First brain scan study to feature THAT dress

Figure and caption from Schlaffke et al., 2015.

Earlier this year a dress nearly broke the internet. A photo of the striped frock (which is actually blue and black) was posted on Tumblr and it quickly became apparent that it looked very different to different people, spawning furious arguments and lively scientific commentary.

Specifically, people disagreed vehemently over whether it was white and gold (that's my perception) or blue and black. Now, writing in the journal Cortex, researchers in Germany have published the first study to scan people's brains while they look at the dress, and the neural findings appear to support earlier, psychological explanations of the phenomenon.

When the dress story went viral, psychologists were quick to explain that this dress provided a striking example of how our perception of the world arises from a combination of incoming sensory information and our interpretation of that information. In the case of colour perception, when light bounces off an object and hits your retina, its mix of wavelengths is determined by the colour of the object and the nature of the light source illuminating it. Your brain has to disentangle the two. Usually it does this very well allowing for something called "colour constancy" – the way that objects of the same colour are perceived the same even under different illumination conditions. However, the mental processing involved in colour perception does leave room for interpretation and ambiguity, especially when the nature of the background illumination is unclear as is the case with the photo of the dress (another illusion that hacks the limitations of this aspect of our visual system is the checker shadow illusion).

For the new study, Lara Schlaffke and her colleagues scanned the brains of 28 people with normal vision while they looked at the photo of the dress. Fourteen of the participants see the dress as white and gold and 14 see it as blue and black. The key finding is that the people who see the dress as white and gold showed extra activation in a raft of brain areas, including in frontal, parietal (near the crown of the head) and temporal (near the ears) regions. Yet, no group differences emerged in a control condition when the participants simply looked at large coloured squares that matched two of the colours that feature in the dress, but without any contextual information also visible (see figure, above).

These results are broadly consistent with the idea that the white/gold perceivers were engaged in more interpretative mental processing when looking at the dress. To oversimplify, their perceptual experience of the dress is based less purely on the "bottom up", raw sensory information arriving at their eyes, and is distorted more by their own assumptions and expectations about the background illumination. The extra activity in their brains during the dress viewing is likely, at least in part, a neural correlate of all this interpretative, "top down" processing.

What the new study can't answer is whether this extra neural processing (or which aspects of it) in the white/gold group is the cause of their perceptual experience of the dress, or the consequence. However, the researchers describe some future approaches that could help address this quasi-philosophical conundrum: for example, by using transcranial magnetic stimulation (TMS) to temporarily disrupt the extra localised neural activity seen in the people who experience the dress as white and gold, we could ask: will they still experience the illusion?

Meanwhile, as someone who's firmly in the white/gold camp, I take satisfaction from this study: I might see the dress as the "wrong" colours, but at least this isn't due to simple-mindedness, but rather it's because my brain's working overtime, doing clever tricks in the background. I'm pretty sure that must be an advantage in at least some situations.

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Schlaffke, L., Golisch, A., Haag, L., Lenz, M., Heba, S., Lissek, S., Schmidt-Wilcke, T., Eysel, U., & Tegenthoff, M. (2015). The brain's dress code: How The Dress allows to decode the neuronal pathway of an optical illusion Cortex, 73, 271-275 DOI: 10.1016/j.cortex.2015.08.017

--further reading--

Visual illusions foster open-mindedness


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

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Life is different for people who think in metaphors

Some people are literal minded – they think in black and white whereas others colour their worlds with metaphor. A new paper published recently in the Journal of Personality and Social Psychology reports on the first standardised measure of this difference, and it shows that having a proclivity for metaphors has real consequences, affecting how people respond to the world around them and even how they interact with others.

A metaphor uses a concrete concept, often sensory (e.g. "light") or location-based (e.g. "forward"), to illuminate a nebulous one, such as emotion or time. While this colouring-in can be useful – and can endure, and transform language – it may not be to everyone’s taste, or necessary for the demands of their day-to-day life. To systematically investigate this, an international research team led by Adam Fetterman developed a measure – which asks people to choose their preference for various metaphors or equivalent literal phrases, for example: “She uses her head” vs. “She makes rational decisions” – and administered it to 132 student participants.

The researchers found a good deal of variability between the students in how they responded, including some who only ever selected the metaphor option, and others only the literal alternative. Scores on the measure correlated with a preference for mental imagery, and they correlated with the amount that participants used metaphoric phrases in a free writing exercise, confirming the test predicts actual behaviour. Conversely, the test scores were not associated with personality factors, with intellectual ability, nor with the ability to visualise, suggesting the test is measuring a mental style rather than a capacity. So, then, a metaphoric thinking style is an actual thing you can measure. But does it matter?

It does. Take the way metaphors can affect our feelings (known as the “metaphor transfer effect”). In a classic example, people rate neutral words as more pleasant when they are printed in a white font rather than a black one – "light" being associated metaphorically with "good". Before now researchers didn’t agree on whether this kind of effect is truly down to reliance on metaphorical representations – a counter explanation is that these effects reflect fundamental, non-conceptual associations between different stimuli that were formed early in life – e.g. through repeated pairings of warmth and affection. However, when Fetterman and his team recruited a further 132 students, they found that those who scored higher on having a metaphoric thinking style also tended to show a greater preference for white-font over black-font words, thus providing good evidence that the metaphor transfer effect is aptly named, after all.

