by Dean Burnett
New memories are laid down by the hippocampus and slowly move out into the cortex as new memories form ‘behind’ them, gradually nudging them along. This gradual reinforcing and shoring up of encoded memories is known as ‘consolidation’. So the short-term-memory approach of repeating something until it’s remembered isn’t essential for making new long-term memories, but it is often crucial for making sure that a specific arrangement of information is encoded.
Say it’s a phone number. This is just a sequence of numbers that are already in the long-term memory. Why would it need to encode them again? By repeating the phone number, it flags up that this particular sequence of numbers is important and requires a dedicated memory to be retained long term. The repetition is the short-term memory equivalent of taking a bit of information, sticking on a label marked ‘Urgent!’ then sending it to the filing team.
So, if the long-term memory remembers everything, how do we still end up forgetting things? Good question.
The general consensus is that forgotten long-term memories are still technically there in the brain, barring some trauma in which they’re physically destroyed (at which point being unable to remember a friend’s birthday will not seem so important). But long-term memories have to go through three stages in order to be useful: they need to be made (encoded); they need to be effectively stored (in the hippocampus and then the cortex); and they need to be retrieved. If you can’t retrieve a memory, it’s as good as not being there at all. It’s like when you can’t find your gloves; you’ve still got gloves, they still exist, but you’ve got cold hands anyway.
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 crisps out of the vending machine when you only paid for one, are usually very easily recalled. As well as the event itself, there’s also all the emotion 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 was 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 were sick 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 for ever, 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 flat 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, bit of a scandal that was. 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 recognise 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 colour, hair colour, bone structure, teeth arrangement; all things that can be used to recognise 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 has someone’s name got 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 mos
t 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.
This doesn’t usually happen when you meet someone (thankfully), so if you wish to learn someone’s name, the only guaranteed way to remember it is to rehearse it while it’s still in your short-term memory. The trouble is, this approach takes time and uses mental resources. And as we saw from the ‘Why did I just come in here?’ example, something you’re thinking about can be easily overwritten or replaced by the next thing you encounter and have to process. When you first meet someone, it’s extremely rare for them to tell you their name and nothing else. You’re invariably going to be involved in a conversation about where you’re from, what you do for work, hobbies, what they arrested you for, that sort of thing. Social etiquette insists we exchange pleasantries on first meeting (even if we’re not really interested), but every pleasantry we engage in with a person increases the odds of the person’s name being pushed out of short-term memory before we can encode it.
Most people know dozens of names and don’t find it takes considerable effort each time you need to learn a new one. This is because your memory associates the name you hear with the person you’re interacting with, so a connection is formed in your brain between person and name. As you extend your interaction, more and more connections with the person and their name are formed, so conscious rehearsing isn’t needed; it happens at a more subconscious level due to your prolonged experience of engaging with the person.
The brain has many strategies for making the most of short-term memory, and one of these is that if you are provided with a lot of details in one go, the brain’s memory systems tend to emphasise the first thing you hear and the last thing you hear (known as the ‘primacy effect’ and ‘recency effect’, respectively),8 so a person’s name will probably get more weight in general introductions if it’s the first thing you hear (and it usually is).
There’s more. One difference between shortand longterm memory not discussed so far is that they both have different overall preferences for the type of information they process. Short-term memory is largely aural, focusing on processing information in the form of words and specific sounds. This is why you have an internal monologue, and think using sentences and language, rather than a series of images like a film. Someone’s name is an example of aural information; you hear the words, and think of it in terms of the sounds that form them.
In contrast to this, the long-term memory also relies heavily on vision and semantic qualities (the meaning of words, rather than the sounds that form them).9 So a rich visual stimulus, like, say, someone’s face, is more likely to be remembered long term than some random aural stimulus, like an unfamiliar name.
In a purely objective sense, a person’s face and name are, by and large, unrelated. You might hear people say, ‘You look like a Martin’ (on learning someone’s name is Martin), but in truth it’s borderline impossible to predict accurately a name just by looking at a face – unless that name is tattooed on his or her forehead (a striking visual feature that is very hard to forget).
Let’s say that both someone’s name and face have been successfully stored in the long-term memory. Great, well done. But that’s only half the battle; now you need to access this information when needed. And that, unfortunately, can prove difficult.
The brain is a terrifyingly complex tangle of connections and links, like a ball of Christmas-tree lights the size of the known universe. Long-term memories are made up of these connections, these synapses. A single neuron can have tens of thousands of synapses with other neurons, and the brain has many billions of neurons, but these synapses mean there is a link between a specific memory and the more ‘executive’ areas (the bits that do all the rationalisation and decision-making) such as the frontal cortex that requires the information in the memory. These links are what allows the thinking parts of your brain to ‘get at’ memories, so to speak.
The more connections a specific memory has, and the ‘stronger’ (more active) the synapse is, the easier it is to access, in the same way that it’s easier to travel to somewhere with multiple roads and transport links than to an abandoned barn in the middle of a wilderness. The name and face of your long-term partner, for example, is going to occur in a great deal of memories, so it will always be at the forefront of your mind. Other people aren’t going to get this treatment (unless your relationships are rather more atypical), so remembering their names is going to be harder.
