Wednesday, 2 September 2015

A supposedly memory-enhancing commercial brain-stimulation device actually impairs memory

It's easy to understand why so many people have been tempted by the futuristic-looking foc.us brain stimulation headset. The manufacturers promise their product will increase brain speed and plasticity and improve mental abilities such as working memory. What's more, the device uses a technology that's usually described as "non-invasive" – transcranial direct current stimulation, or tDCS for short – to send currents apparently safely into your prefrontal cortex.

There is ample lab research to suggest that tDCS can have cognitive benefits (although a recent review questioned such claims). However, the foc.us device is not exactly the same as the CE-certified devices used in this past research, and experts in the field have called for more direct investigations of commercial tDCS products. Others have warned that the biological effects of the technology (altering brain cell activity) shouldn't really be considered non-invasive at all, and that the long-term effects of the devices is unknown.

Now a new study has just been published in Experimental Brain Research that directly tests the effects of the foc.us headset on participants' working memory. Note, this study was on the original foc.us headset which was on sale for several years, but which late last year the company replaced with its CE-certified version 2 product.

Laura Steenbergen and her colleagues assigned 12 participants to receive brain stimulation from the foc.us headset for 20 minutes prior to completing a working memory task; 12 others received stimulation "online", which means it was applied during the working memory task. The headset was worn precisely as the manufacturers instruct, with two electrodes placed on each side of the front of the head (see image, right). Each group conducted a genuine brain stimulation session, and also a "sham" session in which the device was only switched on for thirty seconds and then switched off. Participants couldn't tell which session was real and which was sham. 

The working memory test was a variant of the widely-used n-back task, which involved watching a stream of letters on-screen and looking out for when the current letter matched the letter shown two items earlier (in the easier version of the task), or the letter shown four items earlier (in a devilishly difficult version of the task). This is a test of working memory because it requires that participants keep track of the history of prior letters while at the same time paying attention to new letters.

The take-home finding is bad news for foc.us users and highlights the need for more research on commercially available brain stimulation products. In the active stimulation condition (online or offline), participants actually spotted fewer of the target letters in both the easier and more difficult versions of the working memory task (75 per cent accuracy versus 78 per cent, on average; a statistically significant difference). Meanwhile, reports of uncomfortable sensations such as burning at the electrode and headache were higher in the stimulation condition than in the sham condition. At least in this investigation, the brain stimulation was all pain and no gain.

"foc.us is just one example of a device that can easily be purchased and, without any control or expert knowledge, used by anyone," the researchers said. "The results of our study are straightforward in showing that the claims made by companies manufacturing such devices need to be validated."
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  ResearchBlogging.orgSteenbergen, L., Sellaro, R., Hommel, B., Lindenberger, U., Kühn, S., & Colzato, L. (2015). “Unfocus” on foc.us: commercial tDCS headset impairs working memory Experimental Brain Research DOI: 10.1007/s00221-015-4391-9

--further reading--
The trouble with tDCS? Electrical brain stimulation may not work after all
It's shocking - How the press are hyping the benefits of electrical brain stimulation
Read this before zapping your brain

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

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Saturday, 29 August 2015

Link feast

Our editor's pick of the week's 10 best psychology and neuroscience links:

How Reliable Are Psychology Studies? [short of time? check out our coverage of this story]
Findings from the Reproducibility Project have sent shockwaves through psychology. At The Atlantic, Ed Yong provides commentary and reflection.

OCD: A Monster in My Mind (TV show)
There are 28 days left to watch this BBC Two documentary in which Professor Uta Frith meets the people living with OCD, looks at the therapy available and asks what neuroscience can offer by way of a cure.

Why Do We "Like" Social Media?
Writing for The Psychologist, Ciarán Mc Mahon considers the psychology behind Facebook and more.

Facebook Q&A with Organisational Psychologist Adam Grant
The Wharton School Professor and author of Give and Take took questions on work and psychology.

Yes, Men’s and Women’s Brains Do Function Differently — But It’s a Tiny Difference
A new study claims to have found a link between sex differences in mental performance and sex differences in neural function. I took a look at the evidence, over at New York's Science of Us.

On My Radar: Steven Pinker’s Cultural Highlights
The psychologist and popular science author on data graphics, spectacular planet photography and the ambitious comedy of Amy Schumer.

