Category Archives: Streamed Content

Improving people’s memory by punishing their correct answers

A well-established finding in psychology is that successfully retrieving information from memory serves to consolidate the storage of that information. Each time your brain’s filing clerk tracks down the right information, the more likely he is to find it another time. Psychologists call this the testing effect – practising retrieval of information is far more effective than simply re-studying that same material.

Can this benefit of testing be enhanced? Yes it can. A new study has provided the first ever demonstration of how to enhance the memory consolidation that occurs after correctly answering a test question. Bridgid Finn and Henry Roediger’s important and somewhat surprising new finding is that following a correct answer with an aversive stimulus serves to enhance the consolidation of that memory. It’s like punishing the filing clerk after each correct retrieval makes him even more accurate in the future.

Forty undergrads studied multiple lists of ten word-pairs, each featuring a Swahili word and its English translation. After each list of ten, they were tested. Presented with the Swahili, they had to answer with the English. Here’s the important bit. If they answered correctly, one of three things happened immediately: a blank screen appeared, a neutral picture appeared (e.g. a fork) or a negative, aversive picture appeared (e.g. a dead cat).

After this pattern of study period and test had been followed for ten lists of ten word-pairs, the participants were then given a jumbo test of all 100 Swahili words. Here’s the key result: for those items answered correctly in the earlier mini-tests, it was those that were followed by a nasty picture that were most likely to be accurately recalled in the final jumbo test. Earlier correct answers that had been followed by a neutral pic or blank screen were not so well remembered (and performance was equivalent across the blank/neutral conditions).

“These data are the first to show that arousal following successful retrieval of information enhances later recall of that information,” the researchers said.

A follow-up study was similar to the first but this time correct answers in the initial mini-tests were followed by neutral or aversive pictures that appeared two seconds later, as opposed to appearing immediately as they did in the first study. This was to see if there was a narrow window beyond which a negative stimulus wouldn’t any longer enhance the consolidating effect of correct retrieval. The results were just the same as for the first study, so even two seconds later, a nasty picture is still able to enhance the memory consolidating effect of a correct retrieval. Future studies are needed to test just how long after a correct retrieval this process is still effective, and to see if positive images exert a similar benefit.

Finally, the researchers looked to see if the presentation of a negative pic has its memory enhancing effect after items are merely re-studied, as opposed to recalled. A similar protocol with Swahili-English word pairs was followed as before, but this time, instead of mini-tests after each set of ten word pairs, the participants were simply given the pairs to study again, with each pair proceeded either by a blank screen, neutral picture or nasty picture. This time, there was no benefit of the negative pics. In fact, there was a trend for pairs to be recalled less often if they’d been followed by a nasty pic in the earlier study phase.

Why should negative images boost the consolidating effects of answering a test item correctly? Finn and Roediger aren’t sure but think it has to do with links between the amygdala, which is involved in fear learning, and the hippocampus – a brain area involved in long-term memory storage. This is a rather vague account and doesn’t explain why aversive stimuli only enhance memory after correct retrieval, not further study. By way of further context, a 2006 study showed the presentation of aversive images after to-be-learned stimuli was beneficial during the initial study of that material.


I couldn’t help wondering what Milgram would have made of this study. Recall that participants in his classic obedience research thought they were taking part in an investigation of the effects of punishment on learning. In Milgram’s mock set-up, the “learner” was subjected to an electric shock each time they answered incorrectly. Of course, Milgram wasn’t really studying memory, but this new article suggests that he could have been onto something. Somewhat paradoxically, though, it seems it’s correctly answered items that ought to be followed by an aversive stimulus, not incorrect answers.
_________________________________ Finn, B., and Roediger, H. (2011). Enhancing Retention Through Reconsolidation: Negative Emotional Arousal Following Retrieval Enhances Later Recall. Psychological Science, 22 (6), 781-786 DOI: 10.1177/0956797611407932

This post was written by Christian Jarrett for the BPS Research Digest.

