Remember summary

If you’re of a certain age you might remember January 28, 1986, when a space shuttle careened high in the blue sky over Florida and burst into a ball of flames. The explosion of the Space Shuttle Challenger left no survivors and was witnessed by millions on live television.

Twenty-four hours later, a pair of psychology professors at Emory University asked their students to jot down an account of what they were doing when they either witnessed or learned of the explosion.Two and a half years later, the professors followed up with the students and again asked for a personal account of that fateful January day. For almost every student, the memory had changed.

Whether the penny becomes a semantic memory formed through repetition, or a detail in an episodic memory of a meaningful moment, that memory lives in the hippocampus. However, one extremely important kind of memory – muscle memory – resides somewhere else entirely.

The key message here is: Muscle memory is a unique and vital form of memory that you create in your motor cortex through repeated practice.

There was a man who couldn’t forget anything . . . ever. His name was Solomon Shereshevsky, and for over three decades, psychologists tested him with long and meaningless lists of words and numbers. Throughout, his memory never faltered.

Rather than a sort of superpower, Shereshevsky came to view his memory as a burden. His mind was full of information, much of it useless, and sorting through it all was a never-ending task. On top of it all, like anyone else, Shereshevsky experienced things he’d rather forget.

Classical musicians possess incredible memories. They routinely memorize tens of thousands of notes in sequence, each to be played with its own subtle timing and pressure.

Yo-Yo Ma, the world-renowned cellist, surely ranks high among these memory masters, and yet on one night in the fall of 1999, he forgot his cello – a $2.5 million instrument – in the trunk of a New York City cab.

At 69 years old, a retired engineer named Akira Haraguchi performed a mind-blowing feat. Without any external reminders, he recited pi – that mysterious mathematical constant – to 111,700 digits.

No, Haraguchi is not a memory savant. He isn’t some kind of mathematical genius. In most ways, his brain is, in fact, just like yours.

For many of us, a common lapse in memory looks something like this: You walk into a room, but come to a halt. Looking around, you wonder: Why did I come in here?

Or perhaps you experience the following a few times a day. You’re heading out the front door when suddenly you stop short and slap your pockets. No, not there. Check inside your coat. Where did you leave your keys?

Over the course of two decades, a team of Alzheimer's researchers followed the lives of 678 elderly catholic nuns. The researchers conducted all manner of physical and cognitive tests, and as each nun died, she left her brain to the team for autopsy.

The researchers discovered, as they would amid any group of older brains, some evidence of amyloid plaque, that trigger of Alzheimer’s. Interestingly, even though they also recognized the shrinkages and tangles that go along with the disease, many of these same nuns showed no signs of the disease in life.

If you had to guess, which are you more likely to remember: the number 105799, or Albert Einstein kicking a bagel?

As we’ve learned, memory has a loose grip for abstractions like numbers. But for images and stories memory has a far tighter hold.