Psychologists closing in on claustrophobia

By Carol Clark

We all move around in a protective bubble of “near space,” more commonly known as “personal space.” But not everyone’s bubble is the same size. People who project their personal space too far beyond their bodies, or the norm of arm’s reach, are more likely to experience claustrophobic fear, a new study finds.

The study, to be published in the journal Cognition, is one of the first to focus on the perceptual mechanisms of claustrophobic fear.

“We’ve found that people who are higher in claustrophobic fear have an exaggerated sense of the near space surrounding them,” says Emory psychologist Stella Lourenco, who led the research. “At this point, we don’t know whether it’s the distortion in spatial perception that leads to the fear, or vice versa. Both possibilities are likely.”

Everyone experiences claustrophobic fear to some extent, but there is a wide range of individual differences. About 4 percent of people are estimated to suffer from full-blown claustrophobia, which can cause them to have panic attacks when traveling through a tunnel or riding in an elevator. Some people seek medical treatment for the condition.

Photo: iStockphoto.com

“Increasing our understanding of the factors that contribute to claustrophobia may help clinicians develop more effective therapies for what can be a highly debilitating fear,” says Matthew Longo, one of the study’s co-authors and a psychologist at Birkbeck, University of London.

Claustrophobia is often associated with a traumatic experience, such as getting stuck in an elevator for a long period. “However, we know that some people who experience traumatic events in restricted spaces don’t develop full-blown claustrophobia,” Lourenco says. “That led us to ask whether other factors might be involved. Our results show a clear relation between claustrophobic fear and basic aspects of spatial perception.”

Neural and behavioral evidence shows that we treat space that is within arm’s reach differently from space that is farther away. “It makes adaptive sense to be more aware of things that are closer to the body, for both utilitarian purposes and defensive ones,” Lourenco says. “It also makes adaptive sense to be afraid of things that are too far away from you on the vertical dimension, since there can be a great cost to falling.”

In ongoing work, Lourenco and Longo are investigating how the range of individual differences in spatial perception relates to fear. They are asking normal research subjects, who are not seeking treatment for claustrophobia or acrophobia (the fear of heights), to estimate various distances.

While the subjects who have higher levels of claustrophobic fear underestimate horizontal distances, those who have more acrophobic fear overestimate vertical distances. “One intriguing possibility is that these two types of fear may form opposite ends of a single spatial-perceptual continuum,” Lourenco says.

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Get ready to flash your intelligence

You’re working late in a downtown Atlanta skyscraper. You realize that you are all alone in the building. You glance out the window: Below you see hordes of people start moving chaotically, then spontaneously flow together into an orderly stream.

Don’t be a bystander. It’s time to put on some sensible shoes and listen to those voices in your head. Sign-up to join a science flash mob of hundreds of people demonstrating how molecules evolve and self-assemble.

The first “Group Intelligence” flash mob begins on the Emory Quad next Thursday, April 14 at 7 pm. Group Intelligence will spread to downtown Atlanta’s Woodruff Park the following week. From there, it’s going national and to Europe.

It’s all part of the daring convergence of science and art brought to you by Out of Hand Theater and the Center for Chemical Evolution. The center is a collaboration of Emory and Georgia Tech, funded by the NSF and NASA.

Click here to join Group Intelligence. Remember: It takes a diversity of molecules, and people, to ensure our survival.

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Windstorm reshapes Atlanta forests

Atlanta is known for its mammoth trees, which create a forest atmosphere in some metro areas. Monday’s violent storm felled many of these giants in and around the city, killing six people, damaging property and taking out power.

The storm took down 40 trees on the Emory campus. The university has some of the best-preserved hardwood forests in the Piedmont province of the Southeast. When large trees are downed by storms, it’s part of a natural process of clearing out old growth, explains Carl Brown, adjunct faculty in environmental studies.

Hal Jacobs, who writes the blog Quad Talk, spoke with Brown next to Mizell Bridge and the Carlos Museum. Check out the beautiful scenes of campus forest in his video, above, including a great shot of a hawk.

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What makes yawns contagious?

Bored with your friends? Perhaps it's evolutionary. New research shows that chimpanzees are more likely to "catch" yawns from familiar chimpanzees than strangers. Photo: iStockPhoto.com.

Contagious yawning is not just a marker of sleepiness or boredom. For chimpanzees, it may actually be a sign of a social connection between individuals.

