Category: Behavior/Psychology Page 18 of 28

Dam Good Research on Invasive Beavers in Patagonia

On December 11, 2015

In Animals, Behavior/Psychology, Biology, Environment/Sustainability, Field Research

Alejandro Pietrek and a subject of his research. Photo by Duke Forward.

For three years, Duke student Alejandro Pietrek has bravely grappled with some unusual marauders of the forests and steppes of Patagonia: invasive beavers. A biology graduate student, Pietrek recently presented his dissertation on the “Demography of invasive beavers in the heterogeneous landscapes of Patagonia.” Pietrek has studied over two dozen colonies of beavers in order to answer three questions:

“How do differences between habitats affect the demography of invaders?”
“How does density dependence affect the abundance and distribution of invaders post-establishment?”
“How can we manage biological invasions?”

Pietrek began by explaining how the furry rodents started ravaging the natural habitat of Patagonia, beginning with 20 beavers intentionally introduced into the forests of Tierra del Fuego in 1946. By the late 1960s, the growing colonies spread to the continent.

Today there are an estimated 100,000 individuals in Patagonia, disrupting the regional habitats and destroying biodiversity.

The biologist tackled his first question via quantitative science. “Very simply mathematical models have shown that speed of invasion is determined by two main things: population growth rate and movement,” he said. How the different habitats of Patagonia affected this invasion was what he worked to find out, by measuring colony size and the number of kits. Pietrek directly observed 25 colonies in each habitat over three years, using binoculars and seemingly endless patience. “It was very fun,” he said. He found that steppe habitats tended to have higher numbers of beavers and kits compared to forest.

Beaver Dam – Tierra del Fuego National Park, Argentina – Photograph by Anne Dirkse via Wikimedia Commons

Pietrek believed that the answer to the first question was counterintuitive, and he explored the possible reason in the second, where he figured the cause to be density dependence, as beavers in the steppe were more likely to survive in higher populations, and thus were dependent on living in large colonies for survival. In the forest, colony size wasn’t as important to the survival of the beavers. Pietrek found that as population density increased, the animals’ choice of landform changed: with denser numbers, the beavers were more likely to choose u-shaped valleys and plains than canyons. He noted the importance of identifying the preferred habitat of beavers, as it may allow easier detection of the presence of the invasive species.

Finally, Pietrek applied his findings toward the management of biological invasions. “One thing we can do is to build a model to predict the spread of beavers,” he said. He observed that beavers spread on average 7.8 km per year, though he also used individual-based models as well in order to track juvenile beavers. He found that young beavers tended to disperse and form new colonies, and formed another model in order to track this dispersal pattern. Juvenile beavers will first search for mates within their original colonies, only moving along if none can be found. These findings make for easier tracking of beavers across the landscape, allowing for easier management of their population growth.

Post by Devin Nieusma, Duke 2019

Science a waste of money? “Wastebook” misses big picture

By Robin Smith

On December 7, 2015

In Animals, Behavior/Psychology, Biology, Engineering, Faculty, Science Communication & Education

Duke biologist Sheila Patek explains the big picture behind a recent study on sparring mantis shrimp. Photograph by Roy Caldwell.

Sheep in microgravity. An experiment involving a monkey in a hamster ball on treadmill. These are among more than 100 descriptions of what Senator Jeff Flake, Republican of Arizona, deems wasteful federal spending in “Wastebook: The Farce Awakens,” released on Tuesday, Dec. 8. The latest in a series originally launched by retired Senator Tom Coburn, each “Wastebook” targets a range of federally-funded projects, many of them science-related, which the authors declare a waste of taxpayers’ money.

But what do the researchers behind these projects have to say? We asked Duke biologist Sheila Patek, whose work on fighting mantis shrimp was singled out in Flake’s latest report, to tell us her side of the story:

“What do we stand to learn from basic research on mantis shrimp? It turns out, a lot,” Patek said.