Dos and Don'ts to Preserve Your Brainpower
From changing your diet to partying like you’re 21, David Robson at BBC Future provides six tips for protecting your brain from the ravages of time.

Psychology of Family
Psychology Press has gathered together 150 articles on this topic from its journals and made them free to access.

How Neuroscience Is Helping Answer the Question ‘Who Am I?’
Simon Worrall at the National Geographic interviews Anil Ananthaswamy author of The Man Who Wasn’t There: Investigations Into the Strange New Science of the Self.

The Science of Forgiveness: “When you don’t forgive you release all the chemicals of the stress response
"Researchers are studying how we can let go of our grievances and live a healthier life," says Megan Bettencourt at Salon. "Here's how it works".
_________________________________
 
Post compiled by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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Thursday, 27 August 2015

This is what happened when psychologists tried to replicate 100 previously published findings

While 97 per cent of the original results showed a statistically significant
effect, this was reproduced in only 36 per cent of the replications 
After some high-profile and at times acrimonious failures to replicate past landmark findings, psychology as a discipline and scientific community has led the way in trying to find out more about why some scientific findings reproduce and others don't, including instituting reporting practices to improve the reliability of future results. Much of this endevour is thanks to the Center for Open Science, co-founded by the University of Virginia psychologist Brian Nosek.

Today, the Center has published its latest large-scale project: an attempt by 270 psychologists to replicate findings from 100 psychology studies published in 2008 in three prestigious journals that cover cognitive and social psychology: Psychological Science, the Journal of Personality and Social Psychology, and the Journal of Experimental Psychology: Learning, Memory and Cognition.

The Reproducibility Project is designed to estimate the "reproducibility" of psychological findings and complements the Many Labs Replication Project which published its initial results last year. The new effort aimed to replicate many different prior results to try to establish the distinguishing features of replicable versus unreliable findings: in this sense it was broad and shallow and looking for general rules that apply across the fields studied. By contrast, the Many Labs Project involved many different teams all attempting to replicate a smaller number of past findings – in that sense it was narrow and deep, providing more detailed insights into specific psychological phenomena.

The headline result from the new Reproducibility Project report is that whereas 97 per cent of the original results showed a statistically significant effect, this was reproduced in only 36 per cent of the replication attempts. Some replications found the opposite effect to the one they were trying to recreate. This is despite the fact that the Project went to incredible lengths to make the replication attempts true to the original studies, including consulting with the original authors.

Just because a finding doesn't replicate doesn't mean the original result was false – there are many possible reasons for a replication failure, including unknown or unavoidable deviations from the original methodology. Overall, however, the results of the Project are likely indicative of the biases that researchers and journals show towards producing and publishing positive findings. For example, a survey published a few years ago revealed the questionable practices many researchers use to achieve positive results, and it's well known that journals are less likely to publish negative results.

The Project found that studies that initially reported weaker or more surprising results were less likely to replicate. In contrast, the expertise of the original research team or replication research team were not related to the chances of replication success. Meanwhile, social psychology replications were less than half as likely to achieve a significant finding compared with cognitive psychology replication attempts, but in terms of declines in size of effect, both fields showed the same average reduction from original study to replication attempt, to less than half (cognitive psychology studies started out with larger effects and this is why more of the replications in this area retained statistical significance).

Among the studies that failed to replicate was research on loneliness increasing supernatural beliefs; conceptual fluency increasing a preference for concrete descriptions (e.g. if I prime you with the name of a city, that increases your conceptual fluency for the city, which supposedly makes you prefer concrete descriptions of that city); and research on links between people's racial prejudice and their response times to pictures showing people from different ethnic groups alongside guns. A full list of the findings that the researchers attempted to replicate can be found on the Reproducibility Project website (as can all the data and replication analyses).

This may sound like a disappointing day for psychology, but in fact really the opposite is true. Through the Reproducibility Project, psychology and psychologists are blazing a trail, helping shed light on a problem that afflicts all of science, not just psychology. The Project, which was backed by the Association for Psychological Science (publisher of the journal Psychological Science), is a model of constructive collaboration showing how original authors and the authors of replication attempts can work together to further their field. In fact, some investigators on the Project were in the position of being both an original author and a replication researcher.

