Our jumpiness at nighttime is not just because it's dark

When something goes bump in the night, most of us are little jumpier than we would be in the day. But is that just because it's dark, or is it more to do with our bodies and brains switching to a vigilant nocturnal mode?

Yadan Li and her colleagues have attempted to disentangle the influences of darkness and nighttime. They recruited 120 young women to complete a computer task in a windowless cubicle, which involved them looking at neutral pictures (e.g. nature scenes), scary pictures (e.g. spiders; a person being attacked), and listening to scary sounds (e.g. screams) and neutral sounds (e.g. bird song).

The women were split into four groups: some of them completed the task in the day-time with bright lights on; some in the day-time in darkness; others at night-time with a dim light on; and others at night-time in complete darkness (although presumably the computer screen created some light).

The women who completed the task at nighttime said they found the scary pictures and sounds more scary (than the women tested in the day-time), and this was true regardless of whether they were tested in darkness or light. Moreover, their extra jumpiness was confirmed by recordings taken of their heart-rate and perspiration.

In contrast, the time of testing made no difference to the women's responses to the neutral pictures and sounds. Also, the lighting levels, whether in the day-time or at nighttime, made no difference to the women's reactions to the neutral or scary stimuli.

In other words, the findings appear to suggest that we're more sensitive to threats at nighttime because it's the night, not because it's dark. This raises the possibility that biological factors associated with our circadian rhythm affect our fear-sensitivity, although it's plausible that cultural factors are involved, in that we've learned to be more vigilant at night.

The day-time testing took place at 8.00am and the nighttime testing at 8.00pm (in February, so it was dark outside) – it remains to be seen whether and how the findings might vary at different times of day and night. We also don't know if the same findings would apply to male participants, or participants from different cultures or stages of life (the study was conducted in China where the authors are based, and the student participants had an average age of 22 years).

Li and her colleagues hope their findings will inspire other researchers to explore this topic. "[T]his study is merely a first step in understanding the underlying mechanisms involved in fear-related information processing and has implications for the underlying psychopathology of relevant phobias and anxiety disorders [such as nighttime panic attacks]," they said.

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Li, Y., Ma, W., Kang, Q., Qiao, L., Tang, D., Qiu, J., Zhang, Q., & Li, H. (2015). Night or darkness, which intensifies the feeling of fear? International Journal of Psychophysiology DOI: 10.1016/j.ijpsycho.2015.04.021

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

Can feeling lonely make you hungry?

Loneliness is bad for you. Some experts have even likened it to a kind of disease. What's unclear is how being being lonely leads to these adverse effects on our health. A new study looks at one possibility – that loneliness makes people feel hungrier than normal, thus increasing their food intake and putting them at risk of obesity with all its associated health problems.

Lisa Jaremka and her colleagues asked 42 women (average age 53) to fast for 12 hours before visiting the psych lab. On arrival in the morning, the women were asked to eat an entire 930 calorie meal consisting of eggs, turkey sausage, biscuits and gravy. Before they ate the meal and several times during the seven hours afterwards the women rated their hunger. Their feelings of extreme loneliness had been recorded five months earlier as part of a different study. Their ghrelin levels (ghrelin is a hormone that's associated with hunger and promotes eating) were recorded by blood test before the meal and 2 and 7 hours later.

Among only the women with a healthy weight (based on their BMI), those who reported feeling more lonely exhibited higher ghrelin levels at the end of the day they visited the lab, and said they felt hungrier. This result is consistent with another recent study by the same researchers, that found women who'd experienced more interpersonal stress had higher ghrelin levels and lower leptin (an appetite-suppressing hormone).

Why should loneliness be associated with feeling more hungry? Jaremka and her team speculate that it could be an evolutionary hangover and adaptive in the sense that hunger encourages eating, which encourages greater social bonding. "Eating was a highly social activity throughout human evolution, and today meals are often eaten with other people," they explain. Other research has shown that eating comfort food prompts thoughts of relationships. "Consequently," the researchers said, "people may feel hungrier when they feel socially disconnected because they have either implicitly or explicitly learned that eating helps them feel socially connected and/or provides them with an opportunity for social connection." It's unclear why the same process wasn't triggered in the overweight women.

The study has some methodological issues, among them: the lack of a current loneliness measure; no male participants; and half the small sample of women were cancer survivors recruited from an earlier study. This may limit the generalisability of the findings, but note the main results from this study were the same for all participants regardless of their medical history.

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Jaremka, L., Fagundes, C., Peng, J., Belury, M., Andridge, R., Malarkey, W., & Kiecolt-Glaser, J. (2015). Loneliness predicts postprandial ghrelin and hunger in women Hormones and Behavior, 70, 57-63 DOI: 10.1016/j.yhbeh.2015.01.011

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

Optimism and pessimism are separate systems influenced by different genes

"... the optimist sees the rose and not its thorns; the pessimist stares at the thorns, oblivious to the rose,” Kahlil Gibran.

