Restless, Ever-Changing Memory
Second-year Psychology students participating in the University Honours College follow a workshop on Blogging Science, in which they learn to communicate science to the general public, by means of informing, giving an opinion, and relating issues in science to issues in society. This year a selection of these written blog posts is published on Mindwise. Today’s post is by Thomas Wilschut.
Clive Wearing, also called “the man with no memory”, lost his capability to remember anything that happened longer than 30 seconds ago. Due to a virus infection damaging his hippocampus, an essential brain area related to storing and retrieving memories, he developed almost total amnesia. He spends every 20 seconds having the feeling of “waking up”, like regaining consciousness after being asleep for a long time. He wrote in his diary: “9.34 AM: I am now really, completely awake”. Then he forgot he had written it, crossed out the lines he wrote before, and, minutes later, he wrote: “9.47 AM: Now I am superlatively, actually awake.” His diary contains hundreds of pages filled with these lines.
“memory is absolutely essential for our functioning”
The case of Clive Wearing has become a classic case report in the field of clinical neuropsychology. Our extensive interest in cases like Clive’s originates from the fact that memory is absolutely essential for our functioning. It is devastating to imagine living without long-term memories like Clive, but Clive did have some very short-term memories: he had the ability to live consciously for a short moment before he would forget. Could you imagine living totally without your memories? You could not consciously read this blog, since you would not remember the words that came before and you even wouldn’t remember what reading is. You would not be able to remember much about the world; you probably would not know that you existed, maybe like living in an ever-lasting unconscious dream.
It becomes clear that our lives depend physically and emotionally on our memories when we try to imagine living without them. The importance of our memory has intrigued scientists as well as lay people for decades. Throughout the ages, human memory has been compared with artificial storage units. One of the first people who noted his thoughts on memory was Plato, seeing memory as a writing slate. Soon after, the book became a metaphor, and later, Shakespeare compared memories with scenes in a theatre play. When the first photographs and films were made, our memories came to be seen as a way to store visual information. The analogy that was made next is probably easy to imagine: currently, the functioning of our brain is often compared to the functioning of a computer.
“Throughout the ages, human memory has been compared with artificial storage units.”
Comparing human memory with the factual accuracy of a computer is an easy and reassuring thing to do. There are obvious similarities in the way information is encoded and retrieved. Many problems with our memory, for example when we cannot remember something, can be described as problems with the mechanisms of coding and retrieving information in artificial storage devices. Supporters of the computer-memory analogy would argue that failing to remember something is due to faults in our system of retrieving information. This would, according to them, explain why human memory is sometimes less accurate than a computer.
There is, however, a problem with the computer metaphor. It becomes evident when we notice that memories of certain events can change by later events, new knowledge or merely the passing of time. Often these changes remain unnoticed. Computer files, however, remain unchanged unless we deliberately adjust them. In his book Als Mijn Geheugen Me Niet Bedriegt (English: If My Memory Doesn’t Deceive Me), professor Douwe Draaisma gives the example of traumatic memories, memories of sexual abuse. Oftentimes, children of young age do not label these experiences as sexual, because they are too young, but later these memories may obtain a very different meaning. As you can imagine, suddenly realizing the implications of a childhood memory can be a very upsetting experience. Furthermore, Draaisma explains that memories are sometimes unconsciously changed if people seek an explanation for their own failure or erratic behaviours. Sometimes people adjust or select childhood memories to fit with the person they have become.
“memories of certain events can change”
Memories are never at rest. In that sense, our memory is nothing like a hard drive that is left on a shelf for years. If it was, it might have been easier to understand and help people with amnesia like Clive. The puzzling construct of memory deserves a better metaphor: memory is more like a restless, crowded, evolving city. New houses and buildings arise as new memories are being formed. Major structures for salient events, small temporary projects for unimportant details. Highways form paths between most accessible or recent happenings; narrow alleys form the way to more remote memories. The city grows around old buildings, and with time some are replaced with newer ones. New buildings arise on older foundations. Some original features are still visible; some are forever lost. The city is restless, an ever-changing memory. In most cases, the city will never be quiet, never at ease. Except, perhaps, in cases like Clive’s. What will his city look like, after all those years?
Busato, V. (1999). Het geheugen in een notendop. Amsterdam University Press.
Draaisma, D. (2016) Als mijn geheugen me niet bedriegt. Historische Uitgeverij Groningen.
Draaisma, D. (1995; derde, herziene druk 2003) De metaforenmachine; een geschiedenis van het geheugen. Historische Uitgeverij Groningen.
Roediger, H.L (1980). Memory Metaphors in Cognitive Psychology. Memory & Cognition, 8, 231. https://doi.org/10.3758/BF03197611
Image by othree licenced under CC BY 2.0.