"The present results suggest there is room to improve reproducibility in psychology," the authors of the Reproducibility Project concluded. But they added: "Any temptation to interpret these results as a defeat for psychology, or science more generally, must contend with the fact that this project demonstrates science behaving as it should" – that is, being constantly sceptical of its own explanatory claims and striving for improvement. "This isn't a pessimistic story", added Brian Nosek in a press conference for the new results. "The project shows science demonstrating an essential quality, self-correction – a community of researchers volunteered their time to contribute to a large project for which they would receive little individual credit."
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  ResearchBlogging.orgOpen Science Collaboration (2015). Estimating the reproducibility of psychological science Science

--further reading--
How did it feel to be part of the Reproducibility Project?
A replication tour de force
Do psychology findings replicate outside the lab?
A recipe for (attempting to) replicate existing findings in psychology
A special issue of The Psychologist on issues surrounding replication in psychology.
Serious power failure threatens the entire field of neuroscience 

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

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Hiding negative emotions may take more of a toll on your relationship than faking positive ones, especially if you're extravert

Handling your emotions in a close relationship is often a balancing act. You want to be true to yourself and open with your partner, but there are also times when it seems necessary to exert some emotional control – to hide your frustration, for example, or to feign happiness at their news (perhaps your partner is thrilled about a work trip, which in truth you'd rather they didn't take).

A new study, published recently in the Journal of Psychology, is among the first the explore the toll of these two emotional strategies: hiding negative emotions and faking positive ones. Specifically, Tali Seger-Guttmann and Hana Medler-Liraz wanted to find out how the use of the two strategies in a relationship affects people's satisfaction with that relationship, and whether this varies depending on whether someone is introvert or extravert.

The researchers surveyed hundreds of male and female Israeli participants (average age 32), all of whom were in a relationship of at least six months; half of them were married, the others were living with their partner or dating. The participants answered questions about their levels of extraversion; how often they hid negative emotions like nervousness, hate and anxiety in their relationship; how often they faked positive emotions like happiness, concern and love; and they answered several questions about their relationship satisfaction and also how often they experienced health problems such as fatigue and headaches.

Overall, hiding negative negative emotions was more strongly associated with poorer relationship satisfaction than faking positive emotion. But importantly, this link was moderated by the participants' personality. Hiding negative emotions was linked much more closely to poor relationship satisfaction for extraverts than introverts. Faking positive emotion more often was also, but to a lesser extent than hiding negative emotion, linked with poorer relationship satisfaction, and this was equally true for both introverts and extraverts.

"The fact that both strategies [were] significantly related to less satisfaction with intimate relationships links our results to previous research on the importance and significance of authenticity in close relationships," the researchers said.

Turning to the scores for health problems, there was evidence that hiding negative emotions was linked to more health symptoms for extraverts, but not for introverts, presumably because concealing emotions in this way comes somewhat naturally for introverts but not for extraverts. On the flip side, faking positive emotions was less strongly associated to health problems for extraverts than for introverts – again, perhaps because faking positive emotions is more consistent with an extraverted personality.

Unfortunately, like any cross-sectional research that only surveys people at one point in time, this study requires us to make assumptions about the causal direction between the factors that were measured. The researchers believe that hiding and faking emotions are probably affecting relationship satisfaction and health, but of course it's likely the influence is at least partly in the other direction – when a relationship is going well, censoring our emotional displays is probably not so necessary.

Despite this shortcoming, this is the first study to explore links between hiding and faking emotions and personality, and the researchers say it could "help therapists and counsellors develop a deeper understanding of the interplay between emotional regulation styles (hiding and faking emotions) and personality style, and hence contribute to improving the quality of couples' relationships."

_________________________________ ResearchBlogging.org

Seger-Guttmann, T., & Medler-Liraz, H. (2015). The Costs of Hiding and Faking Emotions: The Case of Extraverts and Introverts The Journal of Psychology, 1-20 DOI: 10.1080/00223980.2015.1052358

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

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Wednesday, 26 August 2015

Having a brain scan changed how these children think about minds and brains

The link between the mind and brain is tricky enough for expert psychologists and neuroscientists to grapple with, let alone young children. Nonetheless, they grow up with their own naive understanding. For example, there's some cute research from the 90s that found, somewhere between age 7 and 9, most children come to see the brain as containing thoughts and memories – they'll say that a skunk with a brain transplant from a rabbit will have memories of being a rabbit. Younger kids, by contrast, recognise the brain is involved in mental activity, but not that it contains thoughts and memories (they think the skunk with a rabbit brain will still have memories of being a skunk).