Another study took this out into the real world, tracking 136 people over a fortnight to see whether the amount of sweet food consumed on a given day influenced how agreeable they were in their interactions with other people. I would have imagined that if there were any effect, it might be simply due to a glucose buzz. But no. The link between sweet food consumption and people’s behaviour that the researchers found was mostly down to thinking style. That is, the effect was much stronger among the highly metaphorical participants: when they were sweet in tooth, they were also sweet in nature (thus adding a nuance to previous research on this link).

Remember, too, that metaphors are supposed to illuminate, particularly when it comes to abstract concepts that can be hard to pin down, like the subtleties of emotions. In another experiment, Fetterman’s team measured participants’ ability to correctly judge most people’s typical emotional response in different situations, such as when something unpleasant was happening that couldn’t be stopped. In this example, the correct response was “distressed”. Crucially, people who scored highly in metaphoric thinking style tended to perform better at this task. This suggests their colourful thinking style actually gave them greater insight into emotions.

In a final experiment, 50 participants spent 5 minutes each day for a week writing about their negative emotions, and they were encouraged to be either literal, "I felt anxious or confused," or metaphorical: "I felt like a leaf in the wind". The participants’ depression symptoms and negative emotion ratings, which were recorded at the start and end of the week, were found to drop in the metaphorical condition only. Although this experiment didn’t measure participants’ metaphoric style, it shows that being encouraged to adopt this style is more effective in alleviating negative feelings on troubling topics.

From an experimenter’s perspective, it’s interesting to note that in the font-colour study, participants who were well below average in metaphor usage didn’t show any significant preference for white words: those transfer effects don’t work on me, Jedi. In fact, if the researchers had just looked at the average scores for the participants as a whole, the metaphor effect would have been undetectable. This suggests the new measure of metaphorical thinking style can help us to investigate meaning-related effects that might be elusive. For example, it might have value in pinning down findings in the contested area of social priming, helping to identity those people likely to be influenced by such effects. Furthermore, we’ve seen that a metaphorical thinking style has emotional benefits, but could it also be useful in non-emotional domains, for instance in the extent to which fishy smells activate sceptical thinking?

One thing’s for sure – whether we prefer a crystal-clear monochrome take on the world, or to ladle on the technicolour, it’s clear that metaphor usage filters how we take in the world, for good and ill.

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Fetterman, A., Bair, J., Werth, M., Landkammer, F., & Robinson, M. (2015). The Scope and Consequences of Metaphoric Thinking: Using Individual Differences in Metaphor Usage to Understand How Metaphor Functions. Journal of Personality and Social Psychology DOI: 10.1037/pspp0000067

--further reading--
Shining a light on why sensory metaphors are so popular

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

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Mindfulness meditation increases people's susceptibility to false memories

By guest blogger Mo Costandi

Mindfulness is a form of meditation that encourages self-awareness by focusing attention on one's thoughts and sensations in a non-judgemental way. The practice is associated with various health benefits, and its popularity has grown enormously in recent years, due largely to endorsement from celebrities such as Oprah Winfrey and Deepak Chopra.

Today, mindfulness meditation forms the basis of therapeutic interventions for a wide variety of physical and psychological ailments, from chronic pain and heart disease to anxiety, stress, and depression. But it may also have unintended negative consequences: according to new research published in the journal Psychological Science, it makes memories less reliable, so that practitioners are more likely to think they can remember something that in fact didn't happen.

Brent Wilson of the University of California, San Diego and his colleagues hypothesised that mindfulness meditation may alter the mental processes that help us to distinguish between our inner mental world and the outer one, and they carried out three experiments to test this idea.

In the first, they recruited 153 undergraduates and randomly assigned them to one of two groups. Those in one group listened to a 15-minute focused breathing exercise (a form of mindfulness meditation) recorded by an experienced Yogi, while the others acted as a control group and listened to a 15-minute mind-wandering exercise, recorded by the same person, which instructed them to think about whatever came to mind. Afterwards all the participants completed a well-established lab test that reveals people’s vulnerability to false memories – they were shown a list of 15 words, including some related to the word trash (but the word trash was itself not present), and then asked immediately afterwards to type as many of the 15 words as they could remember.

The researchers found that participants in both groups recalled the same number of correct words on average, and also that there was mostly little difference between them in the number of falsely recalled words (i.e. remembering words that hadn’t actually appeared in the list). There was one exception, though. Those who had listened to the mindfulness exercise beforehand were significantly more likely to falsely remember seeing the word trash – that is, to experience a false memory for that word – than those who had done the mind-wandering exercise.

Next, Wilson and his colleagues recruited 140 more participants, and asked each one to perform versions of the same false memory test, using six different word lists. They then randomly split the participants into two groups, giving one group mindfulness training, and the other group a mind-wandering exercise, before asking them to repeat the false memory test. This confirmed the results of the first experiment: after the training, participants in the mindfulness condition were significantly more likely to recall words they had not seen (i.e. to experience false memories), as compared with their performance before the training. By contrast, the mind-wandering exercise had no such effect.

