Why all babies love peekaboo

Peekaboo is a game played over the world, crossing language and cultural barriers. Why is it so universal? Perhaps because it’s such a powerful learning tool.

One of us hides our eyes and then slowly reveals them. This causes peals of laughter from a baby, which causes us to laugh in turn. Then we do it again. And again.

Peekaboo never gets old. Not only does my own infant daughter seem happy to do it for hours, but when I was young I played it with my mum (“you chuckled a lot!” she confirms by text message) and so on back through the generations. We are all born with unique personalities, in unique situations and with unique genes. So why is it that babies across the world are constantly rediscovering peekaboo for themselves?

Babies don’t read books, and they don’t know that many people, so the surprising durability and cultural universality of peekaboo is perhaps a clue that it taps into something fundamental in their minds. No mere habit or fashion, the game can help show us the foundations on which adult human thought is built.

An early theory of why babies enjoy peekaboo is that they are surprised when things come back after being out of sight. This may not sound like a good basis for laughs to you or I, with our adult brains, but to appreciate the joke you have to realise that for a baby, nothing is given. They are born into a buzzing confusion, and gradually have to learn to make sense of what is happening around them. You know that when you hear my voice, I’m usually not far behind, or that when a ball rolls behind a sofa it still exists, but think for a moment how you came by this certainty.

The Swiss developmental psychologist Jean Piaget called this principle ‘object permanence’ and suggested that babies spent the first two years of their lives working it out. And of course those two years are prime peekaboo time. Looked at this way, the game isn’t just a joke, but helps babies test and re-test a fundamental principle of existence: that things stick around even when you can’t see them.

Maybe evolution fixed it so that babies enjoy peekaboo for its own sake, since it proved useful in cognitive development, but I doubt it. Something deeper than mere education is going on.

Surprise element

Peekaboo uses the fundamental structure of all good jokes – surprise, balanced with expectation. Researchers Gerrod Parrott and Henry Gleitman showed this in tests involving a group of six-, seven- and eight-month-olds which sound like more fun than a psychology experiment should be. Most of the time the peekaboo game proceeded normally, however on occasion the adult hid and reappeared as a different adult, or hid and reappeared in a different location. Videos of the infants were rated by independent observers for how much the babies smiled and laughed.

On these “trick trials” the babies smiled and laughed less, even though the outcome was more surprising. What’s more, the difference between their enjoyment of normal peekaboo and trick-peekaboo increased with age (with the eight-month-olds enjoying the trick trials least). The researchers’ interpretation for this is that the game relies on being able to predict the outcome. As the babies get older their prediction gets stronger, so the discrepancy with what actually happens gets larger – they find it less and less funny.

The final secret to the enduring popularity of peekaboo is that it isn’t actually a single game. As the baby gets older their carer lets the game adapt to the babies’ new abilities, allowing both adult and infant to enjoy a similar game but done in different ways. The earliest version of peekaboo is simple looming, where the carer announces they are coming with their voice before bringing their face into close focus for the baby. As the baby gets older they can enjoy the adult hiding and reappearing, but after a year or so they can graduate to take control by hiding and reappearing themselves.

In this way peekaboo can keep giving, allowing a perfect balance of what a developing baby knows about the world, what they are able to control and what they are still surprised by. Thankfully we adults enjoy their laughter so much that the repetition does nothing to stop us enjoying endless rounds of the game ourselves.

This is my BBC Future column from last week. The original is here

Why you think your phone is vibrating when it is not

Most of us experience false alarms with phones, and as Tom Stafford explains this happens because it is a common and unavoidable part of healthy brain function.

Sensing phantom phone vibrations is a strangely common experience. Around 80% of us have imagined a phone vibrating in our pockets when it’s actually completely still. Almost 30% of us have also heard non-existent ringing. Are these hallucinations ominous signs of impending madness caused by digital culture?

Not at all. In fact, phantom vibrations and ringing illustrate a fundamental principle in psychology.

You are an example of a perceptual system, just like a fire alarm, an automatic door, or a daffodil bulb that must decide when spring has truly started. Your brain has to make a perceptual judgment about whether the phone in your pocket is really vibrating. And, analogous to a daffodil bulb on a warm February morning, it has to decide whether the incoming signals from the skin near your pocket indicate a true change in the world.

Psychologists use a concept called Signal Detection Theory to guide their thinking about the problem of perceptual judgments. Working though the example of phone vibrations, we can see how this theory explains why they are a common and unavoidable part of healthy mental function.

When your phone is in your pocket, the world is in one of two possible states: the phone is either ringing or not. You also have two possible states of mind: the judgment that the phone is ringing, or the judgment that it isn’t. Obviously you’d like to match these states in the correct way. True vibrations should go with “it’s ringing”, and no vibrations should go with “it’s not ringing”. Signal detection theory calls these faithful matches a “hit” and a “correct rejection”, respectively.

