Category: Cognitive Psychology

The magic number 7 plus or minus 2 in psychology refers to the fact that we can fit about seven pieces of information into our short-term memories.

It is sometimes said human beings are nothing more than a collection of memories.

Memories for people, events, places, sounds and sights.

Our whole world is funnelled in through our memories. In fact, they may be our most prized possessions.

The study of memory has always been central to psychology – this article describes one of its most influential findings.

The title of this article comes from a 1956 study by the psychologist George A. Miller in which he describes the capacity of human memory (Miller, 1956).

The article’s opening has become famous amongst historians of psychology:

“My problem is that I have been persecuted by an integer.

For seven years this number has followed me around, has intruded in my most private data, and has assaulted me from the pages of our most public journals.

This number assumes a variety of disguises, being sometimes a little larger and sometimes a little smaller than usual, but never changing so much as to be unrecognizable.”

The magical number seven (plus or minus 2)

It’s not just Miller who was persecuted by this number though, it’s all of us.

What this magical number represents – 7 plus or minus 2 – is the number of items we can hold in our short-term memory.

So, while most people can generally hold around seven numbers in mind for a short period, almost everyone finds it difficult to hold ten digits in mind.

Remember that memory is a slippery concept: short-term memory for psychologists refers to things that are currently being used by our brains right now.

For example, as you’re reading this post the words you’ve read go into short-term memory for a very short period, you extract some meaning (hopefully) and then the meaning is either stored or discarded.

You’ll probably still have some faint memory of this article tomorrow, but won’t be able to remember most of the actual words.

Disputing the magical number seven

All sorts of experiments and theories have followed disputing the magical number seven approach to memory.

More recent studies have, for example, shown how we put items together in order to ‘chunk’ data.

Still, the basic concept that our immediate short-term memory is relatively limited is still valid.

If you think seven isn’t much then be thankful you’re not a six-month-old infant.

Recent research suggests they can only hold one thing in short-term memory (Kaldy & Leslie, 2005).

Poor little chaps — it explains a lot though.

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The illusion of truth effect in psychology is the tendency to believe false information if it is repeated often enough.

The illusion of truth effect, is very simple: people are more likely to believe something, the more often it is repeated to them.

With repetition, it is easier for the human mind to process a statement relative to other competing ideas that have not been repeated over-and-over again.

Repetition is used everywhere to persuade people, in advertising, politics and the media, and it certainly works.

Examples of the illusion of truth effect

We see ads for the same products over and over again.

Politicians repeat the same messages endlessly (even when it has nothing to do with the question they’ve been asked).

Journalists repeat the same opinions day after day.

Can all this repetition really be persuasive?

It seems too simplistic that just repeating a persuasive message should increase its effect, but that’s exactly what psychological research finds (again and again).

Repetition is one of the easiest and most widespread methods of persuasion because of the illusion of truth effect.

In fact it’s so obvious that we sometimes forget how powerful it is.

People rate statements that have been repeated just once as more valid or true than things they’ve heard for the first time.

They even rate statements as truer when the person saying them has been repeatedly lying (Begg et al., 1992).

That is how powerful the illusion of truth effect is.

And when we think something is more true, we also tend to be more persuaded by it.

Several studies on the illusion of truth have shown that people are more swayed when they hear statements of opinion and persuasive messages more than once.

How the illusion of truth effect works

The illusion of truth effect works at least partly because familiarity breeds liking.

As we are exposed to a message again and again, it becomes more familiar.

Because of the way our minds work, what is familiar is also true — hence the illusion of truth.

Familiar things require less effort to process and that feeling of ease unconsciously signals truth, this is called cognitive fluency.

As every politician knows, there’s not much difference between actual truth and the illusion of truth.

Since illusions are often easier to produce, why bother with the truth?

Reversing the illusion of truth

The exact opposite of the illusion of truth is also true.

If something is hard to think about, then people tend to believe it less.

Naturally this is very bad news for people trying to persuade others of complicated ideas in what is a very complicated world.

Some studies have even tested how many times a message should be repeated for the maximum effect of the illusion of truth.