Now researchers in France have explored how taking part in a neuroimaging experiment influences young children's understanding of the mind-brain link. Their results, published recently in Trends in Neuroscience and Education, suggested that the experience led the children to have a more sophisticated, brain-based understanding of at least some mental functions.

Sandrine Rossi and her colleagues recruited 37 eight-year-olds who two years previously had taken part in a brain scan study. For this, they'd completed some numerical tasks in the scanner and they were also shown images of their brain. Thirty-seven eight-year-olds with no brain-scan experience acted as controls. Both groups of kids were from similar middle-class backgrounds.

To test their understanding of the mind-brain link, the children were introduced to a cartoon character, Julie, and asked to select which parts of her body (hand, eye, mind, mouth, brain or heart) she needed to perform various functions: seeing, talking, reading, counting, dreaming and imagining.

The main differences between the groups occurred when judging what Julie needed to dream and imagine. Here, a majority (nearly 70 per cent) of the children who'd undertaken a brain scan said she'd need both her mind and her brain, compared with around 40 per cent of the controls. The control kids were more likely to say she'd need her mind, without also mentioning she'd need her brain. In other words, the children with brain scan experience appeared to see the mind and brain as more closely linked, at least for dreaming and imagining. Furthermore, when judging what Julie would need to see and talk, the controls more often neglected to mention either her brain or mind, compared with the brain scan kids. In contrast, the groups didn't differ in how often they chose the mouth, hand, heart and eye for the different functions.

This research was inspired by parents' reports that their children had become more brain aware after undertaking a brain scan. Now there is some data to support their anecdotes. "The present study is the first to show an educational effect of participating in an MRI protocol on children's naive mind-brain conceptions," the researchers said.

_________________________________ ResearchBlogging.org

Rossi, S., Lanoë, C., Poirel, N., Pineau, A., Houdé, O., & Lubin, A. (2015). When I Met my brain: Participating in a neuroimaging study influences children’s naïve mind–brain conceptions Trends in Neuroscience and Education DOI: 10.1016/j.tine.2015.07.001

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

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Tuesday, 25 August 2015

How do lying skill and frequency change through life, from childhood to old age?

Young adults – defined here as people aged 18 to 29 – are the most skilled liars, while teens are the most prolific. That's according to a new study published in Acta Psychologica that claims to be the first ever to investigate lying behaviour across the entire lifespan.

The research involved members of the public who were visitors at the Science Centre NEMO in Amsterdam. In all, 1005 people took part, aged from 6 to 77. To test lying ability, Evelyne Debey and her colleagues presented the participants with simple general knowledge questions (e.g. "Can pigs fly?"). These questions had to be answered as quickly as possible, either truthfully or dishonestly, depending on the colour of the YES/NO response options. Taking the pig question as an example, the idea is that a skilled liar ought to be able to answer "yes" very quickly, whereas a poor liar will be delayed when answering dishonestly, or they might even give a reflex honest answer.

Young adults showed the fastest reaction times and lowest error rates on this test of lying. Overall, lying proficiency showed an inverted U-shaped curve through the lifespan, improving through childhood, peaking in young adulthood and then gradually declining into old age. This meant that lying proficiency was the same in the youngest children (aged 6 to 8) as it was in the eldest participants (aged 60 plus).

To measure lying frequency, the researchers asked their participants to report the number of lies they had told during the preceding 24 hours to different people in different situations (e.g. to a stranger or relative; face to face or online), and to describe those lies. Overall, the participants reported telling an average of two lies during that time, which is consistent with past research. Teens admitted to telling more lies (an average of 2.8) than any of the other age groups. Again there was an inverted U-shaped relationship between age and lying such that lying frequency increased during childhood, peaked in adolescence, then decreased through life, so that the oldest group lied with the same frequency as the youngest participants.

The researchers have a theory that the reason lying skill and frequency show this pattern through the lifespan is because of age-related changes in inhibitory control – the idea being that to lie successfully you need to be able suppress the truth, and that young adults have the most inhibitory control.

To test this, the researchers had the same participants complete what's known as a "stop-signal task" – this involved pressing a button to indicate as fast as possible whether an X or an O had appeared on-screen. Crucially, on 25 per cent of these trials a tone sounded that told them to cancel their response. The later this tone sounded, the harder it is to withhold a response. Participants with greater inhibitory control can usually cancel their response even when the stop signal is given very late.

