Here are five memory principles, plus one. After you read them, they may seem self-evident because that’s how memory works.
First, some things are easier to remember than others. In addition to shorter lists being easier than longer lists, the content of the list matters. Lists that have material that we are familiar with or sound similar to our prior knowledge are easier. Items that we can relate to our personal experience or physical being are easier. And lists which have items that are related to each other are easier. Of course, adjacent associated items are the easiest.
Second, memories can be stored in different in different media. Words can be stored by sight, sound or meaning. Sounds can be stored as words or music. People aren’t restricted to one media. We aren’t just visual processors or auditory learners. We can use a wide range of sensory media. But switching to another media can provide cues which aids retrieval.
Third, there are two separate phases of memory. There is what we know (available) and what we can find (accessible). Sometimes we know we know it but can’t find it. This tip-of-the-tongue phenomenon indicates that sometimes we haven’t forgotten that actor’s name; we just can’t find it.
Fourth, memory is generative. We don’t store exact copies of information. We aren’t very good as audio or video recorders. But we are great at meaning extraction. We don’t store the details. We store the instructions. We store fragments and recollect them into a memory.
I have a musician friend who write movie scores. Sometimes he gets a budget that allows him to record a full orchestra in a studio. But often he combines live performances with music he writes his computer. The notes are stored in a MIDI file, basically a text document, which takes up very little space. When the file is played, it triggers his keyboard and electronic synthesizers to generate the sounds. We don’t store full orchestras in our brain. We store the instructions (play this instrument this long on this note). Memory is synthesized from the instructions we store.
Fifth, memories are stable but changeable. We like to think of memory as immutable but our memories are vulnerable to what others tell us, what we want to happen and on the type of questions people ask us. This misinformation effect means that we are very responsive to our environments, even when it comes to memory.
Sixth, sometimes we make up memories. Memories feel permanent and immutable but they are remarkably unreliable. When my daughter was little, she would report that she “remembered” coming out of the hospital after her birth. She remembers the ride in the wheelchair and being able to see herself, held by her Mom, rolling out to the car.
What she remembers are photographs. Like most of us, she sure the details were true. Of course, babies aren’t held on the lap pointed outward. They are held tight against your body and covered with a blanket to keep them warm. As it turns out, the vividness of a memory isn’t a good indicator of its truth.
This phenomenon of false memories is particularly critical when it comes to eye witness testimony. Witnesses can believe they recognize the offender, and have a vivid memory of the event. And it is very compelling to have a witness point and say: “That’s him.” But eye witness testimony is remarkably unreliable. Many jurisdictions no longer will convict a person on the basis of eye witness testimony alone. Some collaborating evidence must also be present.
Our brains are like memory cooks who store the recipe. Usually we use the recipe and produce the proper outcome. But we distort the recipe to fit our prejudices and expectations.
Small changes in questions can produce different results. In a study by Elizabeth Loftus, subjects were shown photographs or videos of two moving cars who come together. In the simulations, no glass was ever broken but those who were asked what happened when the cars “smashed” reported broken glass more often that those asked what happened when the cars “bumped.”
Similarly, questions like “Did you see the stop sign?” produce different answers that if you ask “Did you see a stop sign?” Asking how tall a basketball player is gets different results than asking how short they are. And asking “what shade of blue was the wallet” presupposes there is a wallet, and people remember accordingly.
The exact process of how false memories are generated isn’t clear. It seems that the brain pulls bits for unrelated experiences and combines them into a new “authentic” memory.
People aren’t good at source monitoring. We extract the meaning from conversations and from what we read but we often don’t recall where the information came from. Our focus is on meaning extraction, not making a mental bibliography.
In general, the surprise is not that memories change and are unreliable. The surprise is that they are as reliable as they are.