These will make you feel warm inside.
Lovers' heart beats synchronise when they stare into each other's eyes.
Scientists got 32 couples to sit and face each other for 3 minutes (not all at the same time, we presume). After the time was up, the heart rates of the couples were in sync. They didn't sync for people not involved in romantic relationships.
That warm feeling you get when you read nice messages from your friends and family actually makes you feel warmer.
Expressing your gratitude to other people has been shown to make you happier.
So has writing down three good things about your day every evening every evening.
Flickr: jjpacres / Creative Commons
Lions cuddle and rub heads to maintain their friendships.
Life is harsh for lions, but at least they have their friends.
Flickr: fanz / Creative Commons