“First, mantis shrimp strike with weapons operating at the same acceleration as a bullet in the muzzle of a gun, yet they achieve high performance without explosive materials. They use a system based on muscles, springs and latches and neutralize their opponents with impact-resistant armor. This research helps us understand how animals survive when they have lethal weapons at their disposal but do not actually kill the opponent — something that could change the way we look at future defense systems,” Patek said.

“Second, these crustaceans have properties of extreme acceleration that are of great interest to military and manufacturing engineers. Mantis shrimp use a toothpick-sized hammer that can break snail shells in water that humans can only break with a larger hammer in air. Their small, lightweight hammer resists fracture over thousands of uses. Our research has already led to the development of novel engineered materials that resist impact fracture, based directly on mantis shrimp hammers,” Patek said.

“Third, mantis shrimp do something else that humans cannot: strike in water at the speed of cars on a major highway without causing cavitation, a phenomenon that occurs in systems with rapid motion (like propellers) where implosive bubbles emit heat, light and sound with energy sufficient to wear away steel. Naval engineers have been trying to solve this problem since the invention of the submarine. When we understand how mantis shrimp avoid cavitation during the rotation phase of their strikes while effectively using cavitation during their impact phase, the knowledge will undoubtedly improve the capabilities of ships, submarines, torpedoes and other machines,” Patek said.

“Research that helps us understand and apply the mechanics and evolutionary diversity of natural systems to create a better and safer society for all of us is a wise investment for this country.”

Post by Robin A. Smith, Senior Science Writer

The dangerous persistence of smoking into the 21st century

By Thabit Pulak

On November 16, 2015

In Behavior/Psychology, Lecture, Medicine

The “smoking ring” cigarette billboard advertisement in New York City. Picture Credit: theoldmotor.com

When Harvard historian of science Allan Brandt was a child, he couldn’t help but notice one thing in particular when in the car with his family — the cigarette advertising billboards. At the time, there was a very unique billboard that advertised Camel cigarettes, which actually smoked “rings” from the board. His young mind was captivated by how cool the board looked — and presumably, unaware of the dangers of the product the board was advertising.

As time passed, it became increasingly clear to Brandt and to the American public that smoking cigarettes was bad for you. Brandt’s most recent book – The Cigarette Century, was awarded the Bancroft Prize in 2008. In Brandt’s words, cigarettes are the “most dangerous product ever produced in such large quantities.” And indeed, the numbers are shocking — over 480,000 Americans die annually of tobacco-related diseases.

Given such obvious problems associated with cigarettes, Brandt started wondering, “How could something so bad for you be so advertised in such bold ways?”

The answer, Brandt explained to a Duke audience gathered on Nov. 11 for the 2015 Boyarsky Lecture in Law, Medicine and Ethics, was manipulation — the American public was being grossly manipulated by the bold advertising of cigarettes. Brandt talked about Mr. Edward Bernays, who, according to Brandt, is one of the main founders of the concept of modern public relations, made extensive efforts to put smoking into the mainstream media. One of Bernays’ biggest achievements was the widespread introduction of smoking to Hollywood. The efforts to introduce smoking to mainstream media worked amazingly well. By the mid-1950s, nearly half of all Americans were smoking. To put this into perspective, at the turn of the 20^th century, nearly no Americans were smoking!

However, as more and more research proved that cigarettes were actually harmful to Americans’ health, another curious phenomenon happened, where cigarette companies were actually funding their own research.

Brandt pointed out how this was a thinly disguised attempt to publish misleading conclusions about cigarettes to the public by establishing it as “science.” Such biased research funding occurs today in other industries as well, such as for oil companies, for research concerning climate change.

Children smoking in various developing countries is not uncommon, and poses a huge health risk to them. Picture Credit: CBSNews

However, public health campaigns still showed measurable positive impact — today it is evident that there is a declining trend in the number of smokers in America. However, wouldn’t that mean that the cigarette industry would die down? According to Brandt, it couldn’t be farther from the truth. The cigarette industries have now moved to exporting cigarettes to the developing world, where populations are less educated, and there are fewer regulations concerning such sales.

