A bear can take care of himself in the wild. People are relatively defenseless, and a man alone in the wild finds it tough to survive. He needs a tribe. To function in a tribal environment, we had to learn to do certain things. As with all survival requirements, these have become drives .
Communication involves two things - getting what was said and knowing which person said it.
We must create a way in our minds to tell people apart. We must recognize individuals and remember things about each one. In effect, this means we must create a filing system with a file for each person we know. We have no acute sense that alone is up to this task. Dogs are social animals, but they have an acute sense of smell.