The first ever experimental investigation of laughing at oneself

To be capable of laughing at oneself is usually considered a mark of good character and the foundation of a robust sense of humour. Yet this is a behaviour that’s barely been touched on by psychologists. Opinions have been expressed – for example, La Fave and his colleagues thought that laughing at oneself was never genuine and couldn’t be a truly happy event. But for largely practical reasons, experiments on the topic are non-existent. Now Ursula Beermann and Willibald Ruch have shown one way to do it.

Sixty-seven undergrads rated their own ability to laugh at themselves and they nominated one or two peers to provide third-party ratings of the same. Sneakily, whilst the participants filled out these and other questionnaires at a computer, a screen camera took pictures of them. A little later the participants were asked to rate distorted pictures of the faces of unfamiliar men and women. To their surprise, included in the selection were the sneaky photos taken earlier of themselves. These photos of the participants had also been distorted to be, for example, stretched wide as if looking in a spoon (the Mac “Photobooth” software was used to create these effects).

The participants were filmed while they rated the photos so the researchers could later analyse the footage to see whether the participants laughed at the distorted images of themselves. Ekman’s Facial Action Coding system, which focuses on the flexing of specific facial muscles, was used to decode the participants’ facial expressions, and in particular to look for signs of genuine “Duchenne smiles”, which are symmetrical and involve creasing of the muscles around the eyes. Signs of laughter were also noted.

The findings seemed to validate the new methodological approach. Although 80 per cent of participants flashed a genuine smile at least once on seeing their own distorted image, it was those who claimed to be able to laugh at themselves, and whose peers agreed with this verdict, who showed more frequent and intense smiling and laughter in response to the distorted self-images, and fewer signs of fake smiles or negative emotion. On the other hand, there was no correlation between participants’ ability to laugh at themselves (based on self- and peer-report) and the amount of laughter triggered by distorted images of other people’s faces. This suggests that proclivity for laughing at oneself really is a distinct trait, separate from a general readiness to laugh.

Finally, those participants who laughed more at themselves tended to have more cheerful, less serious dispositions and to be in a better mood on the day of testing.

“…[T]he current study succeeded in providing the first empirical evidence on the phenomenon of laughing at oneself,” the researchers said.

ResearchBlogging.orgBeermann, U., and Ruch, W. (2011). Can people really “laugh at themselves?”—Experimental and correlational evidence. Emotion, 11 (3), 492-501 DOI: 10.1037/a0023444

This post was written by Christian Jarrett for the BPS Research Digest.

We sit near people who look like us

The next time you’re in an audience, turn to the person sat next to you and take a good look. That’s what you look like, that is. Scary eh? Sean Mackinnon and his research team have shown that people sit next to people who resemble themselves. The effect is more than just people of the same sex or ethnicity tending to aggregate – a phenomenon well documented by earlier research. The new finding could help explain why it is that people so often resemble physically their friends and romantic partners (known as “homophily“) – if physically similar people choose to sit near each other, they will have more opportunities to forge friendships and romances.

Mackinnon’s team first noted the seating positions of hundreds of different students in a 31-seat computer lab 21 times over 3 months, and whether or not they were wearing glasses – a simple proxy for physical similarity. The students, it was found, sat next to someone who matched them on glass-wearing status far more often than would be expected if they were randomly distributed (the effect size was .63).

A second study of 18 university classes involving over two thousand students expanded this finding to show people were more likely to sit next to someone who matched them on glass-wearing, hair colour and hair length, than would be expected by chance. This held true even focusing just on females or just on Caucasians, thus showing the physical similarity effect is more than mere aggregation by sex or race.

But what if people sit next to physically similar others simply as a side-effect of tending to sit near to friends or partners who, as prior research has shown, tend to be physically similar? A third study addressed this concern by seeing how close participants sat to a stranger. Seventy-two participants took part in what they thought was a study into non-verbal behaviours, part of which involved pulling a chair up to an unfamiliar co-participant (a role played by an actor) so as to interview each other. As expected, participants who more closely resembled the young lady (a 20-year-old brown-haired Caucasian) tended to choose to sit closer to her.

