How Does The Brain Store Memories And Information?

Neuroscientists reveal how the brain stores memories and information and which part of the brain stores memories.

Neuroscientists reveal how the brain stores memories and information and which part of the brain stores memories.

Imagine you had a tiny device inside your brain that could ‘see’ the moment a new memory was formed.

What would it record?

Since the brain is made up of neurons linked together in a vast network, it seems reasonable to suppose that some part of that network would activate when you, say, saw your first child being born.

But how big a network?

Is that memory contained in a handful of neurons or is it distributed widely across the network?

Fascinating clues come from a study of nine patients who had had electrodes implanted in their brains to help monitor their seizures (Wixted et al., 2014).

These electrodes can monitor the activity of single neurons in the brain.

With their permission, neuroscientists took advantage of this window into the electrical activity of the brain to examine how memories are laid down and recalled.

How does the brain store memories?

For the test, participants simply learned a series of words, then were presented with another list which contained some words they’d learned along with some new ones.

They were asked to say which ones they’d seen before.

The results amazed the study’s first author John T. Wixted:

“Intuitively, one might expect to find that any neuron that responds to one item from the list would also respond to the other items from the list, but our results did not look anything like that.

The amazing thing about these counterintuitive findings is that they could not be more in line with what influential neurocomputational theorists long ago predicted must be true.”

Part of the brain where memories are stored

As expected, the memory was encoded in the hippocampus, an area of the brain that is vital for memory.

What they saw was that the memory for a single word was encoded across hundreds of thousands of neurons in a distributed network.

While this may sound like a lot, it’s actually only a small fraction: the number of neurons firing in response to a single word was about 2 percent of those in the hippocampus.

So, if you could look inside your own brain when a new memory is formed, what you’d see is that a relatively small network of neurons in the hippocampus jumps into action.

When you recall a memory, that same network leaps into action again.

The study’s authors explain:

“[This is]…a sparse distributed coding scheme in which each memory is coded by the activity of a small proportion of hippocampal neurons, and each neuron contributes to the representation of only a few memories.” (Wixted et al., 2014).

The most efficient way to store memories

Some have theorised that this is the most efficient way for the brain to work because:

  • If memories were localised to individual neurons then they could easily be lost if those particular neurons died.
  • If memories were too widely spread across the network, memories would be too easily overwritten or confused.

One of the study’s authors, Dr. Peter N. Steinmetz commented:

“To really understand how the brain represents memory, we must understand how memory is represented by the fundamental computational units of the brain — single neurons — and their networks.

“Knowing the mechanism of memory storage and retrieval is a critical step in understanding how to better treat the dementing illnesses affecting our growing elderly population.”

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How Does Stress Affect Memory?

Stress affects memory negatively through the action of cortisol, the stress hormone.

Stress affects memory negatively through the action of cortisol, the stress hormone.

A link between the stress hormone cortisol and short-term memory problems has been found by research.

Although cortisol is a natural hormone that spikes when we are stressed to help us deal with challenging situations, over time its long-term effects may be detrimental to short-term memory.

This is the first study to link long-term exposure to cortisol with short-term memory problems.

The study, conducted by researchers at the University of Iowa and published in the Journal of Neuroscience, found that high levels of cortisol were associated with a loss of synapses in the prefrontal cortex, a structure that’s important for short-term memory (Anderson et al., 2014).

Study of how stress affects memory

The findings are based on a study of rats which were 21 months old — this meant their brains were roughly equivalent to that of a 65-year-old human.

In the study, rats’ corticosterone levels were measured.

They were then given a T-shaped maze to run through which required them to remember which direction the treats were.

Some of the rats forgot which direction to turn after a short delay — just as human short-term memory decays over a few minutes — but those with higher levels of corticosterone were more likely to forget.

Rats with low levels of corticosterone got the direction right 80% of the time, while those with high levels of corticosterone only got it right 58 percent of the time.

When their brains were examined, it turned out that the stressed and forgetful rats had 20 percent fewer synapses in their prefrontal cortex, suggesting this was the cause of the short-term memory loss.