Scientists at Emory’s Yerkes National Primate Research Center discovered that chimpanzees yawn more after watching familiar chimpanzees yawn than after watching strangers yawn. Their findings, published today in the Public Library of Science One (PLoS ONE), may help scientists understand empathy, the mechanism thought to underlie contagious yawning, in both chimpanzees and humans. The research also may help show how social biases strengthen or weaken empathy.

Yerkes researchers Matthew Campbell and Frans de Waal propose that when yawning spreads between chimpanzees, it reflects an underlying empathy between them.

“The idea is that yawns are contagious for the same reason that smiles, frowns and other facial expressions are contagious,” they write. “Our results support the idea that contagious yawning can be used as a measure of empathy, because the biases we observed were similar to empathy biases previously seen in humans.”

They studied 23 adult chimpanzees that were housed in two separate groups. The chimpanzees viewed several nine-second video clips of other chimpanzees, in both groups, either yawning or doing something else. They yawned 50 percent more frequently in response to seeing members of their group yawn compared to seeing others yawn.

In humans, scientists have identified certain parts of the brain that are activated both when someone experiences pain and when they see someone else experiencing pain. In these experiments, people tend to show more sensitivity for members of the same social group.

The results raise the question of whether contagious yawning among humans shows the same biases: favoring members of the same social group over different social groups.

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Chimps, bonobos yield clues to social brain

Chimps, bonobos yield clues to social brain

The social behaviors of the chimpanzee (left) and the bonobo (right) "mirror individual differences within the human population," says anthropologist James Rilling. Photos, copyright by Frans de Waal.

By Carol Clark

It’s been a puzzle why our two closest living primate relatives, chimpanzees and bonobos, have widely different social traits, despite belonging to the same genus. Now, a comparative analysis of their brains shows neuroanatomical differences that may be responsible for these behaviors, from the aggression more typical of chimpanzees to the social tolerance of bonobos.

“What’s remarkable is that the data appears to match what we know about the human brain and behavior,” says Emory anthropologist James Rilling, who led the analysis. “The neural circuitry that mediates anxiety, empathy and the inhibition of aggression in humans is better developed in bonobos than in chimpanzees.”

The journal of Social Cognitive and Affective Neuroscience published the results, the most comprehensive comparative analysis to date of the neural systems of chimpanzees and bonobos.

“By contributing to our basic understanding of how brain anatomy relates to social behavior, this study may provide clues to the brain dysfunction underlying human social behavioral disorders like psychopathy and autism,” Rilling says.

Chimpanzees and bonobos diverged from a common ancestor with humans about six million years ago, and from each other just one-to-two million years ago. Despite this relatively brief separation in evolutionary terms, the two species exhibit significant differences in social behavior. Compared with chimpanzees, bonobos are more anxious, less aggressive, more socially tolerant, more playful, more sexual and perhaps more empathic.

“Chimpanzees tend to resolve conflict by using aggression, while bonobos are more likely to use behavioral mechanisms like sex and play to diffuse tension,” Rilling says. “The social behaviors of the two species mirror individual differences within the human population.”
Neuroanatomical differences between the brain of the chimpanzee (left) and the bonobo (right) match what we know about the human brain and behavior. Images by James Rilling.

Rilling heads Emory’s Laboratory for Darwinian Neuroscience, a leader in the use of non-invasive neuro-imaging technology to compare the neurobiology of humans and other primates. The anthropology department lab draws on resources of Emory’s Yerkes National Primate Research Center.

“In addition to exploring links between neuroanatomy and different social behaviors, we’re mapping the underlying biology for how species evolve and differentiate,” Rilling says.

A range of imaging and analytical techniques were used in the chimpanzee-bonobo study. Voxel-based morphometry compared the gray matter in standard structural scans of the brains. Diffusion tensor imaging (DTI) captured the white matter connections, to compare the fiber tracts that “wire” the brain.

The results showed that bonobos have more developed circuitry for key nodes within the limbic system, the so-called emotional part of the brain, including the amygdala, the hypothalamus and the anterior insula. The anterior insula and the amygdala are both implicated in human empathy.

“We also found that the pathway connecting the amygdala and the prefrontal cortex is larger in bonobos than chimpanzees,” Rilling says. “When our amygdala senses that our actions are causing someone else distress, we may use that pathway to adjust our behavior in a prosocial direction.”

Chimpanzees have better developed visual system pathways, according to the analysis. Previous research has suggested that those pathways are important for tool use, a skill which chimpanzees appear better at than bonobos.

Rilling conducted the research with Yerkes neuroscientist Todd Preuss; DTI experts Timothy Behrens and Jan Scholz from Oxford University; Emory graduate student Bhargav Errangi; and former Emory student Matthew Glasser.

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