Why do we choose to sit near people who look like ourselves? Clues come from Mackinnon’s final study. One hundred and seventy-four participants looked at photos of eight individuals and rated how much they liked them, how much they perceived them to have similar attitudes, and thought they would be accepted by them. They also said how close they would choose to sit near each person. Consistent with the earlier studies, participants said they’d sit nearer those individuals who resembled them (based on similarity ratings provided by independent judges). They also thought these physically similar individuals would share their attitudes, they liked them more, and they expected to be accepted by them, as compared with their judgments about physically dissimilar others. The shared attitudes factor was the strongest. A further possibility is that seeking proximity to physically similar others is an evolutionary hang-over – an instinct for staying close to genetically similar kin.

“Though perhaps appearing innocuous on the surface, the simple process of choosing to sit beside people who are similar to us can have broad implications at the macro level,” the researchers said. ” … [S]egregation may occur, which can result in myriad prejudices and misunderstandings. Of course, this tendency is merely one portion of the overall processes that contribute to segregation and homophily more generally, but given the implications for racial and ethnic segregation, it is certainly a phenomenon with profound implications worthy of further pursuit.”

ResearchBlogging.orgMackinnon, S., Jordan, C., and Wilson, A. (2011). Birds of a Feather Sit Together: Physical Similarity Predicts Seating Choice. Personality and Social Psychology Bulletin, 37 (7), 879-892 DOI: 10.1177/0146167211402094

This post was written by Christian Jarrett for the BPS Research Digest.

Has the Internet become an external hard drive for the brain?

Last year’s annual question posed by Edge was “How is the Internet changing the way you think?” Several psychologists answered that it was becoming an extension of their minds. “The Internet is a kind of collective memory,’ wrote Stephen Kosslyn (Harvard University). “When I write with a browser open in the background, it feels like the browser is an extension of myself.”

A research team led by Betsy Sparrow has now tested the idea that the Internet really has become a kind of memory prosthesis. First they showed that difficult questions prompted dozens of undergrad participants to think automatically of computers and search engines. Participants tackled either easy or difficult trivia questions and then completed a version of the classic Stroop task: they had to look at a series of words and say what colour ink they were written in. After difficult questions, participants were extra slow at naming the colour of words like “Google”. This is a sign that the search engine concept was salient in their minds and therefore interfered more with the process of colour naming.

Next, a group of dozens more undergrad participants read 40 trivia statements and then typed them into a computer. Half the participants were told that the computer would save their entry, the others were told the entries would be deleted. Participants in the “saved” condition performed worse at a subsequent recall test of the statements, as if they’d relied on the computer as an external memory store. Half the participants in both conditions had been instructed explicitly to try to remember the statements, but this made no difference to their memory performance. “Participants were more impacted by the cue that information would or would not be available to them, regardless of whether they thought they would be tested on it,” the researchers said.

In another task, a group of participants read trivia statements and then typed them out, with a message telling them which folder the statement had been saved in. Ten minutes later they wrote out as many of the statements as they could, and then they attempted to recall which folder each statement, identified by a single prompt, had been saved to (e.g. “What folder was the statement about the ostrich saved in?”). The striking finding here is that participants were better at remembering the location of the statements than the statements themselves. What’s more, they were more likely to remember the location of statements which they’d failed to recall. It’s as if we’ve become adept at using computers to store knowledge for us, and we’re better at remembering where information is stored than the information itself.

“This is preliminary evidence that when people expect information to remain continuously available (as we expect with Internet access), we are more likely to remember where to find it than we are to remember the details of the item,” the researchers said. “One could argue that this is an adaptive use of memory – to include the computer and online searches as an external memory system that can be accessed at will.”


The issue of whether and how the Internet is changing our brains and the way we think tends to generate a lot of hyperbole and hot air. There is in fact a long history of technology exciting such reactions. Against that context, it’s refreshing to have some new, relevant data (also see here) as opposed to yet more excitable conjecture. However, it’s important to keep these new findings in perspective: they hint at how the Internet could be altering our memory habits, but they haven’t demonstrated that this is any different from other forms of memory support. For example, similar results might have been obtained if trivia statements had been written in notebooks or told to friends, as opposed to typed into a computer. Of course it pays to note that the present study didn’t actually involve the Internet at all. And there’s also no evidence here of any irreversible effects  – our minds are likely adapting to technology all the time, as they do to everything else, but there’s no reason they couldn’t adapt back again if necessary.

