Are we now blasé about brain scans?

People are so awestruck by neuroscience, the briefest mention of brain-based jargon or glimpse of a brain scan is enough to send their critical faculties into a flutter. Or so they said. But now a new study finds that in fact most people are singularly non-wowed by the technical brilliance of brain scan images.

Robert Michael and his colleagues performed ten replication attempts of a hugely influential finding published in 2008. Back then David McCabe and Alan Castel reported that undergrad students were more persuaded by a neuroscience news story when it was accompanied by a picture of a brain scan, as compared with a bar chart or no image. The result is mentioned frequently in the popular press as evidence of our neuro-enthrallment. It receives about 40 scholarly citations a year, but until now no-one has checked if the effect is real.

Seven of Michael's ten replications were performed online, three with paper materials, together involving nearly 2000 participants, including members of the public and students. As in the McCabe and Castel study, participants read a news item about brain scans being used to detect criminals. Afterwards the participants said if they agreed with the story's conclusion that brain scans can be used as a lie detector.

Combining the results from the McCabe and Castel study with the new data, overall the presence of a brain scan in the news story had only a tiny effect on participants' answers. On a 4-point response scale (from strongly disagree to strongly agree with the story), this reflected a shift of just 0.07 points or 2.4 per cent in agreement. "The image of the brain exerted little to no influence," the researchers said. The effect of the brain scan image didn't vary with the format of the study - online vs. paper. Participant age and education level also made no difference.

Past research outside of the neuroscience context has shown that images can make accompanying text more understandable and persuasive. The remarkable ineffectiveness of a brain scan in the current replications is therefore something of a puzzle. One explanation is that the impact of the image will vary according to the neuroscience training of the observer. "To people who may not understand how fMRI works, or even where the frontal lobes are, seeing an image of the brain may not be any more helpful than seeing an ink blot," the researchers said. Future research will need to test this.

Another possibility is that people have grown more sceptical of neuroscience since the 2008 McCabe and Castel finding was published. To test this possibility, Michael and his colleagues performed five online replications of another influential study - the 2008 discovery that people were more impressed by bad explanations when they contained gratuitous neuroscience language. This finding was replicated, arguing against the idea that people have become inoculated more generally against the persuasive power of neuroscience.

In the replications of McCabe and Castel, perhaps the addition of a brain scan image failed to make the lie detection news story more convincing because that story already contained persuasive neuroscience language. Regardless, this new paper adds to evidence showing the failure of brain images to sway jurors. And Michael's team said (quoting Martha Farah) it shows "the 'amazingly persistent meme of the overly influential image' has been wildly overstated." Recently, Farah and her colleague Cayce Hook described this phenomenon as the “seductive allure of ‘seductive allure’".

_________________________________

Michael, R., Newman, E., Vuorre, M., Cumming, G., and Garry, M. (2013). On the (non)persuasive power of a brain image. Psychonomic Bulletin and Review DOI: 10.3758/s13423-013-0391-6

--Further reading--
The power of blobs on the brain
Are Brain Scans Really So Persuasive?

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Working memory training does not live up to the hype

According to CogMed, one of the larger providers of computerised working memory training, the benefits of such training is "comprehensive" and includes "being able to stay focused, resist distractions, plan activities, complete tasks, and follow and contribute to complex discussions." Similar claims are made by other providers such as Jungle Memory and Cognifit, which is endorsed by neuroscientist Susan Greenfield.

Working memory describes our ability to hold relevant information in mind for use in mental tasks, while ignoring irrelevant information. If it were possible to improve our working memory capacity and discipline through training, it makes sense that this would have widespread benefits. But that's a big if.

A new meta-analysis by Monica Melby-Lervåg and Charles Hulme has just been published in the February issue of the respected APA journal Developmental Psychology, which combined the results from 23 studies of working memory training completed up to 2011 (PDF is freely available). To be included, studies had to compare outcomes for a working memory training treatment group against outcomes in a control group. Most of the studies available are on healthy adults or children, with just a few involving children with developmental conditions such as ADHD.

The results were absolutely clear. Working memory training leads to short-term gains on working memory performance on tests that are the same as, or similar to, those used in the training. "However," Melby-Lervåg and Hulme write, "there is no evidence that working memory training produces generalisable gains to the other skills that have been investigated (verbal ability, word decoding, arithmetic), even when assessments take place immediately after training."

There was a modest, short-term benefit of the training on non-verbal intelligence but this disappeared when only considering the studies with a robust design (i.e. those that randomised participants across conditions and which enrolled control participants in some kind of activity). Similarly, there was a modest benefit of the training on a test of attentional control, but this disappeared at follow-up.

All of this suggests that working memory training isn't increasing people's working memory capacity in such a way that they benefit whenever they engage in any kind of task that leans on working memory. Rather, people who complete the training simply seem to have improved at the specific kinds of exercises used in the training, or possibly even just at computer tasks - effects which, anyway, wear off over time.

Overall, Melby-Lervåg and Hulme note that the studies that have looked at the benefits of working memory training have been poor in design. In particular, they tend not to bother enrolling the control group in any kind of intervention, which means any observed benefits of the working memory training could be related simply to the fun and expectations of being in a training programme, never mind the specifics of what that entails. Related to that, some dubious studies reported far-reaching benefits of the working memory training, without finding any improvements in working memory, thus supporting the notion that these benefits had to do with participant expectations and motivation.

