Recent research suggests that surrounding yourself with happy people may make you smile more. Participants in the study listened to other people laughing, while researchers measured brain activity using MRI. They found that when a participant heard other people laugh, the part of his or her brain that controls smiling and laughter became active.

This response likely helps people build stronger emotional bonds by mirroring appropriate behavior in social situations. Laughter and cheering -- another sound that caused this brain center to light up -- are common in group situations, where people's social skills are put to the test.

Everyone needs a little more laughter in their life, so test this study out today by smiling at everyone you can. Personally, I just like the idea that when I smile or laugh, I'm doing more than spreading a little sunshine -- I'm lighting up brain centers!