ResearchBlogging.orgB Sparrow, J Liu, and M Wegner (2011). Google effects on memory: Cognitive consequences of having information at our fingertips. Science : 10.1126/science.1207745

[This post was written by Christian Jarrett for the BPS Research Digest.]

Why’s everyone picking on group therapy?

Group therapy just can’t catch a break.

Here’s a video of animals from NYC’s Bronx Zoo with a group therapist working through the difficult feelings they’re having about the budget cuts New York City has proposed for its funding of the zoo:

In politics, a reference to group therapy seems like a pejorative for politicians getting together and feeling sorry for themselves, as in this posting maligning what he apparently views as a “touchy-feely” quality in former GOP Chairman Michael Steele’s new blog. Byard Duncan writes, “Steele’s first post, which is peppered with unnecessary commas and vague paeans to modern technology, reads sort of like group therapy session for the GOP.”

Earlier this month, Representative Tim Murphy (a bona-fide psychologist, it seems) referred to a budget talk between Republican congressional leaders and president Obama as “good group therapy,” apparently referencing the fact that even though no problems were resolved, everyone talked about his or her feelings.

On the sports front, there’s this mock group therapy scenario from the Bleacher Report where member schools from the NCAA’s troubled Big 12 Conference get together with a counselor to make fun of Iowa State and deliver such jewel’s as:

Nebraska: Hey, can you tell me how to cheat and get away with it? I’m getting kind of desperate over here.

Missouri: Me too. Dude, you know that I, like, hate you, but could you tell me how to cheat too?

Oklahoma State: Yo, homes, me too. I’ll pay cash money.

Just this week, the Village Voice noted that a rally to save H & H Bagels’ flagship store on NYC’s Upper West Side. Poking fun of the low turn out, the reporter write, “From the sounds of it, it more resembled a group therapy session [than a rally].”

What can we learn from this about group therapy?

Well for starters, it’s apparently the case that in the mind of reporters, politicians and… whoever wrote the football piece (“writer” seems generous), group therapy is a place where people get together to fight, whine, coddle (or be coddled), and feel sorry for themselves.

Ironically, you see surprisingly little mocking of individual therapy going on. It’s not unheard of, but relative to group therapy, hardly any. You wouldn’t expect much room to feel sorry for yourself in an individual psychotherapy session, would you? Or whining and complaining? Or picking fights? And yet many people expect such things when they think of group therapy.

I wonder where they got that idea?

Babies prefer Picasso

Still life with guitar by Picasso [c.]

Psychologists who study art appreciation have their work cut out. How does one begin to untangle cultural influences from more basic perceptual factors – the cachet from the contours? Well one way is to study babies, because they’re obviously too young to know about cultural fads and artistic reputations.

Trix Cacchione and her team at the University of Zurich presented nine-month old babies with paintings by the cubist painter Picasso and the impressionist Monet. Their first aim was to see if the babies could tell the difference between the two painting styles. They did this by continually presenting the babies with different paintings by one of the artists until they grew bored (known as “habituation”) and then seeing if the babies treated the sight of a painting by the other artist as somehow different, and therefore more worthy of their attention. The finding here was that babies who’d habituated to Monet were thereafter more attracted to a painting by Picasso, as revealed when new paintings by each artist were presented together side by side. There was clearly something novel about a Picasso painting that they perceived and found stimulating, which led them to look at it more. However, the reverse wasn’t true. Babies habituated to Picasso preferred to look at yet another Picasso painting rather than enjoy the greater novelty of a Monet.

Next the researchers checked the babies could distinguish between different paintings by the same artist. They found that babies habituated to one particular Picasso were attracted to a new Picasso more than a repeat. Ditto for Monet – the babies preferred a new Monet to a familiar old one.

So why did the babies prefer to look at yet another Picasso, even after they’d seen loads of them, rather than enjoy the novelty of a Monet? The implication is that the appeal of a Picasso overpowers the novelty of a Monet. There’s clearly something about Picasso, but what is it?