A problem with all meta-analyses, this one included, is that they tend to rely on published studies, which means any unpublished results stuck in a filing cabinet get neglected. But of course, it's usually negative results that get left in the drawer, so if anything, the current meta-analysis presents an overly rosy view of the benefits of working memory training.

Melby-Lervåg and Hulme's ultimate conclusion was stark: "there is no evidence that these programmes are suitable as methods of treatment for children with developmental cognitive disorders or as ways of effecting general improvements in adults' or children's cognitive skills or scholastic achievements."

_________________________________

Melby-Lervåg M, and Hulme C (2013). Is working memory training effective? A meta-analytic review. Developmental psychology, 49 (2), 270-91 PMID: 22612437 Free, full PDF of the study.

--NB.--
This meta-analysis only took in reviews published up to 2011. If you know of any quality studies into the effects of working memory training published since that time, please do share the relevant links via comments. 

--Further reading--
Brain training games don't work.
Brain training for babies actually works (short term, at least)

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Resilient, friendly people are more responsive to placebo treatment

The placebo effect is a wonderful thing. Inert treatments provoke real medical benefits simply by virtue of the patient expecting the intervention to help. But of course, a lot of times placebos don't work, and some people seem to be more responsive to their benefits than others. A new study by researchers at the University of Michigan has set about discovering if personality plays a role here, specifically in relation to placebo treatment for pain.

Marta Peciña and her colleagues provoked pain in 47 men and women by injecting hypertonic saline solution into their jaw muscle. Pain levels without treatment were then compared against the participants' experience each time they received a placebo, in the form of a 15 second intravenous delivery of harmless isotonic saline solution. All the while, the participants were scanned via PET, to see how much activity occurred at the brain's opioid receptors. This was to provide an objective measure of the activity of the brain's own pain relief system.

There was a clear relationship between participants' scores on various personality measures and their responsiveness to placebo. A mix of ego resilience (measured by statements like "I quickly get over and recover from being startled"); high agreeableness (especially altruism and honesty); and low neuroticism (especially low levels of angry hostility) accounted for 25 per cent of the variance in participants' degree of response to the placebo treatment. Moreover, the participants who matched this pattern of traits tended to show more opioid receptor activation in their brains. Surprisingly perhaps, placebo responsiveness was not related to a person's general optimism.

Why should a person's agreeableness be related to their response to placebo treatments? "In the patient-doctor relationship, agreeableness appears likely to contribute to a strong therapeutic alliance," the researchers said, "as well as to frank, collaborative feedback through the therapeutic process. Thus, it appears that individuals high upon this trait are particularly well equipped to fully engage in therapeutic efforts, and in this sense, be a good responder to treatment, even if it is placebo." Meanwhile, the finding for angry hostility fits with past research showing that angry people tend to exhibit less indigenous opioid activity in their brains.

Peciña and her team said their findings, if replicated, could help with future pain research. "Simple to administer measures may aid in the interpretation of clinical trials and the stratification of clinical research volunteers to reduce variability in therapeutic responses," they said.

_________________________________

Peciña, M., Azhar, H., Love, T., Lu, T., Fredrickson, B., Stohler, C., and Zubieta, J. (2012). Personality Trait Predictors of Placebo Analgesia and Neurobiological Correlates Neuropsychopharmacology DOI: 10.1038/npp.2012.227

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Extreme fear experienced without the amygdala

There's a female patient, known in the research literature as S.M., who's been dubbed the "woman with no fear". She has severely damaged amygdala on either side of her brain and consequently is left unmoved by snakes, spiders, horror films, haunted houses and real-life knife attacks. She doesn't even have a sense of personal space. But when S.M. inhaled carbon dioxide for a new study, she was far from calm. Within seconds, she groped desperately for the air mask and cried for help. After researchers removed the mask, S.M.'s entire body went rigid, her toes and fingers flexed taut, toward the ceiling. Her skin was flushed, her eyes wide like a scared animal. Thirty-seconds after the ordeal, she began to calm, finally releasing the experimenter's hand. Later, she recalled the experience she'd had was of panic - "the number one, worst" feeling ever.

The amygdala is an almond-shaped structure found deep on either side of the brain. So many studies have shown it to be involved in learning and experiencing fear, it's become shorthand to refer to it as the brain's "fear centre", even though it's also involved in positive emotional processing. The apparent fearlessness of S.M., who lost her amygdala to Urbach-Wiethe disease (a rare genetic disorder), had previously supported this caricature. But now things have gotten a lot more complicated*. Carbon dioxide inhalation causes unpleasant suffocating feelings and it triggers panic in those susceptible to it. But if S.M. has no "fear centre", how and why did she get so scared and panicky after inhaling?

To check this was no anomaly, Justin Feinstein at the University of Iowa and his colleagues also tested two other patients with bilateral amygdala damage (a pair of identical twins, A.M. and B.G.). These patients also had panic attacks and experienced fear when they inhaled carbon dioxide. They and S.M. said these fearful feelings were entirely novel to them. It's notable too that this wasn't a one off. The patients' panic reaction occurred all over again during a repeat of the carbon dioxide procedure.