According to Brandt, in 2000, four million people died — two million died in the developed world, and two million in the developing world. By the year 2030, over 10 million people total will be killed by cigarette use — three million in developed nations, and seven million in developing nations. The rapid proliferation in such developing countries due to lack of education and awareness is heavily evident, especially with the much higher rate of childhood smoking. It is heavily evident that most of the disease fatalities will be borne by developing nations in the coming years, and will ensure copious profits for cigarette companies for years to come.

While Brandt did acknowledge the very persistent growth of the cigarette companies in the near future, he did not rule out that it was still possible to fight against this. By working together, we can all help bring awareness to the parts of the world where cigarettes are being advertised to uneducated people.

Post by Thabit Pulak, Duke 2018

Iridescent Beauty: Development, function and evolution of plant nanostructures that influence animal behavior

By Anika Radiya-Dixit

On October 27, 2015

In Animals, Behavior/Psychology, Biology, Chemistry, Field Research, Genetics/Genomics

Iridescent wings of a Morpho butterfly

Creatures like the Morpho butterfly on the leaf above appear to be covered in shimmering blue and green metallic colors. This phenomenon is called “iridescence,” meaning that color appears to change as the angle changes, much like soap bubbles and sea shells.

Iridescent behavior of a soap bubble

In animals, the physical mechanisms and function of structural color have been studied significantly as a signal for recognition or mate choice.

On the other hand, Beverley Glover believes that such shimmering in plants can actually influence animal behavior by attracting pollinators better than their non-iridescent counterparts. Glover,Director of Cambridge University Botanic Garden, presented her study during the Biology Seminar Series in the French Family Science Center on Monday earlier this week.

Hibiscus Trionum

The metallic property of flowers like the Hibiscus Trionum above are generated by diffraction grating – similar to the way CD shines – to create color from transparent material.

In order to observe the effects of the iridescence on pollinators like bees, Glover created artificial materials with a surface structure of nanoscale ridges, similar to the microscopic view of a petal’s epidermal surface below.

Nanoscale ridges on a petal’s epidermal surface.

In the first set of experiments, Glover and her team marked bees with paint to follow their behavior as they set the insects to explore iridescent flowers. Some were covered in a red grating – containing a sweet solution as a reward – and others with a blue iridescent grating – containing a sour solution as deterrent. The experiment demonstrated that the bees were able to detect the iridescent signal produced by the petal’s nanoridges, and – as a result – correctly identified the rewarding flowers.

Bees pollinating iridescent “flowers”

With the evidence that the bees were able to see iridescence, Glover set out for the second experiment: once the bees find a specific type of flower, how long does it take them to find the same flower in a different location? Using the triangular arrangement of shimmering surfaces as shown below, Glover observed that iridescence produced by a diffraction grating leads to significant increase in foraging speed as compared to non-iridescent flowers.

Triangular formation of iridescent disks used for experimentation on bees

While iridescence in plants is difficult to spot by a casual stroll through the garden, pollinators such as bees definitely can see it, and scientists have recently realized that insect vision and flower colors have co-evolved.

In order to ensure that pollen is transferred between flowers of the same species, these flowers have developed a unique structure of iridescence. As scientists work on understanding which plants produce these beautiful colors and how the nanoscale structure is passed down through reproduction, we can only look at our gardens in wonder at the vast amount of nature that still remains to be explored and learned.

Wonders of nature in an everyday garden

Beverley Glover is the Director of Cambridge University Botanic Garden and is currently accepting applications for PhD students.

Post written by Anika Radiya-Dixit

Moving Beyond #DistractinglySexy

By Olivia Zhu

On October 26, 2015

In Behavior/Psychology, Faculty, Students

Let’s not talk about Tim Hunt.