Optimists enjoy better health, more success, more happiness, and longer lives, than pessimists. No surprise, then, that psychologists are taking an increasing interest in our outlook on life. An unresolved issue is whether optimism and pessimism are two ends of the same spectrum, or if they're separate. If the traits are separate, then in principle, some people could be highly optimistic and pessimistic – to borrow the poet Gibran's analogy, they would be keenly aware of both the rose and its thorns.

Timothy Bates at the University of Edinburgh has turned to behavioural genetics to help settle this question. He's analysed data on optimism and pessimism gathered from hundreds of pairs of identical and non-identical twins. These were participants from a US survey and their average age was 54. The twins rated their agreement with various statements as a way to reveal their optimism and pessimism such as "In uncertain times, I usually expect the best" and "I rarely count on good things happening to me." They also completed a measure of the "Big Five" personality traits: extraversion, neuroticism etc.

The reasoning behind twin studies like this is that if optimism and pessimism are highly heritable (i.e. influenced by inherited genetic factors), then these traits should correlate more highly between pairs of identical twins, who share all their genes, than between non-identical twins, who share approximately half their genes. And if optimism was found to be more heritable than pessimism, or vice versa, this would indicate different genetic influences on optimism and pessimism.

Another insight from twin studies is to disentangle the relative influence of shared and unique environmental factors – these are the aspects of a twin's upbringing that they share with their sibling, such as parenting style, and those that are unique, such as the friends they keep.

Bates' analysis indicates that optimism and pessimism are subject to shared genetic influences (with each other, and with other personality traits), but also to independent genetic influences, thus supporting the notion that optimism and pessimism are distinct traits, not simply two sides of the same coin.

"Optimism and pessimism are at least partially biologically distinct, resulting in two distinct psychological tendencies," Bates said. He added that this dovetails with neuroscience evidence that's indicated there are separate neural systems underlying optimism and pessimism.

The new findings also suggested there is a "substantial" influence of upbringing on optimism and pessimism (i.e. increasing one and lowering the other, and/or vice versa). This raises the intriguing possibility that optimism might to be some extent a malleable trait that can be encouraged through a child's upbringing.

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Bates, T. (2015). The glass is half full half empty: A population-representative twin study testing if optimism and pessimism are distinct systems The Journal of Positive Psychology, 1-10 DOI: 10.1080/17439760.2015.1015155

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

Spook Me, Please: What Psychology Tells Us About the Appeal of Halloween

By guest blogger Mathias Clasen

It’s the time of year, at least in our part of the world, when darkness encroaches on us—literally and metaphorically. The symbols and agents of darkness dominate Halloween decorations everywhere, and Halloween is growing in popularity across Europe and in the US. According to the National Retail Federation, US Halloween spending now exceeds $7 billion. In the UK, Halloween is worth about £330 million.

Why is this Americanised version of the ancient pagan festival so successful? Is it merely another instance of the McDonaldisation of culture, the increasing hegemony of American commercial culture, explicable in terms of market mechanisms alone? No. The dread scenarios evoked by the paraphernalia of Halloween are deeply fascinating to a prey species such as Homo sapiens. Ghouls, zombies, demons, giant spiders, and horrors hidden in darkness all engage evolutionarily ancient survival mechanisms—and all figure prominently in the scenography of horror films and in Halloween decorations. We seem to love the good thrill of a safe scare, and Halloween provides plenty of those.

Horror films, horror monsters, and the iconography of Halloween are culturally successful because they are well-adapted to engage evolved danger-management adaptations. We know that existence for our prehistoric ancestors was precarious. The threat of predation has been very real and very serious for hundreds of millions of years. As the anthropologist Lynn Isbell has shown, mammals and reptiles have been engaged in a lethal co-evolutionary arms race for a hundred million years or more, and that arms race has profoundly shaped our genome. A hard-wired, adaptive tendency to easily acquire fear of snakes explains the prevalence of snake phobias today, even in snake-less ecologies.

Similarly, the threat posed by poisonous spiders in prehistoric environments has left an eight-legged imprint in human DNA, an imprint that is expressed as a tendency to easily acquire fear of spiders. We are, at the very least, likely to pay close attention if a saucer-sized arthropod scuttles out from under the couch. Spiders engage attention—as recent research documented, spiders override inattentional blindness, our tendency to overlook even striking stimuli in peripheral awareness when we’re engaged in a cognitively taxing task. Another study claimed that five-month-old infants pay closer attention to schematic representations of spiders than to representations that consist of the same graphic elements but do not look like spiders. Spiders are inherently attention-demanding and, to most people, gross and a little scary, and that explains why they feature so prominently in Halloween iconography. They simply perform the functions of engaging attention and eliciting a shudder well.

