Inside the Brains of Jurors

Caltech Neuroscientist Helps Reveal Brain Activity Associated with Mitigating Criminal Sentences

When jurors sentencing convicted criminals are instructed to weigh not only facts but also tricky emotional factors, they rely on parts of the brain associated with sympathy and making moral judgments, according to a new paper by a team of neuroscientists. Using brain-imaging techniques, the researchers, including Caltech's Colin Camerer, found that the most lenient jurors show heightened levels of activity in the insula, a brain region associated with discomfort and pain and with imagining the pain that others feel.

The findings provide insight into the role that emotion plays in jurors' decision-making processes, indicating a close relationship between sympathy and mitigation.

In the study, the researchers, led by Makiko Yamada of National Institute of Radiological Sciences in Japan, considered cases where juries were given the option to lessen the sentences for convicted murderers. In such cases with "mitigating circumstances," jurors are instructed to consider factors, sometimes including emotional elements, that might cause them to have sympathy for the criminal and, therefore, shorten the sentence. An example would be a case in which a man killed his wife to spare her from a more painful death, say, from a terminal illness. 

"Finding out if jurors are weighing sympathy reasonably is difficult to do, objectively," says Colin Camerer, the Robert Kirby Professor of Behavioral Finance and Economics at Caltech. "Instead of asking the jurors, we asked their brains."

The researchers scanned the brains of citizens (potential jurors) while the participants read scenarios adapted from actual murder cases with mitigating circumstances. In some cases, the circumstances were sympathy-inducing; in others, where, for example, a man became enraged when an ex-girlfriend refused him, they were not. The scientists used functional magnetic resonance imaging (fMRI), a type of brain scanning that tracks increases in oxygenated blood flow, indicating heightened brain activity. The participants also had their brains scanned when they determined whether to lessen the sentences, and by how much.  

The team found that sympathy activated the dorsomedial prefrontal cortex, precuneus, and temporo-parietal junction—brain regions associated with moral conflict and thinking about the feelings of others. Similarly, the jurors had increased activity in these regions during sentencing when the mitigating circumstances earned their sympathy. In those cases, they also delivered shorter hypothetical sentences.

In addition to Camerer and Yamada, coauthors on the new paper, "Neural circuits in the brain that are activated when mitigating criminal sentences," are Saori Fujie, Harumasa Takano, Hiroshi Ito, Tetsuya Suhara, and Hidehiko Takahashi of the National Institute of Radiological Sciences; Motoichiro Kato of the Keio University of Medicine; and Tetsuya Matsuda of Tamagawa University Brain Science Institute. Yamada is also affiliated with Tamagawa University Brain Science Institute and Kyoto University School of Medicine; she and Takahashi are additionally affiliated with the Japan Science and Technology Agency.

Kimm Fesenmaier
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Modeling Markets

After the financial crisis of 2008, many of the world's financial markets shut down—a response that surprised experts. "This was something that most theoretical models would not have predicted," says Chris Shannon, the Richard Merkin Professor of Economics and Mathematics.

Shannon, who arrived on campus in mid-January, is one of Caltech's newest faculty members. Her research involves developing mathematical models to understand financial markets and other mechanisms that allocate goods, such as auctions. "I work at the intersection of economics and math," she says, and while her work is highly abstract and theoretical—her papers are often filled with theorems and proofs—her ideas have plenty of real-world implications.

For example, some of the models she works with try to predict how markets would react to uncertainties or new information. Although most models did not predict a widespread shutdown in trade, which was what happened in 2008, one of Shannon's models actually did. "Some of my work suggested that that's exactly what would happen in response to the financial crisis," she says. But, she cautions, that's not to say that she foresaw the crisis—just that such a shutdown was possible, based on a generalized, theoretical model.

Shannon loves her work because it requires mathematical rigor and has implications for society, she says. "I started out interested in math; I was a math major," she says. "Then I became a little more interested in problems that had to do with applications to social problems." That led her to study income inequality while an undergraduate at the University of Kansas, and eventually to a second major in economics.