But there are two other possible combinations: you could mismatch true vibrations with “it’s not ringing” (a “miss”); or mismatch the absence of vibrations with “it’s ringing” (a “false alarm”). This second kind of mismatch is what’s going on when you imagine a phantom phone vibration.

For situations where easy judgments can be made, such as deciding if someone says your name in a quiet room, you will probably make perfect matches every time. But when judgments are more difficult – if you have to decide whether someone says your name in a noisy room, or have to evaluate something you’re not skilled at – mismatches will occasionally happen. And these mistakes will be either misses or false alarms.

Alarm ring

Signal detection theory tells us that there are two ways of changing the rate of mismatches. The best way is to alter your sensitivity to the thing you are trying to detect. This would mean setting your phone to a stronger vibration, or maybe placing your phone next to a more sensitive part of your body. (Don’t do both or people will look at you funny.) The second option is to shift your bias so that you are more or less likely to conclude “it’s ringing”, regardless of whether it really is.

Of course, there’s a trade-off to be made. If you don’t mind making more false alarms, you can avoid making so many misses. In other words, you can make sure that you always notice when your phone is ringing, but only at the cost of experiencing more phantom vibrations.

These two features of a perceiving system – sensitivity and bias – are always present and independent of each other. The more sensitive a system is the better, because it is more able to discriminate between true states of the world. But bias doesn’t have an obvious optimum. The appropriate level of bias depends on the relative costs and benefits of different matches and mismatches.

What does that mean in terms of your phone? We can assume that people like to notice when their phone is ringing, and that most people hate missing a call. This means their perceptual systems have adjusted their bias to a level that makes misses unlikely. The unavoidable cost is a raised likelihood of false alarms – of phantom phone vibrations. Sure enough, the same study that reported phantom phone vibrations among nearly 80% of the population also found that these types of mismatches were particularly common among people who scored highest on a novelty-seeking personality test. These people place the highest cost on missing an exciting call.

The trade-off between false alarms and misses also explains why we all have to put up with fire alarms going off when there isn’t a fire. It isn’t that the alarms are badly designed, but rather that they are very sensitive to smoke and heat – and biased to avoid missing a real fire at all costs. The outcome is a rise in the number of false alarms. These are inconvenient, but nowhere near as inconvenient as burning to death in your bed or office. The alarms are designed to err on the side of caution.

All perception is made up of information from the world and biases we have adjusted from experience. Feeling a phantom phone vibration isn’t some kind of pathological hallucination. It simply reflects our near-perfect perceptual systems trying their best in an uncertain and noisy world.

This article was originally published on BBC Future. The original is here.

The ‘unnamed feeling’ named ASMR

Here’s my BBC Future column from last week. It’s about the so-called Autonomous Sensory Meridian Response, which didn’t have a name until 2010 and I’d never heard of until 2012. Now, I’m finding out that it is surprisingly common. The original is here.

It’s a tightening at the back of the throat, or a tingling around your scalp, a chill that comes over you when you pay close attention to something, such as a person whispering instructions. It’s called the autonomous sensory meridian response, and until 2010 it didn’t exist.

I first heard about the autonomous sensory meridian response (ASMR) from British journalist Rhodri Marsden. He had become mesmerised by intentionally boring videos he found on YouTube, things like people explaining how to fold towels, running hair dryers or role-playing interactions with dentists. Millions of people were watching the videos, reportedly for the pleasurable sensations they generated.

Rhodri asked my opinion as a psychologist. Could this be a real thing? “Sure,” I said. If people say they feel it, it has to be real – in some form or another. The question is what kind of real is it? Are all these people experiencing the same thing? Is it learnt, or something we are born with? How common is it? Those are the kind of questions we’d ask as psychologists. But perhaps the most interesting thing about the ASMR is what happened to it before psychologists put their minds to it.

Presumably the feeling has existed for all of human history. Each person discovered the experience, treasured it or ignored it, and kept the feeling to themselves. That there wasn’t a name for it until 2010 suggests that most people who had this feeling hadn’t talked about it. It’s amazing that it got this far without getting a name. In scientific terms, it didn’t exist.

But then, of course, along came the 21st Century and, like they say, even if you’re one in a million there’s thousands of you on the internet. Now there’s websites, discussion forums, even a Wikipedia page. And a name. In fact, many names – “Attention Induced Euphoria”, “braingasm”, or “the unnamed feeling” are all competing labels that haven’t caught on in the same way as ASMR.