Likewise, the usual suspects in the horror genre’s antagonistic line-up—from supernatural monsters via rotting zombies to homicidal maniacs in masks—all connect squarely with defensive psychological adaptations that arose over evolutionary time in response to dangers in the environment, from the threat posed by hostile conspecifics and lethal pathogens to the bite of hungry carnivores. Although there were no child-eating clowns in prehistoric environments, a character like Pennywise the Dancing Clown has achieved pop-cultural infamy because it effectively targets danger-management mechanisms in human cognitive architecture.

The dangers of pre-historical existence have left deep grooves in human nature. The creatures and situations we typically fear—spiders, snakes, the dark, heights, confined spaces, and so on—are the same creatures and situations that posed real dangers to our evolutionary ancestors, even though they play little role in modern-day mortality statistics in the West. We should be afraid of driving too fast in a car, of smoking cigarettes, of eating unsaturated fats, and so on. Our Halloween decorations should feature such elements prominently, but they don’t. Why? Because humans evolved to swiftly detect, respond to, and develop phobias of stimuli that posed a threat over thousands of generations. The dangers posed by fatty acids and cigarettes are evolutionarily novel and have left no impression in human DNA. When we thrill to supernatural monsters and giant spiders, we are thrilling to the ghosts of dangers past, ghosts that persist in the human central nervous system despite relaxed selection pressures.

Of course the scary costumes and props of Halloween are symbolic and don’t pose any real threat; they provide safe thrills, our love for which has roots deep in our mammalian heritage. Other mammalian infants also find great pleasure in forms of play that allow them to get experience with life-threatening situations in a safe context. Children’s play often revolves around simulating dangerous situations. Witness an infant responding enthusiastically to a game of peek-a-boo, the most primal of horror situations where the primary caretaker disappears from the infant’s field of vision (and thus its world) for a few stress-inducing seconds … only to reappear suddenly, causing a mild startle reaction. Or witness any kid delightedly simulating being chased by a daddy- or a mommy-monster in a session of chase play or hide-and-seek. Such activities serve the adaptive functions of giving children experience with evasion techniques, they build locomotor skills and muscle tone, and they allow the children to get experience with their own cognitive and emotional responses to situations that feel dangerous but aren’t. Such experience could become vital later in life, when they face truly dangerous situations or when they have to face and overcome their own fear.

Halloween has the potential to bring us into contact with our evolutionary heritage by confronting us with reflections of evolutionarily ancient, fear-inducing stimuli. Halloween is here to stay, so we might as well embrace it. When darkness falls, the monsters stir. That’s true of prehistory no less than of horror films—and on the last day of dark October, they all come out to play.
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Post written by Dr Mathias Clasen for the BPS Research Digest. Clasen is assistant professor in literature and media at Aarhus University. He has published on evil in horror fiction, zombies, vampires, and the psychological functions and effects of horror across media, and is currently working on a project on post-apocalyptic science fiction in a biocultural perspective. Several of his writings are available at Academia.edu and Horror.dk.

--further reading--
31 terrifying links for Halloween
The lure of horror

Eye contact makes us more aware of our own bodies

If you've ever felt acutely self conscious upon making eye contact with another person, a new study may help you understand why. Matias Baltazar and his colleagues have found that making eye contact activates people's awareness of their own bodies. That feeling of self consciousness induced by mutual gaze might be based in part on the fact that your brain is suddenly more attuned to your body.

The researchers presented 32 participants with a series of positive and negative images on a computer screen, and after each they asked them to rate the intensity of their emotional reaction. Crucially, each image was preceded either by a fixation cross or a photograph of a man or woman's face. These faces were either looking right at the participants, as if making eye contact, or they had their gaze averted. The participants' were also wired up to a skin conductance machine that measured the sweatiness of their fingers. This provided an objective measure of the participants' emotional reactions to the images, to be compared against their subjective assessments of their reactions.

The participants' accuracy at judging their own physiological reactions was more accurate for those images that followed a photograph that appeared to be making eye contact. "Our results support the view that human adults' bodily awareness becomes more acute when they are subjected to another's gaze," the researchers said.

A problem with this methodology is that greater bodily arousal is known to enhance performance in psychological tests, so perhaps eye contact was simply exerting its effects this way. But the researchers checked, and the boost to self awareness of eye contact wasn't merely a side-effect of increased arousal - the participants' physiological reactivity (an indicator of arousal) was no greater after eye contact photos than after gaze averted photos. The performance-enhancing effect of eye contact was also specific to bodily awareness. The researchers checked this by confronting participants with occasional memory tests through the experiment, for words that had appeared on-screen. Participant performance was no better after looking at faces that made eye contact, compared with the averted gaze faces.

Baltazar and his team said the fact that eye contact enhances our awareness of our own bodies could have therapeutic implications. For example, they said it could "stimulate interoceptive awareness in people whose condition is associated with interoceptive hyposensitivity, [such as] anorexia nervosa and major depression disorder."

