Some memories are easily retrieved because they are more salient (more prominent, relevant, intense). For example, memories for something with a great degree of emotional attachment, such as your wedding day or first kiss or that time you got two bags of chips out of the vending machine when you only paid for one, are usually very easily recalled. As well as the event itself, there are also all the emotions and thoughts and sensations going on at the same time. All of these create more and more links in the brain to this specific memory, which means the aforementioned consolidation process attaches a lot more importance to it and adds more links to it, making it much easier to retrieve. In contrast, memories with minimal or no important associations (for instance, the 473rd uneventful commute to work) get the bare minimum of consolidation, so they’re a lot harder to retrieve.
The brain even uses this as something of a survival strategy—albeit a distressing one. Victims of traumatic events often end up suffering from “flashbulb” memories, where the memory of the car accident or gruesome crime is vivid and it keeps recurring long after the event (see Chapter 8). The sensations at the time of the trauma were so intense, with the brain and body flooded with adrenalin causing heightened senses and awareness, that the memory lodges powerfully and remains raw and visceral. It’s as if the brain took stock of the awful things happening and said, “This right here, this is awful; do not forget this, we do not want to have to go through this again.” The trouble is, the memory can be so vivid it becomes disruptive.
But no memory is formed in isolation, so even in more mundane scenarios the context in which the memory was acquired can also be used as a “trigger” to help retrieve it, as some bizarre studies have revealed.
In one example, scientists got two groups of subjects to learn some information. One group learned it in a standard room; the other group learned it while underwater, wearing full scuba suits.6 They were later tested on the information they were told to learn, either in the same situation or the alternative one. Those who studied and were tested in the same situation performed significantly better than those who studied and were tested in different ones. Those who studied underwater and did the test underwater got much better scores than those who studied underwater but did the test in a normal room.
Being underwater had nothing to do with the information being learned, but it was the context in which the information was learned, and this is a big help in accessing memory. Much of the memory for where information is learned involves the context at the time, so putting someone in the same context essentially “activates” part of the memory, making it easier to retrieve it, like revealing several letters in a game of hangman.
At this point, it’s important to point out that memories for things that happen to us are not the only types of memories. These are called episodic memories, or “autobiographical” memories, which should be self-explanatory. But we also have “semantic” memories, which are for information essentially without the context: you remember light travels faster than sound, but not the specific physics lesson where you learned this. Remembering that the capital of France is Paris is a semantic memory, remembering the time you vomited off the Eiffel Tower is an episodic memory.
And these are the long-term memories we’re consciously aware of. There’s a whole swathe of long-term memories that we don’t need to be aware of like abilities we have without thinking about it, such as driving a car or riding a bike. These things are called “procedural” memories, and we won’t go into them any further because you’ll start thinking about them, and that might make it harder to use them.
In summary, short-term memory is fast, manipulative and fleeting, whereas long-term memory is persistent, enduring and capacious. This is why a funny thing that happened while in school can be something you remember forever, and yet still decide to go into a room but, if distracted even slightly, forget why by the time you get there.
Hey, it’s . . . you! From . . . the thing . . . that time
(The mechanisms of why we remember faces before names)
“You know that girl you went to school with?”
“Can you narrow it down?”
“You know, the tall girl. Dark blond hair but I think she was dyeing it, between you and me. She used to live in the street next to us before her parents divorced and her mother moved into the apartment that the Jones family lived in before they moved to Australia. Her sister was friends with your cousin before she got pregnant with that boy from town—that was a bit of a scandal. Always wore a red coat but it didn’t really suit her. You know who I mean?”
“What’s her name?”
“No idea.”
I’ve had countless conversations like this, with my mother, gran or other family members. Clearly, there’s nothing wrong with their memory or grasp of detail; they can provide personal data about someone that would put a Wikipedia page to shame. But so many people say they struggle with names, even when they’re looking directly at the person whose name they’re trying to recall. I’ve done this myself. It makes for a very awkward wedding ceremony.
Why does this happen? Why can we recognize someone’s face but not their name? Surely both are equally valid ways of identifying someone? We need to delve a bit deeper into how human memory works to grasp what’s really going on.
Firstly, faces are very informative. Expressions, eye contact, mouth movements, these are all fundamental ways humans communicate.7 Facial features also reveal a lot about a person: eye color, hair color, bone structure, teeth arrangement; all things that can be used to recognize a person. So much so that the human brain has seemingly evolved several features to aid and enhance facial recognition and processing, such as pattern recognition and a general predisposition to pick out faces in random images, as we’ll see in Chapter 5.
Compared to all this, what does someone’s name have to offer? Potentially some clues as to their background or cultural origin, but in general it’s just a couple of words, a sequence of arbitrary syllables, a brief series of noises that you’re informed belong to a specific face. But so what?
As we have seen, for a random piece of conscious information to go from short-term memory to long-term memory, it usually has to be repeated and rehearsed. However, you can sometimes skip this step, particularly if the information is attached to something deeply important or stimulating, meaning an episodic memory is formed. If you meet someone and they’re the most beautiful person you’ve ever seen and you fall instantly in love, you’d be whispering the object of your affection’s name to yourself for weeks.