1. Scents and social preference: Neuroscientists ID the roots of attraction

    September 15, 2017 by Ashley

    From the University of California – San Diego press release:

    A baby lamb is separated from its family. Somehow, in vast herds of sheep that look virtually identical, the lost youngling locates its kin. Salmon swim out to the vast expanses of the sea and migrate back home to their precise spawning grounds with bewildering accuracy.

    Scientists have long known about such animal kinship attachments, some known as “imprinting,” but the mechanisms underlying them have been hidden in a black box at the cellular and molecular levels. Now biologists at the University of California San Diego have unlocked key elements of these mysteries, with implications for understanding social attraction and aversion in a range of animals and humans.

    Davide Dulcis of UC San Diego’s Psychiatry Department at the School of Medicine, Giordano Lippi, Darwin Berg and Nick Spitzer of the Division of Biological Sciences and their colleagues published their results in the August 31, 2017 online issue of the journal Neuron.

    In a series of neurobiological studies stretching back eight years, the researchers examined larval frogs (tadpoles), which are known to swim with family members in clusters. Focusing the studies on familial olfactory cues, or kinship odors, the researchers identified the mechanisms by which two- to four-day old tadpoles chose to swim with family members over non-family members. Their tests also revealed that tadpoles that were exposed to early formative odors of those outside of their family cluster were also inclined to swim with the group that generated the smell, expanding their social preference beyond their own true kin.

    The researchers discovered that this change is rooted in a process known as “neurotransmitter switching,” an area of brain research pioneered by Spitzer and further investigated by Dulcis in the context of psychostimulants and the diseased brain. The dopamine neurotransmitter was found in high levels during normal family kinship bonding, but switched to the GABA neurotransmitter in the case of artificial odor kinship, or “non-kin” attraction.

    “In the reversed conditions there is a clear sign of neurotransmitter switching, so now we can see that these neurotransmitters are really controlling a specific behavior,” said Dulcis, an associate professor. “You can imagine how important this is for social preference and behavior. We have innate responses in relationships, falling in love and deciding whether we like someone. We use a variety of cues and these odorants can be part of the social preference equation.”

    The scientists took the study to a deeper level, seeking to find how this mechanism unfolds at the genetic level.

    Sequencing helped isolate two key microRNAs, molecules involved in coordinating gene expression. Sifting through hundreds of possibilities they identified microRNA-375 and microRNA-200b as the key regulators mediating the neurotransmitter switching for attraction and aversion, affecting the expression of genes known as Pax6 and Bcl11b that ultimately control the tadpole’s swimming behavior.

    “MicroRNAs were ideal candidates for the job,” said Lippi, a project scientist in Berg’s laboratory in the Division’s Neurobiology Section. “They are post-transcriptional repressors and can target hundreds of different mRNAs to consolidate specific genetic programs and trigger developmental switches.”

    The study began in 2009 and deepened in size and scope over the years. Reviewers of the paper were impressed with the project’s breadth, including one who commended the authors “for this heroic study which is both fascinating and comprehensive.”

    “Social interaction, whether it’s with people in the workplace or with family and friends, has many determinants,” said Spitzer, a distinguished professor in the Division of Biological Sciences, the Atkinson Family Chair and co-director of the Kavli Institute for Brain and Mind at UC San Diego. “As human beings we are complicated and we have multiple mechanisms to achieve social bonding, but it seems likely that this mechanism for switching social preference in response to olfactory stimuli contributes to some extent.”


  2. High-fat ice cream may not necessarily mean tastier ice cream

    August 6, 2017 by Ashley

    From the Penn State press release:

    Even though ice cream connoisseurs may insist that ice cream with more fat tastes better, a team of Penn State food scientists found that people generally cannot tell the difference between fat levels in ice creams.

    In a series of taste tests, participants were unable to distinguish a 2 percent difference in fat levels in two vanilla ice cream samples as long as the samples were in the 6 to 12 percent fat-level range. While the subjects were able to detect a 4 percent difference between ice cream with 6 and 10 percent fat levels, they could not detect a 4 percent fat difference in samples between 8 and 12 percent fat.

