Who are the cleverest monkeys? And how much of human experience do they really share?

Love, language, guilt, envy, generosity, secrets, lies and sophisticated society are not unique to humans. We share those complex traits with our relatives - the monkeys. Following along as the babies of two different species are reared, viewers learn how and what monkeys teach their young in NATURE "Clever Monkeys." Monkeys around the world rely on that knowledge to adapt to the remarkable variety of environments they now call home. Who are the cleverest monkeys? And how much of human experience do they really share?