But if the brain has already stored someone’s face and name, why do we still end up remembering one and not the other? This is because the brain has something of a two-tier memory system at work when it comes to retrieving memories, and this gives rise to a common yet infuriating sensation: recognising someone, but not being able to remember how or why, or what their name is. This happens because the brain differentiates between familiarity and recall.10 To clarify, familiarity (or recognition) is when you encounter someone or something and you know you’ve done so before. But beyond that, you’ve got nothing; all you can say is this person/thing is already in your memories. Recall is when you can access the original memory of how and why you know this person; recognition is just flagging up the fact that the memory exists.
The brain has several ways and means to trigger a memory, but you don’t need to ‘activate’ a memory to know it’s there. You know when you try to save a file onto your computer and it says, ‘This file already exists’? It’s a bit like that. All you know is that the information is there; you can’t get at it yet.
You can see how such a system would be advantageous; it means you don’t have to dedicate too much precious brain power to figuring out if you’ve encountered something before. And, in the harsh reality of the natural world, anything that’s familiar is something that didn’t kill you, so you can concentrate on newer things that might. It makes evolutionary sense for the brain to work this way. Given that a face provides more information than a name, faces are more likely to be ‘familiar’.
But this doesn’t mean it’s not intensely annoying for us modern humans, who regularly have to make small talk with people we’re certain we know but can’t actually recall right now. That’s the part most people can relate to, the point where recognition turns to full-on recall. Some scientists describe it as a ‘recall threshold’,11 where something becomes increasingly familiar, until it reaches a crucial point and the original memory is activated. The desired memory has several other memories linked to it, and these are being triggered and cause a sort of peripheral or low-level stimulation of the target memory, like a darkened house being lit by a neighbour’s firework display. But the target memory won’t actually activate until it is stimulated above a specific level, or threshold.
You’ve heard the phrase ‘it all came flooding back’, or you recognise the sensation of a quiz question being ‘on the tip of your tongue’ before it suddenly occurs to you? That’s what’s happening here. The memory that caused all this recognition has now received enough stimulation and is finally activated, the neighbour’s fireworks have woken those living in the house and they’ve turned all the lights on, so all the associated information is now available. Your memory is officially jogged, the tip of your tongue can resume its normal duties of tasting things rather than providing an unlikely storage space for trivia.
Overall, faces are more memorable than names because they’re more ‘tangible’, whereas remembering someone’s name is more likely to require full recall than simple recognition. I hope this information means that you’ll understand that if we ever meet for a second time and I don’t remember your name, I’m not being rude.
Actually, in terms of social etiquette, I probably am being rude. But now at least you know why.
A glass of wine to refresh your memory
(How alcohol can actually help you remember things)
People like alcohol. So much so that alcohol-related issues are an ongoing problem for many p
opulations. These issues can be so widespread and constant that dealing with them ends up costing billions.12 So why is something so damaging also so popular?
Probably because alcohol is fun. Aside from causing a dopamine release in the areas of your brain dealing with reward and pleasure (see Chapter 8), thus causing that weird euphoric buzz that social drinkers enjoy so much. There’s also social convention built up around alcohol; it’s almost a mandatory element of celebration, bonding and just general recreation. Because of this, you can see why the more detrimental effects of alcohol are regularly overlooked. Sure, hangovers are bad, but comparing and laughing about the severity of respective hangovers is yet another way of bonding with friends. And the ridiculous ways in which people behave when drunk would be deeply alarming in some contexts (in a school, perhaps, at 10 a.m.) but when everyone does it, it’s just fun, right? A necessary relief from the seriousness and conformity demanded of us by modern society. So, yes, the negative aspects of alcohol are considered a price worth paying by those who enjoy it.
One of these negative aspects is memory loss. Alcohol and memory loss go hand in unsteady hand. It’s a comedy staple in sitcoms, stand-up and even personal anecdotes, usually involving someone waking up after a drunken night and finding himself in an unexpected situation, surrounded by traffic cones, unfamiliar garments, snoring strangers, irate swans and other things that wouldn’t be in a person’s bedroom under normal circumstances.
So how then can alcohol possibly actually help your memory, as the title of this bit suggests? Well, it’s necessary to go over why alcohol affects our brain’s memory system in the first place. After all, we ingest countless different chemicals and substances every time we eat anything, why don’t they cause us to slur our words or pick fights with lamp-posts?
It’s due to the chemical properties of alcohol. The body and brain have several levels of defence to stop potentially harmful substances entering our systems (stomach acids, complex intestinal linings, dedicated barriers to keep things out of the brain …) but alcohol (specifically ethanol, the type we drink) dissolves in water and is small enough to pass through all these defences, so the alcohol we drink ends up spread throughout our bodily systems via the bloodstream. And when it builds up in the brain, several bags of spanners are thrown into some very important workings.