    “I think the most important finding in our study was that there were no differences in consumer acceptability when changing fat content within a certain range,” said Laura Rolon, a former graduate student in food science and lead author of the study. “There is a preconception of ‘more fat is better,’ but we did not see it within our study.”

    The researchers, who released their findings in a recent issue of the Journal of Dairy Science, also found that fat levels did not significantly sway consumers’ preferences in taste. The consumers’ overall liking of the ice cream did not change when fat content dropped from 14 percent to 6 percent, for example.

    “Was there a difference in liking — that was our primary question — and could they tell the difference was our secondary question,” said Robert Roberts, professor and head of the food science department.

    John Hayes, associate professor of food science and director of the sensory evaluation center, said that perception and preference are often two separate questions in food science.

    “Another example of this is how some people might like both regular lemonade and pink lemonade equally,” said Hayes. “They can tell the difference when they taste the different lemonades, but still like them both. Differences in perception and differences in liking are not the same thing.”

    The study may challenge some ice cream marketing that suggests ice cream with high fat levels are higher quality and better tasting products, according to researchers.

    “People think premium ice cream means only high fat ice cream, but it doesn’t,” said Roberts.

    Because there are only slight differences in taste perception and preferences at certain fat levels, ice cream manufacturers may have more latitude in adjusting their formulas to help control costs and create products for customers with certain dietary restrictions without sacrificing taste, according to the researchers.

    “Fat is always the most expensive bulk ingredient of ice cream and so when you’re talking about premium ice cream, it tends to have a higher fat content and cost more, while the less expensive economy brands tend to have lower fat content,” said John Coupland, professor of food science.

    The researchers recruited a total of 292 regular ice-cream consumers to take part in the blind taste tests to determine their overall acceptability of various fat levels in fresh ice cream and to see if they could tell the difference between samples. They changed the fat content by adjusting the levels of cream and by adding maltodextrin, a mostly tasteless, starch-based material that is used to add bulk to products, such as frozen desserts.

    Maltodextrin is not necessarily a healthy fat replacement alternative, according to the researchers.

    “We don’t want to give the impression that we were trying to create a healthier type of ice cream,” said Coupland. “But, if you were in charge of an ice cream brand this information may help you decide if you are getting any advantage of having high fat in your product, or whether it’s worth the economic cost, or worth the brand risk to change the fat level of your ice cream.”

    During storage, ice crystals can increase in size, which affects the quality of the ice cream. Because of this effect, the researchers also studied stored samples and found no significant difference in preference after storage.

    Hayes said that Penn State and the College of Agriculture Sciences’ focus on interdisciplinary research was critical for this work.

    “I think this shows how interdisciplinary and translational food science is,” Hayes said. “You take a physical chemist, a behavioral scientist and someone who knows ice cream processing and put us all together and you can investigate questions like these.”


  3. Neural connections in emotional processing of olfactory stimuli in mice

    August 4, 2017 by Ashley

    From the Asociación RUVID press release:

    The Joint Unit of Functional Neuroanatomy of the universities of Valencia and Jaume I de Castelló has described for the first time the complete map of the neural connections of the anterior cortical nucleus of the amygdala, a key brain region for the emotional processing of olfactory stimuli of mice. The research has been published in the Journal of Comparative Neurology.

    Bernardita Cádiz, María Abellán, Cecília Pardo, Ferran Martínez and Enrique Lanuza form the research team that has characterized the nervous circuit of the anterior cortical nucleus of the amygdala, partially unknown until now. The work describes the relationship between this nucleus and the other structures from which it receives information, as well as the areas of the brain to which it sends information.

    Enrique Lanuza, researcher at the Department of Cell Biology, Functional Biology and Physical Anthropology at the University of València, emphasizes that olfactory information has an intrinsic emotional value. “This work shows that this information reaches directly into the anterior cortical nucleus of the amygdala, which is directly interconnected with areas that process pheromonal information (which plays a key role in rodents’ sexual behaviour) and also with nuclei related to defensive and aggressive behaviour,” says the expert.

    In addition, the member of the Joint Unit of Functional Neuroanatomy points out that this olfactory nucleus of the amygdala is connected with regions that have been shown to be involved in Pavlovian learning, that is, to associate a neutral stimulus with a reward or a negative experience.

