SAN FRANCISCO (KRON) – If you already started decorating for Christmas, consider yourself a happy and friendly person.

New research listed in the Journal of Environmental Psychology finds people who put up their Christmas decorations early tend to be happier and friendlier.

“The results support the idea that residents can use their home’s exterior to communicate attachment and possibly to integrate themselves into a neighborhood’s social activities,” researchers wrote.

Psychologists say Christmas decorations are nostalgic and bring people back to simpler and happier times.

They say it also helps boost dopamine.

So if you’re feeling like a grinch this season, consider putting up your Christmas tree early.