(Okay, a little: He’s the Nobel laureate who told the World Conference of Science Journalists, “Let me tell you about my trouble with girls. Three things happen when they are in the lab: you fall in love with them, they fall in love with you, and when you criticize them, they cry.”)

Instead, let’s talk about the invisible sexism and gender inequality pervasive in graduate school and industry, emphasized the panelists for the Graduate Women in Science’s Fall Career Development Panel, and let’s figure out how to effect meaningful change in the workplace.

Dr. Bruce, Dr. Reiskind, and Dr. Bickford, from left to right

On October 20, Dr. Donna Bickford, Associate Director of the Office of Undergraduate Research at UNC, Dr. Katherine Bruce, Assistant Professor at Salem College, and Dr. Martha Reiskind, Research Assistant Professor at NC State, hosted an honest conversation about microaggressions, social gender norms, and general advice for dealing with a hostile work environment.

Though the panelists and the attending graduate students were loath to talk about one individual’s aggression, they looked incredibly favorably upon the social media movement, #DistractinglySexy, which resulted from Hunt’s comments.

The hashtag movement declares that, “You can be feminine, and you can be a scientist,” said Dr. Bruce, a sociologist. It breaks from reactionary notions that women must adopt masculine behavior in order to excel in their professions, as well as fosters a larger support community for women who may often feel isolated as the only female in their lab.

The biggest disappointment of the #DistractinglySexy campaign though, was the lack of genuine conversation that followed. Dr. Bickford, an English professor, said that many men agreed with the sentiment of the movement but dismissed further concerns of daily sexism in the workplace, citing men like Hunt as anomalies and the sole perpetrators: “There are a few dinosaurs, but they’re dying.”

The panelists addressed the difficult question of how a woman ought to stand up to offending men in the workplace. “You’re damned if you do and damned if you don’t… How do you blow the whistle without being betrayed?” asked Dr. Reiskind, who addresses issues of sexism in her lab. Especially in situations where the perpetrator is in a position of power, calling out sexist behavior carries the risk of being perceived as a “baying witch,” while remaining silent condemns one to perpetual harassment.

On the question of inaction from women, Dr. Reiskind described the utter disbelief, echoed by the other panelists, that often strikes when assault or harassment has occurred– the bizarre nature of the situation may prevent women from speaking up in the immediate moment where action may be conducive to behavior remediation.

Ultimately, this panel set out to solve problems. While no legislation was passed or cases resolved, holding honest, open conversations to more deeply understand issues is the first step in creating gender-equal workplaces.

By Olivia Zhu, Duke 2016

Relationship Between Domestication and Human Social Skills

By Madeline Halpert

On October 6, 2015

In Animals, Behavior/Psychology, Biology, Lecture

Brian Hare wants to know why humans are such big babies.

Well, that was just the provocative title for his Center for Cognitive Neuroscience talk on Oct. 2. What he wants to know is what happens in the development of human babies that socially advances and separates them from their animal counterparts.

Hare, an associate professor of evolutionary anthropology, discussed human evolution and comparisons to our ancestors and chimpanzees, bonobos and even dogs. He explained that the idea of comparing humans to other species suggests that “something very fundamental happened during human evolution that makes us human– a shift in human development.”

First Hare attempted to evaluate whether certain advanced capabilities of humans are present in other species. One means of doing this was by examining if other species think about the thoughts of others. In a video from an experiment “Gaze” that Hare conducted, he looks at a chimpanzee named Dorene, and then suddenly glances upwards. The chimp follows suit, gazing up at the ceiling to see what Hare is looking at. From this behavior, Hare inferred that chimpanzees are in fact capable of thinking about the thoughts of others, like the human species.