She then went to Stanford University, receiving a master's degree in mathematics in 1991 and then a PhD in economics in 1992. She then joined the faculty of the University of California, Berkeley, remaining there until coming to Caltech this year.

"One of the very attractive aspects of Caltech is the intense focus on science, and the opportunity for a lot of very exciting interdisciplinary work," she explains. Although she's not collaborating just yet, she says she's excited to work with Caltech's economists, mathematicians, and even computer scientists. And she's not just looking forward to working with other faculty. "The students are incredibly gifted, so that's also a big attraction." Another advantage of Caltech, she says, is its "unparalleled support for faculty research."

Although Shannon is a native of Kansas, she's come to love California, enjoying many of the outdoor activities the state has to offer. She enjoys trail running, mountain biking, hiking, and kayaking. Although she spent time at Caltech as a Moore Scholar in the fall of 2010, she says, there's still much of Southern California left to explore. 

Marcus Woo

Katz Named Caltech's Inaugural Kay Sugahara Professor

Jonathan N. Katz, chair of the Division of the Humanities and Social Sciences, has been named the Kay Sugahara Professor of Social Sciences and Statistics. The Sugahara family endowed the new professorial chair with a $2 million gift in honor of the late Kay Sugahara, a civic leader and entrepreneur who built the worldwide shipping and oil services business, Fairfield-Maxwell Ltd. The gift is supplemented by an additional $1 million provided by the Gordon and Betty Moore Matching Program.

"We felt that establishing this endowed chair was a fitting tribute to my late father," says Kaytaro Sugahara, the eldest of Kay and Yone Sugahara's three sons, and a Caltech alumnus (BS '61). "He valued education, built his own business empire, and was active in international relations. He would have been proud to have his name associated with the work being done in the Division of the Humanities and Social Sciences at Caltech." 

Kay Sugahara, born to Japanese immigrants in Seattle in 1909, was largely a self-made man. Orphaned at an early age, he went on to graduate from UCLA in 1932 and used his business skills and knowledge of international trade to become a millionaire by the age of 30. He lost most of that when he, his wife, and children were interned in a camp in Granada, Colorado, during World War II. Yet, he remained loyal to his country—volunteering to work with the Office of Strategic Services, the predecessor of the Central Intelligence Agency, in their wartime efforts.

Following the war, he built his shipping business, becoming chairman of the board of the conglomerate Fairfield-Maxwell, which owns and manages oil and chemical tankers, as well as refrigerated and bulk cargo vessels. The company, through its Fairfield Nodal subsidiary, also designs, manufactures, and operates equipment to gather seismic data in both the marine and land environments. Sugahara was also active in international relations, and served as chairman of the US-Asia Institute in Washington, D.C.

As arranged by the Sugahara family, the Kay Sugahara Professorship is designated for an eminent scholar within the Division of the Humanities and Social Sciences who is engaged in education and research in the areas of economics, entrepreneurship, political science, or Asian studies. Katz, the inaugural chair holder, works at the intersection of political science, economics, and statistics. His current research focuses on developing statistical methods and applying those methods to questions about elections and public policy.

"I'm very honored to be recognized with this new title," Katz says. "Many professors never get the chance to meet the donors who support their chairs. But I know and think very highly of the Sugahara family, so this is particularly meaningful for me."

Kay Sugahara once wrote: "There is a tendency today to play things safe, to let caution be our guiding star. That way lies disaster. To succeed, we must blaze new trails, explore new areas, forge new concepts." The Sugaharas believe he would be particularly pleased by the appointment of Dr. Katz as the first to hold this chair.

Kimm Fesenmaier
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Neuroscientists Find That Status within Groups Can Affect IQ

PASADENA, Calif.—Our cognitive abilities and decision-making skills can be dramatically hindered in social settings where we feel that we are being ranked or assigned a status level, such as classrooms and work environments, according to new findings from a team of researchers from the California Institute of Technology (Caltech) and four other institutions. The finding flies in the face of long-held ideas about intelligence and cognition that regard IQ as a stable, predictive measure of mental horsepower. 