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Baltazar M, Hazem N, Vilarem E, Beaucousin V, Picq JL, & Conty L (2014). Eye contact elicits bodily self-awareness in human adults. Cognition, 133 (1), 120-7 PMID: 25014360

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

People's belief in free will is lower when they need to urinate or desire sex

Embodied or grounded cognition is the name for the idea that physical states affect our thoughts and emotions. It's a controversial field, but typical findings include people's judgments of social closeness being shaped by room temperature, and their attentional style by the clothes they wear. A new paper takes things further, asking whether bodily states affect people's philosophical beliefs, specifically their belief in the notion of free will, defined and measured here in the lay sense of having self control and being in charge of one's actions (a typical questionnaire item was "I actively choose what to do from the options I have").

Michael Ent and Roy Baumeister began with an online survey of 23 people with panic disorder and 16 people with epilepsy. Compared with 35 healthy controls, individuals with these conditions believed that people in general have less free will (though their beliefs in their personal free will were no different from controls). The researchers acknowledged that the people with epilepsy and panic disorder may differ from controls in many ways other than their physical illness, but they believe this finding is consistent with their main thesis that having less control of one's body undermines belief in free will.

They further tested this idea with a second online survey of 81 more people (aged 18-70; 29 women), who were asked to rate their current state of needing to urinate, wanting sex, feeling tired, or hungry. People who felt any of these physical needs more strongly, except for hunger, tended to report lower beliefs in their own personal free will.

The anomaly of hunger was explained by a third and final survey with 112 more people, in which they were asked to report their hunger and also whether they were dieting. This time, if dieters were excluded from the analysis, feeling more hunger did go hand in hand with lower beliefs in personal free will. The researchers reasoned that for dieters, feeling hunger was actually a prime for stronger beliefs in free will, since their pangs were a sign they were successfully controlling their urges to eat.

Ent and Baumeister concluded that "embodiment may be a more far-reaching phenomenon than previous research has demonstrated" affecting not only people's views of the world and interactions with others, but also their abstract, philosophical beliefs. "Others have assumed that beliefs about free will are shaped by religious and political doctrines and logical reasoning," they said, "yet such beliefs are at least influenced by bodily cues as seemingly innocuous as a full bladder or an unfulfilled desire for sex."

Some may find these conclusions premature. This was not an experimental study, so rather than states of physical need being induced, they were entirely subjective. Of course physical need is a subjective experience, but the current methodology can't rule out the possibility that people with reduced beliefs in free will also tend to be more sensitive to their physical needs, or more happy to disclose them. In a similar vein, unmeasured factors such as mood or personality could be causally responsible for both greater sensitivity to one's physical needs and a reduced belief in free will. Unmeasured factors, such as differences in affluence and lifestyle, could also help explain the findings for people with epilepsy and panic disorder, without recourse to theories of embodied cognition.

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Ent, M., & Baumeister, R. (2014). Embodied free will beliefs: Some effects of physical states on metaphysical opinions Consciousness and Cognition, 27, 147-154 DOI: 10.1016/j.concog.2014.05.001

--further reading--
More on free will from the Digest archive.
Toilet psychology.

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

When the cuddle hormone turns nasty - oxytocin linked with violent intentions

For many years, the hormone oxytocin was caricatured as the source of all human goodness - trust, altruism, love, and morality. Among the findings that contributed to this picture were the discovery that sniffing oxytocin increases people's trust and generosity in financial games; that it aids face recognition; and that its release is associated with maternal bonding; and with orgasm.

However, the picture has grown a lot more complicated of late, with findings showing that oxytocin has a "dark side" - for example, boosting envy and shadenfreude. Now a team of researchers led by Nathan DeWall has further sullied the reputation of this once idolised molecule. They've demonstrated that for certain people in particular circumstances, exposure to oxytocin might actually lead to increased violence.

The researchers split 93 undergraduates (47 men) into two groups - one group sniffed oxytocin, the other group sniffed a salt water solution. The students didn't know whether they'd received the oxytocin or the placebo, and the researchers were also blinded to who'd received what. Next the students completed two tasks designed to make them stressed, including giving a public presentation to an unfriendly audience. Finally, they answered two questions about their tendency to be physically aggressive, and further questions about how likely it was that they'd engage in violence towards a current or former romantic partner based on how they currently felt.

Here's the main finding - oxytocin boosted the self-confessed likelihood of being violent towards a partner, specifically in those students who admitted that they have a proclivity for physical aggression. DeWall's team think this fits with an emerging, more nuanced understanding of oxytocin's effects. It remains true that the hormone plays an important role in maintaining human relationships, but this isn't always an innocent function. Previous research shows oxytocin can increase intolerance and aggression towards outsiders. Now we learn that for people who typically resort to aggression to keep hold of their romantic partners, stress plus increased oxytocin nudges them towards violence.

"Our findings add to the understanding of the 'prickly side of oxytocin'," said DeWall and his team. "Far from being a panacea for all social ills, oxytocin may have a much more diversified effect, as in the current case."
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  DeWall, C., Gillath, O., Pressman, S., Black, L., Bartz, J., Moskovitz, J., & Stetler, D. (2014). When the Love Hormone Leads to Violence: Oxytocin Increases Intimate Partner Violence Inclinations Among High Trait Aggressive People Social Psychological and Personality Science, 5 (6), 691-697 DOI: 10.1177/1948550613516876

--further reading--
A social 'Viagra' for shy people?
Why do some men insult their partners?