Finally, the researchers generated two hundred pairs of closely related words, such as foot and shoe. They showed one word from each pair to 215 more volunteers, then came the memory test: participants were shown one randomly selected word from each of the word pairs, and asked to report whether or not they had seen it earlier. All of the participants were then asked to listen to the 15-minute mindfulness exercise used previously, before repeating the false memory test. As in the second experiment, the participants were significantly more prone to false memories (thinking they’d seen words that they hadn’t) when they took the test after the training than before it.

Many previous studies have examined the potential benefits of mindfulness meditation, but this is one of only a few to demonstrate potential adverse effects of the practice. The researchers explain their findings in terms of what psychologists call "source monitoring", the process by which we determine the origins of our memories, thoughts, and beliefs. Information from the outside world contains more sensory details than internally generated information, and it is these details that normally help us to discriminate between the two. The essence of mindfulness is to observe one's mental activity non-judgementally, and this, the researchers argue, may increase practitioners’ susceptibility to false memories by diminishing or eliminating those mental processes that would otherwise help them discriminate between internally generated information and information received via the sense organs.    

Source monitoring errors are also widely believed to underlie the auditory and visual hallucinations experienced by people who are diagnosed with schizophrenia. It's therefore tempting to speculate that mindfulness could increase the risk of developing psychotic symptoms in those who may be predisposed to them. Although the current research did not address this specifically, there are some reported cases in the literature (pdf) of people experiencing adverse effects, including hallucinations, after mindfulness. And so the next time you sit down with your legs crossed and begin to chant that mantra, be mindful that meditation could have undesired consequences...

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Wilson, B., Mickes, L., Stolarz-Fantino, S., Evrard, M., & Fantino, E. (2015). Increased False-Memory Susceptibility After Mindfulness Meditation Psychological Science, 26 (10), 1567-1573 DOI: 10.1177/0956797615593705

--further reading--
The Psychology of Mindfulness, Digested

Post written by Mo Costandi (@Mocost) for the BPS Research Digest. Mo trained as a developmental neurobiologist and now works as a freelance writer specialising in neuroscience. He writes the Neurophilosophy blog, which is hosted by The Guardian, and is the author of 50 Human Brain Ideas You Really Need to Know, published by Quercus in 2013. His second book, Neuroplasticity, is due to be published by the MIT Press early next year.

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When you're sitting in a car, things appear closer than they really are

Psychologists have known for some time that how we perceive the world is influenced by our physical capacity to act in it. For example, hills look steeper when you've got a heavy bag on your back. Objects seem nearer when you're holding a tool that allows you to reach further. Now Birte Moeller and her colleagues have extended this line of research to study how sitting in a stationary car affects people's perceptions of distance. Their findings, published recently in Psychonomic Bulletin and Review, have real-life implications: for example, they could help explain why drivers often make misjudgments at traffic lights.

Forty-five participants (aged 19 to 54; 28 women) were allocated to judge distances in one of three conditions. Some of them sat in a Ford Escort, others sat on a chair, and a final group sat on a chair but behind a plastic screen that occluded their vision just the same as the Ford's windscreen. A traffic cone was placed at five different distances from the participants: 4 metres, 8 metres, 12 metres, 16 metres and 20 metres (roughly 13 feet to 65 feet), and a researcher stood by this cone holding two more cones. Each participant's task was to verbally direct the researcher to place his two cones horizontally the same distance from each other as the first target cone was distanced from the participant (thus creating a T-shape, with the participant at the foot of the T and the cones forming the horizontal roof of the T; see image).

Image from Moeller et al, 2015.

All participants tended to underestimate the distances they were judging, which is a well-known phenomenon in perception research (that is, they tended to direct the researcher to place his cones too close together, indicating that they'd underestimated how far the first target cone was located from them).

However, the new and important finding was that the participants who were sitting in a car underestimated distances far more than the participants in the two comparison conditions. The participants in a car underestimated distances by around 40 per cent across all the different distances they were judging, whereas the other participants underestimated by between 15 and 30 per cent, with their underestimations being greater for larger distances.

Another detail was that participants in the car condition underestimated the distances even more when the estimation procedure was repeated after they'd spent a few minutes driving the car. By comparison, the tendency of the other participants to underestimate distances wasn't affected by spending the same time walking around.

Moeller and her colleagues think there could be two complementary reasons why sitting in a car affects people's judgment of distances: the first is that when we're in a car, our potential to act in the world is enhanced, which influences our perceptual system to make us think things are nearer; the second is that the car is effectively integrated into the "body schema" (our sense of where our body extends in space), much as hand-held tools are, so that distances are judged relative to the front of the car rather than to the self. Future research with different sized and powered cars could help disentangle these two effects.

This research has obvious real-life safety implications. While a driver's tendency to underestimate distances could be beneficial in some circumstances, for example by encouraging earlier braking, there are other contexts in which it could be dangerous, such as when judging how much time there is to pass through traffic lights that have turned amber. Also, the very fact that different road users – pedestrians, cyclists and drivers – likely have different perceptions of the same physical distances could help explain how some accidents occur.