"This study tells us the idea that IQ is something we can reliably measure in isolation without considering how it interacts with social context is essentially flawed," says Steven Quartz, professor of philosophy at Caltech and one of the authors of the new study, which appears in the current issue of Philosophical Transactions of The Royal Society B. "Furthermore, this suggests that the idea of a division between social and cognitive processing in the brain is really pretty artificial. The two deeply interact with each other."

"You may joke about how committee meetings make you feel brain-dead, but our findings suggest that they may make you act brain-dead as well," says Read Montague, director of the Human Neuroimaging Laboratory and Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute and corresponding author on the paper.

To investigate the impact of social context on IQ, the researchers divided a pool of 70 subjects into groups of five and gave each individual a computer-based IQ test. After each question, an on-screen ranking showed the subjects how well they were performing relative to others in their group and how well one other person in the group was faring. All of the subjects had previously taken a paper-and-pencil IQ test, and were matched with the rest of the group so that they would each be expected to perform similarly on an IQ test.

At the outset, all of the subjects did worse than expected on this "ranked group IQ task." But some of the subjects, dubbed High Performers, were able to improve over the course of the test while others, called Low Performers, continued to perform below their expected level. By the end of the computer-based test, the scores of the Low Performers dropped an average of 17.4 points compared to their performance on the paper-and-pencil test.

"What we found was that sensitivity to the social feedback of the rankings profoundly altered some people's ability to express their cognitive capacity," Quartz says. "So we get this really quite dramatic downward spiraling of one group purely because of their sensitivity to this social feedback." Since so much of our learning—from the classroom to the work team—is socially situated, this study suggests that individual differences in social sensitivity may play an important role in shaping human intelligence over time.

During the computer-based test, about a third of the subjects underwent brain scans, using functional Magnetic Resonance Imaging (fMRI). This type of imaging allows scientists to track increases in oxygenated blood flow, indicating heightened activity, in the brain. At the start of the test, researchers observed increased activity in all the participants in a brain region called the amygdala, which is associated with fear and emotional arousal. Among High Performers, that activation decreased over time, while it remained steady in Low Performers.

"What is causing the Low Performers to be hindered by the social context is something for follow-up studies, but certainly the suspicion is that it's a dimension of personality that is driving the difference," Quartz says. That dimension could be neuroticism, the tendency to worry or to ruminate about social information. "The pattern of activity that we see originally in both groups, but especially in the low-performing group, is quite similar to the pattern of activity you see in studies looking at the neuroscience of neuroticism."

The researchers also tracked activity in the nucleus accumbens, a part of the brain involved in the processing of rewards. They observed elevated activity in the nucleus accumbens when a subject's rank within the group increased. "That shows that the task was motivationally important to people," Quartz says. "When they saw their rank go up, that was a reward."

The idea for the new study came, in part, from a study published in 1999 in which researchers from Emory University examined social rank—a strong and extremely motivating signal among primates. It has long been known that even monkeys that have never met before can quickly sort themselves based on social standing within the group. The Emory researchers isolated low-ranking rhesus monkeys and taught them a learning task. They found that in the presence of high-ranking group members, the monkeys who had learned the task acted as though they were not familiar with it.

"Social rank isn't as well understood in humans," Quartz says. "So we wanted to see what would happen when social rank becomes salient in a group of humans, as it does in most real-world learning environments. We wanted to see if this has an effect on the expression of IQ."

Throughout the 20th century, IQ was used in different arenas as a way of sorting or classifying people into niches. Because people believed it to be a more abstract notion of cognitive ability, it was thought to have strong predictive validity of mental capabilities even from age six. But IQ was always measured in social isolation. "That reflects a long tradition of intellectual history, of considering rationality and cognition to be this isolated process," Quartz says. "But one of the things that we're learning more and more in social neuroscience is the role of our social contexts and the social adaptation of the brain." Understanding the role social context plays and its differential impact on the brain may ultimately help educators and others to design more effective learning environments.

The present study found some unexpected trends, including the tendency for female subjects to be more affected than males by the implicit signaling of social status during the test. Although all of the subjects scored similarly on the paper-and-pencil IQ test, 11 of the 14 Low Performers on the ranked group IQ task were female, while 10 of the 13 High Performers were male. Due to sample size limitations, additional studies are needed to validate the finding and to investigate possible causes.

