We can perhaps imagine the primal scene in which some hunter-gatherer band clobbers another and runs off with all their food or women because it can speak and therefore more effectively plan and cooperate. But it's more vexing to entertain a situation for the adaptive advantage of the First Grammatical Person. One man who has examined both the challenge and the evidence and come to a conclusion is Mark Turner. It's the climactic moment in a book which intends to transform our whole outlook not so much on literature, but on how we think. For Turner this is but a partial truth.
Rational capacities depend on it.
It is our chief means of looking into the future, of predicting, of planning, and of explaining. It is a literary capacity indispensable to human cognition generally. He begins with an episode from The Thousand and One Nights . It is told as a cautionary tale to Shahrazad by her father after she has explained to him her plan to charm and ultimately to reform the murderous King Shahriyar. A clever but rather arrogant donkey lives in comfortable indolence on a farm.