"In sum," the researchers concluded, "entering a car does more to you than making transportation more comfortable. In fact, the moment you sit in your car, your (distance) perception of the environment seems to adapt to your new 'action potential,' again underlining how strongly related action and perception representations in the cognitive system are."
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  Moeller, B., Zoppke, H., & Frings, C. (2015). What a car does to your perception: Distance evaluations differ from within and outside of a car Psychonomic Bulletin & Review DOI: 10.3758/s13423-015-0954-9

--further reading--
How tools become part of the body
Targets look bigger after a shot that felt good
Walking cane reveals dramatic sensory re-mapping by the brain
Judging others by our own capabilities
Welcome to the weird world of weight illusions

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

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Guilt-prone people are highly skilled at recognising other people's emotions

It's not pleasant to feel perpetually that you're responsible for mishaps and screw-ups, but some people do. Psychologists recognise this as a distinct trait, which they call "guilt-proneness" and now they've discovered that it tends to go hand in hand with an enhanced ability to recognise other people's emotions, at least from their facial expressions.

For the new study published in Cognition and Emotion, Matt Treeby and his colleagues asked 363 people (mostly students; average age 27) to say how they'd feel in 11 hypothetical negative scenarios. For example, one involved making a big mistake on a work project. From the range of answers available, participants who said they'd think "I should have recognised the problem and done a better job" were considered to have shown evidence of guilt-proneness. Another answer participants could choose was "I would feel like I wanted to hide", and answers like this were taken as a sign of shame-proneness as opposed to guilt-proneness. Although guilt and shame sound similar, the latter is associated much more with uncomfortable thoughts about the self ("what does this misdemeanour say about me?") whereas guilt is much more focused on the act itself ("how could I have done that?"). Other response options signalled detachment or lack of concern: "Well, nobody is perfect".

Next, the participants completed an online test that involved looking at photographs of actors displaying different facial expressions of emotion with varying intensities. The participants' challenge was to label each emotion correctly as either happiness, sadness, disgust, fear, anger or shame.

The key finding was that guilt proneness tended to correlate with performance on the emotion-recognition test. Guilt-prone people performed better overall across the different emotions, and they also showed extra sensitivity to recognising low intensity emotions. It's not clear from this research whether being sensitive to other people's emotions contributes to making someone guilt prone, or if instead being guilt-prone leads one to pay more attention to people's emotions, and get more practice at recognising them. Either way, it's an intriguing finding that complements past research showing that guilt-prone people tend to report better than usual psychological adjustment, to avoid anti-social behaviour and have good relationship skills.

The story for shame-prone people was not so rosy. Overall, shame proneness was not related to emotion recognition ability, although there was some evidence that it actually correlated with a poorer ability to recognise other people's happy facial expressions. This result also fits with previous research that's shown shame-prone people tend to have poor empathy skills.

The study is not flawless – for example, the facial stimuli were acted and static and in real life we rely on many different cues to emotion, including body language and tone of voice. However, it's a curious finding that might help guilt-prone people understand that their guilt-proneness is not their fault: it's quite likely a side-effect of their being so well-attuned to other people's emotions.

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Treeby, M., Prado, C., Rice, S., & Crowe, S. (2015). Shame, guilt, and facial emotion processing: initial evidence for a positive relationship between guilt-proneness and facial emotion recognition ability Cognition and Emotion, 1-8 DOI: 10.1080/02699931.2015.1072497

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

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The adaptive mind: Children raised in difficult circumstances show enhanced mental flexibility in adulthood

According to a stream of psychological research, a tumultuous upbringing sets you up for a raw deal later in life. Being raised in households that lack wealth or stability is associated with outcomes that include altered decision-making abilities, memory and general cognitive function. These changes are usually considered impairments, but does a bad childhood really make you less capable, or just different?

The research on decision-making, for instance, reveals "sub-optimal" decisions made by people raised in stressful environments – opting for a small reward now rather than holding out for a big one later – that actually make sense given the person’s history: if nothing is guaranteed in your world, it’s a smart decision to grab what you can now.

One way to look at this is that stressful conditions don’t lessen you so much as condition you. Chiraag Mittal, a grad student at the Carlson School of Management, and his colleagues suspected this might apply to more than decision making. They recently published an article in the Journal of Personality and Social Psychology where they look at cognitive function, specifically executive functioning, to see if the story isn’t only one of deficits.

Executive function is what allows us to process and manage complex behaviour, including paying attention and making decisions. In fact, it contains so many facets that Mittal’s team chose to focus on two. Inhibition is the ability to stay on task in the face of distractions, measured here by accuracy on a simple judgment task (which way points the arrow briefly flashed on-screen?) while being distracted by flashes elsewhere on-screen. This ability is associated with delaying gratification, which is less useful in real-world unpredictable contexts where the "big reward next year" may never come.

Meanwhile, the second facet they looked at, shifting, is the ability to turn from one goal to another as effortlessly as possible – here measured by the efficiency of switching from categorising on-screen targets one way then another (e.g. by colour and then by shape) on given trials, depending on the current rule. Shifting ability is an important skill for anyone living in unpredictable circumstances, and Mittal’s team predicted that adults with that background would do better at this task, and worse at the inhibition task, than those from stable backgrounds.

The data bore out these predictions – when it came to mental flexibility, people with a history of childhood adversity actually outperformed their more fortunate peers. There was a wrinkle – a small-sample replication threw up anomalies, so the researchers ran a more robust third study with 181 student participants. This confirmed the general pattern: participants who said they’d had an unpredictable early life (changes in residence, movement of other cohabitants in and out of home, and changes in parents’ employment status) performed worse at inhibition, but better at shifting. However, this effect only reared its head when the tests were preceded by a task stoking a sense of uncertainty – reading an alarming newspaper account of “Tough Times Ahead”. This fits with past research showing that effects tied to a stressful upbringing often seem only to be elicited in conditions of current unpredictability (a rule that is also true in animal research).