In addition to Quartz and Montague, additional authors on the paper, "Implicit signals in small group settings and their impact on the expression of cognitive capacity and associated brain responses," are Kenneth Kishida of Virginia Tech Carilion Research Institute, Dongni Yang of the Baylor College of Medicine, and Karen Hunter Quartz of the University of California, Los Angeles. Montague is also affiliated with the Wellcome Trust Centre for Neuroimaging in London. The work was funded by the Wellcome Trust Principal Research Fellowship, the Kane Family Foundation, and the National Institutes of Health.

Kimm Fesenmaier
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Caltech Neuroscientists Pinpoint Specific Social Difficulties in People with Autism

New finding provides insight into the psychology of autism-spectrum disorders

PASADENA, Calif.—People with autism process information in unusual ways and often have difficulties in their social interactions in everyday life. While this can be especially striking in those who are otherwise high functioning, characterizing this difficulty in detail has been challenging. Now, researchers from the California Institute of Technology (Caltech) have isolated a very specific difference in how high-functioning people with autism think about other people, finding that—in actuality—they don’t tend to think about what others think of them at all.

This finding, described online this week in the Proceedings of the National Academy of Sciences, sheds light on what researchers call "theory of mind" abilities—our intuitive skill for figuring out what other people think, intend, and believe. One key aspect of such abilities in terms of social interactions is to be able to figure out what others think of us—in other words, to know what our social reputation is. It is well known that social reputation usually has a very powerful influence on our behavior, motivating us to be nice to others.

The Caltech team capitalized on this strong effect by asking people to make real money donations to UNICEF under two conditions: alone in a room or while being watched by a researcher. 

"What we found in control participants—people without autism—basically replicated prior work. People donated more when they were being watched by another person, presumably to improve their social reputation," explains Keise Izuma, a postdoctoral scholar at Caltech and first author on the study. "By contrast, participants with autism gave the same amount of money regardless of whether they were being watched or not. The effect was extremely clear."

To be certain that the subjects with autism really were not thinking about their social reputation in the presence of the other person—as opposed to simply ignoring that onlooker—the researchers showed that everyone, both controls and people with autism, do better on simple math tasks when being watched than when alone.

"This check was important," says Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology at Caltech and the principal investigator on the paper, "because it showed us that in people with autism, the presence of another person is indeed registered, and can have general arousal effects. It tells us that what is missing is the specific step of thinking about what another person thinks about us. This is something most of us do all the time—sometimes obsessively so—but seems to be completely lacking in individuals with autism."

The findings provide a much more precise picture of how people with autism process social information, says Adolphs, and is important not only for use in diagnostic and interventional therapies, but also for educating the general public about the psychology of autism.

Next up for the team: MRI studies to investigate what occurs in the brain during such social interactions, as well as other investigations into the biology and psychology of autism.

Other authors on the PNAS paper, "Insensitivity to social reputation in autism," are Colin Camerer, Robert Kirby Professor of Behavioral Economics at Caltech and Kenji Matsumoto, a neuroscientist at Tamagawa University in Japan. The work was supported by a Simons Foundation Autism Research Initiative, the National Institute of Mental Health, a fellowship from the Japan Society for the Promotion of Science Fellows, and a Global Centers of Excellence collaborative grant from the Japanese government to Caltech and Tamagawa University.

Lori Oliwenstein

Caltech Named World's Top University in New Times Higher Education Global Ranking

PASADENA, Calif.—The California Institute of Technology (Caltech) has been rated the world's number one university in the 2011–2012 Times Higher Education global ranking of the top 200 universities, displacing Harvard University from the top spot for the first time in the survey's eight-year history.

Caltech was number two in the 2010–2011 ranking; Harvard and Stanford University share the second spot in the 2011–2012 survey, while the University of Oxford and Princeton University round out the top five.