These suggest that people have the maximum confidence in an idea after it has been repeated between 3 and 5 times (Brinol et al., 2008).

After that, repetition ceases to have the same effect and may even reverse.

Because TV adverts are repeated many more times than this, advertisers now use subtle variations in the ads to recapture our attention and avoid the illusion of truth backfiring.

This is an attempt to avoid the fact that while familiarity can breed liking, over-familiarity tends to breed contempt.

When the illusion of truth fails

Repetition is effective almost across the board when people are paying little attention, but when they are concentrating and the argument is weak, the effect disappears (Moons et al., 2008).

In other words, it’s no good repeating a weak argument to people who are listening carefully — then the illusion of truth does not operate.

But if people aren’t motivated to scrutinise your arguments carefully then repeat away with abandon—the audience will find the argument more familiar and, therefore, more persuasive.

This suggests we should remain critical while watching TV adverts or the illusion of truth effect will creep in under our defences.

You might think it’s better to let the ads wash over you, without thinking too much, but just the reverse is true.

Really we should be highly critical of the illusion of truth otherwise, before we know it, we’re singing the jingle, quoting the tag-line and buying the product.

When the argument is strong, though, it doesn’t matter whether or not the audience is concentrating hard, repetition will increase persuasion and the illusion of truth effect works.

Unfortunately, I find it’s often people with the best arguments who don’t take advantage of the illusion of truth.

Persuading groups

When people are debating an issue together in a meeting, you can see a parallel effect.

When one person in a group repeats their opinion a few times, the other people think that person’s opinion is more representative of the whole group (see my previous article: loudest voice = majority opinion).

The same psychology is at work again: to the human mind there is little difference between appearances and truth.

What appears to be true might as well actually be true, because we tend to process the illusion as though it were the truth.

It’s a depressing enough finding about the human ability to process rational arguments, but recent research has shown an even more worrying effect.

We can effectively persuade ourselves through repetition — which takes the illusion of truth to new heights.

A study has shown that when an idea is retrieved from memory, this has just as powerful a persuasive effect on us as if it had been repeated twice (Ozubko et al., 2010).

The aspiring sceptic, therefore, should be especially alert to thoughts that come quickly and easily to mind—we can easily persuade ourselves with a single recall of a half-remembered thought.

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The definition of the cocktail party effect in psychology  is when we tune into one voice from many conversations going on in a noisy room.

For psychologists the ‘cocktail party effect’ or phenomenon is our impressive and under-appreciated ability to tune our attention to just one voice from a multitude.

For example, at a party, when bored with our current conversational partner — and for the compulsive eavesdropper — we can allow our aural attention to wander around the room.

Perhaps only the most recidivist eavesdroppers are aware how special the cocktail party effect is.

But even they might be surprised — and worried — by just how much we can miss in the voices we decide to tune out.

What is the cocktail party effect?

The cocktail party effect or phenomenon — our ability to separate one conversation from another — is beautifully demonstrated in a classic study carried out by Colin Cherry (Cherry, 1953).

Cherry used the simple method of playing back two different messages at the same time to people, under a variety of conditions.

In doing so he discovered just how good we are at filtering what we hear, which is how we overcome the cocktail party problem.

To accomplish this task, Cherry reports, participants had to close their eyes and concentrate hard.

In the first set of experiments on the cocktail party effect he played back two different messages voiced by the same person through both ears of a pair of headphones and asked participants to ‘shadow’ one of the two messages they were hearing by speaking it out loud, and later by writing it down.

When doing this they could, with effort, and while hearing the clips over and over again, separate one of the messages from the other.

With the two voice presented together, as though the same person were standing in front of you saying two completely different things at the same time, this task appears to be very hard, but still possible.

Pushing participants further Cherry found he could confuse listeners, but only by having both messages consist entirely of nonsensical platitudes.

Only then were participants unable to pick apart one message from the other.

This is not a wholly satisfying demonstration of the cocktail party effect.

An example of how the cocktail party effect works

The real surprise, though, came in the second set of experiments on the cocktail party effect or phenomenon.