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

Some bisexual men are aroused by women, some aren't - is curiosity the reason?

When a man describes himself as bisexual, we usually take this to mean that he has sexual relations with both men and women, and/or that he is attracted to both sexes. However, prior lab research has found that many men who self-identify as bi-sexual are not in fact sexually aroused - in a physical sense - by the opposite sex.

It's important to remember that physical sexual arousal is only one reflection of a person's sexual desires and identity, not the be all and end all. However, this past research suggests that, from a bio-psychological perspective, the label bisexual is used by a diverse group of men. A new study builds on this idea, and finds that a key distinguishing characteristic among bisexual men is their level of sexual curiosity.

Gerulf Rieger and his colleagues conducted two studies with hundreds of men, some of whom were recruited via university adverts, others via websites where men seek sexual partners. The first study used pupil dilation as an index of sexual arousal. The second study used increase in penile circumference as the measure of sexual arousal.

The men, who rated themselves on a sexual orientation sliding scale from strictly homosexual, to bisexual, to strictly heterosexual, watched video clips of attractive male or female models masturbating in the first study, or, in the second study, short videos of two men having sex, or two women having sex. In both studies, the participants also filled out a 10-item questionnaire about their sexual curiosity. Example items included "If I were invited to watch a porn movie, I would accept" and "Sex without love is appealing to me."

On average, men who self-identified as bisexual showed the sexual arousal patterns you might expect, being less aroused than heterosexual men (but more aroused than homosexual men) by videos featuring women, and more aroused than heterosexual men by videos featuring men. This average data conceals the fact that some bisexual men were aroused by both sexes, while others were aroused only by men. The novel finding from this research is that these arousal patterns were correlated with sexual curiosity. Bisexual men on average reported more sexual curiosity than straight or gay men; moreover, among bisexual men only, greater sexual curiosity was linked with more arousal in response to videos featuring women. Bisexual men with low levels of sexual curiosity tended to be aroused only by other men.

Rieger and his colleagues speculate that shared genetic influences likely account for increased sexual curiosity and bisexual physiological arousal, thus explaining why these two characteristics correlate. They also propose that some bisexual men with elevated curiosity may "reattribute" their curiosity-related arousal to sexual stimuli depicting either sex, "thus increasing their sexual arousal and rewarding experiences associated with both men and women." What about the bisexual men who are only aroused by men? Rieger's team suggest that their identity may be in a transitional stage - perhaps they self-identify as bisexual on the basis of past experiences and relationships, or to conform to societal norms.

"The present findings are in line with the notion that a male bisexual identity can be found in a diverse range of men who differ in sexual attitudes and feelings," the researchers said.

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Rieger G, Rosenthal AM, Cash BM, Linsenmeier JA, Bailey JM, and Savin-Williams RC (2013). Male bisexual arousal: A matter of curiosity? Biological psychology, 94 (3), 479-89 PMID: 24055219

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

Targeted brain stimulation provokes feelings of bliss

It's hard to fathom how our subjective lives can be rooted in the spongy flesh of brain matter. Yet the reality of the brain-mind link was made stark half way through the last century by the Canadian neurosurgeon Wilder Penfield. Before conducting neurosurgery on epilepsy patients he stimulated parts of their brains directly with an electrode, triggering in them subjective sensations that varied according to the source of stimulation.

In a new case study, a team of Swiss and French neurologists followed a similar strategy during brain surgery with a 23-year-old female patient. She has temporal lobe epilepsy and experiences "ecstatic auras" before seizure onset. During these periods she has "intense feelings of bliss and well-being", a floating sensation in her stomach, enhanced senses and time appears to contract.

Fabienne Picard and his colleagues stimulated different parts of the woman's temporal lobes with electrodes to try to find the precise source of her epileptic seizures. In fact none of their stimulations caused her to have a seizure. However they did observe some intriguing subjective experiences in the woman. When they stimulated her anterior-dorsal insula - a brain region implicated in many functions, including representing the internal state of the body - she experienced the same feelings of bliss and ecstasy that she reports prior to a seizure. "I feel really well with a very pleasant funny sensation of floating and a sweet shiver in my arms," she said. Such sensations were not triggered by stimulation in any other part of her temporal lobe.

Prior research has shown that stimulation of other brain regions, including the amygdala and other parts of the insula, can evoke pleasant memories and pleasant sensory experiences, but the researchers said theirs is the first ever account of neurostimulation leading to feelings of bliss or ecstasy. It complements brain imaging research that has found correlations between anterior insula activity and feelings of intense love and joy, and also oneness with God.

