She can tell you how to bring an aircraft out of a stall, but has no memory of her marriage. She can explain an arpeggio, but doesn’t remember the tune to “Happy Birthday.” She can detail the steps to remove excess paint from a watercolor painting, but fails to recognize “Starry Night”.
Lonni Sue Johnson is teaching scientists new things about our brains, after losing a critical part of hers. Infected in 2007 with a form of encephalitis, Johnson would end up losing her hippocampus, much of her medial cortex and parts of other brain regions to the disease. While her lucidity survived the illness, much of her memory did not. The regions of the brain she lost play a crucial role in making new memories and recalling old ones. She now suffers from severe amnesia that has painted over large swathes of her life, including a decade of marriage and a career as an illustrator that saw her work featured on the cover of the New Yorker multiple times.
She nevertheless displays talents, such as the ability to recall particular facts, that puzzle researchers. Recent research by a Johns Hopkins psychologist suggests that Johnson’s condition may hint at nuances of memory formation and recall that researchers have until now overlooked.
A Perplexing Patient
Ever since her illness irrevocably altered her life, Johnson has been the subject of intense psychological scrutiny. In this respect, she is much like her spiritual forebear H.M. — one of the first amnesiac patients to be studied in depth and who provided the basis for our current view of memory. Over the past nine years, she has undergone a battery of tests meant to tease out the limits of her memory and elucidate exactly why some details of her life remain out of reach while others return with remarkable clarity. Along the way, researchers hope to further unravel the mysteries of memory, an essential component of human consciousness that only stubbornly relinquishes its secrets.
Barbara Landau, the director of the Language and Cognition Lab at Johns Hopkins University, has been working closely with Johnson for years now. She has published, along with team members Emma Gregory and Mike McCloskey, a series of papers delving ever deeper into Johnson’s cognitive abilities. While it is easy to determine that Johnson has lost much of her long-term recall, Landau has taken a rigorous approach, breaking down memory into its constituent parts and testing Johnson on them individually. A 2014 paper by researchers from Princeton, on which she was co-author, showed that Johnson was unable to recognize statistical patterns, something that even infants have proven themselves capable of. By contrast, another paper that year from a different member of her team, Jussi Valtonen, revealed that Johnson, an accomplished amateur musician, was capable of learning entirely new pieces of music. The instrumental skill required for such a task takes years of practice and involves disparate skills, from reading music to understanding tempo to holding and playing an instrument.
Johnson’s unique set of strongly developed, high-level skills have given researchers an opportunity to home in on the differences between the two types of memory: explicit and implicit. Explicit memory refers to facts, such as your spouse’s birthday, or who won the 1967 Super Bowl. Implicit memory, also called procedural memory, refers to things that have become routine, such as riding a bike, and thus do not require conscious recall for us to perform. Many amnesiacs, such as H.M., lose their explicit memory and retain the implicit — they can tie their shoes, but don’t recognize their own children. Johnson presents an intriguing contradiction to the idea of a clean divide in our minds. While she may not recognize Beethoven’s Fifth Symphony, she demonstrated the ability to learn a completely new piece of music, relying on her knowledge of musical symbols and the mechanics of playing a viola to do so. Playing an instrument may become a reflex after sufficient training, but knowing how to read musical notes requires explicit knowledge of what they mean, or in other words, reliance on the kind of facts that she shouldn’t be able to recall.
Some Facts Remain
Now, in a new paper published last week in the journal Cognitive Neuropsychology, Landau suggests that we may need to refine our conception of memory. She and her team compared Johnson’s knowledge of art, music, flying and driving — areas in which she displayed a high degree of skill — to a set of experts in those fields, as well as novices. They had each participant take a test that asked very specific questions about each skill area — such as “In what order does a violist most commonly tune the strings on a viola?” or “When flying, how should a pilot maneuver the plane if they encounter severe turbulence?” — and compared the results. They found that while Johnson didn’t score quite as well as the experts, she still did significantly better than those with no experience in a particular skill. In skills such as playing the viola and flying, where she was an amateur, her scores were closer to those of the novices than the professionals. But, when asked about watercolor painting, which was her specialty, she outscored even the experts.
Landau says that their work calls for a reevaluation of the classic view of memory. Specifically, she says that our view of explicit memory, the basic facts that undergird our thought processes, may be too simplistic.
“It’s not that we want to say that we’re calling the divide [between explicit and implicit] into question, that’s not our point,” Landau says. “Our point is that within declarative knowledge, there seem to be different kinds of memories.”
She adds, “there’s something more nuanced than this simple divide going on. For her at least, there’s evidence that this special category of knowledge, what we call skill-related knowledge, is preserved, whereas other kinds of knowledge really are not, even if it’s about the same kind of general domain.”
Skill-Related Facts Remain
The key is that Johnson was only able to recall facts related to areas of knowledge in which she had acquired special skills. Our skills are usually assumed to rely on implicit memory, which is why playing soccer or creating art can feel effortless to those who practice often. Landau’s work suggests that there may be more interplay between the two types of memory than was previously thought.
She references a 2013 paper from researchers at Yale and Johns Hopkins that argues facts may actually play a role in acquiring motor skills, which are usually placed firmly in the “implicit “category. They argue that even rote skills such as playing tennis require our minds to access facts, such as how close to the net a player should be, or what angle to hold the racket based on where an opponent is located.
Landau shows that the connection may go the other way as well. Johnson is able to recall facts connected to skills that she learned before her illness, despite being completely unable to recall information from all other categories. It seems that when we learn a skill, the basic pieces of information that accompany it gets embedded in our brains alongside the implicit knowledge of how to do it. That patients such as Johnson and H.M. retain things such as the ability to perform simple tasks and more complex skills implies that the memories associated with such functions lie in a different part of the brain. While it may be tempting to assume that there is a brain region devoted solely to each of the two types of memory, Johnson stands as living proof to the contrary.
It appears that the grooves we wear deep into our minds are able to hold much more than we thought they could.