What was H.M. like?

He was very pleasant. And he so wanted to be helpful. At the time I met him, he must have been in his late 20s. He’d had really terrible epilepsy ever since a childhood bicycle accident, and the surgery had been beneficial for that. But the excision had made it difficult for him to acquire new long-term memories.

There were things about the past he recalled, but he’d tell you the same joke over and over again, never remembering he’d told it to you earlier. No matter how many times you met him, he couldn’t remember you.

I would give him tests where he had to repeat a set of numbers — 5, 8, 4. He could do it by constantly repeating those numbers to himself or making up formulas. Yet, if I distracted him — and life is constantly distracting — he could no longer give you 5, 8, 4. This was the heart of his incapacity.

What kinds of tests did you give him?

I had to show what he could learn and not learn. It was no good to say, “I have this patient and he cannot learn anything new,” because someone will say, “Brenda, what did you try to teach him?”

So I would hop on a train and go down to Hartford and give H.M. tasks based on learning. One was a puzzle where he had to trace his way out of a maze. He just couldn’t do it. A different one involved giving him a five-pointed star and asking him to trace its outlines while looking in a mirror. This looks easy, but is not. With most people, the more they practice, the better they get. This is really a test for motor-skill learning. Well, H.M. did it!

Seeing this was probably the most exciting thing that ever happened to me. As H.M. tried tracing the star — over 30 times in a three-day period — he showed a beautiful learning curve. He couldn’t recall any of the 30 tries, but he got better.