It's important not to be lulled into thinking this case study has helped identify the brain's "pleasure centre". Many parts of the brain are involved in motivation and hedonic experience. Stimulation of the nucleus accumbens, part of the brain's so-called "reward pathway", is being explored as a treatment for depression (although it has not been linked with the sensations of bliss reported here). Research also shows that rats will press a lever for hundreds of hours so as to receive stimulation of the nucleus accumbens, but it's thought this stimulation may trigger wanting and craving rather than pleasure per se. Activity in orbitofrontal cortex (at the front and bottom of the brain) has been associated with enjoyment of food and other sensory pleasures.

With that caveat aside, this case study makes a useful contribution. "Our findings, if reproduced in future studies, should aid in the understanding of the brain mechanisms causing feelings of happiness/bliss, whether they are elicited externally (for example, by highly positive emotional stimuli) or internally (for example, by religious or deep meditative states, or by seizures)," the researchers said.

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Fabienne Picard, Didier Scavarda, and Fabrice Bartolomei (2013). Induction of a sense of bliss by electrical stimulation of the anterior insula. Cortex DOI: 10.1016/j.cortex.2013.08.013

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

Neuroscience lessons in body awareness from the man with two hearts

Researchers have been taking a keen interest lately in how the brain represents the internal state of the body - a process called interoceptive awareness (IA). There's evidence that poor IA is associated with eating disorders and other mental illnesses, and also that IA is important for social cognition, including empathising with other people. The most popular measure of IA is a person's sensitivity to their own heart beat - a topic we've covered on the Digest before.

Neuroscientists think we detect our own heart-beats via two routes - one is "somatosensory"; that is, we feel the movement of the heart's beat in our skin and this information is processed in the part of the brain that deals with touch. The other route is "vagal", based on fibres that feed directly from receptors in the heart to the brainstem and then onto two brain areas known to be vital for IA: the insular cortex and the anterior cingulate cortex.

Now a study led by Blas Couto and Agustin Ibanez and their colleagues, at the University of Cambridge and INECO, has explored this theory by testing a male patient "with two hearts". The 32-year-old man has a heart condition and is awaiting a transplant. In the meantime he has been fitted with a "left ventricular assist device" (see pic). This is an external pump that aids his failing left ventricle. Approximately the size of a large watch, it sits on his abdomen. Crucially, the frequency of this external pump is out of sync with the man's own heart-beat.

Couto's team tested the patient known as C.S. on a series of heart-beat detection tasks and compared his performance to a small group of healthy controls. Asked to tap a keyboard key in time with his own heart-beat, C.S. tapped in time with his assist device rather than his own heart. The researchers also recorded C.S.'s brain activity with EEG while he attended to his own heart and this showed that activity associated with interoceptive awareness was reduced in his brain compared with controls.

These findings support the idea that there is a dual route to interoceptive awareness and they show how the process of IA is subject to change. The researchers said their results "suggest that somatosensory input produced by the artificial pump ... dominates the input from his endogenous heartbeat." Perhaps most intriguing of all are the results from social and emotional tests. Compared with controls, C.S. showed impairments in empathy, theory of mind (representing other people's mental states), and a decision making task. Against a background of otherwise normal performance on tests of intelligence, language and memory, these selective impairments are consistent with past research showing how IA is important for social and emotional cognition.

The researchers advised the usual caution when interpreting a single case study. They also acknowledged that C.S. was anxious and that this may have affected the results. These concerns aside, Couto and his team said their results show an artificial heart pump may cause an imbalance in cardiac interoception and in turn this could have subtle but important consequences for social and emotional processing.

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Couto B, Salles A, Sedeño L, Peradejordi M, Barttfeld P, Canales-Johnson A, Dos Santos YV, Huepe D, Bekinschtein T, Sigman M, Favaloro R, Manes F, and Ibanez A (2013). The man who feels two hearts: The different pathways of interoception. Social cognitive and affective neuroscience PMID: 23887813

Image produced with the kind permission of Agustin Ibanez.

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

Looking at their own face tunes Westerners to their heartbeat; not so for East Asians

In this study of cross-cultural differences in body representation participants were challenged to keep count of their own heartbeat simply by listening to their body - a measure of what's known as interoceptive awareness (IA).

A cue signalled when to start counting and then another marked the end of the trial 20 to 55 seconds later. The participants' estimates were compared against the true recording taken of their pulse. An important addition to the set-up was that the participants - 20 Westerners and 20 East Asians - completed the challenge either while looking at a photograph of their own face; a photo of a stranger's face; or while looking at a black computer screen (the baseline condition).

The researchers Lara Maister and Manos Tsakiris separated their participants into two groups based on their IA performance in the baseline condition. The key finding is that looking at their own face enhanced the heart-beat counting accuracy of the Westerners whose baseline performance was poor. Yet no such benefit was experienced by the East Asian participants.

Maister and Tsakiris speculated that the sight of their own face triggers different associations for Westerners and East Asians. For Westerners seeing their own face activates a "self as subject" perspective that aids the processing of other self-related information, including internal bodily signals. By contrast, for East Asians, "the external appearance of the self may activate high-level, conceptual processing of the self from a social perspective."

