Category: Memory

Suggestibility of memory in psychology is a major contributor to wrongful convictions, through biased eyewitness testimony.

Suggestibility in psychology refers to the tendency to fill in gaps in memory with information from others that may well be incorrect.

When people are experiencing intense emotions, they show more suggestibility.

In addition, some people display more suggestibility than others, such as those with low self-esteem or who are less assertive.

Suggestibility involves false memory

Suggestibility, one of Daniel Schacter’s sins of memory, is a close cousin of misattribution.

Like misattribution, suggestibility involves the creation of a false memory.

But, while a misattribution is of our own making, a suggestion comes from someone else who is, whether intentionally or not, influencing us.

Human suggestibility has many implications, but some of its most devastating consequences have been played out in the criminal justice system.

Criminal justice systems around the world have treated human memory with undeserved reverence for a long time, while ignoring our inherent suggestibility.

Dubious eyewitness testimony has frequently secured convictions for the most serious of crimes.

Even more incredibly for students of scientific psychology, repressed memories rising to the surface decades after the original event have been accepted by courts as the basis to lock a man away for the rest of his life.

Given the right circumstances people will finger the wrong suspect in a line-up, manufacture false memories and even change their beliefs after having their dreams interpreted.

Example of suggestibility in eyewitness testimony

Faulty eyewitness testimony is one of the leading causes of wrongful convictions in the US.

On the basis of mounting evidence, psychologists have argued that a major contributing factor to these wrongful convictions is suggestibility (Schacter, 1999).

Dramatic evidence for how easily eyewitnesses are swayed through suggestibility comes from a study carried out by Gary Wells and Amy Bradfield at Iowa State University (Wells & Bradfield, 1998).

Like many of the best studies it is deceptively simple, but its implications for the criminal justice system are profound.

Spot the gunman

Participants were asked to watch 8 seconds of grainy security camera footage showing a man walking into a store.

The footage was slowed down so that participants could get as much information as possible.

The quality of the video, however, was not that good.

After watching the video, participants were told that the man is a murderer.

Just after the footage cuts away, the man shot and killed the store’s security guard.

This information is not misleading – the CCTV footage is real – as is the subsequent murder of the security guard.

Participants were then told that their job is to identify the killer from a five-person photospread.

This photospread was identical to the one used in the real case except – and here’s the twist – the real gunman has been removed.

Having been told, though, that the gunman is in the photospread, all the participants identify one of the men.

This is where the experimenters got clever.

They then introduced three different experimental manipulations:

• One group of participants were given no feedback on their choice of suspect.
• The second were told they had made the wrong choice from the photospread and that the answer was one of the other men.
• The third group, though, were congratulated: “Good, you identified the actual suspect.” Although, of course, they hadn’t – no one had.

After this, participants were asked about many aspects of their identification including how certain they were, how good their view of the gunman was and their ability to make out the details of his face.

That’s him, I’m sure!

The results showed that simply congratulating participants on choosing the right suspect had a huge effect on their reports when compared to those told nothing and those told they were wrong.

Those given positive feedback were suddenly much more sure they were right, thought the identification was easier, had a better view, thought their judgement was more trustworthy and would be more willing to testify.

Those given positive feedback even placed more confidence in their own ability to identify the gunman.

Remember that everyone is providing these reports based on exactly the same piece of store camera footage.

Also, remember that everyone is wrong because the real gunman has been removed from the photospread!

Confidence boosted through suggestibility

The surprising thing about this experiment is what a massive effect a simple statement had on such a wide variety of factors.

Giving positive (although incorrect) feedback to participants catapulted their confidence in their identifications much higher than they would have been otherwise.

On a 7-point scale only 15 percent of the eyewitnesses who were given negative feedback rated their confidence in their identification at either a 6 or a 7.

Compare this with the eyewitnesses given positive feedback – 50 percent rated their confidence at either a 6 or a 7.

Participants given positive feedback even thought the security camera footage was clearer.

47 percent rated it at a 6 or 7 out of 7, compared with none of the eyewitnesses given negative feedback.

In a second part of the study, the authors wanted to see whether people have any idea that the feedback they receive affects their confidence in identifying the gunman.