When the older rats were compared with younger ones, the older ones with low levels of the stress hormone performed just as well as the younger ones.

The same could not be said of those with higher levels of the stress hormone.

This study may help to explain why some people’s memory declines so dramatically with age, while others remains relatively unaffected.

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Painless Laser Therapy Improves Memory By 25% In Minutes (M)

The laser treatment that improves memory is known as transcranial photobiomodulation (tPBM).

The laser treatment that improves memory is known as transcranial photobiomodulation (tPBM).


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How To Jog Your Memory: A Well-Known Trick That Works

Eyewitness to a crime remembered twice as many details using this technique that can jog your memory.

Eyewitness to a crime remembered twice as many details using this technique that can jog your memory.

Closing your eyes really can help jog the memory, a study finds.

The results should be useful for helping eyewitnesses to crimes remember more details when questioned by police.

The study, published in the journal Legal and Criminological Psychology, had participants watching an electrician entering a property, doing some work and stealing various items (Nash et al., 2015).

Afterwards, some were asked questions with their eyes open and others with their eyes closed.

The psychologists were also interested to see if building rapport before asking the questions made any difference.

Memory jogged

The results revealed that closing the eyes gave the biggest boost to recall, but establishing some rapport before questioning was also beneficial.

People who had their eyes open and did not have some rapport with questioner only got 41 percent of the questions right.

People with their eyes closed and who had some rapport got 75 percent of the questions right.

Dr Robert Nash, who led the study, said:

“It is clear from our research that closing the eyes and building rapport help with witness recall.

Although closing your eyes to remember seems to work whether or not rapport has been built beforehand, our results show that building rapport makes witnesses more at ease with closing their eyes.

That in itself is vital if we are to encourage witnesses to use this helpful technique during interviews.”

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This Drink Reduces Memory Loss Risk By 47%

The common drink that may protect the brain against memory loss.

The common drink that may protect the brain against memory loss.

Drinking orange juice regularly is linked to a 47 percent lower risk of memory problems with age, research suggests.

Berry fruits, orange and red vegetables and leafy greens may also help protect against memory loss.

The results come from a study that followed 27,842 men for 20 years.

Every four years they were asked about the foods they ate and were given tests of their memory and thinking skills.

They were also asked questions including:

  • “Do you have more trouble than usual remembering a short list of items, such as a shopping list?”
  • “Do you have more trouble than usual following a group conversation or a plot in a TV program due to your memory?”

Those that had six servings of fruit and vegetables a day were 34% less likely to experience poor thinking skills later on.

Eating more fruit and vegetables in midlife was linked to better cognitive health later on — even if the men stopped eating fruit and vegetables.

Dr Changzheng Yuan, study co-author, said:

“One of the most important factors in this study is that we were able to research and track such a large group of men over a 20-year period of time, allowing for very telling results.

Our studies provide further evidence dietary choices can be important to maintain your brain health.”

The study only showed an association, it does not prove causation.

The study was published in the journal Neurology (Yuan et al., 2018).

How To Improve Memory: Concentration, Power, Function

Improve your memory, concentration, power and retention by using these 14 science-backed techniques to increase cognitive function.

Improve your memory, concentration, power and retention by using these 14 science-backed techniques to increase cognitive function.

Many of the usual methods for how to improve memory are well-known, such as using imagery, chunking and the forbidding sounding ‘brain training’.

The problem with most of these methods is they involve a fair amount of mental effort.

So, here are 14 mostly easy ways to improve memory that are backed up by psychological research, many requiring relatively little effort.

Few of these methods for how to improve memory require you to train hard, spend any money or take illegal drugs.

All free, all pretty easy, all natural!

1. A good mood improves memory

Something as simple as getting a bag of candy is enough to improve memory and concentration, research finds.

In fact, anything that quickly puts you in a good mood can improve memory and decision-making.

Professor Ellen Peters, who co-authored the study, said:

“There has been lots of research showing that younger adults are more creative and cognitively flexible when they are in a good mood.

