1. How Gratitude Connects Us To Each Other

Gratitude likely evolved as a biological signal that motivates animals to exchange things for their mutual benefit and can be found in the animal kingdom, especially in primates. When your brain recognizes that someone's done something nice for you, it reacts with gratitude to motivate you to repay them. As human brains got better at reading emotions, selfish individuals were identified and shunned. It became an evolutionary advantage to play well with others. This brought your ancestors closer together and forged bonds and friendships.