Despite the fact that it did have a substantial measurable effect, people denied the feedback had any influence whatsoever.

Feedback to eyewitnesses is still routine

Given the huge effect that feedback can have on confidence, given human suggestibility, clearly eyewitnesses should not be told whether they have identified the suspect or not.

Wells and Bradfield (1998) point out that even when witnesses are not given verbal feedback, it is virtually impossible for police officers to avoid information leaking out through body language.

The solution suggested by Wells and Bradfield (1998) is that those administering the photospreads to eyewitnesses should be blind to the real suspect.

A statement should then be taken before eyewitnesses discover whether they have picked the suspect, and their judgement is affected.

Although they may subsequently inflate their claim, at least this can be compared with their original statement.

Incredibly, ten years later, it is still routine practice in the US and UK for many police forces to provide positive feedback to witnesses.

This is perhaps unsurprising given the police’s interest in securing convictions.

Positive feedback will almost certainly bolster witnesses’ confidence because of their suggestibility, thereby improving the impression they make in court.

Moves to reform police procedures in the US have foundered despite the repeated confirmation of this study’s findings.

Similar moves are afoot in the UK, but changes have only so far been made in some police forces.

→ This post is part of a series on the seven sins of memory:

1. Short-Term Memory vs. Long-Term Memory: Definition And Examples
2. Absent-Mindedness: 2 Factors That Cause Forgetfulness
3. Tip-of-the-Tongue Phenomenon Or Lethologica
4. Misattribution: How Memories are Distorted and Invented
5. Suggestibility: How Memory Is Biased By Suggestions
   • False Memory: Dramatic Examples Of Fake Memories
6. Commitment and Consistency Bias: How It Warps Memory
7. Long-Term Memory: When Persistence Is A Curse

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Doodling is more than just a pleasant waste of time and paper — it boosts focus, memory, concentration and blood flow to the brain.

All sorts of claims have been made for the power of doodling: from it being an entertaining or relaxing activity, right through to it aiding creativity, or even that you can read people’s personalities in their doodles.

The idea that doodling provides a window to the soul is probably wrong.

These ideas about doodling can seem intuitively attractive but it falls into the same category as graphology: it’s a pseudoscience (psychologists have found no connection between personality and handwriting).

Benefits of doodling

Although it’s probably a waste of time trying to interpret a doodle, could the act of doodling itself still be a beneficial habit for attention and memory in certain circumstances?

To test this out Professor Jackie Andrade at the University of Plymouth had forty participants listen to a mock answerphone message which was purportedly about an upcoming party (Andrade, 2009).

People were asked to listen to the message and write down the names of all the people who could come to the party, while ignoring the people who couldn’t come.

Crucially, these participants were pretty bored.

They’d just finished another boring study, were sitting in a boring room and the person’s voice in the message was monotone.

The question is: even though the task is pretty simple, would they be able to concentrate long enough to note down the right names?

Here’s the experimental manipulation.

Half the participants were told to fill in the little squares and circles on a piece of paper while writing down the names — this is the simplest form of doodling.

The rest just listened to the message, only writing down the names.

Memory boosted by 30%

Looking at the results, the beneficial effects of doodling are right there.

Non-doodlers wrote down an average of seven of the eight target names.

But people doodling wrote down an average of almost all eight names.

It wasn’t just their attention that was enhanced, though, doodling also benefited memory.

Afterwards, participants were given a surprise memory test, after being specifically told they didn’t have to remember anything.

Once again people doodling performed better, in fact almost 30 percent better.

So perhaps if you’re stuck in a boring meeting or someone is droning on at you about something incredibly uninteresting, doodling can help you maintain enough focus to pull out the salient facts.

Doodling boosts brain blood flow

Making art activates the brain’s reward pathways, research finds (Kaimal et al., 2017).

Doodling in particular boosts the blood flow through the prefrontal cortex.

The prefrontal cortex (above the eyes) is the area of the brain linked to regulating our higher functions like our thoughts, feelings and actions.

The study had both artists and non-artists either doodling, free drawing or colouring between the lines.

For artists, doodling was linked to slightly higher levels of brain activity.