For these Cherry fed one message to the left ear and one to the right ear — and once again both messages were voiced by the same speaker.

Suddenly participants found the task incredibly easy.

Indeed many were surprised how easily and accurately they could tune in to either one of the messages, and even shift their attention back and forth between the two.

No longer did they have to close their eyes and furrow their brows – this was much easier.

What participants were experiencing here seems much closer to most people’s experience of the cocktail party phenomenon.

At a party people are arrayed all around us and their conversations come from various different directions.

We seem to be able to use this information, which is key to the cocktail party effect, to reject all but the one in which we are interested.

Ignoring rejected speech

Although we are fantastically good at tuning in to one conversation over all the others, we seem to absorb very little information from the conversations we reject.

This is the flipside of the cocktail party effect and where it can get embarrassing.

Cherry’s experiments on the cocktail party effect revealed that people picked up surprisingly little information presented to the other, ‘rejected ear’, often failing to notice blatant changes to the unattended message.

When asked afterwards, participants:

• could not identify a single phrase from the speech presented to the rejected ear.
• weren’t sure the language in the rejected ear was even English.
• failed to notice when it changed to German.
• mostly didn’t notice when the speech to the rejected ear was being played backwards (though some did report that it sounded a bit strange).

Across all the different conditions in these cocktail party effect studies, there were only two aspects of the speech to the rejected ear the participants could reliably identify.

The first was that it was speech compared to a tone, the second was when the speaker suddenly changed from male to female.

Missed your own name

This research on the cocktail party effect doesn’t bode at all well for people with a habit of tuning out of conversations when they  lose interest (you know who you are!).

If you really are listening to someone else it’s likely you won’t hear a word of what’s being said to you directly.

One study has found that two-thirds of people don’t even notice when their own name is slipped into the unattended speech, while those who do notice are likely to be of the extremely distractable variety (Conway et al., 2001).

That demonstrates the power of the cocktail party effect.

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The unconscious, or gut instinct, can do just as well as a conscious, deliberate decision in the business environment.

Instinctive, gut decisions may be just as good as those based on data, a study suggests.

Managers who rely on gut instinct to make decisions about new projects are just as likely to be right as those relying on the data, the research found.

However, relying on gut instinct is much faster, as data analysis typically takes a long time.

Think or blink?

Malcolm Gladwell wrote a well-known book called ‘Blink‘ about the power of the unconscious to make complex decisions in the blink of an eye.

However, since then studies have failed to back up the idea that the unconscious can outperform the conscious mind.

Still, there is evidence that the unconscious, or gut instinct, can do just as well as a conscious, deliberate decision.

And as this study underlines, sometimes gut decisions have other benefits, such as speed and requiring fewer resources.

The study comes at a time when 92 percent of companies are investing in data initiatives, which might prove unnecessary.

About the study

For the research, 122 managers in digital, advertising, publishing and software companies were asked about how they decided to allocate resources to new projects.

Among the ways they reported making decisions were:

1. Majority: making the choice that most people wanted.
2. Experience: going with the option that the most experienced individual preferred.
3. Tallying: choosing the option with the most positive points.

The results showed that managers often relied on a ‘tallying’ approach more than other methods.

More analysis did not provide much of a boost to accuracy in decision-making and took considerably longer, the results showed.

Using instinct and rules of thumb, like tallying positive points, was just as accurate as more data analysis.

Dr Oguz A. Acar, study co-author, said:

“This research shows that data-driven decision-making is not the panacea in all situations and may not result in increased accuracy when facing uncertainty.

Under extreme uncertainty, managers, particularly those with more experience, should trust the expertise and instincts that have propelled them to such a position.

The nous developed over years as a leader can be a more effective than an analytical tool which, in situations of extreme uncertainty, could act as a hindrance rather than a driver of success.”

The study was published in the journal Psychology & Marketing (West et al., 2021).

The definition of the confirmation bias in psychology is that people search for information that confirms their view of the world and ignore what doesn’t fit.

The confirmation bias is the fact that people search for information that confirms their view of the world and ignore what doesn’t fit.

In an uncertain world, people love to be right because it helps them make sense of things.