"It's gratifying to be recognized for the work we do here and the impact it has—both on our students and on the global community," says Caltech president Jean-Lou Chameau. "Today's announcement reinforces Caltech's legacy of innovation, and our unwavering dedication to giving our extraordinary people the environment and resources with which to pursue their best ideas. It's also truly gratifying to see three California schools—including my alma mater, Stanford—in the top ten."

Thirteen performance indicators representing research (worth 30% of a school's overall ranking score), teaching (30%), citations (30%), international outlook (which includes the total numbers of international students and faculty and the ratio of scholarly papers with international collaborators; 7.5%), and industry income (a measure of innovation; 2.5%) are included in the data. Among the measures included are a reputation survey of 17,500 academics; institutional, industry, and faculty research income; and an analysis of 50 million scholarly papers to determine the average number of citations per scholarly paper, a measure of research impact.

"We know that innovation is the driver of the global economy, and is especially important during times of economic volatility," says Kent Kresa, chairman of the Caltech Board of Trustees. "I am pleased that Caltech is being recognized for its leadership and impact; this just confirms what many of us have known for a long time about this extraordinary place."

"Caltech has been one of California's best-kept secrets for a long time," says Caltech trustee Narendra Gupta. "But I think the secret is out!"

Times Higher Education, which compiled the listing using data supplied by Thomson Reuters, reports that this year's methodology was refined to ensure that universities with particular strength in the arts, humanities, and social sciences are placed on a more equal footing with those with a specialty in science subjects. Caltech—described in a Times Higher Education press release as "much younger, smaller, and specialised" than Harvard—was nevertheless ranked the highest based on their metrics.

According to Phil Baty, editor of the Times Higher Education World University Rankings, "the differences at the top of the university rankings are miniscule, but Caltech just pips Harvard with marginally better scores for 'research—volume, income, and reputation,' research influence, and the income it attracts from industry. With differentials so slight, a simple factor plays a decisive role in determining rank order: money."

"Harvard reported funding increases similar in proportion to other institutions, whereas Caltech reported a steep rise (16%) in research funding and an increase in total institutional income," Baty says.

Data for the Times Higher Education's World University Rankings was provided by Thomson Reuters from its Global Institutional Profiles Project (, an ongoing, multistage process to collect and validate factual data about academic institutional performance across a variety of aspects and multiple disciplines.

For a full list of the world's top 200 schools and all of the performance indicators, go to

# # # 

The California Institute of Technology (Caltech) is a small, private university in Pasadena that conducts instruction and research in science and engineering, with a student body of about 900 undergraduates and 1,200 graduate students. Recognized for its outstanding faculty, including several Nobel laureates, and such renowned off-campus facilities as the Jet Propulsion Laboratory, the W. M. Keck Observatory, and the Palomar Observatory, Caltech is one of the world's preeminent research centers.

Kathy Svitil
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Caltech Neuroscientists Record Novel Responses to Faces from Single Neurons in Humans

Finding offers new insights into neural basis of social perception

PASADENA, Calif.—Responding to faces is a critical tool for social interactions between humans. Without the ability to read faces and their expressions, it would be hard to tell friends from strangers upon first glance, let alone a sad person from a happy one. Now, neuroscientists from the California Institute of Technology (Caltech), with the help of collaborators at Huntington Memorial Hospital in Pasadena and Cedars-Sinai Medical Center in Los Angeles, have discovered a novel response to human faces by looking at recordings from brain cells in neurosurgical patients.

The finding, described in the journal Current Biology, provides the first description of neurons that respond strongly when the patient sees an entire face, but respond much less to a face in which only a very small region has been erased.

"The finding really surprised us," says Ueli Rutishauser, first author on the paper, a former postdoctoral fellow at Caltech, and now a visitor in the Division of Biology. "Here you have neurons that respond well to seeing pictures of whole faces, but when you show them only parts of faces, they actually respond less and less the more of the face you show. That just seems counterintuitive."

The neurons are located in a brain region called the amygdala, which has long been known to be important for the processing of emotions. However, the study results strengthen a growing belief among researchers that the amygdala has also a more general role in the processing of, and learning about, social stimuli such as faces.

Other researchers have described the amygdala's neuronal response to faces before, but this dramatic selectivity—which requires the face to be whole in order to elicit a response—is a new insight. 

