The fossil record shows evidence of domesticated dogs at least 31,000 years ago; the first date of domestication is unknown. Believers in the Great Leap Forward assert that human beings made rapid cultural progress starting about 50,000 years ago, when they developed dance, painting, hunting traps, burial, clothes, and jewelery. Could their dogs have helped their cultural development?
Early humans must have been unable to sleep soundly and dream deeply. They must have slept like other large mammals, with their senses sharply attuned to threats in the night. But once they had guard dogs with them, they could go into deep sleep. Surely that had significant benefits for their imaginations. Dogs retained their ability to sense danger while asleep, and humans used the same nighttime hours to refresh their brains and enrich their consciousness.
(This is mere conjecture, asserted with no evidence whatsoever. I haven’t even seriously Googled the topic, let alone studied it.)
PS, the photo shows our dog Barkley zealously guarding my wife Laura.