Indeed, some psychologists think it’s akin to a basic drive.

What is the confirmation bias?

One of the ways they strive to be correct is by looking for evidence that confirms they are correct, sometimes with depressing or comic results:

• A woman hires a worker that turns out to be incompetent. She doesn’t notice that everyone else is doing his work for him because she is so impressed that he shows up every day, right on time.
• A sports fan who believes his team is the best only seems to remember the matches they won and none of the embarrassing defeats to inferior opponents.
• A man who loves the country life, but has to move to the city for a new job, ignores the flight-path he lives under and noisy-neighbours-from-hell and tells you how much he enjoys the farmer’s market and tending his window box.

We do it automatically, usually without realising.

We do it partly because it’s easier to see where new pieces fit into the picture-puzzle we are working on, rather than imagining a new picture.

It also helps shore up our vision of ourselves as accurate, right-thinking, consistent people who know what’s what.

Psychologists call it the confirmation bias and it creeps into all sorts of areas of our lives.

Here are a few examples of the confirmation bias:

 1. Confirmation bias in self-image

“Hey, you look great, have you done something different with your hair?”

Who doesn’t like a compliment? No one. It doesn’t even have to be sincerely delivered, I’ll take it. But what about…

“Hey, you’re a real slime-ball, you know that?”

Who likes insults? Well, we don’t exactly like them but—believe it or not—sometimes we seek them out if they confirm our view of ourselves.

In a study that examined this, people actually sought out information confirming their own view that they were—not exactly slime-balls—but lazy, or slow-witted or not very athletic (Swann et al., 1989).

And this isn’t some kind of self-hating thing; in this study even people with high self-esteem sought out information that confirmed their own negative self-views.

It seems we like to be right, even at a cost to our self-image.

2. Finance example

A study of online stock market investors has looked at how they gathered information about a prospective stock (Park et al., 2010).

The researchers found the confirmation bias writ large.

Investors mostly looked for information that confirmed their hunch about a particular stock.

Those people who displayed the strongest confirmation bias were the most over-confident investors and consequently made the least money.

It seems we like to be right, even if it costs us money.

3. Politics example

People see what they want to see in politics all the time.

The most ironic example is in satire.

Often satire uses sarcasm to make its point: TV satirist Stephen Colbert frequently says the opposite of what he really thinks to make his point (amongst comedians I believe these are called ‘jokes’).

Except the irony is that one study has shown that people who don’t agree with Colbert don’t get that he’s being sarcastic, they think he really means it (LaMarre, 2009).

The beauty is that both liberals and conservatives get what they want: their viewpoints confirmed.

It seems we like to be right, even if it means not getting the joke.

4. Healthcare examples

Despite what many nurses believe, the full moon is NOT linked to busier hospital emergency rooms or more births (Margot, 2015).

The belief that there might be a link is likely down to the confirmation bias.

Despite the belief being remarkably common in hospitals, the study, published in the journal Nursing Research, found no evidence for it.

Similarly there’s NO evidence that the moon has any influence on:

• automobile accidents,
• hospital admissions,
• surgery outcomes,
• cancer survival rates,
• menstruation,
• births,
• birth complications,
• depression,
• violent behaviour,
• or even criminal activity.

Blame it on the confirmation bias

Over the years the confirmation bias has picked up the blame for all sorts of dodgy beliefs. Here are a few:

• People are prejudiced (partly) because they only notice facts which fit with their preconceived notions about other nations or ethnicities.
• People believe weird stuff about flying saucers, the JFK assassination, astrology, Egyptian pyramids and the moon landings because they only look for confirmation not dis-confirmation.
• In the early nineteenth century doctors treated any old disease with blood-letting. Their patients sometimes got better so doctors—who conveniently ignored all the people who died—figured it must be doing something. In fact for many ailments some people will always get better on their own without any treatment at all.

Fight the bias

The way to fight the confirmation bias is simple to state but hard to put into practice.

You have to try and think up and test out alternative hypothesis.

Sounds easy, but it’s not in our nature.

It’s no fun thinking about why we might be misguided or have been misinformed. It takes a bit of effort.