This points to something curious about the way we create knowledge, illustrated by a wonderful story about the scientific history of meteorites. Rocks falling from the sky were considered myths in Europe for centuries, even though stories of their fiery trails across the sky, and actual rocks, were widely, if irregularly reported. The problem was that the kind of people who saw meteorites and subsequently collected them tended to be the kind of people who worked outdoors – that is, farmers and other country folk. You can imagine the scholarly minds of the Renaissance didn’t weigh too heavily on their testimonies. Then in 1794 a meteorite shower fell on the town of Siena in Italy. Not only was Siena a town, it was a town with a university. The testimony of the townsfolk, including well-to-do church ministers and tourists, was impossible to deny and the reports written up in scholarly publications. Siena played a crucial part in the process of myth becoming fact.

Where early science required authorities and written evidence to turn myth into fact, ASRM shows that something more democratic can achieve the same result. Discussion among ordinary people on the internet provided validation that the unnamed feeling was a shared one. Suddenly many individuals who might have thought of themselves as unusual were able to recognise that they were a single group, with a common experience.

There is a blind spot in psychology for individual differences. ASMR has some similarities with synaesthesia (the merging of the senses where colours can have tastes, for example, or sounds produce visual effects). Both are extremes of normal sensation, which exist for some individuals but not others. For many years synaesthesia was a scientific backwater, a condition viewed as unproductive to research, perhaps just the product of people’s imagination rather than a real sensory phenomenon. This changed when techniques were developed that precisely measured the effects of synaesthesia, demonstrating that it was far more than people’s imagination. Now it has its own research community, with conferences and papers in scientific journals.

Perhaps ASMR will go the same way. Some people are certainly pushing for research into it. As far as I know there are no systematic scientific studies on ASMR. Since I was quoted in that newspaper article, I’ve been contacted regularly by people interested in the condition and wanting to know about research into it. When people hear that their unnamed feeling has a name they are drawn to find out more, they want to know the reality of the feeling, and to connect with others who have it. Something common to all of us wants to validate our inner experience by having it recognised by other people, and in particular by the authority of science. I can’t help – almost all I know about ASMR is in this column you are reading now. For now all we have is a name, but that’s progress.

2013-01-25 Spike activity

Quick links from the past week in mind and brain news:

The interesting concept of a ‘possession trance disorder’ diagnosis is discussed by Neurocritic.

BBC News video reports on how Brazil is considering a law to forcibly remove crack addicts from the street into rehab.

Goodbye PDD-NOS, hello Social Communication Disorder. A sneaked-out DSM-5 change for the autism spectrum is covered by Cracking the Enigma.

Nature reports that Henry Markham’s Human Brain Project which is supposedly aiming to ‘simulate the human brain’ (but actually, isn’t) gets kazillion dollar funding.

The DSM-5 will cost $199 a copy, reports DSM-5 in Distress. That’s like 50c a diagnosis.

Brighton Science Festival has a fantastic day on the Science of Sex on 9th February.

China’s One Child Policy may have altered the personality of a generation according to research reviewed by the Nodes of Ranvier blog.

Time magazine on how the tactics used in ‘troubled teen’ reality TV programmes are know to make adolescents worse.

Is there a right age for first sex? an interesting study is briefly covered by Providentia.

Discover Magazine reports that data storage in DNA has become a reality. Sony to sue RNA strands for piracy.

A new Nature NeuroPod has hit the wires. Psychology and Sherlock Holmes, movement and memory.

Colossal has some wonderful abstract 3D sculptures that transform in cylindrical mirrors. Have to be seen.

Compare and contrast: high heels make women’s walk more attractive to males / historically women adopted high heels from male fashion to masculinise their outfits. Found: an evolutionary psychology infinite loop!

BBC Future column: The Psychology Of Tetris

Last week’s BBC Future column. The original is here. There’s a more melancholy and personal version of this column I could have written called ‘I lost years of my life to Sid Meier’s ‘Civiliation’, but since the game is now out on iphone I didn’t have time to write it.

How the secret to the popular game’s success is that it takes advantage of the mind’s basic pleasure in tidying up and uses it against us.

Shapes fall from the sky, all you have to do is to control how they fall and fit within each other. A simple premise, but add an annoyingly addictive electronica soundtrack (based on a Russian folk tune called Korobeiniki, apparently) and you have a revolution in entertainment.

Since Tetris was launched on the world in 1986, millions of hours have been lost through playing this simple game. Since then, we’ve seen games consoles grow in power, and with it the appearance of everything from Call of Duty to World of Warcraft. Yet block and puzzle games like Tetris still have a special place in our hearts. Why are they are so compelling?

The writer Jeffrey Goldsmith was so obsessed with Tetris that he wrote a famous article asking if the game’s creator Alexey Pajitnov had invented “a pharmatronic?” – a video game with the potency of an addictive drug. Some people say that after playing the game for hours they see falling blocks in their dreams or buildings move together in the street – a phenomenon known as the Tetris Effect. Such is its mental pull, there’s even been the suggestion that the game might be able to prevent flashbacks in people with PTSD.