But because of the cognitive declines that come with aging, we weren’t sure that a good mood would be able to help older adults.

So these results are good news.”

2. 40 seconds rehearsal boosts memory

Rehearsing a memory for just 40 seconds could be the key to permanent recall, a study finds.

When rehearsing a memory, the same area of the brain is activated as when laying it down, psychologists found.

Dr Chris Bird, who led the research, said:

“We know that recent memories are susceptible to being lost until a period of consolidation has elapsed.

In this study we have shown that a brief period of rehearsal has a huge effect on our ability to remember complex, lifelike events over periods of 1-2 weeks.

3. Associations improve memory

‘Reminders by association’ are a great tool to help improve memory for something in the future, research demonstrates.

Here are a few examples of ‘reminders by association’:

  • A picture of your family by your desk reminds you to call them and tell them you will be late home.
  • A piece of litter on the floor reminds you to put the bins out.

Little environmental cues like this were enough to double the number of people who remembered to perform some future action.

4. The aroma of rosemary improves memory

The aroma of rosemary essential oil can improve memory, concentration and the ability to remember future events, research finds.

For the study 66 people took various memory tests either in a room that was scented with rosemary or without.

Those breathing the scent of rosemary performed better.

5. How to improve memory: write about your problems

To do complex tasks we rely on our ‘working memory’.

This is our ability to shuttle information in and out of consciousness and manipulate it.

A more efficient working memory contributes to better learning, planning, reasoning and concentration.

One way to improve working memory capacity indirectly is through expressive writing.

You sit down for 20 minutes a few times a month and write about something traumatic that has happened to you.

Yogo and Fujihara (2008) found that it improved working memory after 5 weeks.

Psychologists aren’t exactly sure why this works, but it does have a measurable effect.

6. Vegetables linked to better memory

Eating vegetables — but not fruit — helps improve memory, research finds.

The study of 3,718 people over 65 living in Chicago asked how often people ate particular foods and administered cognitive tests.

Professor Martha Clare Morris, who led the study, explained the results:

“Compared to people who consumed less than one serving of vegetables a day, people who ate at least 2.8 servings of vegetables a day saw their rate of cognitive change slow by roughly 40 percent.

This decrease is equivalent to about 5 years of younger age.”

Green leafy vegetables showed the strongest association with an improved memory — they are also likely to help concentration.

Older people in the study got the greatest benefit from eating more vegetables.

7. Natural scenes improve memory

Nature has a magical effect on us.

It’s something we’ve always known, but psychologists are only just getting around to measuring it.

One of nature’s beneficial effects an easy way for how to improve memory and concentration.

In one study people who walked around an arboretum did 20 percent better on a memory test than those who went for a walk around busy streets.

In fact you don’t even need to leave the house.

Although the effects aren’t as powerful, you can just look at pictures of nature and that also has a beneficial effect (I describe this study in detail here).

8. Say words aloud to improve memory

This is surely the easiest of all method for how to improve memory: if you want to remember something in particular from a load of other things, just say it out loud.

A study (described here) found memory improvements of 10 percent for words said out loud, or even just mouthed: a relatively small gain, but at a tiny cost.

9. Drink hot chocolate

Two cups of hot chocolate a day could help keep the brain healthy, a study finds.

The research involved 60 people whose average age was 73.

They were given tests of memory, concentration, thinking skills and the blood flow in their brains was measured.

People who had impaired blood flow in the brain improved after drinking the flavanol-rich cocoa.

10. Meditation improves memory and concentration

Meditation has been consistently found to improve cognitive functioning, including memory.

But meditation takes time doesn’t it?

Long, hard hours of practice?

Well, maybe not.

In one recent study, participants who meditated for 4 sessions of only 20 minutes, once a day, were able to improve memory, concentration and brain function (the study is described here, also see my beginner’s guide to mindfulness meditation).

11. Exercise improves memory

Long-term memory is improved by exercise four hours after learning, a study finds.