And yet, when the researchers performed the carbon dioxide inhalation with 12 healthy controls, 9 of them exhibited no panic and they reported far less fear than the patients. Three of the controls did panic. The amount of subjective fear and panic reported by these panicky controls and the patients was equivalent, and their physiological signs were similar, such as raised heart-rate. The only difference between the patients and the panicky controls was that the former didn't show any signs of anticipatory anxiety when they saw the apparatus being prepared.

So we have a situation where three out of three patients with bilateral amygdala damage (who are usually fearless) panicked and experienced more fear than nine of the twelve amygdala-intact controls. What's going on? Feinstein and his team think that CO2 inhalation acts on "interoceptive" receptors that project directly to the brainstem and other sites that "underlie fear and panic", whereas other fear-stimuli, like scary films or dangerous animals, are "exteroceptive in nature, mainly processed through visual and auditory pathways that project to the amygdala". The patients were completely unfazed when the procedure was repeated with normal air, supporting the idea that the carbon dioxide played a specific role in provoking fear.

This still leaves the mystery of why the amygdala-damaged patients were more disturbed by the carbon dioxide inhalation than most of the controls. Here the researchers' interpretation is bold. They suggest that an intact amygdala might normally serve to inhibit panic. This isn't as revolutionary as it seems. Feinstein's team point to a study from ten years ago that found patients with panic disorder had amygdala atrophy. So, if we consider this brain structure as the "centre" of anything, perhaps it should be as the centre of calm!

This new study also raises some deep, almost philosophical questions. If the amgydala-damaged patients usually live a life that's entirely fear-free, how did they know to describe their feelings during the inhalation as extreme fear or panic? Can we be sure they really felt fear the way that the rest of us do? The researchers have previously reported that S.M. references fear and anxiety appropriately in conversation, and she can recognise fear in others, so perhaps she does have a solid understanding of the concept. Finally, what do these findings say about the neural correlates of the subjective sense of fear and panic? At the very least it seems the amygdala is not necessary for the conscious experience of fear.
_________________________________

 Justin S. Feinstein, Colin Buzza, Rene Hurlemann, Robin L. Follmer, Nader S. Dahdaleh, William H. Coryell, Michael J. Welsh, Daniel Tranel, and John A. Wemmie. (2013). Fear and panic in humans with bilateral amygdala damage. Nature Neuroscience, DOI: 10.1038/nn.3323

*Please note, this isn't the first documented case of fear in a patient with bilateral amygdala damage. In a 2002 diary study (pdf), one such patient reported normal daily experience of anxiety and fear, but impaired recognition of other people's fearful expressions. S.M. (in the current study) is impaired at recognising fear in static images of faces but she can recognise fear in people's voices and from dynamic displays of fearful faces. One obvious question mark over the 2002 study is the reliance on self-report of fear. 


Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Glimpsed at last - the life of neuropsychology's most important patient

Leborgne's brain

Monsieur Leborgne, nicknamed Tan Tan, for that was the only syllable he could utter (save for a swear word or two), died in the care of the neurologist Paul Broca in Paris on April 17, 1861. Arguably the most important case in the history of neuropsychology, Leborgne's death coincided with a debate raging in scholarly circles about the location of language function in the brain. When Broca autopsied Leborgne's brain, he observed a malformation on the left frontal lobe - "Broca's area" - and concluded this was the site of speech production, a moment that the historian Stanley Finger has described as a "key turning point in the history of the brain sciences".

Broca was far from being the first person to propose that speech function is located in the frontal lobes, but crucially, the evidence from Leborgne helped him persuade the academic community. For centuries experts had believed mental functions were located in the brain's hollows; that the cortex ("husk" in Latin) was little more than a rind of tissue and blood vessels. Today, problems producing language are still termed Broca's aphasia in recognition of Broca's landmark contribution, although Broca in fact named Leborgne's problems aphémie (meaning “without speech”). The Greek term “aphasia” (also meaning “speechlessness”), adopted by medicine, was coined in Broca's day by the physician Armand Trousseau.

Far more is known about Gage's life

In terms of the historical record, Leborgne is like a mirror opposite of Phineas Gage - another of neuropsychology's legendary cases. The story of Gage's life and infamous accident, in which a tamping iron shot through his brain, has been researched in-depth, inspiring books, poems, YouTube skits and snowmen makers along the way. Yet relatively little is known about the brain damage Gage suffered because no autopsy was performed when he died and his brain was never preserved (that hasn't stopped scientists from attempting to simulate the likely damage).

In contrast, Broca was careful to save Leborgne's brain for posterity. He decided against a full dissection, performing a surface examination only. Today the preserved organ is housed at the Musée Dupuytren museum in Paris, where Broca placed it. The brain has been scanned numerous times using modern methods (e.g. PDF), allowing detailed analysis of the location and nature of any lesions. We now know that the frontal lobe damage to Leborgne's brain was more extensive and deeper than Broca had realised based on his superficial examinations. But, contra the situation with Gage, while we are well-informed about Leborgne's brain, before now his identity and life story have remained largely mysterious. Broca's medical notes revealed little.