I had my own Tetris phase, when I was a teenager, and spent more hours than I should have trying to align the falling blocks in rows. Recently, I started thinking about why games like Tetris are so compelling. My conclusion? It’s to do with a deep-seated psychological drive to tidy up.

Many human games are basically ritualised tidying up. Snooker, or pool if you are non-British, is a good example. The first person makes a mess (the break) and then the players take turns in potting the balls into the pockets, in a vary particular order. Tetris adds a computer-powered engine to this basic scenario – not only must the player tidy up, but the computer keeps throwing extra blocks from the sky to add to the mess. It looks like a perfect example of a pointless exercise – a game that doesn’t teach us anything useful, has no wider social or physical purpose, but which weirdly keeps us interested.

There’s a textbook psychological phenomenon called the Zeigarnik Effect, named after Russian psychologist Bluma Zeigarnik. In the 1930s, Zeigarnik was in a busy cafe and heard that the waiters had fantastic memories for orders – but only up until the orders had been delivered. They could remember the requests of a party of 12, but once the food and drink had hit the table they forgot about it instantly, and were unable to recall what had been so solid moments before. Zeigarnik gave her name to the whole class of problems where incomplete tasks stick in memory.

The Zeigarnik Effect is also part of the reason why quiz shows are so compelling. You might not care about the year the British Broadcasting Corporation was founded or the percentage of the world’s countries that have at least one McDonald’s restaurant, but once someone has asked the question it becomes strangely irritating not to know the answer (1927 and 61%, by the way). The questions stick in the mind, unfinished until it is completed by the answer.

Game theory

Tetris holds our attention by continually creating unfinished tasks. Each action in the game allows us to solve part of the puzzle, filling up a row or rows completely so that they disappear, but is also just as likely to create new, unfinished work. A chain of these partial-solutions and newly triggered unsolved tasks can easily stretch to hours, each moment full of the same kind of satisfaction as scratching an itch.

The other reason why Tetris works so well is that each unfinished task only appears at the same time as its potential solution – those blocks continuously fall from the sky, each one a problem and a potential solution. Tetris is a simple visual world, and solutions can immediately be tried out using the five control keys (move left, move right, rotate left, rotate right and drop – of course). Studies of Tetris players show that people prefer to rotate the blocks to see if they’ll fit, rather than think about if they’ll fit. Either method would work, of course, but Tetris creates a world where action is quicker than thought – and this is part of the key to why it is so absorbing. Unlike so much of life, Tetris makes an immediate connection between our insight into how we might solve a problem and the means to begin acting on it.

The Zeigarnik Effect describes a phenomenon, but it doesn’t really give any reason for why it happens. This is a common trick of psychologists, to pretend they solved a riddle of the human mind by giving it a name, when all they’ve done is invented an agreed upon name for the mystery rather than solved it. A plausible explanation for the existence of the Effect is that the mind is designed to reorganise around the pursuit of goals. If those goals are met, then the mind turns to something else.

Trivia takes advantage of this goal orientation by frustrating us until it is satisfied. Tetris goes one step further, and creates a continual chain of frustration and satisfaction of goals. Like a clever parasite, Tetris takes advantage of the mind’s basic pleasure in getting things done and uses it against us. We can go along with this, enjoying the short-term thrills in tidying up those blocks, even while a wiser, more reflective, part of us knows that the game is basically purposeless. But then all good games are, right?

BBC Column: Psychological self-defence for the age of email

My latest column for BBC Future. The original is here. Lots of the points made here apply to technology more generally.

Here’s a pretty safe assumption to make: you probably feel like you’re inundated with email, don’t you? It’s a constant trickle that threatens to become a flood. Building up, it is always nagging you to check it. You put up spam filters and create sorting systems, but it’s never quite enough. And that’s because the big problems with email are not just technical – they’re psychological. If we can understand these we’ll all be a bit better prepared to manage email, rather than let it manage us.

For this psychological self-defence course, we’re going to cover very briefly four fundamental aspects of human reasoning. These are features built into how the human mind works. If you know about them, you can watch out for them and – most importantly – catch yourself when one of these tendencies is leading you astray.

Pay it back

First up is reciprocity – our tendency to want to return like for like, whether that is a smile for a smile or a blow for a blow. Persuasion-guru Robert Cialdini cites reciprocity as being one of the six basic principles of influence: do something for someone, so they’ll feel they have to do something back. Suddenly freebies from salespeople make a lot more sense (and seem a lot more sinister).

Reciprocity works in email because we’re not just sending information through the ether, we’re communicating social information. Each email contains simple meta-messages, things like “I’m interested in what you’re doing”, or “This really matters to me”. Reciprocity means that each email is an invitation to a social encounter, and you know what that means – more emails sent back to you in reply.

