If you're a basketball fan, you know Giannis Antetokounmpo, the Greek forward known for his freakish athletic ability. His team, the Milwaukee Bucks, had just lost a hard-fought playoff series to their rivals, the Boston Celtics, a real disappointment after winning the championship the year before.

Antetokounmpo was more subdued than usual in the post-game interview, but he wasn't heartbroken or distressed. At one point he said:

"At the end of the day, we were playing sports and there's a winner, there's a loser. It was a learning experience, so hopefully, this moment, instead of thinking that we lost something, we can gain and learn in order for us to put ourselves in a position to win another championship."

That's a real-time example of a psychological technique for controlling negative thinking: the blue dolphin rule.

To understand a blue dolphin, you first need to understand the white bear. The "white bear problem," or ironic process theory, holds that trying to suppress a thought makes it come back more often, and often stronger. Psychologist Daniel Wegner studied this in the 1980s, building on a line from Dostoevsky: "Try to pose for yourself this task: not to think of a polar bear, and you will see that the cursed thing will come to mind every minute."

Your white bear might be the thought that you're a failure every time a goal takes longer than planned. Or it might be "don't be nervous" on a loop before a presentation, which usually just makes the nerves worse.

A blue dolphin is a replacement thought, a go-to you can switch to the moment the white bear shows up. You can't stop white bears from appearing. But a blue dolphin makes sure they don't stick around long.