Thankfully, in a new paper, Cezary Domanski at Maria Curie-Sklodowska University in Poland has used archive registers in France to uncover hitherto unknown detailed biographical information about Monsieur Leborgne. Born in Moret-sur-Loing - the picturesque town that inspired Monet and other impressionists - "Tan's" full name was Louis Victor Leborgne. He was the son of Pierre Christophe Leborgne, a school teacher, and Margueritte Savard. He had three older siblings, Lucille, Pierre and Anne, and two younger siblings, Arsene and Louise.

An epileptic since his youth, it was Leborgne's loss of speech that led to him being hospitalised at age 30. Unmarried, he ended up spending the remaining 21 years of his life in hospital. Before this incapacitation through illness, Domanski tells us Leborgne was a "formier" in Paris, a kind of skilled craftsman who made the wooden forms used by shoemakers in their work.  Together with the information on Leborgne's family, this news corrects at least one historical myth. The oft-told idea that Leborgne "was an uneducated illiterate from the lower social class should once and for all be deemed erroneous," writes Domanski.

Based on his inquiries, the Polish historian offers an intriguing speculation - given that Leborgne's birthplace of Moret was home to several tanneries, Domanski wonders if his repeated utterance of Tan was somehow connected to childhood memories of the pretty town.

"One thing remains certain," Domanski concludes, "The memory of the disease and cause of death of 'Monsieur Leborgne' proved far more enduring than the story of his life, which was deemed irrelevant even when the patient was still alive. It is time for Louis Victor Leborgne to regain his identity ...".

In 2009, out of the blue, a photograph was discovered of Phineas Gage. I wonder if we will ever look upon an image of Leborgne?

_________________________________

Domanski CW (2013). Mysterious "Monsieur Leborgne": The Mystery of the Famous Patient in the History of Neuropsychology is Explained. Journal of the history of the neurosciences, 22 (1), 47-52 PMID: 23323531

--Further reading-- 
500 Francs Says Language Is Housed in the Frontal Lobes!
Speaking without Broca's area
Broca’s area: Nomenclature, anatomy, typology and asymmetry

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

How to kill an earworm

If earworms - songs that play in your head - drive you crazy, you'll welcome clues for how to eradicate them that come from a new study by psychologists at Western Washington University, USA.

First - and I realise this doesn't sound appealing - try to avoid songs that you like. The new research suggests they are most likely to become lodged in your head (contrary to the myth that it's obnoxious songs with most earworm potential). If you must listen to a favoured song, check to see if it starts playing in your head right afterwards. If it does, then it's well on its way to becoming an earworm. This is a particular risk is you find that only a part of the song plays in your head.

Ira Hyman Jr. and his colleagues believe this last detail may be a manifestation of the classic Zeigarnik Effect, whereby incomplete tasks remain in memory but evaporate once completed. In the case of earworms, the researchers propose that the playing of only a part of a song in your head leaves it incomplete and thereby increases the likelihood that it will return against your will as an earworm. This insight suggests that one way to squash a developing earworm is to make sure, once a song starts playing in your head, that you see it all the way through (perhaps you will need to listen to the track again to ensure this is possible).

Finally, after listening to music, try to avoid mental tasks that are either too easy or too difficult. Any kind of activity that increases your mind-wandering will also provide fertile ground for an earworm to develop. In the same vein, engaging in an absorbing task will tie up your mental resources and deny the earworm the chance to grow.

These insights are based on a survey and several lab experiments conducted by Hyman Jr. and his team. The survey of 299 students revealed that enjoyable, recently heard songs were more likely to become earworms; that a huge variety of songs become earworms; that musicians experience them more often and re-experience more aspects of songs.

In the experiments, dozens of students listened to and rated three songs by the Beatles and by more contemporary acts like Gaga (ostensibly as part of a completely different research study), then they completed a puzzle task. Afterwards they revealed whether any of the songs had started playing in their heads, and 24 hours later they reported whether the songs had returned as earworms.

Overly challenging sudoku or anagram tasks helped breed more earworms (the former more so than the latter). Beatles songs were just as likely to become earworms as modern hits. Songs played later in the experimental session (therefore more recently heard) were more likely to become earworms; and a song that started playing in the head soon after listening was more likely to become an earworm over the next 24 hours. Only playing part of songs to students, as opposed to the whole track, did not increase the risk of earworms.

"Songs frequently come to mind as intrusive thoughts, and intrusive song cycles are easy to start in both naturalistic and laboratory situations," the researchers said. "In our experimental studies, we have documented that intrusive song cycles are easy to start and manipulate. Therefore, songs may provide a valuable tool for examining why intrusive thoughts occur and how to control intrusive thought cycles."

_________________________________

Hyman, I., Burland, N., Duskin, H., Cook, M., Roy, C., McGrath, J., and Roundhill, R. (2012). Going Gaga: Investigating, Creating, and Manipulating the Song Stuck in My Head. Applied Cognitive Psychology DOI: 10.1002/acp.2897

--Further reading--
Hearing music that isn't there
A natural history of the Earworm - the song that won't get out of your head
What triggers an Earworm - the song that's stuck in your head?


Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Rapping in the brain scanner

In seeking to understand the brain processes underlying creative performance, researchers have already scanned opera singers and actors. Now they've invited rappers to undergo the same treatment. Siyuan Liu and her colleagues were specifically interested in the difference between freestyle rap, which requires the spontaneous generation of rhyming lyrics, and rehearsed rapping.