Just think back to the last time you were away from email for a week: most likely the majority of the emails waiting for you in your inbox were from the first few days of your absence. Lots of our email is self-generated, responses to emails we’ve sent, a natural reaction oiled by the social grease of reciprocity. And this leads to another aspect of human reasoning, which is…

Reaping rewards

A part of us loves getting email – it provides basic proof that we’re part of society (and often more – it’s concrete evidence that someone wants to talk to us, invite us out, or tell us something). Our animal brains use some simple rules for processing rewards. The most fundamental of these rules is the so called Law of Effect, which simply states that if something is followed by a reward, then animals tend to increase the frequency with which they do it.

But the way email is structured to reach us taps into another basic rule the brain uses for processing reward. Irregular rewards have a special power to enforce repeat behaviour, something discovered by psychologists in the early twentieth century, and known for centuries by people who organise gambling (would anyone play slot machines if they just predictably gave you back 80% of the money you put in each time?).

Email drips into your consciousness during the day. Each time you check it you don’t know if you’ll be getting another boring work email, which isn’t very rewarding, or some exciting news or an opportunity, which is very rewarding. The schedule of these constant opportunities for surprise hooks us into checking email. To avoid it, you just need to fix your email so that you collect it all at once at regular intervals, such as every hour or twice a day, rather than checking each email as it arrives.

Close thrill

Hyperbolic discounting is another feature of how we’re wired to think about rewards. Discounting is the diminishing value of rewards as they get further away in time. It’s the thing that means that being offered 100 euros today is far more exciting than being offered 100 euros in ten years time. That discounting is hyperbolic means a reward that is very close gets drastically more attractive.

To see this, try thinking about whether you’d like 10 euros now or 20 euros in a year’s time. If you’re an impatient person maybe you’ll favour the 10 euros now, if you’re patient you can maybe wait for the 20 euros in a year’s time. But if we shift both rewards backwards in time by 10 years, the choice stops being ambiguous: 10 euros in ten year’s time, or 20 euros in eleven year’s time is an easy call. Almost everyone would go for the second option.

What this shows is that the choice of a smaller amount of money only seemed attractive because it was closer in time. Hyperbolic discounting is why people will pay money to pick up today’s news, but won’t even bend down to pick up yesterday’s news. Immediacy creates value in our brains.

Going back to email, think of a time you didn’t check your email for a week. If you’re like me, you probably opened your email expecting lots of exciting news – a sum of all the excitement you experience with each individual email. But actually, a week’s worth of email isn’t very exciting. The interest that email generates as you see it arriving in your inbox is an illusion generated by hyperbolic discounting. Every technology has its own logic, and part of the logic of email is the speed with which it is delivered, with the new mails always pushing their way to the top of the pile. This pull is as insidious as it is intense – apparently 59% of people surveyed by AOL are so addicted to keeping track of their email that they check it in the bathroom.

This is what makes me think that the very speed of email delivery is a handicap – email delivered with a half-hour delay would be easier to judge at its true value, and so be far less distracting.

Responsibility pressure

Finally, a fourth fundamental principle of human reasoning is our sense of ownership or responsibility. I’ve written recently about how we can be tricked into valuing something more by accidents of fate that put that thing in our possession. Email is prey to this bias: once something is there, it is natural to decide that it deserves our consideration, it is somehow our responsibility to read and respond.

Nowhere is this more apparent than the group email and the avalanche of replies that invariably ensues. Strike back by reminding yourself that not all email has to be replied to, that lots of issues will be – and should be – dealt with by other people. Ask yourself: “If I didn’t have this information in my inbox, would I go out looking for it?” Most of the time the answer is probably “no”, and that’s a sign that someone else is controlling your attention.

Unless you diligently maintain the boundaries of exactly what you are responsible for, email becomes a system for letting other people control your time. So delete that email and move on!

Berlin plan #2: Contagious attention

As I’ve mentioned, I’ll be leading a ‘cognitive science safari’ in Berlin on 11th of July. We’ll be generating some experiences based on classic psychology experiments, experiments which tell us important things about how cities organise our perceptions.

Previously I described how I’ll be trying to revive a classic change blindness experiment. For my next trick, I plan to re-mix another classic experiment. This is one by famed social psychologist Stanley Milgram on the drawing power of crowds (Milgram et al, 1969).

We’ve all hear that nothing attracts a crowd like a crowd, but Milgram set out to systematically test this idea. Filming from a sixth floor window, Milgram arranged for collaborators to stop on a busy street and stare up at him. With the video evidence he could then record data on what proportion of passers-by would stop and join the crowd. In agreement with his classic work on obedience to authority, he found that the drawing power of crowds increased rapidly as the first few members joined.

Recently, research led by Princton’s Iain Couzin has provided an improved analysis on how this kind of shared attention spreads through a crowd (Gallup et al, 2012). Using automated tracking tools, the new research showed that people only follow the gaze of people near them, and – like traffic jams – attention tends to spread backwards in the crowd, rather than between people next to each other, or facing each other. There’s a great write-up of this research over at Ed Yong’s Discover blog: What are you looking at? People follow each other’s gazes, but without a tipping point.

