When you move in unison with other people, particularly when it's to music, there are a couple of hormones and neurotransmitters that increase. Endorphins [are] the big one, and endorphins are part of what make you feel so good. But endorphins are also a bonding hormone ... It also increases oxytocin, which is a hormone that helps us feel close to other people and form these social bonds. And oxytocin also has the side effect of dampening down fear and anxiety. So, we start to feel braver, and we start to feel more optimistic.