Supporting this interpretation, past research has shown cross-cultural differences in brain activity when Westerners and East Asians view their own face, including in areas related to representation of the self.

This study is the first to look at cultural differences in how external (visual) bodily information interacts with internal bodily signals. Caution is need as the sample size was small, as acknowledged by the researchers. Nonetheless they said their results suggest "exteroceptive and interoceptive self-awareness may be integrated in a different way in individuals from East Asian cultures as compared to those from Western cultures."

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Lara Maister and Manos Tsakiris (2013). My face, my heart: Cultural differences in integrated bodily self-awareness. Cognitive Neuroscience DOI: 10.1080/17588928.2013.808613

--Further reading--
What your Facebook picture says about your cultural background
People who are more aware of their own heart-beat have superior time perception skills
Embodying another person's face makes it easier to recognise their fear

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

Atheists as stressed as believers when daring God to do bad things

Why are most people in the world religious? Some say it is because we're naturally predisposed to believe in a god or gods and that religion brought evolutionary advantages to our ancestors. But if that's the case, how come there are over half a billion atheists in the world? One theory is that atheists consciously suppress their instincts for religion, with only varying degrees of success. A new study provides tentative support for this idea. Marjaana Lindeman and her colleagues report that atheists get just as stressed as religious people when they ask God to do nasty things, as in "I dare God to make someone murder my parents cruelly."

The researchers tested 16 atheists and 13 religious people (Finns aged 17 to 45 recruited via a skeptics group and bible group, respectively). The participants were wired up to a skin conductance machine that records the sweatiness of the fingers - a basic marker of stress. Next the participants read aloud 36 sentences - some were requests for God to do something awful; others were offensive statements not involving God (e.g. it's okay to kick a puppy in the face); and the remainder were neutral (e.g. I hope it's not raining today).

The participants' views about this experience differed as you'd expect. The religious folk found the God-related statements more unpleasant than the atheists. However, they were no more likely than the atheists to refuse to utter the God statements, or to retract them later when given the chance. Most importantly, skin conductance was higher for both participant groups when reading the God statements compared with the neutral statements. Moreover, across both groups, skin conductance when reading the God statements did not vary according to a person's level of religious belief. The atheists seemed to get just as stressed as believers when daring God to do awful things.

An obvious flaw in this evidence is that the mention of God was confounded with horrible outcomes. Perhaps the atheists were stressed reading the God statements simply because of the ideas involved, not because of God's role per se. A second study examined this with nineteen more Finnish atheists (aged 20 to 30). The participants were wired up to the skin conductance machine while they uttered unpleasant sentences involving God (e.g. "I dare God to make me die of cancer") or not involving God (e.g. "I wish I would die of cancer"). Signs of stress were higher for the God statements, suggesting the involvement of God brings some extra stress to atheists beyond the unpleasant outcomes involved.

"The results imply that while atheists' and religious individuals' beliefs about God and explicit attitudes towards God statements are different, they become equally emotionally aroused when daring God to do unpleasant things," the researchers said.

The study has its limitations - the participant samples were very small for a start - and the findings are difficult to interpret. Certainly it would be inappropriate to conclude that the results prove atheists believe in God at a subconscious level. Other plausible explanations for the findings include atheists finding the God statements stressful because they know friends or family who do believe in God; or perhaps atheists experience stress reading the God statements because the wording implies God is real, which runs counter to their own beliefs.

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Lindeman, M., Heywood, B., Riekki, T., and Makkonen, T. (2013). Atheists become emotionally aroused when daring God to do terrible things. International Journal for the Psychology of Religion DOI: 10.1080/10508619.2013.771991

--Further reading--
The unscientific thinking that forever lingers in the minds of physics professors
Religion causes a chronic biasing of visual attention
The children of securely attached mothers think that God is close
Can God make people more aggressive?

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

Investigating the love lives of the men and women who have no sense of smell

Around 1 in 7,500 otherwise healthy people are born with no sense of smell, a condition known as isolated congenital anosmia (ICA). So dominant are sight and hearing to our lives, you might think this lack of smell would be fairly inconsequential. In fact, a study of individuals with ICA published last year showed just how important smell is to humans. Compared with controls, the people with ICA were more insecure in their relationships, more prone to depression and to household accidents.

Now, in a follow-up paper involving the same 32 patients with ICA, Ilona Croy and her colleagues have looked at how this lack of a sense of smell affects their sexual relationships. The researchers' analysis uncovered an intriguing sex difference. Compared with 15 age-matched controls, the 10 men with no sense of smell reported having substantially fewer sexual partners in their lifetime (male controls averaged five times the number of partners). In contrast, women with no sense of smell averaged just as many sexual partners as women with smell.

On the other hand, the 22 women (but not the men) without a sense of smell tended to report feeling more insecure in their relationship with their current partner, than did the healthy controls. This insecurity was specific to their sexual partner and wasn't found in relation to friendships or maternal attachment.