One of the conclusion of Couzin’s recent study was that there wasn’t a tipping point for crowd gathering – no magic threshold where a crowd would just get bigger and bigger under its own `attentional gravity’.

Well, this sounds like a challenge to me, and I think I’ve thought of a way we can try and hack these experiments for added interest. Milgram and Couzin’s experiments both had a single crowd looking at a relatively uninteresting phenenon (Milgram filming from his window, a pair of experimenters filming surreptitiously). In Berlin, I’d like to try to plug two crowds into each other, so to speak. We’ll start off as in Milgram’s experiment, with one person looking up at the experimenter (Perhaps on the bridge overlooking Alexanderplatz – although suggestions welcome). The rest of us can watch the behaviour of passers-by: will they join the person staring up at the bridge? What kind of person will stop to have a look? How long will they stay? We’ll add more people to this crowd and should be able to see the patterns Milgram and Couzin observed: what is the effect of a bigger crowd? How far does the influence of the crowd extend?

Next, we’ll see if we can generate a self-sustained crowd by having more and more people join the experimenter on the bridge – creating two crowds watching each other, both attracting the attention of their nearby passers-by. If my reading of Iain Couzin’s research is right then there should be a stable equilibrium where the crowds reach a certain size and stop growing. If his theory is wrong, we could generate an endlessly growing crowd, driven by the power of positive feedback until it encompasses the whole population of the world – a Psychology equivalent to grey goo or one of those particle physics experiments which risks creating a black hole in the centre of Planet Earth.

Okay, so that second possibility is unlikely, but we are sure to generate a rich field in which to observe the interply of shared attention among the city-crowd. So please join me in Berlin as we travel the spectrum from science to speculation to experience in an attempt to unravel the mysteries of psychology in the city. As ever, I’m eagar to meet any mindhacks.com readers who live in Berlin and would like to come along (or even help out). Get in touch!

Original announcement: Meet me in Berlin
Plan #1: The Change Blindness Experiment
Make sure you check out the video of the analysis technique on Iain Couzin’s page here (it’s the one where everyone in the crowd looks like they’ve got a yellow arrow protruding from their foreheads).
HT to Vaughan Bell for the phrase ‘cognitive science safari’


Gallup, A.C., Hale, J.J., Garnier, S., Sumpter, D.J.T., Kacelnik, A., Krebs, J. & Couzin, I.D. (2012) Visual attention and the acquisition of information in human crowds. PNAS, published online April 23rd, open access.

Milgram, S., Bickman, L. & Berkowitz, L. (1969) Note on the drawing power of crowds of different size. Journal of Personality and Social Psychology 13, 79–82.

A misdirection of mind

Scientific American has an excellent video where two neuroscientists and a street magician with remarkable pickpocketing skills explain how illusionists manipulate our attention.

It’s a hugely entertaining piece and really highlights how the idea of ‘sleight of hand’ is itself a misdirection, as the most important of the magician’s manipulations is to alter where we focus and what we expect.

The people featured in the video were all involved in the recent scientific discussions about what stage magic can teach cognitive neuroscience about the mind and brain.

You’ll also notice there is a bit of scientific sleight of hand that happens at about the 9 minute mark where the all-purpose ‘mirror neuron‘ theory is pulled out of a hat as an explanation that stretches way beyond what we actually know about the mirror system.

It doesn’t say whether mirror neurons can also saw a woman in half but I’m sure someone will suggest it in the near future.

Despite this moment of unsubstantiated speculation, the video is an excellent guide to the psychology of attention and great fun to boot.

Link to video ‘Neuroscience meets magic’.

Why are overheard phone conversations so distracting?

Psychological Science has a brilliantly conceived study that explains why overhearing someone talk on a mobile phone is so much more annoying than simply overhearing two people in conversation.

It turns out that a one-sided conversation (brilliantly named a ‘half-a-logue’) draws in more of our mental resources because the information is less predictable – like being fed a series of verbal cliff-hangers.

Overheard Cell-Phone Conversations: When Less Speech Is More Distracting.

Psychol Sci. 2010 Sep 3. [Epub ahead of print]

Emberson LL, Lupyan G, Goldstein MH, Spivey MJ.

Why are people more irritated by nearby cell-phone conversations than by conversations between two people who are physically present? Overhearing someone on a cell phone means hearing only half of a conversation-a “halfalogue.” We show that merely overhearing a halfalogue results in decreased performance on cognitive tasks designed to reflect the attentional demands of daily activities. By contrast, overhearing both sides of a cell-phone conversation or a monologue does not result in decreased performance. This may be because the content of a halfalogue is less predictable than both sides of a conversation. In a second experiment, we controlled for differences in acoustic factors between these types of overheard speech, establishing that it is the unpredictable informational content of halfalogues that results in distraction. Thus, we provide a cognitive explanation for why overheard cell-phone conversations are especially irritating: Less-predictable speech results in more distraction for a listener engaged in other tasks.


