“In A Perpetual Present: The Strange Case of the Woman Who Can’t Remember Her Past—Or Imagine Her Future”, Erika Hayasaki2016-04-10 (psychiatry, neuroscience)⁠:

As they regale me with talk of their younger selves and their trips to Jamaica, Aruba, Cozumel, and Mazatlán, they present the very picture of well-adjusted adulthood on the verge of retirement. Except for one fairly major thing. As we chat, McKinnon makes clear that she has no memories of all those cruises. No memories of buying the lizard or finding that oilcloth collage. She doesn’t remember any vacation she’s ever taken. In fact, she cannot recall a single moment in her marriage to Green or before it.

For decades, scientists suspected that someone like Susie McKinnon might exist. They figured she was probably out there, living an ordinary life—hard to tell apart from the next person in line at the grocery store, yet fundamentally different from the rest of us. And sure enough, they found her (or rather, she found them) in 2006. “I don’t remember being smaller or having to reach up for things. I have no impressions of myself as a kid.” McKinnon is the first person ever identified with a condition called severely deficient autobiographical memory. She knows plenty of facts about her life, but she lacks the ability to mentally relive any of it, the way you or I might meander back in our minds and evoke a particular afternoon. She has no episodic memories—none of those impressionistic recollections that feel a bit like scenes from a movie, always filmed from your perspective. To switch metaphors: Think of memory as a favorite book with pages that you return to again and again. Now imagine having access only to the index. Or the Wikipedia entry.

…McKinnon first began to realize that her memory was not the same as everyone else’s back in 1977, when a friend from high school, who was studying to be a physician’s assistant, asked if she would participate in a memory test as part of a school assignment. When her friend asked basic questions about her childhood as part of the test, McKinnon would reply, “Why are you asking stuff like this? No one remembers that!” She knew that other people claimed to have detailed memories, but she always thought they embellished and made stuff up—just like she did. McKinnon’s friend was so disturbed by her responses that she suggested McKinnon get her memory checked by a professional. McKinnon put the exchange aside for almost three decades. Then one day in 2004, she came across an article about Endel Tulving, the researcher who had originally characterized the difference between episodic and semantic memory.