This led Hare to examine another behavior that is advanced in humans: cooperation. Hare explained that in previous laboratory research, chimpanzees were found to be incredibly uncooperative. Hare’s studies in the field, however, proved the opposite. In an experiment with Alicia Melis and Michael Tomasello, two chimps were put in adjacent, but separate rooms. A treat was visible with a string leading to each chimpanzee. If one animal pulled the string, it just got the string. But if both pulled cooperatively, they ended up with the food. The researchers found that 95% of the chimps could work together to solve this problem to get an equal payoff for both of them. Hare did note, however, that if the chimps had communicated, they could have solved the problem more efficiently.

This showed that where chimpanzees might differ from the human species is in their inability integrate cooperation and communication. With children, Hare explains, this is a fundamental part of development that is established early in life. Because of this, Hare wondered if there is something motivationally different about the structure of cooperation between humans and other species, something that also shows early in development.

When humans work together, Hare said, they understand they have a shared goal and will adjust to different roles to complete the task. This has led to, from an evolutionary perspective, a very “strange” behavior in humans, in which they do things together simply because they like to. Hare calls this “we psychology.” Hare showed two videos side by side: one of his son rolling a ball to his mother, Vanessa Woods, and another of a chimp in a cage rolling a ball with Woods. When Woods stopped playing the game, the chimp reached out of the cage and grabbed her arm and pushed the ball so it would roll back to him. From this, Hare inferred that, like humans, chimps may also have a small tendency for “we psychology.”

In another study, Hare compares two-year-old children to adult and juvenile chimpanzees. In terms of physical cognition, the species were very similar to one another. On the social problem solving front, however, human children were already outperforming juvenile and adult chimpanzees. This study, along with the culmination of his earlier research, reinforced Hare’s idea that something very fundamental happens early in human development that differentiates human’s social and communicative capabilities from other species: domestication.

“It’s not just that kids are solving problems better, but it may even be that the way kids cognitively organize has changed,” he said.

Hare explains that just knowing the cause to be domestication was not enough, however. He wanted to understand how this worked. Hare referenced extensive breeding research conducted by Dmitri Konstantinovich Belyaev, in which he studied the domestication of the fox. Not only did these foxes show behavioral changes due to domestication, they also displayed morphological and physiological changes: floppy ears, curly tails and high levels of serotonin. Belyaev also found that, like humans, foxes use gestures and communicative cues. So, Hare concluded that the process of domestication influences a realm of social and biological characteristics and could be manipulated and interpreted in many different ways, especially in our own development.

“This doesn’t just happen as a result of artificial selection, or human selection. It can happen as a result of natural selection,” Hare said. “So then we turn to our own species and start looking at whether there’s any evidence in our own evolution for this.” he said.

By Madeline Halpert, Class of 2019

Mighty Research Grows from DIBS Seeds

By Devin Nieusma

On September 16, 2015

In Behavior/Psychology, Faculty, Science Communication & Education

Groundbreaking neuroscience studies, referred to as the “final frontier” of research by Duke Institute for Brain Sciences director Allen Song, were the focus of the grand opening celebration at DIBS last week.

The Institute celebrated its new home underground at the Levine Science Research Center with a symposium and then a party on Sept. 10.

Faculty and students across multiple schools and disciplines worked together for the chance to earn dibs on DIBS seed money in a competition known as the Incubator Awards. Each project sought seed grants of up to $150,000 for their research in the hopes that they could show enough promise to earn outside funding and continue their work.

Dr. Greg Crawford presenting his project, “Epigenetics of Neuronal Differentiation”

The awards program began in 2007, and it’s working. DIBS seed funding of $3.4 million has been given to 34 projects which then garnered $40 million in federal and foundation grants to Duke.

These research projects have resulted in 36 research publications, three invention disclosures and patents, and more than 30 undergraduate and graduate students becoming involved with pioneering investigations into the human’s most complex organ.

Here are a few of the award-winning projects:

With their project, “Disentangling Autism,” scientists Kafui Dzirasa (Psychiatry & Behavioral Sciences); Yong-hui Jiang (Pediatrics & Medical Genetics); and William Wetsel (Psychiatry & Behavioral Sciences) sought to improve understanding of the pathology of autism by comparing mice with a gene for autism called SHANK3-KO with those who were born without it.