Dr Girija Kaimal, who led the study, said:

“This shows that there might be inherent pleasure in doing art activities independent of the end results.

Sometimes, we tend to be very critical of what we do because we have internalized, societal judgements of what is good or bad art and, therefore, who is skilled and who is not.

We might be reducing or neglecting a simple potential source of rewards perceived by the brain.

And this biological proof could potentially challenge some of our assumptions about ourselves.”

Why doodling is beneficial

But why does it work?

We can’t tell from this study but Andrade speculates that doodling helps people concentrate because it stops their minds wandering but doesn’t (in this case) interfere with the primary task of listening.

When people are bored or doing a simple task, their minds naturally wander.

We might think about our weekend plans, that embarrassing slip in the street earlier or what’s for supper.

Perhaps doodling, then, keeps us sufficiently engaged with the moment to pay attention to simple pieces of information.

It’s like keeping the car idling rather than turning it off.

On idle we’re still paying some attention to our surroundings rather than totally zoning out.

Obviously doodling is not a task you want to indulge in while concentrating on a complicated task, but it may help you maintain just enough focus during a relatively simple, boring task, that you can actually get it done better.

Research on doodling might sound a little trivial but it’s fascinating because it speaks to us about many facets of human psychology, including mind wandering, zoning out, attention and the nature of boredom.

Plus it’s a really nice idea that doodling has a higher purpose, other than just wasting time and paper.

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Misattribution of a memory in psychology is when some original true aspect of a memory becomes distorted through time, space or circumstances.

Misattribution of memory is a psychological phenomenon that involves the creation of memories that are false in some way.

Sometimes known as source misattribution, misattribution of memory sometimes involves false memories, sometimes when forgotten memories return (cryptomnesia) and also when confusing the source of memories.

However, it is best explained with a true story…

Example of misattribution

One evening in 1975 an unsuspecting Australian psychologist, Donald M. Thomson, walked into a television studio to discuss the psychology of eyewitness testimony.

Little did he know that at the very moment he was discussing how people can best remember the faces of criminals, there was someone encoding his own face as a rapist.

The day after the television broadcast Thomson was picked up by local police.

He was told that last night a woman was raped and left unconscious in her apartment. She had named Thomson as her attacker.

Thomson was shocked, but had a watertight alibi. He had been on television at the time of the attack and in the presence of the assistant commissioner of police.

It seemed that the victim had been watching Thomson on television just prior to being attacked.

She had then confused his face with that of her attacker.

That a psychologist talking about identifying the faces of criminals should be the subject of just such a gross memory failure – and at the very moment he was publicly explaining it – is an irony hard to ignore.

Donald Thompson was completely exonerated but many others have not been so lucky.

Gary Wells at Iowa State University and colleagues have identified 40 different US miscarriages of justice that have relied on eye-witness testimony (Wells et al., 1998).

Many of these falsely convicted people served many years in prison, some even facing death sentences.

Donald Thomson’s ordeal, though, is a perfect example of Harvard psychologist Daniel L. Schacter’s fourth sin of memory (Schacter, 1999).

Unlike the first three sins, which all involve being unable to access memories, this is the first sin that involves the creation of memories that are false in some way.

When a memory is ‘misattributed’ some original true aspect of a memory becomes distorted through time, space or circumstances.

Daily misattribution

While misattributions can have disastrous consequences, most are not so dramatic in everyday circumstances.

Like the other sins of memory, misattributions are probably a daily occurrence for most people.

Some examples that have been studied in the lab are:

• Misattributing the source of memories. People regularly say they read something in the newspaper, when actually a friend told them or they saw it in an advert. In one study participants with ‘normal’ memories regularly made the mistake of thinking they had acquired a trivial fact from a newspaper, when actually the experimenters had supplied it (Schacter, Harbluk, & McLachlan, 1984).
• Misattributing a face to the wrong context. This is exactly what happened to Donald Thomson. Studies have shown that memories can become blended together, so that faces and circumstances are merged.
• Misattributing an imagined event to reality. A neat experiment by Goff and Roediger (1998) demonstrates how easily our memory can transform fantasy into reality. Participants were asked either to imagine performing an action or actually asked to perform it, e.g. breaking a toothpick. Sometime later they went through the same process again. Then, later still they were asked whether they had performed that action or just imagined it. Those who imagined the actions more frequently the second time were more likely to think they’d actually performed the actions the first time.

