Is Our Past Experience "All There?"

[david_myers]

If the hardiest weed in our cognitive neuroscience garden is that “we only use 10 percent of our brains,” the next hardiest weed is this myth: “All our past experience is ‘in there’ and potentially retrievable by hypnosis or brain stimulation.”

I could almost believe this, after marveling at my aging mother-in-law, a retired pianist and organist. At age 88, her blind eyes could no longer read music. But sitting at a keyboard, she could flawlessly play hundreds of hymns, even ones she had not thought of for 20 years.

How and where did her brain store those myriad notes? For a time, some surgeons and memory researchers marveled at patients’ apparently vivid memories triggered by brain stimulation during surgery. Did this prove that our whole past, not just well-practiced music, is “in there,” in complete detail, just waiting to be relived?

That’s what neurosurgeon Ben Carson presumed in this 2013 tweet:

And that’s what he said again on March 6^th in his first speech as Secretary of the U.S. Department of Housing and Urban Development: “I could take the oldest person here, make a hole right here on the side of the head, and put some depth electrodes into their hippocampus and stimulate, and they would be able to recite back to you verbatim a book they read 60 years ago. It’s all there; it doesn’t go away.”

Alas, everything is wrong about this. Our flawed memories, as every introductory psychology student learns, are constructions that incorporate both our past and recent experiences. Moreover, the hippocampus, while a vital part of our memory processing, is not a long-term computer memory stick.

And about those brain-stimulated memory flashbacks . . . . As Elizabeth Loftus has reported, they appear invented, not a vivid reliving of long-forgotten experiences.

But our memory imperfections have a silver lining. As Williams James wrote in Principles of Psychology, “If we remembered everything, we should on most occasions be as ill off as if we remembered nothing.” To discard the clutter of useless or out-of-date information—where we parked the car yesterday or our old phone number—is surely a blessing. So be glad that neurosurgeon Ben Carson, who knows a lot, is wrong about memory.