Cacchione’s team looked at a whole range of factors: Picasso’s use of vivid colours, sharp contours, and his use of squares and other figurative elements (Monet pictures, by contrast, are more subtle and realistic). But each time the researchers removed one of these elements, for example by using black and white pictures of the paintings, the babies still preferred Picasso.

The most likely explanation then is that it’s something about these elements in combination that appeals to babies. One further factor, which the current study didn’t look at, is luminance or “perceived lightness”. The researchers said it’s possible that babies prefer Picasso because of the greater luminance of his paintings. Crucially, luminance is processed mostly by the dorsal visual stream (the “where pathway”). This would fit with the idea that babies don’t yet have a fully developed visual system – in particular the ventral stream (also known as the “what pathway”) is immature.

“Many of Monet’s paintings have so little luminance contrast that it is impossible to recognise their elements on the basis of dorsal processing,” the researchers said. “It is possible that infants preferred paintings by Picasso, because they were easier to process and afforded the most stimulation to their still developing visual system.”

A final possibility is that there’s something about Monet that babies don’t like, rather than there being something particularly appealing about Picasso. Only further studies with more babies and different artists will get to the truth of why there appears to be something about Picasso.

ResearchBlogging.orgCacchione, T., Möhring, W., and Bertin, E. (2011). What is it about Picasso? Infants’ categorical and discriminatory abilities in the visual arts. Psychology of Aesthetics, Creativity, and the Arts DOI: 10.1037/a0024129

This post was written by Christian Jarrett for the BPS Research Digest.

Does crying really make you feel better?

Psychologists have made surprisingly little progress in explaining why we cry. A popular idea is that crying is cathartic – that the tears of sadness wash away life’s woes like detritus carried off in the tide. This has been supported by retrospective surveys that ask people how they felt after previous bouts of crying. Lab studies, by contrast, which involve participants watching weepie movies, have found crying to have no such benefit. Both approaches, however, are seriously flawed. Findings from the retrospective approach are prone to memory distortion and people’s answers are likely influenced by the popular cathartic idea. Lab studies, meanwhile, suffer from a lack of realism.

A superior method is to have participants complete a daily crying diary for an extended period of time, to be completed each night – soon enough to reduce memory distortions, but not too intrusive to interfere with the behaviour under observation. Believe or not, just one diary study of crying has been conducted before. Now Lauren Bylsma and her colleagues have performed the second, involving 97 female undergrads who completed a crying diary, including questions about daily mood and crying context, for between 40 and 73 days. In all, 1004 crying episodes were documented, and all participants cried at least once. Most bouts of crying were triggered by conflict; the next most common reason was loss, followed by personal failing.

Bylsma’s headline finding is that crying mostly had little positive benefit, at least not on overall daily mood. Not only did crying episodes tend to be preceded by two days of lower daily mood, they were also associated with lower daily mood on the day of crying and lower daily mood on two successive days afterwards. For mood in the specific moments after a crying session, the results were more encouraging. Most often mood was reported as unchanged (60.8 per cent), but 30 per cent of sessions were associated with a positive mood change, with 8.8 per cent leading to a deterioration in mood.

Other findings included: more intense (but not longer) crying episodes were associated with more positive mood outcomes, as were crying episodes that followed a feeling of inadequacy and that triggered a positive change in the situation. Also, crying in the company of one other person was associated more often with positive mood change than was crying alone or crying in the company of multiple people. Conflict tears tended not to be associated with a positive mood change, undermining the idea that tears can defuse social tensions.

The study has its limitations – for example, the mood scale only had a three-point range, and of course it’s a shame that men weren’t included too. But even granted these limitations, the researchers emphasised that theirs was “the first extended examination of the relationship between crying and mood using detailed contextual information from multiple crying episodes and, as such, represents an important step towards understanding this striking human behaviour.”

ResearchBlogging.orgBylsma, L., Croon, M., Vingerhoets, A., and Rottenberg, J. (2011). When and for whom does crying improve mood? A daily diary study of 1004 crying episodes. Journal of Research in Personality, 45 (4), 385-392 DOI: 10.1016/j.jrp.2011.04.007

Related Digest item: What does crying do for you?