Unintentional plagiarism

So far we’ve seen how easily people move around the events, faces and sources of their memories.

Each of these are situations where people are retrieving a real memory, but mistaking one or more of its aspects.

Schacter (1999), however, points to another common type of misattribution: when we attribute an idea or memory to ourselves that really belongs to someone else.

Unintentional plagiarism has been examined in a number of studies.

In one straightforward early study people were asked to generate examples of particular categories of items, like species of birds.

It was found that people, without realising, plagiarised each other about 4% of the time (Brown & Murphy, 1989).

Subsequent studies using more naturalistic procedures have found much higher rates using different types of tasks – sometimes as much as 27%.

That’s a very high rate and probably helps to explain why we see so much unintentional repetition across many different areas of human culture.

Musicians, writers and artists of all stripes have to work extremely hard to avoid unintentionally plagiarising each other.

If a song that has been unintentionally plagiarised becomes a hit, it can easily end up making the lawyers a lot of money.

When George Harrison was sued for (unintentionally) plagiarising a Chiffons’ hit “He’s So Fine”, a claim that started in 1971 dragged on until the 1990s!

All made up

Although memories often have some basis in reality, whether we’ve mixed up some details or even the memory’s source, sometimes they are just completely false.

During the 1960s and 70s psychologists discovered a way of reproducing this false memory effect in the lab.

In the classic study conducted by James Deese at Johns Hopkins University, participants are given lists of semantically related words (Deese, 1959).

For example: red, green, brown and blue.

Later they have to try and recall them, at which point they often recall related words that were not actually presented, like purple or black.

Later studies have replicated this finding using more complicated procedures that help to counteract some of the problems with this early study.

Nevertheless there is still the question of whether these laboratory-based tasks really do tell us anything about how we behave in the real world.

Are we really this prone to completely false memories in real life?

New evidence suggests we may well be.

Brown and Marsh (2008) found that some people could be induced to think they had visited an unfamiliar place simply by being shown photos of that location.

Misattribution of memory and the self

These sorts of studies on the misattributions of memories can be existentially disturbing.

This is because each of us is effectively the accumulation of our experiences, our memories. Who we are is – at least partly – what has happened to us.

Discovering the scientific evidence for how easily memories become confused, distorted or just plain break through from fantasy to reality is like discovering that part of ourselves is fabricated, false in some way.

As psychologist William James points out in the opening quote, memories can be carved from both reality and our dreams.

Away from the existential crisis and back to practicalities, Daniel Schacter suggests that misattributions may actually be useful to us (Schacter, 1999).

The ability to extract, abstract and generalise our experience enables us to apply lessons we’ve learnt in one domain to another.

And, a lot of the time, we simply don’t need to know the exact details of an experience: we may not remember the exact score, but we know our team won.

We get the gist.

Similarly, when we actually do need to know the details, we can take steps to encode the memory securely so we don’t make misattributions.

But there’s no doubting that in some circumstances misattributions can have frightening consequences – just ask anyone falsely convicted by eyewitness testimony.

Just ask Donald Thomson.

→ This post is part of a series on the seven sins of memory:

1. Short-Term Memory vs. Long-Term Memory: Definition And Examples
2. Absent-Mindedness: 2 Factors That Cause Forgetfulness
3. Tip-of-the-Tongue Phenomenon Or Lethologica
4. Misattribution: How Memories are Distorted and Invented
5. Suggestibility: How Memory Is Biased By Suggestions
   • False Memory: Dramatic Examples Of Fake Memories
6. Commitment and Consistency Bias: How It Warps Memory
7. Long-Term Memory: When Persistence Is A Curse

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The method of loci, or memory palace, is an effective technique to enhance memory and even to create a store of positive memories.

The ‘method of loci’ technique (literally method of places) for enhancing memory has been around for thousands of years.

The method of loci technique was recommended by the Roman philosopher Cicero.

In 2006 Lu Chao used the method of loci technique to recall π to 67,890 places (he recited it for 24 hours and 4 minutes before he made a mistake).

