Want to feel happier? Science says to start decorating for Christmas early.

“In a world full of stress and anxiety people like to associate to things that make them happy and Christmas decorations evoke those strong feelings of childhood,” McKeown continued.

Psychologist Deborah Serani told Today that changing the scenery inside and outside our homes is a great way to get a quick hit of feel-good hormones.

"It does create that neurological shift that can produce happiness," she said. "I think anything that takes us out of our normal habituation, the normal day in, day out ... signals our senses, and then our senses measure if it's pleasing or not.

"Christmas decorating will spike dopamine, a feel-good hormone," Serani added.

Putting up holiday decorations also sends an excellent message to our neighbors. A study published in the Journal of Environmental Psychology found that people who decorate for the holidays are seen by their neighbors as more sociable.

The study found that people who decorate for the holidays are perceived as “friendly and cohesive” and that the added holiday cheer can change people’s perceptions of their neighbors. People believe that their unsociable neighbors are actually more social if they put up decorations. The study concluded that “residents can use their home's exterior to communicate attachment and possibly to integrate themselves into a neighborhood's social activities.”

So decorating your home for the holidays will not only make your family happier but make your neighbors’ as well. Looks like a win-win here.

YouGov conducted a survey to find out when most people feel it's appropriate to start decorating for the holidays. A poll of 2,748 U.S. adults who celebrate Christmas, Chanukah or Kwanzaa found that 27% put their winter holiday decorations up before Thanksgiving, while 69% wait until after Thanksgiving. The most common time was the day after Thanksgiving when 25% of people started decorating for the winter holidays.

But what about those bah-humbug neighbors who will judge you if you start decorating too early? Serani says that they may have some bad memories from childhood associated with the holidays so their disdain may have nothing to do with you at all.