It’s distasteful reading a book which challenges our political beliefs, or considering criticisms of our favourite film or, even, accepting how different people choose to live their lives.

Trying to be just a little bit more open is part of the challenge that the confirmation bias sets us.

Can we entertain those doubts for just a little longer?

Can we even let the facts sway us and perform that most fantastical of feats: changing our minds?

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Time can feel so slow because our perception is warped by life-threatening situations, eye movements, tiredness, hypnosis, age, the emotions and more…

The mind does funny things to our time perception.

Just ask French cave expert Michel Siffre.

In 1962 Siffre went to live in a cave that was completely isolated from mechanical clocks and natural light.

He soon began to experience a huge change in his perception of time.

When he tried to measure out two minutes by counting up to 120 at one-second intervals, it took him 5 minutes.

After emerging from the cave he guessed the trip had lasted 34 days.

He’d actually been down there for 59 days.

His perception of time was rapidly changing.

From an outside perspective he was slowing down, but the psychological experience for Siffre was that time was speeding up.

But you don’t have to hide out in a cave for a couple of months to warp time, it happens to us all the time.

Our experience of time is flexible; it depends on attention, motivation, the emotions and more.

1. Life-threatening situations

People often report that time seems to slow down in life-threatening situations, like skydiving.

But are we really processing more information in these seconds when time seems to stretch?

Is it like slow-motion cameras in sports which can actually see more details of the high-speed action?

To test this, Stetson et al. (2007) had people staring at a special chronometer while free-falling 50 metres into a net.

What they found was that time resolution doesn’t increase: we’re not able to distinguish shorter periods of time when in danger.

What happens is we remember the time as longer because we record more of the experience.

Life-threatening experiences make us really pay attention but we don’t gain superhuman powers of time perception.

2. Time doesn’t fly when you’re having fun

We’ve all experienced the fact that time seems to fly when we’re having fun.

Or does it?

What about when you’re listening to a fantastic uplifting piece of music?

Does time seem to fly by, or conversely, does it seem to slow down?

When this was tested by Kellaris (1992), they found that when listeners enjoyed the music more, time seemed to slow down.

This may be because when we enjoy music we listen more carefully, getting lost in it.

Greater attention leads to perception of a longer interval of time.

The same thing happens when you have a really good, exciting day out.

At the end of the day it can feel like you ate breakfast a lifetime ago.

You enjoyed yourself enormously and yet time has stretched out.

The fact that we intuitively believe time flies when we’re having fun may have more to do with how time seems to slow when we’re not having fun.

Boredom draws our attention to the passage of time which gives us the feeling that it’s slowing down.

Or—prepare yourself for a 180 degree about-face—it could all be the other way around.

Perhaps you’re having fun when time flies. In other words, we assume we’ve been enjoying ourselves when we notice that time has passed quickly.

There’s evidence for this in an experiment by Sackett et al. (2010).

Participants doing a boring task were tricked into thinking it had lasted half as long as it really had.

They thought it was more enjoyable than those who had been doing exactly the same task but who hadn’t been tricked about how much time had passed.

Ultimately it may come down to how much you believe that time flies when you’re having fun.

Sackett and colleagues tested this idea as well and found it was true.

In their experiments, people who believed more strongly in the idea that time flies when you’re having fun were more likely to believe they were having fun when time flew.

So, the whole thing could partly be a self-fulfilling prophecy.

3. The stopped clock illusion

The stopped clock illusion is a weird effect that you may have experienced.

It happens when you look at an analogue watch and the second-hand seems to freeze for longer than a second before moving on.

I always thought this was because I just happened to look at it right at the start of the second, but this is actually an illusion.

What is happening is that when your eyes move from one point to another (a saccade), your perception of time stretches slightly (Yarrow et al., 2001).

Weirdly, it stretches backwards.

So, your brain tells you that you’ve been looking at the watch for slightly longer than you really have.

Hence the illusion that the second-hand is frozen for more than a second.

This happens every time our eyes move from one fixation point to the next, it’s just that we only notice it when looking at a watch.