But you don’t have to be a specialist memoriser or super-brain to find the technique useful; it has dramatic effects on recall for even the most humble of us.

And the method of loci technique might even be useful for fighting depression — but more on that later…

The method of loci technique

The method of loci technique, which relies on spatial memory, is remarkably simple to explain, but does require some mental effort to set up.

What you do is think of a place that you know really well, like a house you lived in as a child or your route to work.

Then you place all the things you want to remember around the house as you mentally move around it.

Each stop on the journey should have one object relating to a memory.

The more bizarre and surreal or vivid you can make these images in the method of loci, the better they will be remembered.

Doubling memory capacity with method of loci

Remarkable things can be achieved by training memory using the method of loci technique.

People in one study doubled their memory capacity in just 40 days of working 30 minutes per day (Dresler et al., 2017).

Even without doing any further training, their memory was still working at a higher level four months later.

Professor Martin Dresler, the study’s first author, said:

“After training we see massively increased performance on memory tests.

Not only can you induce a behavioral change, the training also induces similar brain connectivity patterns as those seen in memory athletes.”

Becoming a memory athlete

Researchers took brain scans before and after the training.

They found that after training in the method of loci technique people’s brains were more similar to ‘memory athletes’ — those who train their memories for international competitions.

Typically, top memory athletes can memorise a series of 500 digits in just five minutes.

None of the memory athletes were born with special memory skills, they simply worked on them over the years, said Professor Dresler:

“They, without a single exception, trained for months and years using mnemonic strategies to achieve these high levels of performance.”

The two training methods used in the study were:

• Practising remembering sequences of numbers.
• Method of loci — sometimes called a memory palace.

Method of loci was most effective

After training, people could usually remember about twice as many words.

The method of loci technique, though, worked the best in the long-run.

Professor Dresler said:

“Once you are familiar with these strategies and know how to apply them, you can keep your performance high without much further training.”

The brain scans showed there were 25 critical points of connectivity among the memory athletes.

The research also highlighted two vital hubs of connectivity in the brain regions related to learning.

Professor Dresler said:

“It makes sense that these connections would be affected.

These are exactly the things we ask subjects to do when using method of loci for memorization.”

Memory palace of happy times

“I’m going to my happy place!”

Saying this in moments of stress has become a rather tired joke.

And the joke conceals the fact that having a so-called ‘happy place’, or even several happy places can help boost mood when times are hard.

However, the problem with thinking back to happy moments from the past is that it’s hard if you’re not in the habit.

Indeed, people experiencing depression find it particularly difficult.

Worse, when they do recall happier times, they tend to do it abstractly, focusing on the causes, meaning and consequences, and looking for clues as to how to regain it.

Unfortunately it’s re-experiencing the pleasure that gives you the boost in the moment, not thinking about it abstractly.

The problem is frequently memory.

To feel better by thinking back to past glories, you’ve got to pull up the right memories and in the requisite detail.

This can be hard enough for the most equable of souls and nearly impossible when low mood strikes.

What is required is a really strong technique for instantly conjuring up the right moments from the past so that you feel right there, in the moment.

And this is where the method of loci fits in.

If you carried out this process for a series of good memories, you’d have what is called a ‘memory palace’ of happy times that you could return to in moments of stress.

Testing the method of loci for emotions

But, can creating a memory palace be effective even for depressed people: those who find it particularly difficult to remember happy times?

That’s what was tested in a study by Dalgleish et al. (2013) who recruited 42 participants who were currently experiencing a major depressive disorder or who had suffered in the past and were now in remission.

Half the participants were taught the method of loci technique.

Here’s an example of how one person encoded a memory to give you the flavour:

“…one participant in the main study had generated a memory of an important conversation over coffee in New York with her best friend. She associated the memory with the front of her childhood home (one of her selected loci) by imagining the fascia of the house transformed into an outlet of a popular U.S. coffee chain with her friend standing outside smiling and dressed as a barista.”

Everyone rehearsed 15 of these self-affirming memories and placed them around their memory palaces using the method of loci technique.

They then practised going around their individual mental routes until they could easily retrieve the memories and the associated feelings in high levels of detail.