    “Although experiments have been performed on mice, these areas of the brain are evolutionarily highly conserved, and it is therefore reasonable to expect an important similarity with the human brain,” explains Lanuza. In addition, “smells are particularly evocative stimuli, and often very pleasant or unpleasant, so that we avoid being in places where it smells bad. Thus, to smell good is a good social letter of presentation,” says the lecturer of the Faculty of Biological Sciences of the University of València.

    The experiment was carried out with 15 female mice Mus musculus, the species of this most common rodent. The team has performed intracerebral injection of tracers (inert molecules), detectable by the emission of fluorescent light or by their chemical characteristics. In this way, thanks to the tracing of these molecules, the research team has observed the connections of this key structure in the processing of the emotional value of odours.


  4. Visual illusion could help you read smaller font

    August 2, 2017 by Ashley

    From the Association for Psychological Science press release:

    Exposure to a common visual illusion may enhance your ability to read fine print, according to new research published in Psychological Science, a journal of the Association for Psychological Science.

    “We discovered that visual acuity — the ability to see fine detail — can be enhanced by an illusion known as the ‘expanding motion aftereffect‘ — while under its spell, viewers can read letters that are too small for them to read normally,” says psychological scientist Martin Lages of the University of Glasgow.

    Visual acuity is normally thought to be dictated by the shape and condition of the eye but these new findings suggest that it may also be influenced by perceptual processes in the brain.

    Interest in the intersection between perception and reality led Lages and co-authors Stephanie C. Boyle (University of Glasgow) and Rob Jenkins (University of York) to wonder about visual illusions and how they might affect visual acuity.

    “The expanding motion aftereffect can make objects appear larger than they really are and our question was whether this apparent increase in size could bring about the visual benefits associated with actual increases in size,” Boyle explains. “In particular, could it make small letters easier to read?”

    To find out, the researchers employed a tool that can be found in any optometrist’s office: the classic logMAR eye chart. On this chart, letters are arranged in rows and the letters become increasingly smaller and more difficult to read as you move down the chart. Optometrists calculate visual acuity based on the size at which a person can no longer reliably identify the letters.

    In two related experiments, the researchers presented a total of 74 observers with a spiral pattern that rotated either clockwise or counterclockwise for 30 seconds followed by a set of letters, which participants were asked to identify. The font size of the letters became increasingly smaller over subsequent trials.

    The experiment revealed that participants’ visual acuity differed depending on which spiral they saw.

    Participants who started with normal visual acuity and saw clockwise spirals — which induce adaptation to contracting motion and cause subsequent static images appear as if they are expanding — showed improved visual acuity. That is, they were able to identify letters at smaller font sizes after exposure to the clockwise spiral.

    Those who saw counterclockwise spirals — which induce adaptation to expanding motion and cause later images to appear as if they are contracting — actually performed worse after exposure to the spirals.

    A third experiment, in which each participant saw both types of spirals over two sessions, showed similar results: Seeing clockwise spirals that induced an expanding motion aftereffect enabled participants to read letters at smaller font sizes.

    “We were pretty impressed by the consistency of the effect. No matter how you break it down — by letter size, by letter position — the performance boost is there,” says Jenkins. “And there was a correlation with initial ability: The harder people found the task, the more the illusion helped them.”

    But don’t throw out your eyeglasses just yet: The researchers note that the overall boost to visual acuity is small and fleeting.

    Nonetheless, this common visual illusion reveals a fundamental aspect of how we see, showing us that our ability to discriminate fine detail isn’t solely governed by the optics of our eyes but can also be shaped by perceptual processes in the brain.


  5. Daily movement program has positive impact on children’s learning

    July 29, 2017 by Ashley

    From the Loughborough University press release:

    Following a daily movement program can improve children’s physical development levels and has the potential to boost their chances in the classroom, researchers from Loughborough University have found.

    Academics from the University’s School of Sport, Exercise and Health Sciences have been working with two schools and more than 40 Foundation Stage children in a year-long study.

    They found that those who took part in a daily movement program for one academic year showed greater improvements in throwing/catching, balance and manual dexterity compared to those not taking part in the program.