In a follow-up with a smaller sample, the researchers made use of an ongoing collection of data from a group of people born into poverty between 1975 and 1976 . Using recorded details on their upbringing at multiple time points between birth and ten years old, coders could produce more reliable ratings of the participants' childhood experience of unpredictable circumstances. Due to time constraints, only shifting ability could be looked at, but again the earlier finding was replicated: when primed with uncertainty, people who had been raised in greater turmoil performed better. A meta-analysis combining the results from all four of the researchers’ studies strongly confirmed this effect.

The mental process of inhibition allows people to pursue goals and underlies the willpower to stick with things, characteristics that encourage personal success. But shifting ability is also associated with a higher-order ability that’s important in life: creativity. People from disadvantaged, unstable backgrounds undoubtedly face challenges, but this research suggests, if not a bright side, a more nuanced one. People aren’t passively victimised by their circumstances – they adapt to them, sometimes in ways that make it easier to thrive in challenging conditions.

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Mittal, C., Griskevicius, V., Simpson, J., Sung, S., & Young, E. (2015). Cognitive adaptations to stressful environments: When childhood adversity enhances adult executive function. Journal of Personality and Social Psychology, 109 (4), 604-621 DOI: 10.1037/pspi0000028

--further reading--
Poverty shapes how children think about themselves
Why is poverty associated with mental health problems for some people, but not others?
Testing the American Dream - can the right mix of personality and IQ compensate for poverty?
When depressed mothers give birth to thriving babies

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

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Psychologists study twins to learn more about the roots of procrastination

With so many digital distractions a mere mouse click away, procrastination is easier than ever. You want, nay need, to work on an important project, yet find yourself browsing Twitter, making coffee, checking email – basically anything other than doing what you should be doing. Daniel Gustavson and his colleagues – the authors of a new twin study of procrastination published in the Journal of Experimental Psychology: General – sum it up as "the irrational delay of an intended course of action".

Much has been written about why we fall prey to this habit in the moment (the all-important job is perceived as too challenging, the other tasks and distractions seem easier, and so on), but Gustavson and his colleagues wanted to learn more about why some of us are generally more prone to procrastination than others. Do we inherit a predisposition for procrastination in our genes, and what other mental abilities are related to the procrastination habit?

The researchers recruited 386 pairs of same-sex twins, 206 of whom were identical twins, meaning they have the same genes, and 179 were non-identical, meaning they share on average half their genes. After missing data were removed, the final sample included 401 women and 350 men (average age 23). The twins completed a questionnaire about their proclivity for procrastination (this involved rating their agreement with statements like "I am continually saying 'I'll do it tomorrow'"), and they answered questions about their proneness to "goal failures" (tested through questions like "Do you find you forget what you came to the shops to buy?").

The twins also completed several measures of their "executive function", including their powers of inhibition (e.g. one task involved resisting the reflex to glance at a square that appeared on-screen, and looking instead in the opposite direction), their ability to shift mind-sets (e.g. categorising shapes on a coloured background by their shape one minute, then by their colour, depending on changing task instructions), and their ability to juggle information in memory over short periods of time.

By comparing similarities in executive function performance, procrastination proneness and goal failures between identical and non-identical twins, the researchers were able to deduce how much of an influence genes have on these traits and abilities, and how much overlap there is in the genetic influence on the different measures. In simple terms, a higher correlation on a particular measure among identical twins compared with non-identical twins would indicate a greater role for genes.

Here are some of the key findings. The tendency to procrastinate was found to be partly inherited – 28 per cent of variability in this trait was explained by genetic influences (though note, this includes gene-environment interactions, such as a procrastinator choosing a job – like being a blog editor – that makes procrastination easier). Moreover, 17 per cent of the procrastination variability that was explained by genes overlapped with the genetic influences on goal failures – that is, many of the same genes influencing procrastination appear to play a role in the ability to manage goals. Also, environmental influences common to both procrastination and goal management explained a further 28 per cent of variation in procrastination.

The tendency to procrastinate also correlated with overall executive function ability – that is, people who said they procrastinated more tended to achieve an overall poorer score on the executive function tests. And again there was genetic overlap: many of the genetic influences on executive function were found to be the same as those shared by both procrastination and goal management.

There was one caveat in the association between procrastination proneness and executive function. Procrastinators actually tended to perform better on the ability to shift mind-sets, presumably because having a butterfly mind gives you a certain mental flexibility even though it makes it difficult to focus.

The findings help to pick apart the root causes of procrastination. At a genetic and behavioural level, they show that a tendency to procrastinate tends to go hand in hand with an ability to manage goals, and mostly a poorer ability to control one's own mind, in terms of inhibition and juggling information.