"Our interpretation of this initially puzzling effect is that the brain cares about representing the entire face, and needs to be highly sensitive to anything wrong with the face, like a part missing," explains Ralph Adolphs, senior author on the study and Bren Professor of Psychology and Neuroscience and professor of biology at Caltech. "This is probably an important mechanism to ensure that we do not mistake one person for another and to help us keep track of many individuals."

The team recorded brain-cell responses in human participants who were awaiting surgery for drug-resistant epileptic seizures. As part of the preparation for surgery, the patients had electrodes implanted in their medial temporal lobes, the area of the brain where the amygdala is located. By using special clinical electrodes that have very small wires inserted, the researchers were able to observe the firings of individual neurons as participants looked at images of whole faces and partially revealed faces. The voluntary participants provided the researchers with a unique and very rare opportunity to measure responses from single neurons through the implanted depth electrodes, says Rutishauser.  

"This is really a dream collaboration for basic research scientists," he says. "At Caltech, we are very fortunate to have several nearby hospitals at which the neurosurgeons are interested in such collaborative medical research." 

The team plans to continue their studies by looking at how the same neurons respond to emotional stimuli. This future work, combined with the present study results, could be highly valuable for understanding a variety of psychiatric diseases in which this region of the brain is thought to function abnormally, such as mood disorders and autism.

Other Caltech authors on the paper are Oana Tudusciuc, a postdoctoral scholar in neuroscience and psychology, and Dirk Neumann, visiting associate in biology. Medical collaborators on the study include Adam Mamelak, a neurosurgeon at Cedars-Sinai; and Huntington Memorial Hospital's Christopher Heller, neurosurgeon; Ian Ross, neurosurgeon; Linda Philpott, neuropsychologist; and William Sutherling, medical director of the Epilepsy and Brain Mapping Program. The work in the paper "Neuronal responses selective for whole faces in the human amygdala," was supported by the National Science Foundation, the Pfeiffer Family Foundation, and the Gordon and Betty Moore Foundation.

Katie Neith

Hedging Your Bets

How the Brain Makes Decisions About Related Bits of Information

PASADENA, Calif.—When making decisions based on multiple interdependent factors—such as what combination of stocks and bonds to invest in—humans look at how the factors correlate with each other, according to a new study by researchers from the California Institute of Technology (Caltech) and University College London.

The finding suggests our brains are constantly doing calculations that enable us to keep track of correlations between dynamic factors. These correlations allow us to observe the outcome of one action and then infer the outcomes of other related actions or events without having to experience them individually. This leads to quicker responses than would be possible if we made all choices based on rules of thumb or through trial and error, as scientists had previously assumed. The new study, to be published in the September 22 issue of the journal Neuron, also identifies the regions of the brain involved in tracking these correlations. 

For Peter Bossaerts, one of the authors of the study and a professor of finance at Caltech, the implications in terms of the financial choices that people make are particularly interesting. “When investing in more than one asset, such as stocks and bonds, it is important that one does so with the right mix, which is determined by the correlation between the returns on the assets," says Bossaerts, the William D. Hacker Professor of Economics and Management. "What we wanted to know was, 'How do people actually make such judgments?'"

To get to the heart of that question, the researchers scanned the brains of 16 subjects using functional magnetic resonance imaging (fMRI), which measures activity in the brain, while the subjects played a game of resource management. The subjects were instructed to adjust the proportion of energy coming from two renewable energy sources—a solar plant and a wind farm—in an effort to create the most stable energy output possible.

In the game, the outcomes of the two energy sources varied with each other. So, for example, when they were positively correlated, the wind blew while the sun was shining, so each source generated power. The researchers changed the correlation between the two sources throughout the experiment, thus requiring the subjects to continuously revise their predictions of the outcomes of those correlations in order to perform well.

The team found that the subjects changed their behaviors to reflect new correlations far faster than they could have had they been relying on simple trial and error. Instead, they were estimating the correlation between the sources, tracking mistakes in their estimations, and adjusting their estimates of the correlation on the fly. 