The rest of the participants also recalled 15 positive events but used a memory technique that you’ll be more familiar with from school.

They simply rehearsed them over-and-over again until it seemed to have gone in.

The results

Unsurprisingly, both groups reported that remembering happy past memories made them feel better.

But, the key for the researchers was to see whether people could still recall the memories one week later, in a surprise telephone call.

The results showed that the participants who had rehearsed the memories repeatedly had forgotten, on average, two of them.

In contrast, the average barely dropped for those who had used the method of loci.

This is an encouraging result and suggests that the method of loci is an effective way to easily a set of happier times, even in people who find it difficult to do so.

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The tip-of-the-tongue phenomenon or lethologica in psychology is when the memory is right there and yet for some reason you can’t quite access it.

The tip-of-the-tongue phenomenon or lethologica in psychology is when you know a word, but cannot think of it.

Technically, the tip-of-the-tongue phenomenon in psychology is a temporary inability to retrieve an item from memory.

The infuriating internal monologue during the tip-of-the-tongue phenomenon goes something like this:

“What’s the name of that guy who was in that film with…you know the one…he’s…no, no it’s not Denzel Washington, the other guy.

Oh God, I know it, it’s right there.

It’s on the tip of my tongue!

This is driving me crazy…!

I can see his face.

This is ridiculous!

No, not Denzel Washington!”

The tip-of-the-tongue phenomenon

The tip-of-the-tongue or ‘TOT’ phenomenon, also known as lethologica, is now well-documented in psychology.

It is a very common example of what memory expert Daniel L. Schacter calls ‘blocking’, one of the seven sins of memory (Schacter, 1999).

The tip-of-the-tongue phenomenon is the experience that the memory is right there and yet for some reason you can’t quite access it.

Sometimes all you can think about is something similar, say another actor who is often in the same types of films.

It’s this memory that seems to block the retrieval of the one you really want.

Other times there’s apparently nothing blocking the memory’s retrieval other than your mind’s stubborn refusal.

Studies on tip-of-the-tongue style blocking have shown that around half of the time we will become ‘unblocked’ after about a minute.

The rest of the time it may take days to recover the memory from the tip-of-the-tongue.

As anyone getting on in years will tell you, tip-of-the-tongue blocking increases with age.

Older adults certainly experience more problems recalling names than younger adults.

One study finds college students have one or two tip-of-the-tongue moments a week, while older adults experience the tip-of-the-tongue phenomenon between two to four times per week.

Tasting words on the tip-of-the-tongue

One fascinating aspect of the tip-of-the-tongue phenomenon is the study of synaesthetes.

Synaesthesia is a fairly common condition where people have a cross-wiring in their brains between senses (see: types of synaesthesia).

This means that people with synaesthesia may experience numbers as colours, sounds as images or even words as tastes.

This last category, a rare form known as lexical-gustatory synaesthesia, provides an opportunity to study the TOT phenomenon in an unusual way.

Simner and Ward (2006) figured that if the cross-wiring in synaesthetes’ brains turns words into tastes, perhaps they would literally be able to taste words that are on the tips of their tongues before they could even recall the word itself.

Magically, there’s evidence this really does happen.

Simner and Ward set about inducing tip-of-the-tongue states in the lab by showing 6 participants with this rare form of synaesthesia pictures of unusual objects, such as a platypus.

In some trials, the experimenters managed to successfully induce a tip-of-the-tongue state in the synaesthetes.

Amazingly, these lexical-gustatory synaesthetes did actually feel a taste on their tongues as they struggled for the word to describe the picture.

In one case a participant tasted tuna when she was trying to remember the word ‘castanet’.

To check the answers were correct, participants were asked after the study which taste they associated with each word in the study.

The tastes they reported being on the tip of their tongues matched up with their word-taste associations.

But what if the synaesthetes are just making these tastes up?

Well, to check, the experimenters called them up more than a year later in a surprise retest.

Sure enough, the participant who reported that the word ‘castanets’ was associated with the taste of tuna, still did so, even after a year.

Similarly, the other 5 synaesthetes in the study all consistently reported their particular connections between tastes and words.