Gustavson and his team warned that identifying the actual genes involved in procrastination, executive function and goal management remains a long way of, and that many hundreds or thousands of gene variants are likely involved. They also cautioned that their study can't tell us about the causal relationships, if any, between the studied traits – it's tempting to assume that poor executive function or goal management causes procrastination, for example, but it's theoretically possible the influence could run the other way, both ways, and/or that other factors not studied here are more relevant, such as personality or intelligence. Nonetheless, the researchers did offer some brief practical advice on the back of their findings:

"Training subjects on how to set good goals may improve their ability to manage these goals and avoid procrastination ... Moreover, helping subjects retrieve their important long-term goals and use those goals to avoid getting side-tracked by short-term temptations (e.g. developing implementation intentions) might also be effective at reducing procrastination."

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Gustavson, D., Miyake, A., Hewitt, J., & Friedman, N. (2015). Understanding the Cognitive and Genetic Underpinnings of Procrastination: Evidence for Shared Genetic Influences With Goal Management and Executive Function Abilities. Journal of Experimental Psychology: General DOI: 10.1037/xge0000110

--further reading--
The cure for procrastination? Forgive yourself!
Psychologists investigate a major, ignored reason for our lack of sleep - bedtime procrastination
Forgive yourself for relaxing in front of the TV and the couch time might actually do you some good

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

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New genetic evidence suggests face recognition is a very special human skill

Example stimuli from Shakeshift and Plomin, 2015.

A new twin study, published today in PNAS, of the genetic influences on face recognition ability, supports the idea that face recognition is a special skill that's evolved quite separately from other aspects of human cognition. In short, face recognition seems to be influenced by genes that are mostly different from the genes that influence general intelligence and other forms of visual expertise.

The background to this is that, for some time, psychologists studying the genetics of mental abilities have noticed a clear pattern: people's abilities in one domain, such as reading, typically correlate with their abilities in other domains, such as numeracy. This seems to be because a person's domain-specific abilities are strongly associated with their overall general intelligence and the same genes that underlie this basic mental fitness are also exerting an influence on various specific skills.

Nicholas Shakeshaft and Robert Plomin were interested to see if this same pattern would apply to people's face recognition abilities. Would they too correlate with general intelligence and share the same or similar genetic influences?

The researchers recruited 2,149 participants, including 375 pairs of identical twins who share the same genes, and 549 non-identical twins, who share roughly half the same genes, just like typical siblings (overall the sample was 58 per cent female with an average age of 19.5 years). The participants completed a test of their face processing skills, including memorising unfamiliar faces, and also tests of their ability to memorise cars, and their general intelligence, in terms of their vocabulary size and their ability to solve abstract problems.

Comparing the similarities in performance on these different tests between identical and non-identical twin pairs allowed the researchers to estimate how much the different skills on test were influenced by the same or different genes.

All the abilities – face recognition, car recognition and general mental ability – showed evidence of strong heritability (being influenced by genetic inheritance), with 61 per cent, 56 per cent, and 48 per cent of performance variability in the current sample being explained by genes, respectively.

Crucially, performance on face recognition was only moderately correlated with car recognition ability (r = .29 where 1 would be a perfect correlation) and modestly correlated with general mental ability (r = .15), and only 10 per cent of the genetic influence on face recognition ability was the same as the genetic influence on general mental ability (and likewise, only 10 per cent of the genetic influence on face memory was shared with the genes affecting memory for cars).

Essentially, this means that most of the genetic influences on face recognition ability are distinct from the genetic influences on general mental ability or on car recognition ability. Shakeshaft and Plomin said this "striking finding" supports the notion that there is something special about human facial recognition ability. These results add to others that have suggested face recognition is a special mental ability – for instance, some have argued that faces alone trigger brain activity in the so-called "fusiform face area" (although this claim has been challenged); and unlike our ability to recognise other objects or patterns, our ability to recognise faces is particularly impaired when faces are inverted, consistent with the idea that we use a distinctive "holistic" processing style for faces.

The story is complicated somewhat by the researchers' unexpected finding that recognition ability for cars was also linked with distinct genetic influences that mostly did not overlap with the genetic influences on general mental ability. Perhaps, the researchers surmised, the tests of general mental ability used here (a vocab test and the well-used Raven's Progressive Matrices) did not adequately tap the full range of what we might consider general mental abilities. Whatever the reason, it remains the case that this new research suggests that face recognition ability is influenced by a set of genetic influences that are largely distinct from those implicated in a similar form of visual recognition (for cars) and implicated in vocab ability and abstract reasoning. Based on this, the researchers concluded they'd shown for the first time that "the genetic influences on face recognition are almost entirely unique."

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Nicholas G. Shakeshaft, & Robert Plomin (2015). Genetic specificity of face recognition PNAS

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

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Extraverts are surprisingly good at mind-bending puzzles

The solitary inventor, buried away in garage or shed, is the classic depiction of introvert as born problem-solver. But new research, published recently in Psychological Studies, suggests that it’s extraverted people who perform better at classical tests of problem-solving, thanks to their tendency to be motivated in ways that are helpful for achieving.

Vidya Athota at the University of Notre Dame, Australia and Richard Roberts at the Center for Innovative Assessments in New York ran computerised sessions of the Tower of Hanoi test (see a model below), in which participants disassemble a tapering tower of disks threaded onto a pole, in order to eventually reassemble them into a new tower on another pole. To do this, they make use of a third, spare pole to help fulfil the task rule that in forming the new tower you must only lay new discs onto larger ones.