Twelve male professional rappers had their brains scanned while they engaged in freestyle rap and while they performed raps they'd learned earlier. Rappers usually like to gesticulate energetically as they perform, but this would have distorted the brain images so they had to keep still. No worry - "... debriefing indicated that participants' performance was not affected by the motion restraints," the researchers said. The fMRI brain scanner is effectively a powerful magnet so it would also have been imperative that the rappers remove all of their bling before the scan began.

The main finding was that freestyle rapping versus rehearsed rapping was associated with increased activation in medial (inner) areas at the front of the brain, especially on the left-hand side, and concomitant reductions in activity in dorsolateral frontal areas, especially on the right-hand side. These patterns of activation were anti-correlated - the greater the increases in left-medial areas, the more the reductions on the right lateral areas. Liu and her team think this reflects a kind of disinhibition, whereby supervisory attentional systems allowed creative areas of the brain to have free reign. The researchers said this fitted the possibility that the creative process of freestyle rap is experienced as largely occurring outside of conscious awareness. "This is is not inconsistent with the experience of many artists who describe the creative process as seemingly guided by an outside agency," they added.

Freestyle rapping also exercised language areas more powerfully than rehearsed rapping, likely indicative of the need to find appropriate rhyming words. The researchers also looked for other connectivity patterns by seeing how activity levels correlated across the brain. The medial frontal areas engaged by freestyle rap appeared to be connected to activity in prefrontal motor regions, the left amygdala and on to the right inferior frontal gyrus and inferior parietal lobes - what the researchers called a network integrating "motivation, language, emotion and motor function" and which they proposed could reflect the psychological state of "flow". Critics will likely wince at the excesses of reverse inference in this study - making assumptions about the role played by different brain areas during rapping based on the activity of those regions in other studies.

"We speculate that the neural mechanisms illustrated here could be generalised to explain the cognitive processes of other spontaneous artistic forms," the researchers concluded. Eminem was unavailable for comment.

_________________________________

Liu, S., Chow, H., Xu, Y., Erkkinen, M., Swett, K., Eagle, M., Rizik-Baer, D., and Braun, A. (2012). Neural Correlates of Lyrical Improvisation: An fMRI Study of Freestyle Rap. Scientific Reports, 2 DOI: 10.1038/srep00834

--Further reading--
Opera singing in the brain scanner

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Labs worldwide report converging evidence that undermines the low-sugar theory of depleted willpower

One of the main findings in willpower research is that it's a limited resource. Use self-control up in one situation and you have less left over afterwards - an effect known as "ego-depletion". This discovery led to a search for the underlying physiological mechanism. In 2007, Roy Baumeister, a pioneer in the field, and his colleagues reported that the physiological correlate of ego-depletion is low glucose. Self-control leads the brain to metabolise more glucose, so the theory goes, and when glucose gets too low, we're left with less willpower.

The breakthrough 2007 study showed that ego-depleted participants had low blood glucose levels, but those who subsequently consumed a glucose drink were able to sustain their self-control on a second task. In the intervening years the finding has been replicated and the glucose-willpower link has come to be stated as fact.

"No glucose, no willpower," wrote Baumeister and his journalist co-author John Tierney in their best-selling popular psychology book Willpower: Rediscovering Our Greatest Strength (Allen Lane, 2012). The claim was also endorsed in a guide to willpower published by the American Psychological Association earlier this year. "Maintaining steady blood-glucose levels, such as by eating regular healthy meals and snacks, may help prevent the effects of willpower depletion," the report claims.

But now two studies have come along at once (following another published earlier in the year) that together cast doubt on the idea that depleted willpower is caused by a lack of glucose availability in the brain. In the first, Matthew Sanders and his colleagues in the US report what they call the "Gargle effect". They had dozens of students look through a stats book and cross out just the Es, a tiresome task designed to tax their self-control levels. Next, they completed the famous Stroop task - naming the ink colour of words while ignoring their meaning. Crucially, half the participants completed the Stroop challenge while gargling sugary lemonade, the others while gargling lemonade sweetened artificially with Splenda. The participants who gargled, but did not swallow, the sugary (i.e. glucose-containing) lemonade performed much better on the Stroop task.

The participants in the glucose condition didn't consume the glucose and even if they had, there was no time for it to be metabolised. So this effect can't be about restoring low glucose levels. Rather, Sanders' team think glucose binds to receptors in the mouth, which has the effect of activating brain regions involved in reward and self-control - the anterior cingulate cortex and striatum.

The other study that's just come out was conducted by Martin Hagger and Nikos Chatzisarantis based in Australia and the UK. Their approach was similar to Sanders' except that participants gargled and spat out a glucose or artificially sweetened solution prior to performing a second taxing task, rather than during. Also, this research involved a series of 5 experiments involving many different ways of testing people's self-control, including: resisting delicious cookies; reading boring text in an expressive style; unsolvable puzzles; and squeezing hand-grips. But the take-home finding was the same - participants who gargled, but did not swallow, a glucose drink performed better on a subsequent test of their willpower; participants who gargled an artificially sweetened drink did not. So again, willpower was restored without topping up glucose levels. Moreover, the benefit of gargling glucose was displayed only by participants who'd had their self-control taxed in an initial task. It made no difference to participants who were already in an untaxed state.