Exercising directly after learning, though, does not improve memory at all.

In addition, brain scans revealed that exercise lead to more precise representations of memories in the hippocampus.

The scientists are not sure yet why exercise after learning improves memory.

However, they write:

“Considering that the exercise intervention took place after learning, delayed exercise most likely affected memory retention through an impact on memory consolidation.”

12. Predict your memory performance

Simply asking ourselves whether or not we’ll remember something is an unusual method for how to improve memory.

This works for both recalling things that have happened in the past and trying to remember to do things in the future.

When Meier et al., (2011) tested people’s prospective memory (remembering to do something in the future), they found that trying to predict performance improves memory.

On some tasks people’s performance increased by almost 50 percent.

13. Use your body to improve memory encoding

We don’t just think with our minds, we also use our bodies.

For example, research has shown that we understand language better if it’s accompanied by gestures.

We can also use gestures to encode memories.

Researchers trying to teach Japanese verbs to English speakers found that gesturing while learning helped improve memory (Kelly et al., 2009).

Participants who used hand gestures which suggested the word were able to recall almost twice as many Japanese words a week later.

14. Use your body to improve memory recall

Since our bodies are important in encoding a memory, they can also help improve memory recall.

Psychologists have found that we recall past episodes better when we are in the same mood or our body is in the same position (Dijkstra et al., 2007).

This works to a remarkably abstract degree.

In one study by Cassasanto and Dijkstra (2010), participants were better able to retrieve positive memories when they moved marbles upwards and negative memories when they moved marbles downwards.

This seems to be because we associate up with happy and down with sad.

Exercise and memory training

If all these methods seem a bit lazy, then you can always put in a bit more effort.

Probably the best way of improving your overall cognitive health is exercise.

Studies regularly find that increasing aerobic fitness is particularly good for executive function and working memory (check out this previous article on which cognitive enhancers work).

Conversely, stay in bed all the time and your working memory gets worse (Lipnicki et al., 2009).

Take your memory training to the limit and an incredible study by Ericsson et al. (1980) shows what can be achieved.

Our typical short-term memory span is about 7 things.

In other words we can hold around seven things in mind at the same time.

These researchers, though, increased one person’s memory span to 79 digits after 230 hours of practice, mostly using mnemonic systems.

Shows what you can do if you put in the hours.

That said, I’ll be sticking to a nice walk around the park.

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The Foods That Protect And Improve Your Memory

Higher consumption of these foods was linked to improved memory by the study.

Higher consumption of these foods was linked to improved memory by the study.

Eating more fruits and vegetables protects against memory loss, research finds.

Fruits and vegetables also help reduce the risk of heart disease.

Higher consumption of protein-rich foods was also linked to improved memory by the study.

A previous study, though, found that it is vegetables, more so than fruits, that really help to preserve memory.

Green leafy vegetables showed the strongest association with a better memory in that study.

More than two servings of vegetables per day was linked to the slowest rates of cognitive decline in older people.

Vegetables contain high amounts of vitamin E, which lowers the risk of cognitive decline.

Green leafy vegetables are also a key component of the MIND diet, which is frequently linked to memory improvements and reducing the risk of dementia.

Two other foods in the Mediterranean diet that have been individually linked to improved memory are nuts and mushrooms.

The Western diet

Set against these beneficial foods, one of the main enemies of healthy brain aging is sugar.

Eating too much sugar is linked to brain shrinkage.

Similarly, red meats, organ meats, butter and high-fat dairy can increase Alzheimer’s risk.

Unfortunately, these last two sentences pretty much define the so-called ‘Western diet’.

In other words, what many eat in the modern Western world is bad for the memory and bad for the brain overall.

Brain benefits of cereals

The latest study included 139,096 older Australians who were tracked over almost a decade.

Along with the finding that fruits, vegetables and protein improved memory, the researchers also found that cereals may be protective for those over 80.

Dr Luna Xu, the study’s first author, said:

“Our present study implies that the healthy eating suggestions of cereals consumption in the prevention of memory loss and comorbid heart disease for older people may differ compared to other age groups.”

