Willingness to sacrifice

I think we can all agree that love implies some degree of compromise and sacrifice. Sacrifices could range from small ones—choosing to paint the kitchen in your spouse’s favorite color, not yours—all the way to life-altering sacrifices.

Your loved one might want you to move with him or her across the country or to a completely different one. As love evolves, your willingness to make more sacrifices increases. Some might say that this is due to the fact that partners become more synced up, and it all starts with the vagus nerve, which is found in your brain.

That nerve supposedly plays a huge role in everything, from facial expressions to the rhythm of your heart.

Constant thoughts

If the person you care about is front and center of your thoughts, then maybe you’ve started dreaming about them. Well, this is one of those things that takes part in the whole dopamine cycle and is responsible for rewarding these positive thoughts of yours.

According to 2005 research, you might want to thank another part of your brain for that: the anterior cingulate cortex. Experts oftentimes link the brain region to obsessive-compulsive behavior, which somehow explains why the frequency of your thoughts might seem to move toward the level of obsession.