Klaus Wunderlich, lead author of the Neuron paper, began designing the study while a graduate student in computation and neural systems at Caltech. Now a researcher at the Wellcome Trust Centre for Neuroimaging at University College London, Wunderlich says there is an evolutionary importance to such correlations: “Imagine our ancestors foraging for food in the woods. They could spend their time either collecting berries or hunting deer," he says. "Now imagine they have previously observed that deer eat berries. So, as they are foraging, if they notice a lack of fresh berries, they can infer that there are lots of deer around and instead focus on hunting.”

In the financial world, where returns dictate that the appropriate mix of stocks and bonds should be determined by their correlation, the results from this study should disprove the need for rough rules of thumb such as one that says more risk-averse people should put a larger percentage of their money into bonds. "We show in this research that people combine sources in an optimal way, taking into account explicitly, and not through trial and error, how outcomes are correlated,” Bossaerts says. 

When the researchers looked at the fMRI scans of the subjects as they played the game, they saw increased activity in two regions of the brain commonly associated with emotion—the insula and the anterior cingulate cortex. They believe the brain makes predictions about correlation strengths in the insula and tracks the accuracy of its predictions in the anterior cingulate cortex.

Bossaerts says that the location of these correlation-forming and outcome-tracking functions in regions of the brain often thought of as "emotional" provides additional evidence that rational mathematical thinking and emotions are not at odds. "It is integral to good decision-making to be emotional," he says. "Being completely emotion-free can be detrimental, especially when making decisions under uncertainty." 

The results also indicate that damage to these parts of the brain—through drug use or medication, for example—could easily lead to errors in decision-making or in understanding correlations.

The Neuron paper is titled "Hedging your bets by learning reward correlations in the human brain." In addition to Wunderlich and Bossaerts, coauthors include Mkael Symmonds and Raymond Dolan, both from the Wellcome Trust Centre for Neuroimaging. The work was supported by a Wellcome Trust Program Grant and a Max Planck Research Award.

Kimm Fesenmaier

Captivated by Critters: Humans Are Wired to Respond to Animals

PASADENA, Calif.—Some people feel compelled to pet every furry animal they see on the street, while others jump at the mere sight of a shark or snake on the television screen. No matter what your response is to animals, it may be thanks to a specific part of your brain that is hardwired to rapidly detect creatures of the nonhuman kind. In fact, researchers from the California Institute of Technology (Caltech) and UCLA report that neurons throughout the amygdala—a center in the brain known for processing emotional reactions—respond preferentially to images of animals.

Their findings were described in a study published online in the journal Nature Neuroscience.

The collaborative research team was responsible for recruiting 41 epilepsy patients at the Ronald Reagan UCLA Medical Center; these patients were already being monitored for brain activity related to seizures. Using electrodes already in place, the team recorded single-neuron responses in the amygdala as study participants viewed images of people, animals, landmarks, or objects. The amygdalae are two almond-shaped clusters of neurons—cells that are core components of the nervous system—located deep in the medial temporal lobe of the brain.  

"Our study shows that neurons in the human amygdala respond preferentially to pictures of animals, meaning that we saw the most amount of activity in cells when the patients looked at cats or snakes versus buildings or people," says Florian Mormann, lead author on the paper and a former postdoctoral scholar in the Division of Biology at Caltech. "This preference extends to cute as well as ugly or dangerous animals and appears to be independent of the emotional contents of the pictures. Remarkably, we find this response behavior only in the right and not in the left amygdala."

Mormann says this striking hemispheric asymmetry helps strengthen previous findings supporting the idea that, early on in vertebrate evolution, the right hemisphere became specialized in dealing with unexpected and biologically relevant stimuli, or with changes in the environment. "In terms of brain evolution, the amygdala is a very old structure, and throughout our biological history, animals—which could represent either predators or prey—were a highly relevant class of stimuli," he says. 