Image: Ævar Arnfjörð Bjarmason/ Wikipedia. 

The 195 student participants tried to solve as many rounds of this that they could in three minutes, and also completed questionnaires on personality and personal values, specifically pleasure-oriented and service-oriented approaches to the world (essentially measuring how much they prioritised having fun in life versus concern for the welfare of others).

Athota and Roberts found the more extraverted participants solved more Towers of Hanoi, but only because they tended to be more interested in pursuing pleasure in the form of sensual gratification and especially stimulation and excitement. When these two values were accounted for, extraversion in itself didn’t provide extra predictive power.

At first blush, stimulation and sensual gratification sound like drives that would lead people away from cracking codes and straight onto a rollercoaster, no seatbelt required, thanks. But cognitive work that promises a satisfying payoff is facilitated by a higher appetite for rewards, which seems to be what we’re seeing here, with participants marshalling their focus and mental resources to beat the tower as often as possible.

By revealing why extraverts tackle certain tasks better, this study helps us figure out when they may not. Being strongly attracted to pleasure is associated with extraversion, but the promised thrill of success won’t be prominent in every creative challenge – problem solving is often about more than tackling circumscribed puzzles – so we shouldn’t expect extraverts to excel on all challenges. That said, when we look at this issue from other angles – such as the types of people who make more creative scientists – extraverts also defy expectations, tending to be among the most creative. Just as the notion that extraverts always make better salespeople is mistaken, we should be aware that think-work is not the sole domain of the introvert, but will suit different personality types better according to the specific characteristics of task, incentives, and social environment.

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Athota, V., & Roberts, R. (2015). How Extraversion + Leads to Problem-Solving Ability Psychological Studies, 60 (3), 332-338 DOI: 10.1007/s12646-015-0329-3

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

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Mental effort is contagious

If you're about to dive into a piece of work that requires intense mental focus, you might find it helps to sit next to someone else who is concentrating hard. According to an ingenious new study published in Psychonomic Bulletin and Review, mental exertion is contagious: if a person near you is straining their synapses in mental effort, their mindset will automatically intensify your own concentration levels.

Psychologists have known since at least the 1960s that the presence of other people affects our own performance in predictable ways. For example, the 1965 Social Facilitation Theory describes how the presence of other people makes it easier to perform well-rehearsed, automatic behaviours. Yet company can also be distracting and make it more difficult to perform behaviours that require mental control.

Kobe Desender at Vrije Universiteit in Belgium and his colleagues wanted to build on these findings by testing whether it makes a difference to our performance what other people present are doing – and specifically, if someone else is using a lot of mental effort, does that affect how much mental effort we exert ourselves?

Thirty-eight participants (20 women; average age 22) performed a version of what's known as the "Simon task" in pairs. Coloured squares appeared on either the left or right-hand side of a computer screen. When two of the four possible colours of square appeared, the person sat to the left of the screen was required to press the 'd' keyboard key as fast as possible with their left hand. When either of the two other possible coloured squares appeared, the person on the right was required to press the 'k' key as fast as possible with their right hand. Superior performance is revealed through faster responding and fewer errors. Although the task was performed in pairs in this way, there was no need or possibility for collaboration between partners, nor was there any competition.

Image from Desender et al, 2015. (A) shows the set-up for the first experiment, (B) for the second experiment.

An important thing to understand about this task is that it was easier for participants to respond to a target square (i.e. one that was a colour that they had been instructed to respond to) when it appeared on the same side that they were sitting, and that was therefore also the same side as the hand they were using to respond – that is, when the target and response were congruent. Also, the higher the proportion of congruent trials that a participant was subjected to, the easier the task would become, because they could switch to a more automatic mode of responding.

The researchers manipulated task difficultly individually for each person in a pair by varying their proportion of congruent versus incongruent trials. The issue of stimulus-repsonse congruence also provided a ready indicator of a person's concentration levels. If a person was trying really hard, their performance would be less affected by whether their target squares were congruent or not.

Desender and his team were especially interested in those instances when they made the task super difficult for one participant (he or she had only 10 per cent congruent trials), but they kept the difficulty medium for the other participant (they had a 50/50 mix of congruent and incongruent trials). In this situation, the participant in the difficult version was required to use maximum mental effort to succeed. The intriguing finding is that this mental effort influenced their partner. A person playing alongside someone who was forced to concentrate really hard was themselves less influenced by their own targets' congruency – a sure sign that they too were trying harder than normal. Somehow one person's hidden mental effort seemed to influence the other.

Further analysis confirmed that this effect was not caused simply by one player mimicking the other's response speed. Nor was it that the participants were influenced by looking at their partner's ratio of congruent and incongruent trials and seeing that their task was more difficult. The researchers ruled out this possibility in a follow-up study in which each player had their own display, and a piece of cardboard stopped them from being able to see their partner's squares (see figure B above).

The researchers don't know what led one player's levels of mental effort to contaminate their partner, but they speculate that perhaps it had to do with body posture. Maybe the person forced to concentrate extra hard adopted a more tense body posture and this sign of mental effort automatically influenced their partner to also concentrate extra hard. However, they added that a "more radical hypothesis should also be considered, such as the possibility that effort exertion is influenced by a difference in scent of someone else exerting high or low effort."

