Rossano's theory might not hold well in some scientific circles. For starters, most researchers doubt that a genetic mutation separated humans from Neanderthals. They think humans simply became better at expressing the cognitive abilities they had always possessed.
Evolutionary biologist Richard Klein of Stanford University does believe that a genetic mutation caused the human-Neanderthal rift about 50,000 years ago. But Klein thinks that this mutation occurred rapidly and randomly—not gradually and as a result of the environment, as Rossano suggests.
"There was a radical change in behavior," he says. "It's not true that it built up gradually."
Klein also doubts that meditation is the cause of the mutation. Rossano's argument is based on a flawed notion of evolution called the Baldwin effect, says Klein, which strays from the traditional Darwinian theory that mutations are basically random.
Other scientists are more open to the idea that an environmental factor such as meditation could have caused a genetic mutation, says cognitive archaeologist Frederick Coolidge of the University of Colorado at Colorado Springs.
But even if the Baldwin effect did play a role, early humans likely harbored a greater cognitive potential than Neanderthals to begin with, he says.
"I don't think sitting in groups staring into a fire would have enhanced everyone," says Coolidge. "There was a background of mutations [in humans] that the environment had not yet selected for, and they became selected for because of these rituals."