    The participating children also improved their overall levels of physical development from the 32nd percentile to the 50th (an improvement of approximately 18 percentile points) bringing them back in line with scores for children of the same age established in 2007.

    A child’s physical development level impacts their ability to complete simple tasks such as sitting still, holding a pencil, putting on their shoes, and reading — all skills essential for school.

    Tests carried out by the team in 2016 found a larger number than previously estimated were starting school with lower than desirable levels of physical development, with almost 30% of children presenting with symptoms typically associated with dyslexia, developmental coordination disorder (dyspraxia), and ADHD.

    To try and redress this decline in pupils’ physical development Loughborough’s Dr Rebecca Duncombe and Professor Pat Preedy created ‘Movement for Learning’.

    The daily program gives children opportunities to move, improve fine and gross motor skills and inhibit primitive reflexes (baby reflexes that should no longer be present). Activities include throwing, catching, balancing, drawing large letters in the air, articulating sounds and skipping.

    To assess the effectiveness of the program the team recruited children from two schools, with some doing the daily Movement for Learning exercises and others not.

    “The results show a definite improvement for those children that took part in the Movement for Learning program,” explains Dr Duncombe. “We know that there is a link between physical development and achievement in the classroom so the findings of this research are especially important. We are hopeful that, as a result of this project, we will be able to help reverse the recent decline in physical readiness for school and for learning.”

    Professor Pat Preedy added: “Changes in our modern world mean that many children are moving less and are not developing the physical skills that they need for learning. It has been most rewarding to see how a short, daily program can help children to get back on track for learning.”

    Fifty other schools are currently following the Movement for Learning program and are due to provide feedback after the summer. The team plan to make the program freely available for all schools by 2018.


  6. Mouse study suggests sense of smell affects metabolism

    July 26, 2017 by Ashley

    From the University of California – Berkeley press release:

    Our sense of smell is key to the enjoyment of food, so it may be no surprise that in experiments at the University of California, Berkeley, obese mice who lost their sense of smell also lost weight.

    What’s weird, however, is that these slimmed-down but smell-deficient mice ate the same amount of fatty food as mice that retained their sense of smell and ballooned to twice their normal weight.

    In addition, mice with a boosted sense of smell — super-smellers — got even fatter on a high-fat diet than did mice with normal smell.

    The findings suggest that the odor of what we eat may play an important role in how the body deals with calories. If you can’t smell your food, you may burn it rather than store it.

    These results point to a key connection between the olfactory or smell system and regions of the brain that regulate metabolism, in particular the hypothalamus, though the neural circuits are still unknown.

    “This paper is one of the first studies that really shows if we manipulate olfactory inputs we can actually alter how the brain perceives energy balance, and how the brain regulates energy balance,” said Céline Riera, a former UC Berkeley postdoctoral fellow now at Cedars-Sinai Medical Center in Los Angeles.

    Humans who lose their sense of smell because of age, injury or diseases such as Parkinson’s often become anorexic, but the cause has been unclear because loss of pleasure in eating also leads to depression, which itself can cause loss of appetite.

    The new study, published this week in the journal Cell Metabolism, implies that the loss of smell itself plays a role, and suggests possible interventions for those who have lost their smell as well as those having trouble losing weight.

    “Sensory systems play a role in metabolism. Weight gain isn’t purely a measure of the calories taken in; it’s also related to how those calories are perceived,” said senior author Andrew Dillin, the Thomas and Stacey Siebel Distinguished Chair in Stem Cell Research, professor of molecular and cell biology and Howard Hughes Medical Institute Investigator. “If we can validate this in humans, perhaps we can actually make a drug that doesn’t interfere with smell but still blocks that metabolic circuitry. That would be amazing.”

    Riera noted that mice as well as humans are more sensitive to smells when they are hungry than after they’ve eaten, so perhaps the lack of smell tricks the body into thinking it has already eaten. While searching for food, the body stores calories in case it’s unsuccessful. Once food is secured, the body feels free to burn it.

