If you’re not a natural Pollyanna, take heart. “Research shows that change is possible, even if you’ve had the same mindset since you were 10 years old,” says happiness researcher Shawn Achor, head of GoodThink and author of The Happiness Advantage. “When it comes to things like pessimism, genes may play a role, but they’re not the end of the story.”

Willing yourself to be more optimistic probably won’t get you very far, but focusing on what you’re grateful for can shift your outlook, he says.

Not sure where to start? “Try to think of three new things you’re happy about while brushing your teeth at night,” Achor says. The word new is important—if you let yourself repeat items, you might default to some variation of “family, friends, and health” every day. But if you have to come up with three novel, specific reasons to be happy or grateful, your brain will naturally start making mental notes of things you can include in your list throughout the day.

And all that scanning for silver linings and unexpected kindness and moments of joy? Well, that’s basically the difference between a pessimist and an optimist. In fact, when Achor and his team asked a group of mild pessimists to try the habit for 21 days, then re-tested their outlooks with a battery of psychological tests, they found most people in the group tested as mild optimists. “You can do this with 4-year-old kids or 84-year-old adults,” says Achor. “Even a one-minute happiness habit can begin to affect the other 24 hours in your day.”

And if you need still more reason to start flexing your gratitude when you reach for the toothpaste, consider this: Achor’s research shows that people with a more positive mindset are 40 percent more likely to get a promotion and report having more creativity and productive energy. As Achor says, “Most people think happiness follows success, when really investing in your happiness now might be what helps you get there.”