The team began using brain scans of the mice, after noting the many limitations of comparing behavioral abnormalities of affected mice to humans with the disorder. The brain scans revealed that the mice with the gene had atypical brain connectivity. The researchers intend to work with the National Institutes of Health (NIH) to use these results in order to develop drugs that provide better treatment for autism.

“Retinal Imaging Biomarkers for Alzheimer’s Disease,” hoped to improve on the limited and invasive options for diagnosing the disease. A team that included James Burke (Neurology); Scott Cousins (Ophthalmology); Sina Farsiu (Biomedical Engineering and Ophthalmology); Eleonora Lad (Ophthalmology); Guy Potter (Psychiatry & Behavioral Sciences); and Heather Whitson (Medicine, Geriatrics) worked in the Duke Imaging Processing Lab to identify Alzheimer’s patients by examining their eyes.

Blue stain shows where the HARE5 gene was active in this unusually big-brained mouse embryo. (Debra Silver)

The same neuro-inflammatory injuries found in the brain may also be seen in the retina, which is much more visible to doctors looking for a diagnosis. While there have been previous studies on the subject, they have been limited by factors such as small sample size and outdated imaging techniques. Using DIBS’s resources allowed the team to circumvent these issues and gather valuable data. The team’s next steps include studying the retina damage’s association with age-related macular degeneration, as well as completing one-year follow-up examinations of the patients’ progression.

“Brain Evolution” was a project launched by Blanche Capel (Cell Biology); Debra Silver (Molecular Genetics & Microbiology); and Greg Wray (Biology) with the goal of learning about the role of enhancers that regulate genes in brain development. The scientists studied how HARE5, an enhancer that is very pronounced in humans, was involved in the development of the cerebral cortex.

Mice raised with human HARE5 were shown to have a 12% larger brain on average than their typical counterparts. This was the first functional demonstration that species-specific enhancers impact development of the cerebral cortex. Future goals of the team include studying how HARE5 affects adult mice, as well as investigating the roles of HARE2 and HARE3.

(Watch video of DIBS education staff Len White and Minna Ng sharing real human brains with visitors to the “Think Inside the Box” kickoff celebration.)

[youtube https://www.youtube.com/watch?v=3N_1uQxWkpw&w=560&h=315]

Post by Devin Nieusma

E-cigarettes might help smoking cessation

By Madeline Halpert

On September 10, 2015

In Behavior/Psychology, Cancer, Cardiology, Global Health, Lecture, Medicine

Research has shown that nicotine replacement therapies such as the patch, gum lozenges and nasal spray are only 25 percent effective in smoking cessation within the first year of use.

Jed Rose, Ph.D.

Jed Rose, Director of the Duke Center for Smoking Cessation, thinks the use of e-cigarettes, or electronic nicotine delivery systems (ENDS) could be a better way to quit smoking.

Rose spoke Tuesday in a session sponsored by the Center on Addiction and Behavior Change.

He said nicotine replacement is delivered at a slower rate and a lower dose than in actual cigarettes, so it fails to curb craving among smokers. Replacements also don’t replicate one of the main sensory behaviors of smoking: inhalation.

Rose discussed a study in which he and his colleagues anesthetized participants’ airways to see if they could detect the smoke, while keeping the same dose of nicotine to the brain. When participants couldn’t feel the smoke as much, there were more cravings for cigarettes and less satisfaction.

An e-cigarette vaporizes nicotine with battery power, avoiding the combustion byproducts of burning tobacco. (via Wikimedia Commons)

They’ve also found that replacement treatments, when given on a temporary basis of just one year, often resulted in relapse.

So what does an e-cigarette actually do? The battery of this electronic cigarette heats an oil that vaporizes the nicotine with a substance called propylene glycol. The gas is released and condenses immediately into a cloud of smoke.