    Zapping olfactory neurons

    The researchers used gene therapy to destroy olfactory neurons in the noses of adult mice but spare stem cells, so that the animals lost their sense of smell only temporarily — for about three weeks — before the olfactory neurons regrew.

    The smell-deficient mice rapidly burned calories by up-regulating their sympathetic nervous system, which is known to increase fat burning. The mice turned their beige fat cells — the subcutaneous fat storage cells that accumulate around our thighs and midriffs — into brown fat cells, which burn fatty acids to produce heat. Some turned almost all of their beige fat into brown fat, becoming lean, mean burning machines.

    In these mice, white fat cells — the storage cells that cluster around our internal organs and are associated with poor health outcomes — also shrank in size.

    The obese mice, which had also developed glucose intolerance — a condition that leads to diabetes — not only lost weight on a high-fat diet, but regained normal glucose tolerance.

    On the negative side, the loss of smell was accompanied by a large increase in levels of the hormone noradrenaline, which is a stress response tied to the sympathetic nervous system. In humans, such a sustained rise in this hormone could lead to a heart attack.

    Though it would be a drastic step to eliminate smell in humans wanting to lose weight, Dillin noted, it might be a viable alternative for the morbidly obese contemplating stomach stapling or bariatric surgery, even with the increased noradrenaline.

    “For that small group of people, you could wipe out their smell for maybe six months and then let the olfactory neurons grow back, after they’ve got their metabolic program rewired,” Dillin said.

    Dillin and Riera developed two different techniques to temporarily block the sense of smell in adult mice. In one, they genetically engineered mice to express a diphtheria receptor in their olfactory neurons, which reach from the nose’s odor receptors to the olfactory center in the brain. When diphtheria toxin was sprayed into their nose, the neurons died, rendering the mice smell-deficient until the stem cells regenerated them.

    Separately, they also engineered a benign virus to carry the receptor into olfactory cells only via inhalation. Diphtheria toxin again knocked out their sense of smell for about three weeks.

    In both cases, the smell-deficient mice ate as much of the high-fat food as did the mice that could still smell. But while the smell-deficient mice gained at most 10 percent more weight, going from 25-30 grams to 33 grams, the normal mice gained about 100 percent of their normal weight, ballooning up to 60 grams. For the former, insulin sensitivity and response to glucose — both of which are disrupted in metabolic disorders like obesity — remained normal.

    Mice that were already obese lost weight after their smell was knocked out, slimming down to the size of normal mice while still eating a high-fat diet. These mice lost only fat weight, with no effect on muscle, organ or bone mass.

    The UC Berkeley researchers then teamed up with colleagues in Germany who have a strain of mice that are supersmellers, with more acute olfactory nerves, and discovered that they gained more weight on a standard diet than did normal mice.

    “People with eating disorders sometimes have a hard time controlling how much food they are eating and they have a lot of cravings,” Riera said. “We think olfactory neurons are very important for controlling pleasure of food and if we have a way to modulate this pathway, we might be able to block cravings in these people and help them with managing their food intake.”


  7. Now or later: How taste and sound affect when you buy

    July 16, 2017 by Ashley

    From the Brigham Young University press release:

    There’s a reason marketers make appeals to our senses; the “snap, crackle and pop” of Rice Krispies makes us want to buy the cereal and eat it. But as savvy as marketers are, they may be missing a key ingredient in their campaigns.

    New research finds the type of sensory experience an advertisement conjures up in our mind — taste and touch vs. sight and sound — has a fascinating effect on when we make purchases.

    The study led by marketing professors at Brigham Young University and the University of Washington finds that advertisements highlighting more distal sensory experiences (sight/sound) lead people to delay purchasing, while highlighting more proximal sensory experiences (touch/taste) lead to earlier purchases.

    “Advertisers are increasingly aware of the influence sensory cues can play,” said lead author Ryan Elder, associate professor of marketing at BYU. “Our research dives into which specific sensory experiences will be most effective in an advertisement, and why.”

    Elder, with fellow lead author Ann Schlosser, a professor of marketing at the University of Washington, Morgan Poor, assistant professor of marketing at San Diego State University, and Lidan Xu, a doctoral student at the University of Illinois, carried out four lab studies and a pilot study involving more than 1,100 study subjects for the research, published in the Journal of Consumer Research.