This post was written by Christian Jarrett for the BPS Research Digest.

Start small? Hardly

Not once have I picked up the phone at my NYC therapy office and heard the words, “I’d like to make just a few small changes in my life.” And yet so many people seem satisfied to pass along that age-old, conservatizing little adage: “start small.”

Start small?

It seems beyond question to me that this is precisely the opposite of what needs to happen. Perhaps it’s easier to hear because taking on everything seems overwhelming. Call me quirky, but it’s taking on just this one little thing that seems overwhelming to me.

Let me explain:

It’s all connected

Just as the “leg bone’s connected to the knee bone, and the knee bone’s connected to the thigh bone,” and so on, all the different parts of your emotional life are connected. There’s a relationship between your work life and your diet and your sex life and your relationship with your family and your mood and everything else. In fact, the relationships between these emotional parts are way more complex than the relationships between your body parts (which are, of course, way more complicated than that song suggests).

In fact, emotional stuff is connected to other emotional stuff (not to mention other people’s emotional stuff) in such a way that changes in one part can’t help but effect the other parts. It seems to me it would be impossible to actually  change just one or two small little pieces.

It’s more work. And that’s the good news.

If you give up the notion that it’s possible to change “just this one thing,” and recognize that the various bits and pieces or our lives are all part of a larger whole, then you can start to see change in a whole new light. Let’s face it, even when we’re determined to do one part of our lives differently, sometimes we fail (or at least get stuck). But if everything is connected, then that opens up a lot of other options. It’s sort of like a house with many doors. If the front door is locked, you’ve got other ways to try to get in. The more you embrace just how much everything in your life is related to everything else in your life, the more ways there are of getting in.

You’d like an example:

Sara is trying to loose weight. Try as she might, she can’t seem to stick to a diet. My advice? Take a look at what’s going on around the issue of diet. What emotional issues related to food (or not related to food) are going on her life (mood, frustration)? How’s her social life? What’s Sara doing for fun? How does Sara feel about her job?

You see how not all of the questions relate directly to food? What’s prioritized here is helping Sara make lots of changes in her life, not just with eating. If we’re stuck in trying to make changes with food, we have to look for other things to work on, and that doesn’t mean we’re ignoring the issue of food. What we’re doing is saying, “Hey, everything’s related to food (and everything else).” We’re finding another way in.

It’s just like shoveling snow

It’s more like shoveling ice, to be precise. If you’ve lived in a wintry climate (or owned a car in NYC), you know well that when shoveling a driveway or walkway there are often patches that have gotten compressed and are harder move. Hack away as you might, you just can’t get that one particular chunk to budge. You learn quickly to move on from that very spot, and start going at the chunk of ice from another angle. You keep hacking until you find a spot that will move. If you keep doing this, eventually, you get back to that first chunk and, more often than not, it budges.

Now you’ve got something new to think about with all that stuff you’re stuck on.

What are you waiting for? All you have to do to get started is to just make lots and lots of really huge changes.

That doesn’t sound so hard, does it?

Men are as motivated by cute baby faces as women

Cuteness as an evolutionary adaptation

Both Charles Darwin and Konrad Lorenz, the pioneering ethologist, wrote about the appeal of baby faces as a possible adaptive mechanism. They surmised that babies’ perceived cuteness could be nature’s way of ensuring the little terrors get looked after. Now a team led by Morten Kringelbach and Christine Parsons has shown that men are as motivated by baby faces as women. Kringelbach is the same researcher who a few years ago showed that looking at baby faces, as opposed to adult faces, is associated with a distinct pattern of brain activity in the orbitofrontal cortex – a kind of neural “cuteness response”.

For the new study, 31 men and 37 women (average age 20 years), all with limited experience of babies, looked at photographs of the faces of 70 babies (aged 3 to 12 months), each shown for five seconds, and rated their attractiveness. These results conformed to cultural stereotypes about gender differences, with the women tending to rate the babies as more attractive than the men (no such gender difference emerged for the rating of adult faces). A desire to conform to gender roles could have played a role here. However, both men and women rated as more attractive those baby faces that most closely conformed to the cute ideal: a large rounded forehead, large low-set eyes, a short and narrow nose and a small chin.

