Many moral truths seem obvious: Violence is wrong, lying is wrong and slavery is wrong.

And yet people change their minds about them: They celebrate violence in wars and sports, they lie many times a day, according to research, and – in earlier centuries – they defended and practiced slavery. This malleable moral sense produces bitter disagreements and disappointments. Are our moral principles so easily outmaneuvered by selfishness, irrationality or plain evil?

Not so, according to a new book, “Between Fixed and Fickle: Why Our Moral Views Keep Changing,” by Audun Dahl, associate professor in the Department of Psychology and College of Human Ecology. Building on psychological research with children, adolescents and adults, he offers a more hopeful explanation of moral change across lifespans, situations and history.

Dahl, who leads the Developmental Moral Psychology Lab, will discuss the book during an April 30 launch event hosted by Buffalo Street Books in downtown Ithaca. He discussed his research with the Chronicle.

Question: What are the fixed and fickle ideas about morality that your title refers to?

Answer: The “fixed” part is the idea that a moral truth is self-evident and unchanging. For many of us, the notions that violence and slavery are wrong are such fixed ideas. We just can’t imagine how a reasonable, well-intentioned person could take any other view. Then we go into the world, and we realize that people disagree with us. They do take other views, and they have accepted violence, lying, slavery and worse. Seeing that, we can’t help wondering why: Why can’t these people see these plain moral truths?

Then comes the “fickle” part: Whoever can’t see our fixed moral truths must be blinded by selfishness, irrationality or unruly passions. Those people must have a fickle moral sense, one easily derailed, deluded or overrun by amoral forces. They must think it’s OK for their side to lie and harm, wrong for anyone else to lie and harm, because they’re selfish or irrational.

In that story, moral change gets chalked up to amoral forces, across the lifespan, across situations and across history. My book tries to rid us of that story, outside and inside psychology.

Q: Why is it such a popular explanation of moral change?

A: It’s an appealing theory because it lets us hang onto our own fixed truths and dismiss those who disagree with us as deluded. It’s also politically useful, since it inoculates your followers against the counterarguments of the other side. If the other side is crazy or evil, why listen to them?

Q: What’s wrong with the story of the fixed and fickle? Aren’t some people evil and some irrational?

A: Sure, people might do selfish, irrational or evil things. But to know whether that’s why their moral views change, we need to investigate. We need to ask questions, to gather data, to draw inferences, to check our assumptions and interpretations. Those investigations are the specialties of psychological science, but we all do them, every day. And when we do those kinds of investigations, it tends to turn out that the moral sense isn’t so fickle, and other people aren’t quite so selfish or irrational, after all.

The first thing to notice is that the story of the fixed and fickle is always a story about other people. It’s very hard to look at the changes you yourself undergo, from childhood to adulthood, and attribute those changes to your own selfishness, irrationality or blind obedience. It’s possible you lucked out and became among the few who were handed a real, reliable morality – but not very likely. It turns out that we often misconstrue the psychology of the people we disagree with on moral issues.

Q: What’s the alternative explanation of moral change that your book proposes?

A: The basic idea is that children, adolescents and adults mostly change their moral views when they see reasons to do so. I argue that people can see three kinds of reasons for changing their moral views: concerns, connections and coordinations. They can see reasons to change their moral concerns, as when they start to think that all current and future humans are endowed with equal rights. They can see reasons to connect those concerns to new issues, as when they begin to think that our burning of fossil fuels today will harm the humans of tomorrow. And they can see reasons to change how they coordinate those concerns, for example, with current and future humans: They can start to judge that we should make small sacrifices of welfare today – flying less, or eating less meat – to promote the welfare of future humans. These three types of reasons for moral change can bring changes across our lifetimes, from one situation to the next, or even across history.

Q: Once we understand the reasons behind other people’s moral views, must we also excuse them? 

A: Not at all. In the book, I separate our moments of moral psychology, when we try to understand each other’s moral views, from our moments of moralizing, when we evaluate those moral views. Scientific psychology can help with the former but not the latter: Science can help us realize why our moral views keep changing, but it can’t tell us how our moral views ought to change. When you learn the reasons for my moral changes, you might judge me more mildly, or you might judge me more harshly, depending on what you learned my reasons to be. And if the evidence reveals me as selfish or evil, you’ll have every right to judge me for that.

Q: Who should read your book?

A: The ideal reader is simply someone interested in moral change. Morality doesn’t belong to one discipline, and it doesn’t belong to the academy; it calls for diverse perspectives and diverse tools. In the book, I wanted to incorporate the views I felt most urgently about – and then invite into the conversation as many other views as I responsibly could.