Why is the e-cigarette safer? It’s the combustion products in smoke, rather than the nicotine, that are responsible for most smoking-related disease. Rose cited the 2010 Surgeon General’s Report that backs up this claim that nicotine itself is not responsible for cardiovascular problems or cancers.

Rose thinks that e-cigarettes could be the best of both worlds, allowing smokers the same sensory effects they enjoy, while possibly avoiding other health hazards of regular cigarette smoking.

Rose also addressed concerns about formaldehyde being present in e-cigarettes. He says this is rare, and only occurs with e-cigarettes that have higher voltages which causes overheating to occur. While there is evidence from two trials that the new devices help smokers to stop smoking long-term compared with placebo, unfortunately, very few studies have looked at this issue. Rose also shares concerns that the new product could be picked up by youth who wouldn’t normally smoke cigarettes, or serve as a gateway between e-cigarettes and real ones.

In the end, however, he thinks this product has the potential to be highly effective in treating addiction, and hopes it will be evaluated further.

“The agency that has to sort through this is the FDA,” he said. “They have to prove that it will help society as a whole. It has to benefit the health of the population.”

By Madeline Halpert

Four-Fifths of a Banana is Better than Half

By Karl Bates

On August 24, 2015

In Animals, Behavior/Psychology, Guest Post, Neuroscience, Students

Fractions strike fear in the hearts of many grade schoolers – but a new study reveals that they don’t pose a problem for monkeys.

Even as adults, many of us struggle to compute tips, work out our taxes, or perform a slew of other tasks that use proportions or percentages. Where did our teachers and parents go wrong when explaining discounts and portions of pie? Are our brains simply not built to handle quantitative part-whole relationships?

Fractions and logical relationships are some of the things a wild macaque might think about while grooming and being groomed. (image copyright Lauren Brent)

To try to answer these questions, my colleagues and I wanted to test whether other species understand fractions. If our fellow primates can reason about proportions, our minds likely evolved to do so too.

In our study, which appears online in the journal Animal Cognition, Marley Rossa (Trinity 2014), Dr. Elizabeth Brannon, and I asked whether rhesus monkeys (Macaca mulatta) are able to compare ratios.

We let the monkeys play on a touch-screen computer for a candy reward. First we trained them to distinguish between two shapes that appeared on the screen: a black circle and a white diamond. When they touched the black circle, they heard a ding sound and received a piece of candy. But when they touched the white diamond, they heard a buzz sound and did not get any candy. The candy-loving monkeys quickly developed a habit of choosing the rewarding black circle.

$http://www.free-training-tutorial.com/math-games/fraction-matching-equivalent1.html$

Fractions example taken from sheppardsoftware.com

Next we introduced fractions. We showed two arrays on the screen, each with several black circles and white diamonds. The monkeys’ job was to touch the array having a greater ratio of black circles to white diamonds. For example, if there were three black circles and nine white diamonds on the left, and eight black circles and five white diamonds on the right, the monkey needed to touch the right side of the screen to earn her candy (8:5 is better than 3:9).

We didn’t always make it so easy, though. Sometimes both arrays had more black circles than white diamonds, or vice versa. Sometimes the array with the higher black-circle-to-white-diamond ratio actually had fewer black circles overall. They needed to find the largest fraction of black circles. For example, if there were eight black circles and 16 white diamonds on the left (8:16), and five black circles and six white diamonds on the right (5:6), the correct answer would be the latter, even though there were more black circles on the left side. That is how we made sure that monkeys were paying attention to the relative numbers of shapes in both arrays.

The monkeys were able to learn to compare proportions. They chose the array with the higher black-circle-to-white-diamond ratio about three-quarters of the time. Impressively, when we showed them new arrays with number combinations they had never seen before, the monkeys still tended to select the array with the better ratio.