Hagger and Chatzisarantis agree with the interpretation of the Sanders' group, except they make a distinction. The effect of glucose binding to receptors in the mouth could either stimulate activity in brain regions like the anterior cingulate that tend to show fatigue after a taxing task. Or they say that glucose in the mouth could trigger reward-related activity that prompts participants to interpret a task as more rewarding, thus boosting their motivation. The explanations are complementary and need not be mutually exclusive.

The key point is the new results suggest depleted willpower is about motivation and the allocation of glucose resources, not about a lack of glucose. These findings don't prove that consuming glucose has no benefit for restoring willpower, but they suggest strongly that it's not the principle mechanism. It's notable that the new findings complement previous research in the sports science literature showing that gargling (without ingesting) glucose can boost cycling performance.

"While our findings are consistent with the predictions of the resource-depletion account, they also contribute to an increasing literature that glucose may not be a candidate physiological analog for self-control resources," write Hagger and Chatzisarantis. "Instead ego-depletion may be due to problems of self-control resource allocation rather than availability." An important next step is to conduct brain-imaging and related studies to observe the physiological effects of gargling glucose on the brain, and on motivational beliefs. There are also tantalising applications from the new research - for example, could the gargle effect (perhaps in the form of glucose-infused chewing gum) be used as a willpower aid for dieters and people trying to give up smoking?

_________________________________

Hagger, M., and Chatzisarantis, N. (2012). The Sweet Taste of Success: The Presence of Glucose in the Oral Cavity Moderates the Depletion of Self-Control Resources. Personality and Social Psychology Bulletin DOI: 10.1177/0146167212459912

Sanders, M., Shirk, S., Burgin, C., and Martin, L. (2012). The Gargle Effect: Rinsing the Mouth With Glucose Enhances Self-Control. Psychological Science DOI: 10.1177/0956797612450034

--Further reading--
From The Psychologist: Roy F. Baumeister outlines intriguing and important research into willpower and ego depletion.

Post written by Christian Jarrett for the BPS Research Digest.

Introducing the SuperAgers - the elderly people whose brains have stayed young

They say the slow inevitable decline sets in during our early twenties. Like a rocket reaching its apogee, once the brain is fully developed there is the briefest lull, and then it's all downhill, the last neural areas to develop being the first to start unravelling. By the time of old age, so certain are the impairments in mental processing that psychological tests are age-adjusted - "You're slow Bob, but not for your age. For an 80-year-old you're doing just fine."

But wait. A team led by Theresa Harrison at the Cognitive Neurology and Alzheimer's Disease Center at Northwestern University say they've identified a group of elderly individuals whose brains appear relatively immune to the physical effects of ageing.

Harrison and her colleagues identified these 12 "SuperAgers" (average age 84) by their exceptional mental performance. They outperformed 10 typical healthy older folk (average age 83) on a test that involved recalling lists of words, and they matched the performance of 14 healthy middle-aged volunteers (average age 58). The SuperAgers also matched the middle-aged on tests of naming things, attention and task switching, and identifying drawings by category.

Using a structural brain scanner, the researchers found that the SuperAgers had brains that seemed to have resisted the erosive influence of time. Whereas the typical older participants had thinner cortices and smaller average brain volumes (244mm cubed average) than the middle-aged (306mm cubed), the SuperAgers' brain surfaces were just as thick as the middle-aged and their brain volumes (288mm cubed) not significantly different in statistical terms. Moreover, there was one brain region - the left anterior cingulate - that was actually thicker in the SuperAgers than in the middle-aged.

"These findings are remarkable," the researchers said, "given the numerous reports that grey matter loss is a common, if not universal, part of normal ageing."

Across the groups, brain volume correlated with episodic memory performance. Although cingulate thickness did not, Harrison's team still think it's interesting that this region was thicker in the SuperAgers. Relevant here is previous research showing that early protein accumulations in the cingulate region have been detected in Alzheimer patients.

This new study provides a tantalising demonstration that continuing neural decline into old age is not inevitable. Crucial now is to find out why the SuperAgers are so well preserved. It's not known, for example, if they had larger brains and greater cognitive reserves to begin with, or if their brains have simply aged more slowly than usual. Perhaps their lifestyles will hold clues, although the obvious role of education appears not to be relevant with this group. Their time in education was no longer than the other participants and in fact only four of them went to university.

"Identifying the underlying factors that promote this trajectory of unusually successful cognitive aging may lead to novel insights for preventing age-related cognitive impairments or strategies for evading the more severe changes associated with Alzheimer’s disease," the researchers said.

_________________________________

Theresa M. Harrison, Sandra Weintraub, M.-Marsel Mesulam, and Emily Rogalski1 (2012). Superior Memory and Higher Cortical Volumes in Unusually Successful Cognitive Aging. Journal of the International Neuropsychological Society DOI: 10.1017/S1355617712000847

Post written by Christian Jarrett for the BPS Research Digest.

Most brain imaging papers fail to provide enough methodological detail to allow replication

Amidst recent fraud scandals in social psychology and other sciences, leading academics are calling for a greater emphasis to be placed on the replicability of research. "Replication is our best friend because it keeps us honest," wrote the psychologists Chris Chambers and Petroc Sumner recently.