The participants' ability on this stop-signal task increased through childhood and peaked in young adulthood. However, performance after this age remained relatively stable. Moreover, performance on the stop-signal task did not correlate strongly with lying proficiency. This appears to undermine the researchers' theory about inhibitory control, but they argued that there are different types of inhibitory control and that perhaps a different measure of a different kind of inhibition (such as the Stroop Test, which measures the ability to deal with interfering mental demands) would have correlated more strongly with lying ability.

In a field that so often relies on student research participants, this study stands out for its involvement of the general public across wide range of ages. However, as the researchers acknowledge, the findings come with many caveats. Among these is the fact the study was cross-sectional – it doesn't tell us anything about how the same people's propensity for, and ability to, lie changes as they age. Also, the test of lying ability was artificial and involved none of the emotional consequences of real-life lies. Note too that, as shown in past research, lying frequency was highly skewed so that half the participants reported telling no lies in the previous 24 hours, and over 50 per cent of the lies were told by prolific liars who made up just 9 per cent of the sample.

_________________________________ ResearchBlogging.org

Debey, E., De Schryver, M., Logan, G., Suchotzki, K., & Verschuere, B. (2015). From junior to senior Pinocchio: A cross-sectional lifespan investigation of deception Acta Psychologica, 160, 58-68 DOI: 10.1016/j.actpsy.2015.06.007

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

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Monday, 24 August 2015

People's "coming out" experiences are related to their psychological wellbeing years later

Last year, the US psychologists Clayton Critcher and Melissa Ferguson reported interesting research showing that fatigue from concealing sexual identity can actually hinder cognitive performance. This cost stacks upon others: complications in forming close relationships, concerns about inauthenticity, and damage to psychological and physical health in the longer term all suggest that concealment is not a great position to stay in. And yet "coming out" can also be challenging, and in some cases lead to no better or even worse life outcomes than before. Not all coming-out experiences are the same, as a new study shows.

William Ryan at the University of California, Santa Barbara, and his team, recruited online 28 lesbian, 25 gay, and 55 bisexual people; overall the sample had slightly more women than men. Participants were asked to cast their mind back to up to four disclosure (coming out) experiences: to their mother, father, best friend, and the person they first disclosed to (in many cases also one of the first three).

For each disclosure partner, the participant rated how much 19 different descriptions applied to the way this person responded – some were negative (e.g. “be furious”), and others positive, (e.g. “thanked me for sharing”). Participants who experienced a higher frequency of negative reactions from a best friend or father reported significantly lower levels of present self-esteem, and negative reactions from disclosure partners of any kind were associated with current depressive symptoms.

These are associations between events often ten or more years ago and wellbeing in the present day, so you would be justified in wondering how this might be happening. Ryan’s team hypothesised that each coming-out experience provides insight into whether the discloser will be able to act freely and authentically around that person, as we know such a sense of autonomy is critical for wellbeing.

To investigate this, participants were asked to evaluate the amount of autonomy in each relationship as it currently stands, via items like “When I am with my [best friend], I feel pressured to behave in certain ways.” If negative reactions produced or prophesied low autonomy, and low autonomy was the true culprit for today’s low wellbeing, then the statistical relationship between past reactions and current wellbeing would be fully mediated by autonomy, and the data showed it was. But as always with cross-sectional research, it’s possible to sketch other directions for causality’s arrow: perhaps the negative aspects of past autobiographical events come to mind more strongly for those currently experiencing depressive symptoms.

That said, these postulated effects of past disclosure experiences on feelings of autonomy provide a plausible mechanism that provides the basis for more research (e.g. longitudinal). The results also revealed a further interesting possibility worth concluding on. Whereas the negative aspects of the disclosure were important for later wellbeing, the relative strength of any positive reactions – “See things through my eyes”; “accept my positive feelings” – didn’t seem to matter. This might suggest that your most important job when reacting to a disclosure from someone close is to Do No Harm. Don’t worry about a flawless response, just make it clear that your support for them isn’t conditional on their sexuality.

_________________________________ ResearchBlogging.org

Ryan, W., Legate, N., & Weinstein, N. (2015). Coming Out as Lesbian, Gay, or Bisexual: The Lasting Impact of Initial Disclosure Experiences Self and Identity, 14 (5), 549-569 DOI: 10.1080/15298868.2015.1029516

--further reading--
When gay men reveal their homosexuality later in an interaction, prejudice toward them is reduced
Intervention helps reduce homophobia
Is sexism the reason why so many heterosexual men are prejudiced towards gay men?

