around others; guilt, in contrast, appears to help us maintain our self-respect and moral values.
Guilt Differs Radically Between Cultures
The really interesting element of guilt is its cultural component. What a society values, and what it determines as a matter worthy of feeling guilt, is highly relative. For instance, your family may think skipping a meal around the table is worth a heavy dose of the guilts, while your best friend's parents may turn on the guilt when she doesn't share her weed with them. And not only do offenses considered guilt-worthy vary from group to group — whether guilt operates more as a method of fostering cooperation or as a way of making people obey moral strictures may actually depend on how it works in different societies.
A 2014 study that examined and compared the brains of people from Germany with the brains of people from Japan found that the two groups actually experience guilt and shame differently on a physical level. While many of the neurobiological signals of guilt were the same, there were also some significant differences; Japanese people experiencing guilt, for instance, showed more activity in a brain region linked to perspective, while Germans were more likely to show activity in the parts related to emotion and memory. Cultural and national perspectives on guilt have been emphasized before; the American anthropologist Ruth Benedict described America as having a "guilt culture," where moral conscience was meant to control behavior, and Japan a "shame culture," where behavior was moderated via how it looked to others. It's an incredibly broad-brush descriptor for an entire culture, of course — but it does highlight the importance of context when it comes to how and why we feel guilt in the first place.
And there's another important factor: gender. Women and men, it seems, experience guilt differently, at least in the West. A 2010 Spanish study found that, compared to women, men experience a lower amount of guilt-related emotions — partially because of the cultural emphasis that requires women to be more compassionate and sensitive to others.
Our ability to feel guilt, and why we experience it, isn't just something looming out of our evolutionary past; it's created by a variety current cultural pressures and expectations, from our religious background to our gender. I don't know if that'll make you feel better next time you're experiencing a pang for missing your friend's birthday, but hey, at least now you know those pangs aren't just frustrating — they're also a key part of human emotional evolution.