What do you do when you know your children are about to fail? Do you lend a helping hand? Or do you stand back and let them fall on their faces? Offering help might seem like the natural and loving choice--but research shows it's also the wrong one.

One morning, Jessica Lahey saw that her son had gone off to school and forgotten his homework. She was headed that way. But, after thinking about it, she left his homework sitting on the table. Lahey is the author of the bestselling book The Gift of Failure, and she knew that not having his homework when he needed it would benefit her son more in the long run than having her rectify his oversight. Sure enough, his teacher gave him an extra assignment, and also some tips on how to avoid forgetting his homework in the future. Lahey told Quartz that those tips helped him much more than getting his homework delivered to him would have.

Most parents would have brought the homework to school. But that's because they don't know just how bad an effect helping kids avoid failure can have. To illustrate the point, Lahey recounts an experiment by psychologist Wendy Grolnick, who invited mothers and children to play together and captured their play sessions on video. Grolnick made note of which mothers helped their kids figure out what to do while playing, and which mothers let their kids figure things out for themselves. 

Later, Grolnick put each of the kids alone in a room with a challenging task to perform. The children with helpful mothers who advised and directed them during play simply gave up when they grew frustrated with the task. But the children with mothers who held back, encouraging them to be independent, were able to stick with the task despite their frustration. 

Trading happiness today for unhappiness tomorrow.

Lahey says this means that parents who help their kids avoid failure are making a bad bargain--helping their children be happier in the short term, but setting them up for failure and unhappiness in the future. Instead, she says, you should hope for your children to push through "being a little anxious and a little scared" in order to become a little more competent and self-reliant.

Parental aid is particularly toxic when it comes to the child's relationship with his or her school, Lahey writes. In fact, the idea for the book came in part from her observations as a middle-school teacher. Parents would argue with her over grades, while students seemed increasingly unable to take on any kind of challenge. "Teaching has become a push and pull between opposing forces in which parents want teachers to educate their children with increasing rigor, but reject those rigorous lessons as 'too hard' or 'too frustrating' for their children to endure," she writes in her book.

Why is it so hard not to jump in and help children, even when we know they're better off figuring things out for themselves? Simple--we're human, and rescuing someone we love feels really good. Whereas not helping out can make people feel like they're bad parents. They might even get criticized for it, as Lahey did when she told a friend about leaving her son's homework where she'd found it.

Even so, it's worth making the effort. Lahey has heard some heartbreaking stories of children who got help with everything when they were small and grew into teenagers who are flummoxed by simple tasks. That's bad for every kid. So next time you see your children about to fail, grit your teeth and let them. They'll be happier for it in years to come.