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.

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Saturday, 22 August 2015

Link feast

Our pick of this week's best psychology and neuroscience links:

What It’s Like to Have ADHD As a Grown Woman
"Having ADHD is challenging regardless of gender but in a world predisposed to undermining women, not having your shit together can feel like a dereliction of feminine duty," writes Rae Jacobson at NY Mag's The Cut.

How to Have a Better Brain (audio)
All week BBC Radio 4 broadcast a series of short programmes on ways to look after the health of your brain.

Identity Is Lost Without A Moral Compass
"Research on neurodegenerative diseases suggests that, more than anything else, moral traits like kindness and integrity define who we are," writes Nathan Collins at the Pacific Standard.

A Real-life Cure for the Worriers of the World
Liz Hoggard at the Independent reviews the new book Anxious: The Modern Mind in the Age of Anxiety by Joseph E LeDoux.

Don't Hate the Phone Call, Hate the Phone
In an fascinating tour of design history and social behaviour, Ian Bogost at The Atlantic argues that one of the reasons we've fallen out of love with phone calls is the way modern mobile phones are designed and connected.

How Autistic People Helped Shape the Modern World 
Carl Zimmer interviews Steve Silberman for WIRED about his new book, NeuroTribes: The Legacy of Autism and the Future of Neurodiversity.

What is it Like To Have Never Felt An Emotion
Some people with “alexithymia” seem to lack the capacity to feel joy, sorrow or love. David Robson at BBC Future discovers the challenges and surprising advantages of the condition.

The Neuroscience of Being a Selfish Jerk
Over at NY Mag's Science of Us I discussed an intriguing brain scan study of people who score high on the Dark Triad trait of Machiavellianism.

The Neuron’s Secret Partner
For years, glial cells have stood in the shadow of neurons. In this short feature for Nautilus, Ferris Jabr celebrates the important function of glial cells – they are, he says, the brain’s architects, doctors, police, janitors, and gardeners.

Walking the Talk and Looking to be Heard
A group of psychologists who are walking 100 miles to highlight the impact on austerity on mental health have reached their halfway point. Ella Rhodes at The Psychologist speaks to the walk's organiser.
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Post compiled by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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Friday, 21 August 2015

Free personality tests are more reliable and efficient than the paid variety

In most areas of life, we expect the free versions of products to be sub-standard compared with the "premium" paid-for versions. After all, why would anyone pay for something if the free equivalent were better? However, a new study of personality tests boots this logic off the park – psychologists at the University of Texas report in the Journal of Psychology that free tests are more reliable and efficient than their paid-for, proprietary counterparts.

To measure test reliability, Tyler Hamby and his colleagues dug out personality test data collected in five prior meta-analyses of the Big Five personality traits. Meta-analyes combine data from many studies in a given field, and the Big Five is the dominant personality theory in contemporary psychology, which breaks personality down into five main dimensions, including Extraversion and Conscientiousness. In the end, the researchers ended up with usable data from 345 samples from 288 studies involving 161,091 participants.

Crucially, 142 of these research samples had completed free personality tests such as the Big Five Inventory and various versions of the International Personality Item Pool. The other samples had completed paid-for personality tests such as versions of the NEO Five Factor Inventory. For their analysis, Hamby and his team compared the "alpha coefficients" of the different personality tests – for any given test, this essentially involves looking at the scores from the questionnaire items that supposedly measure the same trait and seeing how well they correlate with each other. If a test has what's known as good internal consistency, then the scores for its items that measure the same construct should show a high correlation.

A note of caution: The researchers didn't look at test–re-test reliability, a different measure which tells you how well participants' test scores correlate when they take the same test at different times. Nor did they compare the tests' validity, which is the evidence for whether the tests are truly measuring what they're supposed to be measuring. In other words, this study certainly shouldn't be taken as the final word on the merit of free and paid-for personality tests.

These caveats aside, overall there was a small, but inconsistent (applying to some traits but not others) difference in reliability between free and paid tests, in favour of the free tests. But it doesn't end there. When you use alpha coefficients to measure internal consistency in this way, the outcome is confounded by the number of items in the test. Longer tests with more items tend to achieve higher reliability scores. This is relevant to the current investigation because paid-for tests tend to be much longer (80 per cent on average) than the free versions. When Hamby and his colleagues controlled for test length (by estimating reliability at 12 items for each trait), they found the free tests had higher reliabilities than the paid-for tests for all five personality traits.