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Desender, K., Beurms, S., & Van den Bussche, E. (2015). Is mental effort exertion contagious? Psychonomic Bulletin & Review DOI: 10.3758/s13423-015-0923-3

--further reading--
Social flow - how doing it together beats doing it alone
Faster, Higher, Stronger: The Psychology of Competition
Guilt is catching
The smell of fear more powerful than previously realised

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

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Images of ultra-thin models need your attention to make you feel bad

By guest blogger Tom Stafford

We all know that fashion models have unrealistic bodies. Even if they aren’t photoshopped, most of us could never be that thin, at least not without making ourselves ill. Previous research has suggested that viewing pictures of unrealistically thin female models makes young women feel bad – leaving them dissatisfied with their own bodies, more sad, angry and insecure.

A crucial question is whether the effect of these thin-ideal images is automatic. Does the comparison to the models, which is thought to be the key driver in their negative effects, happen without our intention, attention or both?  Knowing the answer will tell us just how much power these images have, and also how best we might protect ourselves from them.

There are at least two plausible reasons psychologists have for suspecting such comparisons might be automatic. One is evolutionary – we’re a social species, so perhaps we instinctively compare ourselves against the people around us, to figure out where we are in the social hierarchy. Our ancestors didn’t have photographs, but it’s possible that modern media is hijacking a process that was once useful in our biological history. The second reason is practice: things we do again and again become automatic. Maybe, especially for some people, comparing themselves with media images has become a habit.

To test the idea that comparing ourselves to thin-ideal images is an automatic process, Stephen Want and colleagues at Ryerson University, Canada, invited 116 female Canadian undergraduate students, with an average age of 19, and an average body mass index of 21 (the healthy range is between about 19 and 26), to take part in what they were told was an experiment testing how short-term memory is affected by mood, personality and exposure to images.

Under this cover story, participants were given a difficult memory task (remembering a string of different digits, such as 78639946) or an easy memory task (remembering an easy string, such as 11111111). They were told they would have to keep these digits in mind while they looked at images of several fashion models or cats. All participants were, in fact, shown pictures of fashion models, 12 of them for 10 seconds each. The purpose of this deception was to prevent the participants guessing that the researchers were interested in the effect of the images – this reduces the likelihood that the participants performed in a certain way to meet the researchers’ expectations.

But the memory task wasn’t just part of the cover story, it was central to the study design. One feature of automatic processes is their efficiency: automatic processes can occur when you are mentally occupied whereas non-automatic processes require your attention. Following this definition, the idea was that the difficult memory task group would only be able to make automatic social comparisons, whereas the easy memory task group would be able to make both automatic and effortful social comparisons. If images have negative effects automatically, they should be seen in both groups – they might even be stronger in the harder memory task group, if the distraction of the task stopped participants from having reasonable thoughts about why they shouldn’t compare themselves to the models.

The results were clear. Participants who were preoccupied by the difficult memory task were unaffected by the images – afterwards their mood and satisfaction with their appearance was indistinguishable from their feelings at the beginning of the experiment. But the easy memory task group showed the classic effect of thin-ideal images – they felt worse in terms of their mood, and they felt worse about their appearance specifically.

A second experiment, recruiting 177 participants, replicated the first with different images, and also showed that it wasn’t merely having the mental capacity to think about appearance that produced the effect. A group that was given the easy memory task but shown pictures of coloured rectangles rather than fashion models didn’t suffer any negative effects on their mood or appearance satisfaction.

In addition, participants in this second experiment rated the importance of media images as a source of information about appearance, and the pressure they felt to emulate celebrities and other media figures. The researchers’ logic was that if the comparison process is automatic through practice, it is participants who scored highly on this questionnaire who would be most likely to show the harmful comparison effect from looking at models.

As you would expect, in the easy memory condition, it was those participants who rated themselves most highly on this questionnaire who were most affected by the images. But in the difficult memory condition – the one in which only efficient, automatic, processes could be generating comparisons to the thin-ideal images – the media-engaged participants’ mood and satisfaction with their appearance was unaffected, just like their peers who felt less pressure to emulate celebs.

Taken together, the two experiments are a strike against the idea that we automatically compare ourselves to thin-ideal media images, even those of us most likely to feel like we ought to – young women who rate themselves as preoccupied with the media and their appearance.

Perhaps this is grounds for optimism. It might mean we can starve these images of their negative power by not paying them attention. But despite this, it shows again that when we do focus on these images they make us feel bad. Thin-ideal images are so prevalent in our society that even a temporary effect could produce a consistent load of misery for individuals who attend to them. So the deeper question is how society would need to change so that such images are less prevalent, or so that paying attention to them is no longer celebrated as a priority.

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Want, S., Botres, A., Vahedi, Z., & Middleton, J. (2015). On the Cognitive (In)Efficiency of Social Comparisons with Media Images Sex Roles DOI: 10.1007/s11199-015-0538-1

--further reading--
Video protects girls from the negative effects of looking at ultra-thin models
By age three, girls already show a preference for thin people
How do women and girls feel when they see sexualised or sporty images of female athletes?

Post written by Tom Stafford, a psychologist from the University of Sheffield who is a regular contributor to the Mind Hacks blog. He is on twitter as @tomstafford and his latest book is 'For argument's sake: evidence that reason can change minds'.

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