You know what discrimination is when you see it. It’s a worker getting fired because of their age. It’s a promotion going to a man over a more-qualified woman simply because of her gender. It’s a company giving all of the less desirable jobs to workers of a certain ethnicity.

But why does it happen? No matter what it looks like — (those are merely three examples out of many) — why do people engage in this type of behavior? Why is it something that workers have to worry about?

The overall reason, many experts agree, lies in a fundamental belief that one person is better than another. This often starts with stereotypes about a specific group. When someone believes these stereotypes and allows it to influence their thinking, they may then make decisions that work against anyone who falls into this group.

For instance, the owner of a company may believe that men are harder workers than women. He may then only hire or only promote men, discriminating against women as a group. He doesn’t take the time to actually consider each candidate individually. These choices aren’t based in reality or facts gleaned through interviews. He just applies this misguided opinion to all female workers and acts upon it.

At the root of that decision is his belief that men are better than women. That’s the fundamental flaw with this line of thinking, and it’s the reason discrimination can be so hard to combat. As long as people hold these inaccurate beliefs about people who are not like themselves — based on things like gender, race, age or religion — we will have workplace discrimination. It is important for anyone who is discriminated against to understand their legal options.