Is there any reason for paid-for tests to be less reliable? The authors say their findings are not entirely surprising – one possible explanation is that researchers or practitioners who use paid-for tests are often forbidden from adapting them in any way (for example, adding/removing items or changing the wording of items). This is to protect the proprietary status of the product, but of course forbidding any changes is unscientific because it prevents progress by making it impossible to test whether revised versions would be superior.

At least for research purposes (as opposed to in applied settings), these new results stack heavily in favour of free tests. Not only do free tests match or exceed the reliability of paid-for tests, they are also shorter which helps encourage participants to complete all test items and reduces participant drop-out rates. "Assuming that a particular scale has been properly validated, we tentatively recommend using free scales to measure Big Five traits in personality research," the researchers said. It will be interesting to see if this finding applies to other areas of psychology research where free and paid-for tests are available.

_________________________________ ResearchBlogging.org

Hamby, T., Taylor, W., Snowden, A., & Peterson, R. (2015). A Meta-Analysis of the Reliability of Free and For-Pay Big Five Scales The Journal of Psychology, 1-12 DOI: 10.1080/00223980.2015.1060186

--further reading--
Our bias for the left-hand side of space could be distorting large-scale surveys.

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

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Thursday, 20 August 2015

Why do more intelligent people live longer?

By guest blogger Stuart Ritchie

It’s always gratifying, as a psychologist, to feel like you’re studying something important. So you can imagine the excitement when it was discovered that intelligence predicts life expectancy. This finding is now supported by a large literature including systematic reviews, the most recent of which estimated that a difference of one standard deviation in childhood or youth intelligence (that’s 15 IQ points on a standardised scale) is linked to a 24 per cent lower mortality risk in the subsequent decades of life. That’s a pretty impressive link, but it immediately raises a critical question: why do brighter people live longer?

A new study (pdf) published in the International Journal of Epidemiology attempts to provide new, biological evidence to answer this question. But first, let’s think through the possibilities. We know that people with higher IQ scores tend to be healthier, possibly because they eat better, exercise more, are better able to understand health advice, are less likely to be injured in accidents and deliberate violence, and also because they tend to have better jobs. Here, the causal arrow is pointing from IQ to longevity – the effects of being smarter cause you to die later. But there are other explanations: what if having a lower IQ is just an indicator of an underlying health condition that’s the real cause of earlier death? Or what if the genes for having a healthier body are also the genes for having a healthier brain, and the causal pathway is from this third variable (i.e. genetics) to both IQ and longevity?

The authors of the new study, Rosalind Arden and colleagues, tested this last hypothesis, known as "genetic pleiotropy" (the idea that the same genes influence multiple different traits). They took three twin datasets, selecting in total 1,312 twin pairs where one or both of the twins had died. Then they correlated the twins’ IQ scores with the lengths of their lives (or their life expectancies, for those still living).

As they expected, the researchers found an overall lifespan-IQ correlation, albeit a small one (r = 0.12, where 1.00 would be a perfect match). Importantly, by comparing the correlations in identical twins (who share all their genes) versus fraternal twins (who share approximately half), they were also able to estimate the "genetic correlation" – the overlap in the two traits that’s caused by genetic differences. They found that, overall, 95 per cent of the correlation in IQ and longevity was due to genetics.

So, is this a final answer to the debate over the IQ-mortality connection? Does this show that, perhaps depressingly, the link isn’t due to changeable lifestyle factors, but actually some kind of genetic "system integrity" that underlies brightness and longer lives?

Ritchie's critically acclaimed
new book is out now.
Not so fast. The important part is in the phrase "due to genetics". In a 2013 Nature Reviews Genetics article, geneticist Nadia Solovieff and colleagues outlined all the potential causal mechanisms that might make two traits genetically correlated. They drew a critical distinction between "biological" and "mediated" pleiotropy. The former is the "obvious" inference, which is that the same genes cause both intelligence and longevity. But the latter possibility is that the variables only appear to be genetically correlated, because genes cause one factor, which then goes on to cause the other. That is, if genes cause intelligence, and intelligence (via lifestyle choices etc.) causes a longer lifespan, we’d still see the same genetic correlation, even if those genes have no direct effect on lifespan itself. If true, this would still be pleiotropy of a sort: the genes linked to intelligence are having an indirect effect on lifespan. But as the authors acknowledge in their paper, this "pleiotropy-lite" interpretation of the new findings would mean we don’t yet have knockdown evidence for the genetic "system integrity" idea.