    Time and time again, their experiments found that people caught up in the taste or touch of a product or event were more likely to be interested at an earlier time.

    In one experiment, subjects read one of two reviews for a fictional restaurant: One focused on taste/touch, the other emphasized sound/vision. Participants were then asked to make a reservation to the restaurant on a six-month interactive calendar. Those who read the review focusing on the more proximal senses (taste and touch) were significantly more likely to make a reservation closer to the present date.

    In another experiment, study subjects read ad copy for a summer festival taking place either this weekend or next year. Two versions of the ad copy existed: one emphasizing taste (“You will taste the amazing flavors…”) and one emphasizing sound (“You will listen to the amazing sounds…”).

    When subjects were asked when they would like to attend, those who read the ad copy about taste had a higher interest in attending a festival this weekend. Those who read ads emphasizing sounds were more likely to have interest in attending the festival next year.

    If an advertised event is coming up soon, it would be better to highlight the more proximal senses of taste or touch — such as the food served at the event — than the more distal senses of sound and sight,” Schlosser said. “This finding has important implications for marketers, especially those of products that are multi-sensory.”

    As part of the study, researchers also learned an interesting insight into making restaurant reviews more helpful. In their field study, the authors analyzed 31,889 Yelp reviews to see if they could find connections between the sensory elements of a reviewer’s experience and the usefulness of a review.

    They found reviews from people who emphasized a more distal sense (such as sight) were rated more useful when the review used the past tense (“We ate here last week and…”), while people emphasizing a proximal sense (touch) had more useful reviews when they used the present tense (“I’m eating this right now and it is so good!”).

    “Sensory marketing is increasingly important in today’s competitive landscape. Our research suggests new ways for marketers to differentiate their products and service, and ultimately influence consumer behavior,” Elder said. “Marketers need to pay closer attention to which sensory experiences, both imagined and actual, are being used.”


  8. Taking photos of experiences boosts visual memory, impairs auditory memory

    July 12, 2017 by Ashley

    From the Association for Psychological Science press release:

    A quick glance at any social media platform will tell you that people love taking photos of their experiences — whether they’re lying on the beach, touring a museum, or just waiting in line at the grocery store. New research shows that choosing to take photos may actually help us remember the visual details of our encounters.

    The findings are published in Psychological Science, a journal of the Association for Psychological Science.

    “Our research is novel because it shows that photo-taking itself improves memory for visual aspects of an experience but can hurt memory for nonvisual aspects, like auditory details,” the authors say.

    This research was conducted by Alixandra Barasch (New York University Stern School of Business), Kristin Diehl (USC Marshall School of Business), Jackie Silverman (The Wharton School of the University of Pennsylvania), and Gal Zauberman (Yale School of Management).

    Previous research has suggested that being able to take photographs or consult the Internet may allow us to outsource our memory, freeing up cognitive resources but potentially impairing our ability to remember.

    Barasch, Diehl, Silverman, and Zauberman hypothesized that this offloading effect may hold for factual information, but might not apply when it comes to the experiences we deliberately choose to photograph.

    “People take photos specifically to remember these experiences, whether it’s a fun dinner with friends, a sightseeing tour, or something else,” they argue.

    Of course, the reality is that most of the photos we take will probably never get a second glance. The researchers wondered: How well do we remember the experiences we photograph if we never revisit the photos? Furthermore, does taking photos affect memory for what we saw differently than for what we heard?

    In one experiment, the researchers had 294 participants tour a real-life museum exhibit of Etruscan artifacts. The participants stashed their belongings before starting the tour but some were allowed to keep a camera on them. Those with a camera could photograph anything they wanted in the exhibit and were told to take at least 10 photos. As the participants toured the exhibit, they listened to an accompanying audio guide.

    At the end of the tour, they answered multiple-choice questions asking them to identify objects they had seen or complete factual statements from the audio guide.

    The results showed that those who took photos visually recognized more of the objects compared with those who didn’t have a camera. But they also remembered less auditory information than their camera-less peers.

