"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," she added.
While redecorating your home might lift your mood, in general, Christmas decorations in particular trigger your happy hormones. The bright colours generally used in these items contribute to that happy feeling.
For some people, Christmas decorations also invoke a sense of nostalgia and joy for times past, taking them back to their childhood and their families.
As a bonus side-effect, some research has also shown that people will think you're more sociable and friendlier if you have Christmas decorations up.