Legendary brainiac Sherlock Holmes was a self-described “omnivorous reader with a strangely retentive memory for trifles.” While he fancied his impeccable memory one of a kind, new research suggests that the ways we remember things are more widely shared than we think.
In the study, published this week in Nature Neuroscience, a team of scientists from Princeton University discovered that the brain activity patterns of different people remembering Sherlock episodes all looked strikingly similar. Their observations suggest that there’s a fundamental similarity in the way certain types of memories manifest in the brain.
For a long time, scientists took it for granted that people recalled memories in different ways. After all, it would make sense that every individual would remember an episode of Sherlock in slightly altered ways. Don’t we all focus on different things? Apparently not: The results of this study, carried out on 17 participants, show that memories of specific narratives not only trigger nearly identical patterns of brain activity but also tend to be “edited” in very similar ways.
In the study, each participant watched a 50-minute episode of the BBC miniseries and was asked to recap the episode while their brain activity was monitored using fMRI, a device that tracks changes in blood flow in the brain. When the scientists compared the fMRI readings, they saw the same patterns over and over again: heightened — and, crucially, event-specific — activity in the brain’s default-network, medial-temporal, and high-level visual areas. In other words, different brain activity patterns were elicited by certain scenes, and these differences were shared by the participants.
There was even evidence that participants “reshaped” their memories in similar ways. Analyzing the verbal recaps of all the participants, the researchers noticed that all of them seemed to pare down their stories in similar ways, omitting certain details and focusing on others, and the corresponding brain patterns had similarly shaped holes. These brain signatures, they write, “are altered systematically across people into shared memory representations for real-life events.”
“These results reveal the existence of a common spatial organization for memories in high-level cortical areas,” the authors write. Their conclusion calls to mind the results of a 2015 experiment showing that the highly similar brain activity patterns of skilled pilots doing drills showed signs of being “transferred” to the brains of novice pilots through transcranial direct current stimulation. Could the same thing be possible with memories?
The study’s lead author, Janice Chen, Ph.D., dismissed that possibility in an interview with New Scientist, but she offered one highly effective, low-tech alternative to transferring memories: Simply recounting a story. “I would say that you implant your thoughts into another person’s brain quite easily, simply by telling them what you are thinking or remembering,” she said. “You remember it and, at the same time, they imagine it.” This ability, she says, was likely what allowed ancient humans to pass on useful survival information from one generation to the next.
It also probably explains why Sherlock, in his efforts to keep his mystery-deciphering memories to himself, spends so much of his time avoiding conversation altogether.