While these sorts of experiences are alien to the majority of us, Simner and Ward suggest that this link between words and tastes may nevertheless be active in all of us, but at an unconscious level.

Resolving the tip-of-the-tongue phenomenon

So how do we finally remember what’s on the tip of our tongues?

One theory has it that our memory can be jogged by hearing a word that sounds similar (James & Burke, 2000).

While this is probably true, in real life it’s just plain good luck if our memory is jogged by the environment and the tip-of-the-tongue moment is relieved.

Nowadays, though, we have a new tool for resolving those tip-of-the-tongue nuisances: look it up on the internet.

→ This post is part of a series on the seven sins of memory:

1. Short-Term Memory vs. Long-Term Memory: Definition And Examples
2. Absent-Mindedness: 2 Factors That Cause Forgetfulness
3. Tip-of-the-Tongue Phenomenon Or Lethologica
4. Misattribution: How Memories are Distorted and Invented
5. Suggestibility: How Memory Is Biased By Suggestions
   • False Memory: Dramatic Examples Of Fake Memories
6. Commitment and Consistency Bias: How It Warps Memory
7. Long-Term Memory: When Persistence Is A Curse

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The different types of long-term memory, examples, its purpose and the benefits and even dangers of its persistence over the years.

Long-term memory in psychology refers to the storing of information in memory over long periods, typically weeks, months or years.

In fact, anything we hold in our minds for more than about 30 seconds is considered long-term memory.

Long-term memory is usually contrasted with short-term memory.

Short-term memory, for psychologists, means the things that are in your mind right now, and only those things.

On the other hand, long-term memory is anything you store to be retrieved at a later time.

Types of long-term memory

Long-term memory is often divided into two types:

• Implicit memories: includes those that are mostly unconscious, such as how to drive a car or operate a computer.
• Explicit or declarative memories: those that are available to consciousness, such as events and knowledge about the world.

Examples of long-term memory

Simple examples of long-term memory include:

• Remembering an important day, such as a birthday or holiday.
• Knowing how to ride a bicycle.
• Remembering the words to a song.
• Knowing how to type.
• And so on…

The list is potentially endless because long-term memories encompass everything stored in our mind for later retrieval and even things we cannot retrieve but are stored there anyway.

Purpose of long-term memory

It is easy to see the positive, adaptive nature of memory’s persistence.

Our very survival relies on the fact that we remember when bad consequences follow from particular situations.

Living in a comfortable modern society may mean a person has relatively few real life-threatening dangers to face on a regular basis.

But when people are exposed to more precarious environments, making the same mistake twice can be disastrous.

Persistence of long-term memory

The fact that long-term memories persist, though, puts it on the list of Daniel L. Schacter’s seven sins of memory.

Persistence is the most polarised in its effect on us (Schacter, 1999).

While the persistence of memory can be vital to our survival, at the same time it can leave us haunted by past events we might rather forget.

As in surrealist Salvador Dali’s most famous painting, ‘The Persistence of Memory‘, memories can weigh heavily on our minds; thoughts, like ants, scurrying: endlessly searching for who knows what.

Long-term memory and PTSD

For those suffering from post-traumatic stress disorder (PTSD), images and long-term memory of a traumatic event become an intrusive and sometimes unbearable part of everyday experience.

The trauma continues to resurface, again and again, from long-term memory despite attempts at thought management or repression.

Of course being able to repress long-term memory would provide some relief for sufferers, but is it possible?

Repressing long-term memory

Professor Richard McNally and colleagues from Harvard University wanted to find out whether long-term memory could be effectively repressed by trauma sufferers using a ‘directed forgetting’ procedure: essentially just telling people to forget (McNally et al., 1998).

They studied a group of 14 women who had been sexually abused as children and compared them with a control group.

Participants in both groups were directly asked either to remember a particular word or to forget it.

Some of the words they were asked to remember or forget were related to traumatic memories (e.g. ‘abuse’).

What Professor McNally and colleagues found was that control participants were more likely to forget trauma words they were told to forget, while remembering trauma words they were told to remember.

It seemed control participants could successfully suppress their memories.

The same could not be said of participants who had suffered traumatic experiences.

These participants were unable to consciously forget words that were trauma-related.

