When the born-again pastor’s wife said she might be OK with evolution, I could feel my eyes widen.

Here’s why. Born-again Christians—sometimes called evangelicals, the Religious Right, etc.—take the Bible literally. As one bumper sticker puts it, “God said it. I believe it. That settles it.” Holding to this doctrine means believing that God literally created the world in six days, as written in Genesis 1.

At least that’s what I thought I knew about born-again Christianity. And I thought I had a good reason for knowing it. I spent my teens and twenties in the born-again culture. Even now, I attend the annual convention of an Episcopal diocese that is dominated by born-again folks.

As it turns out, though, I don’t know much. It took a two-hour conversation with the pastor’s wife—a dialogue—to show me that.

This isn’t the only time a dialogue has opened my eyes to my own misperceptions. After a born-again relative read an early draft of my book, she called me out on a passage that criticized her brand of faith for rigid thinking. As we exchanged views via email, she pointed out that many groups exhibit this thinking. More important, her comments—made gently and civilly—embodied a distinct lack of the rigid thinking that I had attributed to her group.

What I’m learning through these experiences is that we broad-brush any group at our peril. Labeling people as born-again, or liberal, or Southern, or Latino—and failing to go beyond the label—leaves us unable to see them as unique individuals. Instead, we perceive each person as a unit of a monolithic culture, and we respond to what we think we know about that culture. Our perceptions stay the same, and we do not grow.

When we dialogue with an individual in that group, everything changes. Suddenly the subtle variations come to the fore. We have to hold our preconceptions about the group more lightly. We see the essential humanity behind the stereotype. And our perspective expands so that, the next time, we can approach the other with less presupposition and more openness.

Yes, sometimes we don’t know what we think we know. But there’s a great way to learn: one dialogue at a time.