So how do we tease apart the two possible explanations for the genetic correlation? In the paper, the authors suggest we study non-human animals (for which the literature on cognitive ability is growing fast) where we can more readily control the "lifestyle" factors, thereby isolating any potential direct effects of the same genes on both intelligence and longevity. Really, though, we might have to wait until we have a long list of genes that are reliably linked to human intelligence. If we knew a good number of those, we could test whether they also influence health and lifespan – if they did, this would be evidence for true "biological" pleiotropy. We’d know then that the link between IQ and lifespan is down to some people simply winning the genetic lottery, rather than to lifestyle factors that any of us could change.

Conflict of interest: Stuart Ritchie is a postdoc in the lab of Ian Deary, one of the co-authors of the paper discussed here.

_________________________________ ResearchBlogging.org

Arden, R., Luciano, M., Deary, I., Reynolds, C., Pedersen, N., Plassman, B., McGue, M., Christensen, K., & Visscher, P. (2015). The association between intelligence and lifespan is mostly genetic International Journal of Epidemiology DOI: 10.1093/ije/dyv112

--further reading--
How do you prove that reading boosts IQ?

Post written by Stuart J. Ritchie, a Research Fellow in the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh. His new book, Intelligence: All That Matters, is available now. Follow him on Twitter: @StuartJRitchie

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Wednesday, 19 August 2015

The powerful motivating effect of a near win

If you while away time in a games arcade – play some coin pushers here, a few fruit machines there – you will soon be familiar with that frustrating and enlivening sensation of the near win that follows getting four cherries out of five. New research from INSEAD suggests that these tantalising near wins produce high levels of motivational arousal, that encourage us to chase whatever alternative rewards are then available.

In one fascinating experiment, Monica Wadhwa and JeeHye Christine Kim gave lottery scratch-cards to 164 US shoppers about to enter a fashion store. A row of six winning symbols earned $20, and the cards were rigged so a third of participants won, a third lost abjectly, and a third nearly made it, with five in a row. Shoppers then went about their shopping, and on exiting the store, were asked to share their till receipts. The near-winners had made significantly more purchases than the other groups.

Why? Goal-gradient theory, proposed in the 1930s, suggests that when a reward is one hundred steps away, your initial step progresses you only one per cent towards your payoff. However, once you are almost in reach, the payoff for each effortful act is much higher, meaning we become more physiologically aroused and ready to act. But should the reward be snatched away, the readiness to act doesn’t disappear. Instead, it tends to be transferred to other sources; in the above example, the shoppers who just missed out on the lotto card were well positioned to seek out other rewards, thanks to the availability of tills.

Other experiments showed a near win encouraging participants to make more effort in a card-sorting task when money was on the line, to hurry more towards a chocolate bar, and even to salivate more heavily to images of high-value currency.

There is a caveat. Tightly-focused lab experiments demonstrated that almost winning really only matters when the heightened state of anticipation is prolonged. In a diamond-seeking video game, players who were just one diamond short of victory, but discovered very early that they’d lost (they turned over a tile showing a fatal rock rather than the winning diamond), did not show the near-win effect. By contrast, players who were just one diamond short, and who stayed alive in the game for a sustained amount of time (they avoided any rocks until the very end), did show the near-win effect – after the game had finished, they raced to get a chocolate bar, as if channelling the heightened motivation built up by their near win.

Wadhwa and Kim point out that we already know that repeatedly nearly winning a game can facilitate addiction to it, via heightened production of dopamine, the neurotransmitter associated with motivation and the anticipation of pleasure, among other functions. This new study show this feeling generalises beyond the game. If you almost vanquish the end-of-level boss, you might be more motivated to pound out that tricky article … or reward yourself with a bag of pretzels. So be aware of what you surround yourself with!

_________________________________ ResearchBlogging.org

Wadhwa, M., & Kim, J. (2015). Can a Near Win Kindle Motivation? The Impact of Nearly Winning on Motivation for Unrelated Rewards Psychological Science, 26 (6), 701-708 DOI: 10.1177/0956797614568681

--further reading--
How losing can increase your chances of winning

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.

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