Psychologist Clive Wynne believes domesticated dogs developed from wolves who may have had a mutation that made them able to tolerate proximity to humans enough to eat their trash. That contrasts with the "hunter's helper hypothesis" that envisions humans and wolves feeding cooperatively. In Wynne's "dumpster-diver hypothesis," the trash became a mechanism of evolutionary pressure, selecting for more tolerant dogs. Although the hypothesis has some supporters, it is not universally accepted. According to researcher Mia Cobb, "the take-home message is that dogs and people have co-evolved over a long time, opportunistically exploiting each other to various degrees."