Grudges come naturally to kids — gratitude must be taught

By Peter Blake, Nadia Chernyak and Yarrow Dunham for The Conversation

Kids have no problem remembering who plays fair. Natalia Lebedinskaia/

Have you heard this tale? In ancient times, an escaped slave hid in a cave only to encounter a wounded lion. Although afraid, the man helps the lion, removing a thorn from its paw. The lion is forever grateful, shares his food with the man and, eventually, saves his life.