There’s good news for frustrated parents trying to get their kids to eat their vegetables (or go to sleep, or clean their rooms): Science shows that using reverse psychology can, indeed, work.

Reverse psychology is part of a phenomenon of psychology called “reactance,” said Jeff Greenberg, a professor of social psychology at the University of Arizona.

The idea of reactance is that people are deeply motivated to protect their freedoms, Greenberg said. When people feel that their freedom is threatened — for example, they think someone is taking away their ability to make their own choices — they react against that threat, he said. Thus, they may feel angry or defensive and try to reverse the threat, he said.

Essentially, reverse psychology takes advantage of a person’s reactance, Greenberg told Live Science.

When you use reverse psychology on a person, you’re threatening his or her perceptions of freedom, he said. Threatening this freedom makes it more appealing to choose to exercise that freedom, he said.

Take, for example, a kid who won’t eat his broccoli. When a parent says, “You can’t eat the broccoli,” suddenly, eating it becomes more appealing to the kid, Greenberg said. So, although the kid never wanted the broccoli in the first place, he felt free to choose, Greenberg said. When you take that freedom away, eating the broccoli becomes more attractive, he said.

Greenberg noted that using reverse psychology doesn’t always work. It is more likely to work on people who are more prone to reactance, he said.

People who are irritable, stubborn and emotional tend to be more prone to reactance, Greenberg said. People who are more agreeable and compliant, on the other hand, tend to be less prone, he said.

There’s also some limited evidence that men are a little more prone to reactance than women, he added.

As for your toddler who just won’t eat his broccoli, Greenberg noted that there are phases in childhood where kids are more susceptible to reverse psychology. Between ages 2 and 4, for example, kids can be more emotional and more rebellious, so reverse psychology may be more likely to work on them, he said. But by age 4, when kids are a bit more socialized and less likely to throw temper tantrums, they start to become less susceptible to reverse psychology, he said.

The other classic example is adolescence. When teens are rebelling against their parents, they may be susceptible to reverse psychology, Greenberg said. That’s a time period when parents say one thing, and teens want to do the opposite, he said.

The other thing about children, particularly younger children, is that they are less cognitively developed, and thus may not realize that their parents are using reverse psychology on them, adults are more likely to see through it, Greenberg noted.

Indeed, attempts to use reverse psychology on adults can backfire, Greenberg said. They’ll react against the attempt to manipulate them with reverse psychology, he said. You can end up with “reverse reverse psychology” in a sense, he added.

But there’s no reason to say it won’t work on adults; it just has to be very subtle, Greenberg said.