Most of us hold a handful of moral truths we consider unmovable. For example, violence, lying, and slavery are wrong. Yet, people regularly act against these truths. Some people cheer for violence in war or sports, others lie multiple times a day, and for centuries, otherwise reasonable people defended slavery.

The gap between what we believe and how we behave raises an uncomfortable question: Are our moral principles easily overridden by selfishness or circumstances?

Audun Dahl’s Theory on Shifting Moral Views

Not necessarily, according to a new book by Audun Dahl, associate professor of psychology at Cornell’s College of Human Ecology and director of the Developmental Moral Psychology Lab. His book, Between Fixed and Fickle: Why Our Moral Views Keep Changing, draws on decades of research to offer an evidence-based theory of why moral views shift.

Dahl describes a familiar pattern of thinking he calls the story of the “fixed and fickle.” First, we treat our own moral convictions as fixed and self-evident — so obvious that no reasonable, well-meaning person could see things differently. But when we encounter people who disagree, we conclude their moral sense must be fickle — easily corrupted by self-interest, irrationality, or unruly emotion.

It’s a tidy explanation, and a flattering one as it lets us keep our convictions intact while writing off anyone who disagrees with us. It’s also politically useful, since it insulates one’s followers against the other side’s counterarguments.

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

Dahl’s book points out a blind spot in the “fixed and fickle” explanation: it’s usually a story we tell about other people. Few of us look back at our own moral evolution from childhood through adulthood and attribute changes to our own selfishness or poor reasoning. We tend to assume we got lucky and ended up with the “correct” morality, while everyone who disagrees must have gone wrong somewhere.

Dahl’s Three Reasons for Moral Change

Dahl’s alternative explanation is that people typically change their moral views when they encounter genuine reasons to do so. His book identifies three types of reasons that people change their beliefs.

People can develop new moral concerns, such as believing that all current and future humans deserve equal rights.
They can form new connections between existing concerns and new issues. For example, someone may realize that today’s fossil fuel use will harm tomorrow’s children.
People can shift how they balance competing concerns. For instance, they can decide that modest sacrifices today, like flying less, or eating less meat, are worth it to slow climate change and protect future generations.

“These three types of reasons for moral change can bring changes across our lifetimes, from one situation to the next, or even across history,” Dahl said.

In the book, Dahl makes an important point: Understanding why someone changes their moral views is separate from evaluating whether that change was positive or negative.

“Science can help us realize why our moral views keep changing, but it can’t tell us how our moral views ought to change,” he said. “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 are.”

The take-home message is: The next time you find yourself baffled by someone whose moral views differ sharply from your own, or surprised by how much your own views have shifted over time, it’s worth thinking about the reasons behind the change. Dahl’s research suggests that kind of curiosity tends to reveal a much less cynical picture of human nature than the “fixed and fickle” story would have us believe.