I was listening to a story on NPR years ago. An author had set out to write a book about his immigrant grandparents. Among other places, he traveled to the village in Northern Ireland where his grandparents had lived before immigrating.

He visited an infamous tree in a field just outside of town. It was infamous because once when his mother was a little girl, a “local boy” who was involved in one of the Irish Independence movements, had been lynched in that tree. And for many days afterward, the local British soldiers stationed guards on it round the clock, to prevent anyone from cutting the body down and giving the young man a proper burial.

The author’s mother, grandparents, and aunts and uncles had all told the story many times. His mother had a particularly moving way of describing herself as a small child, clutching her own mother’s hand as the stood in the tall grass, close enough to see, but far enough that the soldiers would ignore them. His grandmother had agreed, even explaining how she had argued with some neighbor about whether her daughter should see such things.

The author was able to verify all the particulars of the young man’s lynching, his long delayed funeral, and so forth. It was that tree, in that field where it had happened. There was only one problem with the identical story that all of this relatives who had been there told. The young man had been lynched exactly 6 days after the author’s mother was born. So, while it was possible that his grandmother had carried her new born baby out to the field to see the atrocity, there was no way his mother could have remembered it. And certainly, as a six-day-old infant, she would not have been standing on her own two feet in the tall grass, clutching her mother’s hand.

The author realized that what must have actually happened is that some years after the incident, his grandmother had taken his mother, her young daughter, out to the field in question, to look at the empty tree and hear the story of the horrible thing the soldiers had done. It’s quite possible there were several such trips, before the family left Ireland and moved to America. The description his mother had heard from her parents, other older relatives, and neighbors, of the body hanging in the tree with the soldiers standing guard, had evoked a vivid image, which his mother had interposed onto her actual memories of visiting the field.

And the grandparents and other relatives similarly modified their own memories when, over the years, they would tell the story to new acquaintances, and the author’s mother (first as a young girl), would interject her own recollection of the day. The first few times perhaps one uncle might have said, “Really? I thought you would be too young to remember,” but our memories don’t have timestamps on them, and it’s easy to lose track of exactly how long one event (the gruesome death of a neighbor) took place after another (the birth of a niece).

The author wound up talking to a lot of experts on memory, and instead of writing a book about his ancestors, wrote a book about memory, and how it grows, mutates, and reshapes itself to fit our perception of the meanings of our life.

I had my own rather dramatic experience in realizing that I had edited my own memories. I have a couple of friends, J and K, that I have known for over thirty years. When I first met them, they had recently broken up after having dated for a while, but they were trying to keep it amicable. Over the years they were both part of a large group of my friends that attending sci fi cons together and participated in related activities. For a while, J lived in California. During that time, K started dating L. K and L broke up. A few years later, J had moved back to Washington, she and K started dating, and eventually married.

Some years after that, I was telling another friend about this particularly funny event that had happened at a sci fi con, and mentioned both J and K’s parts. J didn’t remember the incident at all. I told a few more details, K chimed in with some supporting evidence. J admitted it sounded like something she would have said, and we moved on to another topic.

And then it hit me. Feeling horrified, I turned to J and said, “Oh, I am so sorry…” She started laughing, because she figured it out from the look on my face. It hadn’t been J experiencing the fiasco with us, it had been L. I apologized probably a bit too profusely, because J laughed and said that K did the same thing all the time.

I spent a while afterward trying to remember those couple of years when K had been dating L and also hanging out with our gang. I could only recall four incidents, total. All of them were ones which, from my perspective, exemplified L’s worst personality traits. I couldn’t recall one single incident in which she was not being pretentious, condescending, or disdainful.

I know that can’t be accurate. No one is awful all the time, and K would never be comfortable hanging out with someone who was, let alone nearly getting married to her. Obviously, I made the decision that K’s involvement with L had been a mistake of such proportions that I wished it hadn’t happened. And my subconscious has dutifully excised any pleasant memories of L from my memory. Any memories that have been kept, have had J substituted for L, in accordance with the other judgement I came to that J and K belong together and always have.

It was disturbing when I first realized it had happened. I still find it disturbing that I have to wrestle with my own memories when talking about events with these friends. I can make myself remember that it was L, not J, in the one story. But it makes me wonder what else in that memory has been emphasized, or obscured, or maybe borrowed from some other similar experiences.

It’s scary to realize just how unreliable one’s own recollection can be.