For replication to be possible, scientists need to provide sufficient methodological detail in their papers for other labs to copy their procedures. Focusing specifically on fMRI-based brain imaging research (a field that's no stranger to controversy), University of Michigan psychology grad student Joshua Carp has reported a worrying observation - the vast majority of papers he sampled failed to provide enough methodological detail to allow other labs to replicate their work.

Carp searched the literature from 2007 to 2011 looking for open-access human studies that mentioned "fMRI" and "brain" in their abstracts. Of the 1392 papers he identified, Carp analysed a random sample of 241 brain imaging articles from 68 journals, including PLoS One, NeuroImage, PNAS, Cerebral Cortex and the Journal of Neuroscience. Where an article featured supplementary information published elsewhere, Carp considered this too.

There was huge variability in the methodological detail reported in different studies, and often the amount of detail was woeful, as Carp explains:

"Over one third of studies did not describe the number of trials, trial duration, and the range and distribution of inter-trial intervals. Fewer than half reported the number of subjects rejected from analysis; the reasons for rejection; how or whether subjects were compensated for participation; and the resolution, coverage, and slice order of functional brain images."

Other crucial detail that was often omitted included information on correcting for slice acquisition timing, co-registering to high-resolution scans, and the modelling of temporal auto-correlations. In all, Carp looked at 179 methodological decisions. To non-specialists, some of these will sound like highly technical detail, but brain imagers know that varying these parameters can make a major difference to the results that are obtained.

One factor that non-specialists will appreciate relates to corrections made for problematic head-movements in the scanner. Only 21.6 per cent of analysed studies described the criteria for rejecting data based on head movements. Another factor that non-specialists can easily relate to is the need to correct for multiple comparisons. Of the 59 per cent of studies that reported using a formal correction technique, nearly one third failed to reveal what that technique was.

"The widespread omission of these parameters from research reports, documented here, poses a serious challenge to researchers who seek to replicate and build on published studies," Carp said.

As well as looking at the amount of methodological detail shared by brain imagers, Carp was also interested in the variety of techniques used. This is important because the more analytical techniques and parameters available for tweaking, the more risk there is of researchers trying different approaches until they hit on a significant result.

Carp found 207 combinations of analytical techniques (including 16 unique data analysis software packages) - that's nearly as many different methodological approaches as studies. Although there's no evidence that brain imagers are indulging in selective reporting, the abundance of analytical techniques and parameters is worrying. "If some methods yield more favourable results than others," Carp said, "investigators may choose to report only the pipelines that yield favourable results, a practice known as selective analysis reporting."

The field of medical research has adopted standardised guidelines for reporting randomised clinical trials. Carp advocates the adoption of similar standardised reporting rules for fMRI-based brain imaging research. Relevant guidelines were proposed by Russell Poldrack and colleagues in 2008, although these may now need updating.

Carp said the reporting practices he uncovered were unlikely to reflect malice or dishonesty. He thinks researchers are merely following the norms in the field. "Unfortunately," he said, "these norms do not encourage researchers to provide enough methodological detail for the independent replication of their findings."

_________________________________

Carp J (2012). The secret lives of experiments: Methods reporting in the fMRI literature. NeuroImage, 63 (1), 289-300 PMID: 22796459

--Further reading-- Psychologist magazine opinion special on replication.
An uncanny number of psychology findings manage to scrape into statistical significance.
Questionable research practices are rife in psychology, survey finds.

Post written by Christian Jarrett for the BPS Research Digest.

Judges are more lenient toward a psychopath when given a neuro explanation for his condition

Last month, a prescient editorial in the New York Times warned that a greater understanding of the neural correlates of behaviour risks having a distorting effect on the criminal justice system. John Monterosso and Barry Schwartz highlighted their own research showing that people are far more forgiving of crimes with ostensibly neurobiological causes, compared with psychological causes - a worrying demonstration of what they called "naive dualism" given that "all psychological states are also biological ones."

Now a multi-disciplinary team of psychologist Lisa Aspinwall, legal scholar Teneille Brown and philosopher James Tabery, has surveyed nearly 200 state trial court judges in the U.S., showing how their decision making is swayed by a neurobiological explanation for psychopathy.

The judges read about a case, based loosely on real events, in which a robber brutally attacked a restaurant manager who refused to hand over any money. All judges were given evidence from the prosecution or defence that said the perpetrator had been diagnosed with psychopathy - an untreatable condition. Additionally, half of them were also presented with expert evidence from a neurobiologist about the causes of psychopathy, including genetic factors. The perpetrator had been tested and had low MAOA activity - a profile, the judges were told, previously associated with increased propensity for anti-social behaviour. The neurobiologist also explained how this genetic profile leads to brain abnormalities that impair the psychopath's ability to tell right from wrong.

Compared with what they estimated to be their usual sentencing for aggravated battery (9 years), overall the judges said they would give a higher sentence to the psychopathic perpetrator in the current case - 12.93 years. This shows the criminal's psychopathy was overall treated as an "aggravating factor", a sign of utilitarian thinking on the part of the judges, in the sense that he was highly likely to be violent in the future.

