HHave you ever had the experience where a smell or a taste pulls you into a world of memory? One bite of a cookie of a similar kind to the ones in your old school cafeteria, and suddenly you can practically see the linoleum floors and hear the squeak of plastic chairs. Most people can have this sudden reverie – I can’t.
Whenever I came across descriptions of this phenomenon – Proust’s madeleine scene, for example, or the memory bubbles in the movie Inside Out – I always assumed it was some kind of metaphorical device. I had no idea that most people actually relive moments from their past in some sensory detail, even if it’s a little shaky or faint.
I understood that my version of memories is not nearly as richly textured. Just now I heard a song I once played in my high school band, and it reminded me of the time a (minor) violinist named Barbara almost punched me after I fixed her bow.
But I don’t remember what she looked like, what the band room smelled like, or the fear I must have felt when I saw her fists ball up. All I remember is the story – a story I had to tell right after, and then tell and retell until it bore a groove in my brain.
Sensory memories that you can replay are called episodic memories, while remembered facts and stories are known as semantic memories. It may seem like a subtle difference, but these two types of memory rely on different brain networks.
We know this because of amnesia like Kent Cochrane. Cochrane was in a motorcycle accident that destroyed both of his hippocampi – deep brain structures that coordinate the repetition of old memories. After his accident, he could still tell you about his life, but only as dry facts: his brain did not generate a feeling of warmth to talk about his happiest moments with loved ones, or sadness about past loss. It was as if he were simply reading a biography of himself.
I’m a science writer, so when I started to suspect that my memory was a little off, I dove into the research and found descriptions of a condition known as severely impaired autobiographical memory. It’s not a disorder: it just describes people at one extreme of the human memory spectrum. SDAMers rely heavily on semantic memory, while people with HSAM – highly superior autobiographical memory – put all their cards on the episodic side, and neurotypicals land somewhere in the middle. I wanted to know if I was an outlier.
It took the better part of a year to confirm my self-diagnosis, but in relative terms it’s lightning fast. For more than a century, serious scientists largely ignored the subject of internal experience, on the grounds that it was impossible to verify or disprove what people claimed was going on in their minds.
But in just the past few years, that has changed. For example, researchers recently invented a way to test whether people can visualize in their “mind’s eye”: one cool study found that most people’s pupils narrow in response to imagined light, but this was not true for people who cannot visualize.
I didn’t participate in that study, but I did sign up for a few others. In a higher-tech version of the pupil constriction study, I was thrown into an fMRI machine and asked to visualize places and faces. My brain was just sitting there doing nothing, just like the non-visualizers’ pupils.
I also participated in a study using a technique called descriptive experience samplingwhich involved wearing a beeper that randomly interrupted me several times a day so that I could report exactly what my internal experience was at that moment.
The verdict? Almost everyone has a much livelier inner life than I do. When other people are talking quietly to themselves, replaying past moments or thinking about the future, I just exist…. I spend about 46% of my time simply taking in sensory experiences. The rest of my waking hours I mostly space out – an activity scientists charitably label “unsymbolized thinking”.
Discovering that my conscious experience was so different from most people’s, I began asking friends and family members about their own thoughts. Their answers shocked me: the inner lives of the people I am closest to were very different from mine.
I once asked my friend Miriam why she seemed obsessed, and it turned out that she was mentally replaying and analyzing a recent conversation she had with her sister, trying to turn down No Scrubs on her internal radio station, and debating about what to wear to the party we were late to.
At that moment everything that was going on was in me mind was a feeling of impatience, but this emotion quickly subsided as soon as I understood why Miriam was moving so slowly.
I used to think that my ability to focus, my quick recovery from setbacks and my inability to hold grudges were positive character traits – reflections and results of my work ethic and generosity. But I now see them as the result of my unusual brain architecture. Most people are haunted by their past in a way I can’t quite fathom, and it’s not something you decide to do. It’s just a function of how neurotypical memory works.
Am I missing a richly meaningful part of the human experience? Perhaps. Sometimes I wish I could remember dancing with my husband at our wedding, or remember the milky smell of holding my newborn niece for the first time.
When I started this journey, part of me hoped that I could retrain my memory and learn how to relive happy moments from my life. But the more I heard about the neurotypical experience of memory, the more I came to appreciate how my brain keeps me in the present.
From what I’ve heard, negative memories come up as often as wedding dances. In the end, what I took away from all the research wasn’t memory tips: it was a sense of wonder at the existence of the vast spectrum of human experience, with many of us perfectly happy and largely functional despite of our strange brain. That, and I stopped trying to meditate. As it turns out, I am diagnosably zen.
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Sadie Dingfelder is the author of Do I Know You?: A Faceblind Reporter’s Journey into the Science of Sight, Memoryand Imagination