This suggests that people who have experienced a trauma lose conscious cognitive control over aspects of their long-term memory.

It seems that the persistence of long-term memory is too strong for us to consciously control: suppression is not an option.

Depression and long-term memory

The intrusive persistence of disturbing past episodes recurring from long-term memory may also be particularly important in depression.

In fact this persistence can produce a dangerous cycle which may be key to the maintenance of depressive disorders.

Ruminating over past events from long-term memory can lead to depression, while depression can then lead straight back in to rumination.

It is a vicious circle.

There’s evidence for this depressive cycle from studies which show two different aspects of memory’s persistence.

1. Depression leads to rumination

Studies have examined the unconscious ways depressed people process their memories.

Watkins et al. (1996), for example, compared depressed participants to a control group in how they responded to positive and negative words.

The results showed that while the control group tended to be biased towards remembering more positive words, the depressed participants pulled out more negative words from long-term memory.

This suggests that depressed people are more likely to recall negative events  from long-term memory — the first part of the depressive cycle.

2. Rumination leads to depression

To test whether rumination can feed back into depression, Lyubomirsky, Caldwell and Nolen-Hoeksema (1998) put one group of students in a ruminative mood using a simple self-focussing task.

They wanted to see how these moods affected the type of long-term memory they then recalled:

• The first group were put into a ruminative mood with an exercise which focussed attention internally. They were, for example, asked to recall and think about one of their dreams.
• The second group turned their attention outwards by, for example, thinking about the shape of clouds in the sky. This was designed as a filler task to help block self-focussed thoughts.

Participants were then asked to recall at least eight incidents from long-term memory — anything they liked.

The results showed that those participants who had been put in a ruminative mood tended to recall more negative memories from long-term memory than those who’d been engaged in the filler task.

This experiment is evidence for the second part of the depressive cycle: that ruminative thinking leads to the recall of more negative memories from long-term memory.

This in turn is likely to lead to depression.

Taken together these two studies, and others like them, suggest the persistence of long-term memory can play an important role in the maintenance of depression.

Both depression and traumatic stress disorders may partly be the regrettable downsides of memory systems that are designed to keep us alive.

→ This post is part of a series on the seven sins of memory:

1. Short-Term Memory vs. Long-Term Memory: Definition And Examples
2. Absent-Mindedness: 2 Factors That Cause Forgetfulness
3. Tip-of-the-Tongue Phenomenon Or Lethologica
4. Misattribution: How Memories are Distorted and Invented
5. Suggestibility: How Memory Is Biased By Suggestions
   • False Memory: Dramatic Examples Of Fake Memories
6. Commitment and Consistency Bias: How It Warps Memory
7. Long-Term Memory: When Persistence Is A Curse

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Memory loss risk reduced by this common drink.

Coffee could reduce the risk of memory loss by up to 70 percent, research suggests.

The study found that drinking three or more cups per day was associated with better memory than just one cup per day.

In women over 80, the reduction in risk was 70 percent for those drinking three or more cups.

In those over 65, the risk reduced by 30 percent for the same amount of coffee.

While this study focused on women, others have shown a neuroprotective effect in men as well.

The study suggests that drinking coffee may help to delay dementia, although it cannot prevent it.

For the French study, 7,017 people were tracked for four years.

Their coffee intake was measured and they were given memory tests.

The results showed that women had better memories when drinking three or more cups of coffee per day, especially at higher ages.

Although the same effect was not found for men, more recent studies have detected the same neuroprotective effect for men.

Dr Karen Ritchie, the study’s first author, said:

“Women may be more sensitive to the effects of caffeine.

Their bodies may react differently to the stimulant, or they may metabolize caffeine differently.”

Although caffeine slowed the rate of memory decline, it did not reduce the chance of developing dementia.

Dr Ritchie said:

“While we have some ideas as to how this works biologically, we need to have a better understanding of how caffeine affects the brain before we can start promoting caffeine intake as a way to reduce cognitive decline.

But the results are interesting — caffeine use is already widespread and it has fewer side effects than other treatments for cognitive decline, and it requires a relatively small amount for a beneficial effect.”

The study was published in the journal Neurology (Ritchie et al., 2007).