    These findings provided evidence that taking pictures can enhance visual memory. To test their hypotheses in a more controlled environment, the researchers designed a virtual art-gallery tour. Participants navigated through the gallery on screen as they would in real life and some were able to take pictures of what they saw on screen by clicking an on-screen button.

    Again, participants who were able to take pictures were better at recognizing what they saw and worse at remembering what they heard, compared to those who couldn’t take pictures.

    When the researchers examined visual memory for specific objects, they found that participants who were able to take pictures performed better on visual memory tasks regardless of whether the objects in question were the most or least photographed. Photo-takers even had better visual memory for aspects of the exhibit they didn’t photograph, compared with participants who weren’t able to take pictures.

    “These findings suggest that having a camera changes how people approach an experience in a fundamental way,” the authors say. “Even when people don’t take a photo of a particular object, like a sculpture, but have a camera with them and the intention to take photos, they remember that sculpture better than people who did not have a camera with them.”

    Pooling findings from all four studies, the researchers found that taking photos had a reliably positive effect on visual memory and a smaller but reliable negative effect on auditory memory.

    Even participants who thought their photos would be deleted and those who were instructed to “mentally take a photo” showed enhanced visual memory and impaired auditory memory relative to participants who couldn’t take pictures.

    Together, these experiments suggest that photographing our experiences doesn’t outsource our memory so much as it focuses it, funneling our attention toward visual aspects of our experiences and away from others.


  9. When lovers touch, their breathing, heartbeat syncs, pain wanes

    July 10, 2017 by Ashley

    From the University of Colorado at Boulder press release:

    Fathers-to-be, take note: You may be more useful in the labor and delivery room than you realize.

    That’s one takeaway from a study released last week that found that when an empathetic partner holds the hand of a woman in pain, their heart and respiratory rates sync and her pain dissipates.

    The more empathic the partner and the stronger the analgesic effect, the higher the synchronization between the two when they are touching,” said lead author Pavel Goldstein, a postdoctoral pain researcher in the Cognitive and Affective Neuroscience Lab at CU Boulder.

    The study of 22 couples, published in the journal Scientific Reports last week, is the latest in a growing body of research on “interpersonal synchronization,” the phenomenon in which individuals begin to physiologically mirror the people they’re with.

    Scientists have long known that people subconsciously sync their footsteps with the person they’re walking with or adjust their posture to mirror a friend’s during conversation. Recent studies also show that when people watch an emotional movie or sing together, their heart rates and respiratory rhythms synchronize. When leaders and followers have a good rapport, their brainwaves fall into a similar pattern. And when romantic couples are simply in each other’s presence, their cardiorespiratory and brainwave patterns sync up, research has shown.

    The new study, co-written with University of Haifa Professor Simone Shamay-Tsoory and Assistant Professor Irit Weissman-Fogel, is the first to explore interpersonal synchronization in the context of pain and touch. The authors hope it can inform the discussion as health care providers seek opioid-free pain relief options.

    Goldstein came up with the idea after witnessing the birth of his daughter, now 4.

    “My wife was in pain, and all I could think was, ‘What can I do to help her?’ I reached for her hand and it seemed to help,” he recalls. “I wanted to test it out in the lab: Can one really decrease pain with touch, and if so, how?”

    Goldstein recruited 22 long-term heterosexual couples, age 23 to 32, and put them through a series of tests aimed at mimicking that delivery-room scenario.

    Men were assigned the role of observer; women the pain target. As instruments measured their heart and breathing rates, they: sat together, not touching; sat together holding hands; or sat in separate rooms. Then they repeated all three scenarios as the woman was subjected to a mild heat pain on her forearm for 2 minutes.

    As in previous trials, the study showed couples synced physiologically to some degree just sitting together. But when she was subjected to pain and he couldn’t touch her, that synchronization was severed. When he was allowed to hold her hand, their rates fell into sync again and her pain decreased.

    “It appears that pain totally interrupts this interpersonal synchronization between couples,” Goldstein said. “Touch brings it back.”

    Goldstein’s previous research found that the more empathy the man showed for the woman (as measured in other tests), the more her pain subsided during touch. The more physiologically synchronized they were, the less pain she felt.

    It’s not clear yet whether decreased pain is causing increased synchronicity, or vice versa.