Memory loss is one of the most common early symptoms of dementia.

People suffering from dementia often have other conditions, said Dr Xu:

“The dietary intervention in chronic disease prevention and management, by taking into consideration the fact that older populations often simultaneously deal with multiple chronic conditions, is a real challenge.”

Diet is key to fighting these conditions, said Dr Xu:

“To achieve the best outcome for our ageing population, strong scientific evidence that supports effective dietary intervention in preventing and managing co-occurring chronic conditions, is essential.”

The study was published in the International Journal of Public Health (Xu et al., 2020).

Misinformation Effect In Psychology: Real Life Examples

The misinformation effect in psychology refers to memories being changed after the event — as demonstrated by Loftus and Palmer (1974).

The misinformation effect in psychology refers to memories being changed after the event — as demonstrated by Loftus and Palmer (1974).

The misinformation effect in psychology is the tendency for people’s recall to get less accurate when they are given more information afterwards.

in other words, someone’s memories can be altered after the event by things that other people say or do.

This is particularly important in areas like eyewitness testimony, which could determine criminal guilt.

Imagine a witness is asked misleading questions which cause their memories of the event to be warped — someone’s life could hang in the balance.

The misinformation effect occurs because of two of the sins of memory: misattribution and suggestibility.

Real life example of a personal memory

The misinformation effect is also important in more mundane circumstances, such as people’s personal histories.

For example, I have a memory from when I was three years old of playing in a sandpit.

I don’t remember much else about it other than this sandpit was outside the building in which I lived.

For years I used to think this was my earliest memory, now I’m not so sure and here’s why.

Misinformation effect example

The work of Elizabeth Loftus, a renowned expert on human memory, has been extremely influential in this area as one of her early studies demonstrates.

Like some of the best experiments, although Loftus and Palmer’s (1974) study on the misinformation effect was quite simple, its implications were profound.

In the first of two experiments, 45 participants watched a film of a car accident.

Nine of these were then asked this specific question: “About how fast were the cars going when they hit each other?”.

The other four groups of nine were asked an almost identical question but with one important difference.

Instead of the word hit, the words ‘smashed’, ‘collided’, ‘bumped’, and ‘contacted’ were used.

The wording of question changed the answer

The participants who were asked the question using the word ‘smashed’ as opposed to ‘contacted’, estimated the cars were travelling, on average, almost 10mph faster.

The other words were fanned out in between.

So, what is this telling us?

Probably, that because people are not good at gauging the speed of a car, the cue comes from the experimenter.

If the experimenter asks the question using the word ‘smashed’, the participant assumes it was going faster than if they say ‘contacted’.

The misinformation effect after one week

It’s in the follow-up study that things get interesting.

The same experiment was repeated roughly as before, but with 150 participants.

This time, however, participants filled out a questionnaire about the crash and were then asked to return in a week.

As before, the question about the speed of the crash was varied between groups.

Some read ‘hit’, some ‘smashed’ and so on.

One week later participants returned and were asked to fill out a questionnaire about the accident in which was hidden a crucial question: “Did you see any broken glass?”.

As broken glass is indicative of a more serious accident, so greater speed, Loftus and Palmer expected the group in which the word ‘smashed’ had been used would be more likely to indicate there was broken glass.

This was exactly what they found.

What causes the misinformation effect

There are a number of different theories as to why the misinformation effect occurs.

  • Misleading information may simply overwrite the original memory.
  • The misleading information may be blended with the original memory to create a hybrid.
  • The misinformation may simply be used to fill in the gap if there is no memory of the occurrence.
  • The misinformation effect may be partly a recency effect: in other words because the information was inserted into memory more recently, it is easier to recall.

