Here is an excerpt from an article written by Amy Gallo for Harvard Business Review and the HBR Blog Network. To read the complete article, check out the wealth of free resources, obtain subscription information, and receive HBR email alerts, please click here.

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When a colleague is mean to you, it can be hard to know how to respond. Some people are tempted to let aggressive behavior slide in the hopes that the person will stop. Others find themselves fighting back. When you’re being treated poorly by a coworker, how can you change the dynamic? And if the behavior persists or worsens, how do you know when you’re dealing with a true bully?

[Here are the first three of seven recommendations she offers.]

What the Experts Say: “When it comes to bad behavior at work, there’s a broad spectrum,” with outright bullies on one end and people who are simply rude on the other, says Michele Woodward, an executive coach and host of HBR’s recent webinar: “Bullies, Jerks, and Other Annoyances: Identify and Defuse the Difficult People at Work.” You may not know which end of the spectrum you’re dealing with until you actually address the behavior. If it’s a bully, it can be difficult ­— if not impossible — to get the person to change, says Gary Namie, the founder of the Workplace Bullying Institute and author of The Bully at Work. But in most cases, you can ­— and should ­— take action. “Know that you have a solution, you’re not powerless,” says Woodward. Here are some tactics to consider when dealing with an aggressive colleague.

Understand why: The first step is to understand what’s causing the behavior. Research from Nathanael Fast, an assistant professor at the University of Southern California’s Marshall School of Business, proves a commonly held idea: People act out when their ego is threatened. “We often see powerful people behave aggressively toward less powerful people when their competence is questioned,” he says. Namie agrees: “People who are skilled and well-liked are the most frequent targets precisely because they pose a threat.” So it may help to stroke the aggressor’s ego. Fast explains: “In our study, we saw that if the subordinate offered gratitude to the boss, it wiped out the effect,” he says. Even a small gesture, such as ending an email with “Thanks so much for your help” or complimenting the person on something you genuinely admire, can help.

Look at what you’re doing: These situations also require introspection. “It’s very easy to say, ‘Oh, that person is a jerk,’” Woodward says. But perhaps you work in a highly competitive culture or one that doesn’t prioritize politeness. Consider whether you might be misinterpreting the behavior or overreacting to it or whether you’ve unknowingly contributed to the problem. Have you in any way caused the person to feel threatened or to see you as disloyal? Self-evaluation can be tough so get a second opinion from someone you trust, who will tell you the truth, not just what you want to hear. Don’t put too much of the blame on yourself, however. “It’s important to balance not being threatening with not being a doormat, which just invites more aggression,” Fast says. Namie agrees: “Targets regularly assume it’s their fault,” when it’s not.

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Here is a direct link to the complete article.

Amy Gallo is a contributing editor at Harvard Business Review. You can follow her on Twitter at @amyegallo.