One explanation is that our brains are filling in the gap while our eyes move from looking at one thing to the next.

4. Too tired to tell the time

When things happen very close together in time, our brains fuse them together into a single snapshot of the present.

For vision the shortest interval we can perceive is about 80 milliseconds.

If two things happen closer together than that then we experience them as simultaneous.

The shortest possible gap in time we can distinguish across modalities (say visual and auditory) is between 20 and 60 milliseconds (Fink et al., 2006).

That’s as little as a fiftieth of a second.

When we’re tired, though, our perception of time goes awry and we find it more difficult to distinguish between short spaces of time.

This fact can be used to measure whether people are too tired to fly a plane, drive a truck or be a doctor.

Indeed just such simple hand-held devices that quickly assess your tiredness are already being developed (Eagleman, 2009).

5. Self-regulation stretches time perception

The effort of trying to either suppress or enhance our emotional reactions seems to change our perception of time.

Psychologists have found that when people are trying to regulate their emotions, time seems to drag on.

Vohs and Schmeichel (2003) had participants watch an 11 minute clip from the film Terms of Endearment.

Some participants were asked to remain emotionally neutral while watching the clip and others were told to act naturally.

Those who tried to suppress their emotions estimated the clip had lasted longer than it really had.

6. Altered states of consciousness

People report all sorts of weird experiences with time when taking drugs like psilocybin, peyote or LSD.

Time can seem to speed up, slow down, go backwards, or even stop.

But you don’t need drugs to enter an altered state of consciousness, hypnosis will do the trick.

People generally seem to underestimate the time that they’ve been under hypnosis.

One study found this figure was around 40 percent (Bowers & Brenneman, 1979).

7. Does time perception change with age?

People often say the years pass more quickly as they get older.

While youthful summers seemed to stretch on into infinity, the summers of your later years zip by in the blink of an eye.

A common explanation for this is that everything is new when we are young so we pay more attention; consequently it feels like time perception expands.

With age, though, new experiences diminish and it tends to be more of the same, so time seems to pass more quickly.

Whether or not this is true, there is some psychological evidence that time passes quicker for older people.

One study has found that people in their 20s are pretty accurate at guessing an interval of 3 minutes, but people in their 60s systematically overestimate it, suggesting time is passing about 20 percent more quickly for them (Mangan & Bolinsky, 1997).

8. The emotional experience of time perception

The emotions we feel in the moment directly affect our perception of time.

Negative emotions in particular seem to bring time to people’s attention and so make it seem longer.

Research on anxious cancer patients, those with depression and boredom-prone individuals suggests time perception stretches out for them (reported in Wittmann, 2009).

Just like life-threatening situations, negative emotions can concentrate our attention on the passage of time and so make it seem longer than it really is.

This effect may be made worse by our efforts to regulate these negative emotions (see number 5), which also has the effect of stretching time.

9. Body temperature changes time perception

If you’ve ever had a fever then you’ll know that body temperature can have strange effects on time perception.

Experiments have found that when body temperature is raised our perception of time speeds up (Wearden & Pento-Voak, 1995).

Conversely when we are cooled down, our sense of time also slows down.

10. What’s your tempo?

Setting aside emotions, age, drugs and all the rest, our perception of time is also affected by who we are.

People seem to operate to different beats; we’ve all met people who work at a much slower or faster pace than we do.

Psychologists have found that people who are impulsive and oriented towards the present tend to find that time moves faster for them than others (from O’Brien et al., 2011).

There’s little research on this but it’s likely that each of us has our own personal tempo.

Research has found that when different people listen to metronomes the number of beats per minute they describe as comfortable ranges from as slow as 40 bpm up to a high of 200 bpm (Kir-Stimon, 1977).

This is a large range and may help to explain why some people seem to operate at such a different pace to ourselves.

Time perception is relative

The last words on time come from two great thinkers; first Albert Einstein:

“Put your hand on a hot stove for a minute, and it seems like an hour.

Sit with a pretty girl for an hour, and it seems like a minute.

That’s relativity.”

And finally, Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy and the Dirk Gently books:

“Time is an illusion.

Lunchtime doubly so.”

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