Factors influencing the misinformation effect

Several factors can influence the misinformation effect, which include:

  • Personality: introverts may be particularly susceptible to the misinformation effect.
  • Age: young children are also particularly susceptible to the misinformation effect.
  • News reports: when people read news reports they naturally incorporate these into their memories of events they may or may not have witnessed.
  • Discussing events with other witnesses: as people who have witnessed an even discuss it with each other, their memories can become distorted in this way.
  • Time: when the misinformation is provided recently it tends to supersede older memories.
  • Repeated exposure: The more times people are exposed to a piece of misinformation, the greater the misinformation effect.

Memories are malleable

Reporting their experiment Loftus and Palmer adopt a cautious tone as befits a journal article.

For them it is a replication of a fact already known.

That the phrasing of a question about an event can affect our memory for that event.

For me, although the experiment is deceptively simple, it goes to the heart of how memories are constructed.

It makes me wonder if that childhood sandpit in my mind’s eye is really something I can remember.

What about your childhood memories?

What about your memory for last week?

To what extent are things you remember happening a week ago affected by intervening events and people?

The beauty of Loftus and Palmer’s experiment is it shows how important other people can be in shaping our own memories.

Whether or not my memory is real or a construction isn’t so important in the context of that sandpit, but what if I’m an eyewitness to a serious crime, called to testify in court?

What if an adult ‘recovers’ a memory of being abused by their parents as a child?

The answers to these questions have vital impacts on the lives of all those involved.

Loftus’ later work has taken in both of these highly controversial questions, and more.

Still, my thoughts often return to this original study in more mundane, personal terms.

Do I really remember that sandpit?

I can see myself sitting there, playing, looking up past the building, into the sky.

If that memory is false, can I ever really remember anything true at all?

How to avoid the misinformation effect

A number of strategies have been suggested to fight the misinformation effect:

  • Use questions: the misinformation effect can be combatted by asking questions and avoiding declarative statements.
  • Corrections and warnings: the misinformation effect can be fought be reminders that misinformation may be included in information being presented.
  • Self-awareness: being self-aware and having more confidence in one’s memory can combat the misinformation effect.

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This Vitamin Provides Triple Protection Against Memory Loss

The memories of people with low levels of this vitamin decline three times faster.

The memories of people with low levels of this vitamin decline three times faster.

Low levels of vitamin D among older people are linked to memory loss, a study finds.

Those with low levels of vitamin D decline three times faster than those with adequate levels.

Professor Joshua Miller, one of the study’s authors, said:

“Independent of race or ethnicity, baseline cognitive abilities and a host of other risk factors, vitamin D insufficiency was associated with significantly faster declines in both episodic memory and executive function performance.

This work, and that of others, suggests that there is enough evidence to recommend that people in their 60s and older discuss taking a daily vitamin D supplement with their physicians.

Even if doing so proves to not be effective, there’s still very low health risk to doing it.”

The study included almost 400 older people and around 60% had low levels of vitamin D.

In fact, around one-quarter were found to be deficient (very low) and 35% insufficient (just low) in vitamin D.

African-Americans and Hispanics were more likely than white people to be low in vitamin D.

These are high-risk groups because those with darker skins cannot absorb as much from the sun.

The results showed that the cognitive abilities of people deficient in vitamin D declined two to three times faster than those with adequate levels.

Professor Charles DeCarli, the study’s first author and director of the Alzheimer’s Disease Center at the UC Davis, said:

“We expected to see declines in individuals with low vitamin D status.

What was unexpected was how profoundly and rapidly [low vitamin D] impacts cognition.”

The other major source of vitamin D is the diet — particularly consumption of dairy products.

Professor DeCarli said:

“I don’t know if replacement therapy would affect these cognitive trajectories.

That needs to be researched and we are planning on doing that.

This is a vitamin deficiency that could easily be treated and that has other health consequences.

We need to start talking about it.

And we need to start talking about it, particularly for people of color, for whom vitamin D deficiency appears to present an even greater risk.”

The study was published in the journal JAMA Neurology (DeCarli et al., 2015).

Suggestibility Of Memory In Psychology: Definition & Examples

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

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
  6. Commitment and Consistency Bias: How It Warps Memory
  7. Long-Term Memory: When Persistence Is A Curse

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