Our results suggest that monkeys understand the magnitude of ratios. They also indicate that monkeys might be able to answer another type of question: analogies. These four-part statements you may have seen on standardized tests take the form “glove is to hand as sock is to foot.”

This kind of reasoning requires not only recognizing the relationship between two items (glove and hand) but also how that relationship compares with the relationship between the other two items (sock and foot). Understanding the relationships between relationships — that is, second-order relationships — was believed to require language, making it possibly a uniquely human ability. But in our study, monkeys successfully determined the relationship between two fractions – each one a relationship between two numbers – to make their choices.

If monkeys can reason about ratios and maybe even analogies, our minds are likely to have been set up with these skills as well.

The next step for this line of research will be to figure out how best to employ these in-born abilities when teaching proportions, percentages, and fractions to human children.

CITATION: “Comparison of discrete ratios by rhesus macaques (Macaca mulatta)” Caroline B. Drucker, Marley A. Rossa, Elizabeth M. Brannon. Animal Cognition, Aug. 19, 2015. DOI: 10.1007/s10071-015-0914-9

Guest post by graduate student Caroline B. Drucker. Caroline is curious about both the evolutionary origins and neural basis of numerical cognition, which she currently studies in lemurs and rhesus monkeys.

Hugs Before Drugs – The Price of Emotional Neglect

By Karl Bates

On August 3, 2015

In Behavior/Psychology, Guest Post, Neuroscience

Every exhausted parent can be tempted to check out at times, especially when the little ones are testing limits.

A happy child, presumably not neglected, buried in sand. (D. Sharon Pruitt via Wikimedia Commons)

But when moments of autopilot become months or years, that is considered emotional neglect and it’s strongly linked to the subsequent development of clinical depression in children. Ahmad Hariri’s lab at Duke studies emotional neglect, defined as a caregiver consistently overlooking signs that a child needs comfort or attention, even for something positive.

“Early in life, during infancy, an emotional neglectful parent would regularly be unresponsive and uninvolved with their child,” said Jamie Hanson, a postdoctoral researcher in Hariri’s group. “In early childhood, parents would be clearly unengaged in playing with the child, showing little to no affection during interactions.”

In a study published online in Biological Psychiatry, Hanson, Hariri and their collaborator Douglas Williamson of the University of Texas Health Sciences Center San Antonio, found that the more emotional neglect the children had experienced in their lives, the less responsive their brain was to a reward (winning money in a card game). They had scanned the brains of 106 children between 11 and 15 years of age, and then again two years later.

The scientists focused on the ventral striatum, a brain area known to fire up in response to positive feedback. This region is thought to play a role in optimism and hopefulness, and its dysfunction has been associated with depression. The team wondered: Are the kids with dulled ventral striatum activity more likely to have symptoms of depression? They were.

Ahmad Hariri

Depression rates start to rise around 15 or 16 years of age, and that’s why the team focused on this age. The cohort of kids they studied were part of Williamson’s Teen Alcohol Outcomes Study (TAOS), and Hanson and Hariri hope to continue following them.

In a different cohort called the Duke Neurogenetics Study, Hariri’s team has found that the responsiveness of the ventral striatum and the amygdala — another area that handles life stress — may help predict how likely young adults are to develop problem drinking in response to stress or to engage in risky sexual behavior.

Being able to identify the children or young adults who are at risk for depression and anxiety is a tall order. But the possibility that we could one day funnel extra support to these individuals and help them avoid a lifetime of medicines and therapy is what keeps Hariri and his team going.

Personally, as a parent, I’m excited see what the Hariri group will do next. During our interview, I couldn’t help running a few scenarios by him and Hanson. Am I emotionally neglecting my toddler if she’s having a tantrum and I have to leave the room or I’ll scream?

“You can have a bad week,” said Hariri, who is also a dad. “You’re not ruining your kid.”

Guest post by Kelly Rae Chi, a Cary-based freelance writer who covers brain science for Duke Research.