Link to PubMed entry for study.

Distractingly attractive

Driver distractions are a major cause of road accidents. A new study has found that just a simple conversation with someone else in the car can be enough to increase driver errors and that the risk is greater if we fancy the passenger.

The research was conducted in a driving simulator by Cale Whitea and Jeff Caird from the Cognitive Ergonomics Research Laboratory (CERL) at the University of Calgary in Canada where they investigated something called a looked-but-failed-to-see error.

This is a form of change blindness, where we look at a scene but fail to notice something has changed. This is an important source of risk when driving, as we may be going through the motions of scanning the road but not taking in new information.

The study looked at how many of these errors would occur when drivers navigated their way through a simulated city, while also tracking their eye movements and errors with motorbikes and pedestrians on dangerous left-turns.

Crucially, the study compared how people performed when they were alone or with an opposite-sex passenger but also asked them about how attracted they were to the passenger and tested levels of extroversion and anxiety.

The results were striking:

Passenger conversations can be distracting. Higher rates of [looked-but-failed-to-see] LBFTS errors occurred when engaged in conversations with attractive passengers. In particular, those drivers who were most extroverted and attracted to the passenger also tended to be more anxious, drove slower, responded less to the pedestrian, and were involved in a greater number of emergency incidents with the motorcycle.

Considering eye gaze behavior was unaffected, the relationship between these social factors and performance variables suggest the nature of conversational distraction is cognitive. This attentional interference was sufficient in eliciting an eight-fold increase in LBFTS errors involving the motorcycle and four-times more pedestrian incidents.

In other words, conversation did not alter how people looked at the road, but it did affect how many dangerous situations people noticed – they just didn’t take them in. Fancying the passenger meant drivers missed more hazards. Their mind was clearly on other things.

Contrary to what parents might say (‘you were just showing off!’) participants actually drove more slowly when they were attracted to the passenger, but still made more errors.

It’s probably worth noting that it wasn’t the hotness of the passenger which was tested in the experiment, but the attraction of the driver, and that the distracting effect was stronger in women than men.

Link to PubMed entry for study.

Do the test: change blindness versions

dothetest.co.uk, is the Transport for London site which brought you the urbanised inattentional blindness video. Now they’re back with a feast of change blindness-YouTube goodness, here, here, and here.

The moral is the same, and evidence-based: even large things can be hard to spot if you don’t know they are there, so look out for cyclists.


Transport for London have combined two of my favourite things: safety for cyclists and classic Psychology experiments. The website dothetest.co.uk provides a test of awareness that Mind Hacks fans will instantly recognise as an updated (urbanised!) version of Hack #41: “Make Things Invisible Simply by Concentrating (on Something Else)”. Fantastic!

Link to the awareness test here

Link to a previous post on mindhacks.com discussing inattentional blindness

Resisting temptation is energy intensive

Cognitive Daily has just published a great write-up and demonstration of a study that illustrates how self-control is an energy intensive process that puts a big drain on the body’s glucose levels.

The article tackles a recent study [pdf] led by psychologist Matthew Gailliot that found that exercising self-control in either conversations or in lab tasks reduces blood glucose levels.

The researchers also found that initial glucose levels can predict how well people do on these tasks and that self-control can be temporarily boosted by giving people a sugary drink.

Cognitive Daily’s have recreated one of the lab tasks. Go and check it out, it’s an excellent demonstration. It makes the task wonderfully clear but also illustrates how even such simple self-control tasks are so difficult.

This sort of ‘self-control’ is heavily linked to attention – in part, the ability to focus yourself on one particular thing and not get drawn into perceptual or emotional distractions.

This study doesn’t tackle brain function, but another recent paper by Gailliot [pdf] does link these findings to what we know about the neuropsychology of ‘self-control’.

This ability is particularly associated with the frontal lobes, which are known to play a key role in inhibiting inappropriate responses.

You can see control break down in interesting ways after frontal lobe damage, which can often lead to a range of impulsive behaviours.

For example, patients with damage to this area might display utilisation behaviour, where they are unable to resist carrying out actions presented by their environment.

The affected person might be unable to walk past a door without trying to open it or sit in front of a coffee cup without sipping it, even when they know it’s too hot to drink.

What’s interesting, is that as the CogDaily article illustrates, we seem to have a mild form of this when we are low on energy or fatigued.

It’s interesting to speculate that the reason we get ‘snappy’ when tired is because we’re less able to control the emotions sparked by small annoyances.

Link to great CogDaily article on self control (try the demo!).

Are attention and consciousness the same thing?