In another part of the experiment, performed either before or after the attractiveness ratings, the participants were able to press a button repeatedly to control how long each baby face remained on the screen. This was taken as a measure of how much the participants were motivated to look at the faces. In this case the men scored just the same as the women. Moreover, for both men and women it was those faces that most closely conformed to the cute ideal that they made the effort to look at for longer.

“Our findings indicate that both men and women appraise what is colloquially described as a ‘cute’ unfamiliar infant positively, and they will work to see that infant for longer than an infant with less ‘cute’ features,” the researchers said. “This is in line with previous studies showing that ‘cuter’ infants are rated as more friendly, cheerful, and likeable and are rated as more ‘adoptable’.”

ResearchBlogging.orgParsons, C., Young, K., Kumari, N., Stein, A., and Kringelbach, M. (2011). The Motivational Salience of Infant Faces Is Similar for Men and Women. PLoS ONE, 6 (5) DOI: 10.1371/journal.pone.0020632

This post was written by Christian Jarrett for the BPS Research Digest.

Why is a touch on the arm so persuasive?

A gentle touch on the arm can be surprisingly persuasive. Consider these research findings. Library users who are touched while registering, rate the library and its personnel more favourably than the non-touched; diners are more satisfied and give larger tips when waiting staff touch them casually; people touched by a stranger are more willing to perform a mundane favour; and women touched by a man on the arm are more willing to share their phone number or agree to a dance. Why should this be? Up until now research in this area has been exclusively behavioural: these effects have been observed, but we don’t really know why. Now a study has made a start at understanding the neuroscience of how touch exerts its psychological effects.

Annett Schirmer and her colleagues used EEG to record the surface electrical activity of the brains of dozens of female participants who were tasked with looking at neutral or negative pictures (e.g. a basket or a gun to the head). Before each picture appeared, the participants were sometimes touched on the arm by a female friend; touched by a mechanical device (a pressure cuff); or they received no touch. The idea was to see whether and how being touched changed the way the brain responded to emotional and neutral pictures.

A further detail is that the mechanical touch was described as either under the friend’s control, with the friend located elsewhere, or under computer control. This was to see if physical proximity matters and whether it matters who does the touching. For comparison, a final experiment also tested the effect of an auditory tone, which preceded some pictures but not others.

The most important finding is that a touch on the arm enhanced the brain’s response to emotional pictures, as revealed by the size of what’s known as the late positive component (LPC) of electrical brain activity. The LPC is thought to be associated with evaluative mental processes and a touch led to a greater LPC for emotional pictures compared with neutral ones.

Touch had this effect regardless of how it was administered and who did the administering (friend or machine). This suggests the reported effects of touch are largely “bottom up” – that is, based mainly on the incoming stimulation – rather than “top down”, to do with beliefs about the meaning of the touch. Unlike touch, the auditory tone didn’t increase the brain’s sensitivity to emotional pictures.

“Emotional information presented concurrently with touch may be more motivating such that more processing resources are allocated to them than to emotional information presented without touch,” the researchers said.

One consequence of this, Schirmer’s team speculated, could be that the touched person is primed to be more altruistic, consistent with previous behavioural results. “Based on the present findings,” they explained, “we propose that such behaviour occurs because the tactile signal alerts its recipient and enhances the processing of concurrent events, particularly if they are emotional. Such enhanced processing may then, among others, boost empathy and increase the likelihood that the touch recipient acts in favour of the toucher.”

ResearchBlogging.orgSchirmer, A., Teh, K., Wang, S., Vijayakumar, R., Ching, A., Nithianantham, D., Escoffier, N., and Cheok, A. (2011). Squeeze me, but don’t tease me: Human and mechanical touch enhance visual attention and emotion discrimination. Social Neuroscience, 6 (3), 219-230 DOI: 10.1080/17470919.2010.507958

This post was written by Christian Jarrett for the BPS Research Digest.