    It could be that touch is a tool for communicating empathy, resulting in an analgesic, or pain-killing, effect,” said Goldstein.

    Further research is necessary to figure out how a partner’s touch eases pain. Goldstein suspects interpersonal synchronization may play a role, possibly by affecting an area of the brain called the anterior cingulate cortex, which is associated with pain perception, empathy, and heart and respiratory function.

    The study did not explore whether the same effect would occur with same-sex couples, or what happens when the man is the subject of pain. Goldstein did measure brainwave activity and plans to present those results in a future study.

    He hopes the research will help lend scientific credence to the notion that touch can ease pain.

    For now, he has some advice for partners in the delivery room: Be ready and available to hold your partner’s hand.


  10. Detecting social signals may have affected how we see colors

    June 29, 2017 by Ashley

    From the New York University press release:

    The arrangement of the photoreceptors in our eyes allows us to detect socially significant color variation better than other types of color vision, a team of researchers has found. Specifically, our color vision is superior at spotting “social signaling,” such as blushing or other facial color changes — even when compared to the type of color vision that we design for digital cameras and other photographic devices.

    “Our color vision is very strange,” says James Higham, an assistant professor in NYU’s Department of Anthropology and one of the study’s co-authors. “Our green receptor and our red receptor detect very similar colors. One would think that the ideal type of color vision would look different from ours, and when we design color detection, such as for digital cameras, we construct a different type of color vision. However, we’ve now shown that when it comes to spotting changes in color linked to social cues, humans outshine the type of color vision we’ve designed for our technologies.”

    The study, which appears in the journal Proceedings of the Royal Society Biological Sciences, focuses on trichromatic color vision — that is, how we process the colors we see, based on comparisons among how red, green, and blue they are.

    One particularly interesting thing about how our visual system is structured is how significantly it differs from that of cameras. Notably, the green and red photoreceptors we use for color vision are placed very close together; by contrast, the equivant components in cameras are situated with ample (and even) spacing among them. Given that cameras are designed to optimally capture color, many have concluded that their ability to detect an array of colors should be superior to that of humans and other primates — and wondered why our vision is the way it is.

    One idea that has been well-studied is related to foraging. It hypothesizes that primate color vision allows us to detect between subtle shades of green and red, which is useful, for example, when fruit are ripening against green leaves in a tree. An alternative hypothesis relates to the fact that both humans and primates must be able to spot subtle changes in facial color in social interactions. For instance, some species of monkeys give red signals on their faces and on genitals that change color during mating and in social interactions. Similarly, humans exhibit facial color changes such as blushing, which are socially informative signals.

    In their study, the researchers had 60 human subjects view a series of digital photographs of female rhesus macaque monkeys. These primates’ facial color has been known to change with their reproductive status, with female faces becoming redder when they are ready to mate. This process, captured in the series of photographs, provides a good model for testing the ability to not only detect colors, but also to spot those linked to social cues — albeit across two species.

    In different sets of photographs, the scientists developed software that replicated how colors look under different types of color vision, including different types of color blindness, and the type of trichromatic vision seen in many artificial systems, with even spacing of the green and red photoreceptors. Some of the study’s subjects viewed photos of the transformation of the monkeys’ faces as a human or primate would see them while others saw pictures as a color-blind person would and others as a camera would. During this period, the study’s subjects had to discriminate between the different colors being exhibited by the monkeys in the photos.

    Overall, the subjects viewing the images using the human/primate visual system more accurately and more quickly identified changes in the monkeys’ face coloring.

    “Humans and many other primates have an unusual type of color vision, and no one is sure why,” first author Chihiro Hiramatsu of Japan’s Kyushu University notes. “Here, we provide one of the first experimental tests of the idea that our unusual vision might be related to detecting social signals in the faces of others.”

    “But, perhaps more importantly, these results support a rarely tested idea that social signaling itself, such as the need to detect blushing and facial color changes, might have had a role in the evolution or maintenance of the unusual type of color vision shown in primates, especially those with conspicuous patches of bare skin, including humans, macaques, and many others,” concludes co-author Amanda Melin of the University of Calgary.