However, among the judges exposed to a neurobiological account of psychopathy, the diagnosis also had a "mitigating" effect on their decision-making. Judges in this condition sentenced the attacker to an average of 12.83 years compared with the 13.93 years given by judges who didn't receive the neurobiological information. Although the judges in receipt of the neurobiology didn't agree with the explicit suggestion that the attacker had compromised free will or moral responsibility, their open-ended explanations for their sentencing suggested otherwise. The neural evidence "makes possible an argument that psychopaths are, in a sense, morally 'disabled'," said one.

Aspinwall and her team described as a "double-edged sword" the way that psychopathy, accompanied by neurobiological explanation, can have both an aggravating and mitigating effect at once. Supporting this, judges who received the neurobiological testimony, and heard the psychopathic diagnosis from the defence counsel, tended to mention "weighing" or "balancing" factors over twice as often as judges in the other conditions. "Psychopathy may make the defendant less morally culpable, but it increases his future dangerousness to society," said one. "In my mind, these factors balance out ...".

This new research adds to a growing literature showing how people seem to be particularly beguiled by neuroscientific evidence. Last year, for example, a study reported that people were more persuaded by brain-scan-based lie-detection evidence compared with more traditional lie-detection approaches. This study also isn't the first to examine the factors affecting the decision making of judges. For instance, it was shown last year that hungry judges are less forgiving.

_________________________________

Lisa G. Aspinwall, Teneille R. Brown, & James Tabery (2012). The Double-Edged Sword: Does Biomechanism Increase or Decrease Judges' Sentencing of Psychopaths? Science : 10.1126/science.1219569

Post written by Christian Jarrett for the BPS Research Digest.

The Alien awakened by a rubber hand

What happens if you administer a tactile illusion to a brain-damaged patient whose hand is out of their control? A team of researchers has done just that, figuring that illusions could offer new insights into complex neuropsychological disorders.

The patient in question was a 69-year-old lady whose left-sided stroke had left her with alien hand syndrome*. Most of the time her right hand was held in a clenched position that she couldn't open. Occasionally, accompanied by a mild electric sensation, it moved involuntarily, jerking, or even slapping her in the face.

Michael Schaefer and his colleagues at Otto-von-Guericke University Magdeburg tested the lady on two sensorimotor illusions - the traditional rubber hand illusion and the lesser-known somatic rubber hand illusion. The first involved the patient placing one of her arms on the table-top, with the other underneath. A rubber arm was placed alongside her real arm on the table. The researcher then stroked the patient's hidden arm and the rubber arm in synchrony. When the illusion works it creates the sensation of feeling in the rubber arm, as if it's a part of the person's body. In fact the patient experienced no feeling in the rubber arm at all, regardless of whether it was her healthy arm or alien arm that was being stroked under the table. The rubber hand illusion doesn't work for everyone so this null finding is not particularly surprising.

Things got more interesting when the researchers tested their patient with the somatic rubber hand illusion (see picture, above). This procedure involved the rubber arm being placed between the patient's two real arms on a table-top. This time, the patient was blindfolded and the researcher (wearing plastic surgical gloves) picked up one of the patient's hands and used it to tap the rubber hand. At the same time, and in synchrony, the researcher tapped the patient's other hand. This procedure creates the strong illusion for the participant that they are touching their own hand rather than the rubber hand - a feeling that the patient said she experienced.

But something surprising also happened when the researchers tried out this illusion. Within moments, the patient's alien hand leapt up off the table and was grabbed by her healthy hand. She said she felt an electric sensation in her alien hand prior to it rousing. The illusory experience seemed to have awakened her alien hand. This effect occurred every time the procedure was repeated. But crucially it only happened when it was the patient's healthy hand that was used to tap the rubber hand, whilst the patient's alien hand was simultaneously tapped by the researcher (and not when the illusion was done the other way around). The awakening effect also disappeared when the procedure was repeated with the patient's blindfold removed, which is known to destroy the illusion.

All this suggests that it wasn't touching the alien hand per se that roused it, but rather it was the experience of the body illusion. Schaefer and his colleagues think that their patient has a disconnect between the anterior supplementary motor area (SMA) at the front of her brain (involved in inhibitory control) and other brain regions involved in movement. They reckon this impaired motor integration somehow interacted with the illusory feelings of body ownership triggered by the rubber hand trick. Perhaps, they said, the illusion further weakened the SMA's already compromised control of the alien hand.

"Although our results should be confirmed by further studies, we believe that the examination of experimental-induced illusions in patients with disorders of self-embodiment is promising and might help us to develop treatments for these diseases in the future."

 _________________________________


Michael Schaefer, Hans-Jochen Heinze, and Imke Galazky (2012). Waking up the alien hand: rubber hand illusion interacts with alien hand syndrome. Neurocase: The Neural Basis of Cognition DOI: 10.1080/13554794.2012.667132

Further reading: Sergio Della Sala on the bizarre ‘Dr Strangelove syndrome’ and what it tells us about free will (Psychologist magazine article).
Simulating anarchic hand syndrome in the lab (earlier Digest report).

*Some experts prefer the term anarchic hand syndrome for this patient's condition, reserving the term alien hand syndrome for a distinct but related condition in which the patient no longer believes the hand is theirs. For consistency I decided to use the terminology adopted by the authors of this paper.

Post written by Christian Jarrett for the BPS Research Digest.