Psychologists have often wondered whether attention and consciousness are the same thing. Can we only be conscious of things we pay attention to? And can we attend to things we’re not conscious of?

A paper [pdf] published last year suggests that they are, in fact, separate mental processes.

William James, one of the founder of modern psychology, wrote that “everyone knows what attention is” when trying to define it.

Similarly, as neuroscientist Susan Greenfield has pointed out, scientists often rely on a ‘we all know what we’re talking about, don’t we?’ definition of consciousness.

It turns out that attention is easier to define that consciousness, and in psychology it generally refers to the preferential processing of one source of information over another.

This can be measured experimentally because it’s possible to see how experience of one thing affects performance on another task, even if the person isn’t aware of experiencing anything in the first place.

We described an example of this last week, in a study that found that people could make accurate beauty judgements for faces presented so quickly they didn’t consciously recognise them.

This study, and many others on ‘implicit’ or ‘subliminal’ perception, demonstrate that people can attend to something without being conscious of it.

Being conscious of something we haven’t attended to, and where attention is nearly absent, is a bit more tricky.

The paper, by cognitive scientists Christof Koch and Naotsugu Tsuchiya, suggests that getting ‘gist’ impressions might be one example.

Experiments show that when photographs are unexpectedly flashed up in front of participants for no more than 30ms, they don’t have time to focus on any part of it, but can report a general gist or summary of the image.

Consciousness and attention have also been shown to have opposite effects in some instances.

When participants try to find two embedded images within a rapidly flashed stream of pictures, they often fail to see the second image – an effect known as ‘attentional blink‘.

However, one study [pdf] found that distracting people during this task, actually made them better at it, they were more likely to consciously detect the second image.

Reducing their attention to the task seemed to increase their conscious awareness.

The Koch and Tsuchiya paper has many more examples if you’re interested in trying to untangle these closely related processes.

pdf of ‘Attention and Consciousness: Two Distinct Brain Processes’ (via SciCon).

Why email is addictive (and what to do about it)

Email is addictive

Like lots of people who sit in front of a computer all day, I am addicted to email. This worries me for two reasons. The first is the sheer strength of my compulsion. I must hit the ‘get mail’ button at least a hundred times a day. Sometimes, if I don’t have any new mail, I hit it again immediately, just to check. I interrupt my work to check my mail even when I know that I’m not going to find anything interesting and that I should just concentrate on what I am suppossed to be doing. When I come back to my office it’s the first thing I do. If I’m prevented from checking my mail for more than a few hours I get a little jumpy and remain that way until I have.

This is all rather sad, but the second reason I am worried by my email addiction is that I work in a psychology department and we’re supposed to understand how these things work. Now email isn’t a drug – it doesn’t deliver a chemical into your bloodstream. Yet it is clearly addictive. I’m a normal rational person (which is to say I’m just normally maladjusted) and I know that I don’t need to check my email as often as it do – certainly not immediately after checking it the first time for Goodness’ sake! – but still I am compelled. What’s going on, and can psychological science help me out?

Read more below the fold

Continue reading “Why email is addictive (and what to do about it)”

Mind Hacking at the gym

weights.jpgMost of the time it feels as though our perception of the world is based on what’s out there, what psychologists call ‘stimulus-driven’ or ‘bottom up’ processing. But in reality, our perceptual experience is a seamless mixture of both what really is out in the world and what we expect to be out there (so-called ‘top down’ or ‘concept-driven’ processing). Tom gave an elegant example of this in a recent post, describing how so many people hadn’t noticed the erroneous use of the word ‘conservations’ in the Mind Hacks book, when it should have said ‘conversations’ – in this case readers saw what they expected, not what was written.

I was struck by a couple of similar examples in recent visits to the gym. On the first occasion I’d just finished on the running machine where I have to really crank up my MP3 player volume to drown out the loud music played over the public speakers. When I sat down in the far quieter weights section, the volume on my headphones suddenly felt painfully loud in this quieter environment, and so I quickly jabbed the volume down a few notches. I felt such a relief as the music gradually softened and my eardrums were saved. It was only much later that I realised my MP3 player’s controls were in the lock position – I hadn’t turned the volume down at all. My expectations had overridden the true information arriving at my senses.

On my next visit I proudly grabbed two 14kg (don’t laugh!) dumbbells for some bicep curls. I’d worked up to this weight over recent months and considered it my limit. I was pumping away but my left arm was really struggling, which I put down to it being my weaker arm. Still, I persevered and did my usual number of reps. It was only when I went to replace the dumbbells that I saw the weight in my left arm was 18kg! – someone had put the weights in the wrong places… Well, I thought, maybe I’ve not been pushing myself enough, but no, later on when I went to try out some curls with 18kg weights, it was hopeless: when I ‘knew’ what the weight was it ‘felt’ too heavy!

Anyone got some other examples?