"This is a pretty novel finding, since most amygdala research in the past was usually about faces of people and emotions related to fear rather than pictures of animals," adds Ralph Adolphs, a coauthor on the paper and Bren Professor of Psychology and Neuroscience and professor of biology at Caltech. "Nobody would have guessed that cells in the amygdala respond more to animals than they do to human faces, and in particular that they respond to all kinds of animals, not just dangerous ones. I think this will stimulate more research and has the potential to help us better understand phobias of animals."

The study is also a clear illustration of how scientists doing basic research can benefit from working with collaborators in a clinical setting and vice versa.

"This is a good example of how special situations in neurosurgery—in this case, patients who are treated in order to cure their epilepsy—can provide a unique window into the workings of the human mind," says Itzhak Fried, a UCLA neurosurgeon and a coauthor of the study.

"A category-specific response to animals in the right human amygdala" was featured online on August 28 as an advance online publication of Nature Neuroscience. The Caltech team was led by Christof Koch, Troendle Professor of Cognitive and Behavioral Biology, and included Julien Dubois, Simon Kornblith, Milica Milosavljevic, Moran Cerf, Naotsugu Tsuchiya, and Alexander Kraskov. Rodrigo Quian Quiroga and Matias Ison from the University of Leicester also contributed to the study.

The research was supported by the European Commission, the National Research Foundation of Korea, the National Institute of Neurological Disorders and Stroke, the G. Harold and Leila Y. Mathers Foundation, the Gimbel Discovery Fund, and the Dana Foundation.  

Katie Neith
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Pondering Decisions

The sky is gray, but you're not sure if the clouds will clear or rain will pour. Do you grab an umbrella when you go outside?

Decisions like this are filled with ambiguity, and we're faced with them every day, whether picking stocks or choosing the sweetest watermelon at the store. "Almost every decision has some ambiguity," says Kota Saito, an economist who develops empirical and mathematical models on how people make decisions—gaining insight into human behavior that can inform socioeconomic policy. This fall, he joins Caltech as an assistant professor and the newest faculty member of the Division of the Humanities and Social Sciences. 

In mid-August, just a few days after he arrived in Pasadena, Saito's office in Baxter was still relatively empty, with a bare bookcase and blank walls. His whiteboard, however, was already crowded with letters, symbols, and equations that describe how people make choices. Saito's research focuses on two types of decision making: decisions that are inherently ambiguous (do you grab the umbrella?) and those that deal with inequality and fairness—for example, how you would distribute certain goods. "Suppose I only have one chocolate bar," he says. "How should I share it with you?"

Although his research is theoretical and mathematical in nature, he explains, a crucial part of his work is the use of experimental evidence to establish a set of principles about human behavior. Classical economics assumes that a given person, being "rational," will want all the goods for himself. Therefore, in the chocolate-bar scenario, he would keep the entire bar and not share. But data shows that decision making is more subtle and complex, and that people actually take into account how their decisions affect others. 

Saito takes this type of observed data and whittles it down to several simple principles. For example, one of those principles might say that a person prefers an outcome where no one receives anything rather than an outcome in which one lucky person gets everything. Then he mathematically proves that a person's choice satisfies those principles if and only if that choice is governed by a certain equation called a utility function. The utility function describes how people weigh the costs and benefits of a decision.

The ideas from his research can be used to inform policy in which inequality and fairness matter, such as the tax code—an especially hot political topic these days. But since his equations are based on controlled, idealized scenarios, Saito cautions against applying them directly to the real world. Nevertheless, he says, gleaning new insights into how people evaluate choices and how they consider the effects of those choices on others is important when forming socioeconomic policies.

Saito has been interested in psychology, political science, and sociology since he was a teenager. But he found himself drawn to the mathematical approaches in decision theory, which led him to study economics; he earned an MS from the University of Tokyo in 2007 and a PhD from Northwestern last spring. Now at Caltech, Saito hopes to show students that the experimental and mathematical methods normally used for the natural sciences can also be applied to the social sciences.

"I'm happy to be here," he says. "Caltech is the best place for microeconomic theory and experimental economics, and I'm excited to work with my new colleagues." And Southern California's weather is always a plus: "It's a really wonderful place—especially because I'm from Chicago," he says. "Here it's always sunny."

Which means he can probably leave his umbrella at home.

Marcus Woo


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