A couple hundred-thousand years ago—sometime after our hominid ancestors had controlled fire, but long before they were telling ghost stories—early humans huddled around campfires to meditate and partake in shamanistic rituals. Today, when we slow down for a yellow light, recognize a dollar sign or do anything, really, that involves working memory, we have these ancient brainstorming sessions to thank.
That's the somewhat controversial connection psychologist Matt J. Rossano is making. Ritualistic gatherings sharpened mental focus, he argues. Over time, this focus strengthened the mind's ability to connect symbols and meanings, eventually causing gene mutations that favored the enhanced memory we now possess.
"We have decent evidence that shamanistic rituals may go very deep into history, and that these rituals might have had positive psychological effects," says Rossano of Southeastern Louisiana University, whose theory appears in the February Cambridge Archaeological Journal.
Fossil records suggest that anatomically modern humans split from Neanderthals about 200,000 years ago. Around that time, says Rossano, early humans practiced shamanistic meditation to help heal the sick.
The deep focus achieved during such rituals strengthened parts of the brain involved in memory, argues Rossano. Recent brain research supports this notion. In 2005, neuroscientist Sara Lazar of Harvard University studied people with meditation experience and found that several areas of their brains—notably, areas associated with attention—were thicker than normal.
As neural areas of attention grew stronger, the minds of subsequent generations became better equipped to hold information and make the connections necessary in modern working memory, Rossano suggests.
Eventually these connections led to complex forms of symbolism, which begin to show up in the archaeological record around 50,000 years ago. Archaeologists have found cave paintings from this time that display sophisticated symbolism, such as a lion-headed man that presumably infers some personality trait.
These intricate symbols seem to require a higher sense of associative memory compared with more primitive attempts at symbolizing—for example, using red ochre pigment to depict blood.
"If you're going to use symbols, you have to be able to think abstractly and hold one thing in mind while recognizing that the literal thing is not really its meaning," Rossano says. "That might be difficult to do if you can't keep attention long enough."
Hunting, tool-making and some other activities of that age also exercised the brain's memory systems, but only meditation distinguished human ancestors from Neanderthals, Rossano argues.
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."