Across both sexes, the impact of a loss of smell makes sense given the mounting evidence for the social importance of smell, for example we can use smell to detect other people's anxiety; people with more empathy are more likely to remember your smell; and smells convey at least some personality traits. Also, common sense suggests people without a sense of smell might worry about any odours they could be exuding without their knowledge. But the question still remains - why should not having a sense of smell affect men and women differently?

The researchers surmised that not having smell reduces men's "exploratory sexual behaviour", perhaps due to their lack of social confidence. Consistent with this interpretation, there was a negative correlation between the male (but not female) patients' levels of social insecurity and their number of sexual partners.

On the other hand, the researchers think the effect of a lack of smell on women makes sense in light of past research suggesting that smell is more important for their relationship security, than it is for men. For instance, a study published in 2008 found that a half of the women surveyed had worn someone else's clothes (usually a partner's) because of its smell, compared with just 13 per cent of men. Also relevant - the female patients' had lower social confidence than the female controls, and this correlated with their lack of relationship security.

Other research has shown that odour is more important to women than it is to men in choosing a partner: women supposedly prioritise good odour over good looks, men the opposite, although it's not clear how this fits with the current findings. Women also seem to have a superior sense of smell, on average, compared with men, and value the sense more highly.

Croy and her colleagues acknowledged the need for caution given their small sample size, but they said their results emphasise "the importance of the sense of smell for intimate relationships."

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Croy, I., Bojanowski, V., and Hummel, T. (2013). Men without a sense of smell exhibit a strongly reduced number of sexual relationships, women exhibit reduced partnership security – A reanalysis of previously published data. Biological Psychology, 92 (2), 292-294 DOI: 10.1016/j.biopsycho.2012.11.008

--Further reading--
Humans can track scents like a dog.
Brain response to putative pheromones in homosexual men.

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

How to design a street that's mentally rejuvenating

More people worldwide now live in cities than in the countryside. Combined with sprawl and the loss of urban green spaces, this means that many of us are unable to enjoy the restorative effects of a natural setting. But what's to say the built environment, designed well, can't have a rejuvenating effect too? "The built environment can be more beautiful than nature," the British planning minister said recently, "and we shouldn’t obsess about the fact that the only landscapes that are beautiful are open — sometimes buildings are better."

What's clear is we need more research on the psychological effects of urban design. Sadly, planning, architecture and psychology tend not to speak to one other. A new study takes us a step in the right direction. Pall Lindal and  Terry Hartig presented hundreds of Icelandic participants with dozens of computer-designed residential, terraced streetspaces that varied in two main ways - the degree of variety and complexity in the building design, in terms of the ornateness of the roofline and facades; and building height, which varied from one to three stories.

Participants were asked to imagine that they were walking down the street, mentally exhausted after work. They then rated each streetscape in terms of its restorative potential, how much they liked it, its "fascination" (how much it offers the chance to explore and discover), and its ability to give a break from routine (what the researchers called "being away").

Examples of streets judged to have least (left), medium, and maximum (right) restorative power. 

Greater architectural variation in the street scene and lower building height both contributed to the perception that the environment was restorative - allowing the participants to "rest and recover their abilities to focus". Greater architectural variety also tended to go hand in hand with a greater sense of fascination and with "being away" (although not with preference), factors which explained the link with perceived restorative power. In contrast, higher buildings were associated with a diminished sense of "being away" and were judged less restorative.

The findings make sense in terms of increased building intricacy and variety allowing the mind to alight on the visual scene, find interest, and therefore disengage from prior mental toils and challenges. Excess building height, on the other hand, fosters a sense of too much enclosure, which clashes with our instinctual preference for a minimal level of openness - possibly an evolutionary hang-over allowing us to notice predators.

Although this study is a welcome contribution to the psychology of architecture, it suffers from numerous limitations. Among these is the fact most of the Icelandic participants reported a lack of familiarity with urban scenes of this kind - results could be different in other countries. Also, the participants didn't experience actual streets, and only perceived, rather than actual, restorative powers were measured. Finally, the levels of architectural variety were minimal - no fewer than 50 per cent of the buildings in any scene were identical. Higher levels of variation could have an adverse effect.

Notwithstanding these issues, the researchers said "their results affirm that densely built urban residential settings need not lack restorative quality, and that the design of the built environment can play a significant role in affecting perceptions regarding possibilities for restoration."

"Such information is needed in the effort to create urban environments that are sustainable in social and psychological terms," they added, "as well as in ecological terms."

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Lindal, P., and Hartig, T. (2013). Architectural variation, building height, and the restorative quality of urban residential streetscapes. Journal of Environmental Psychology, 33, 26-36 DOI: 10.1016/j.jenvp.2012.09.003

--Further reading--

Is there a psychologist in the building?
Do urban environments trigger a mindset that's focused on the bigger picture?
Living in a city, or growing up in one, is associated with heightened brain sensitivity to social stress

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