Ditch Day? It’s Today, Frosh!

Today we celebrate Ditch Day, one of Caltech's oldest traditions. During this annual spring rite—the timing of which is kept secret until the last minute—seniors ditch their classes and vanish from campus. Before they go, however, they leave behind complex, carefully planned out puzzles and challenges—known as "stacks"—designed to occupy the underclassmen and prevent them from wreaking havoc on the seniors' unoccupied rooms.

Follow the action on Caltech's Facebook, Twitter, and Instagram pages as the undergraduates tackle the puzzles left for them to solve around campus. Join the conversation by sharing your favorite Ditch Day memories and using #CaltechDitchDay in your tweets and postings.

          

 

Home Page Title: 
Ditch Day? It’s Today, Frosh!
Writer: 
Exclude from News Hub: 
No
News Type: 
In Our Community
Exclude from Home Page: 
Wednesday, May 11, 2016
Noyes 147 (J. Holmes Sturdivant Lecture Hall) – Arthur Amos Noyes Laboratory of Chemical Physics

Administrative Contact Information Session

Why We Do What We Do: A Conversation with Omer Tamuz

Omer Tamuz, a newly arrived assistant professor of economics and mathematics, studies how people make decisions based on what they know and what they don't know, and how they exchange this information with one another. We sat down with him to talk about mathematical models of behavior, and life as a new member of the Caltech faculty.

Tell us about your research.

I study how people exchange information and learn from each other, in a theoretical sense. We make assumptions about how people behave and we try to model this behavior with math. For example, we generally assume that people will behave rationally—which means, they will always make the optimal choice given the information they have. While this assumption is not always true in reality, it is the framework I work in. There is this huge, rich theory you can build, with unending depth and interesting turns and twists and beautiful math, and very non-trivial things going on that you can learn… and maybe sometimes this assumption is not so outrageous and can give us insights about the real world.

I study these things in a very abstract way. There's a thing that you either know or don't know—let's call that 0 or 1—and a thing that you can do or not do. Let's also call that 0 or 1. You want to match the thing you do to the thing you know.

What I want to know is: what information are people getting, and how does this match up the actions that they take? Creating a general theory for this behavior should be applicable to many different scenarios.

Can you give us an example of this in our daily lives?

Here's one example I like. It is due to Robert Aumann, a professor at the Hebrew University of Jerusalem who won the 2005 Nobel Memorial Prize in Economic Sciences. Imagine that you and I are discussing who's going to be the Democratic nominee for president. We both have watched some TV, read some surveys, and seen our friends' opinions on our Facebook feeds. Many people I know are supporting Bernie Sanders, and many people you know are supporting Hillary Clinton. So then I ask you: What do you think is the probability that Hillary gets the nomination? And you say, 0.9, or 90 percent. And I think—wow, but my feed is entirely Bernie, and if you had asked me first, I would have said 30 percent. But now that you've said 90, well… maybe you have some information that I don't know. So I'll revise my probability guess to be 80 percent. And then you follow that same thought process and you revise your opinion. And so forth.

The economic theory says that, in the end, we must agree. If we are two rational people who are making the correct calculations and inferences, there is no scenario where we agree to disagree. It's a very short proof. And it's one of the reasons why Aumann won the Nobel Prize.

You also have a joint appointment in mathematics. Tell us about your research in that field.

My math research is pretty unrelated to my economics work. I study groups—which are the set of symmetries of a certain object. So if I have a cube, I can rotate it many different ways and still get an object that looks exactly the same. All of these rotations—or operations—that I can do to the cube, together they form a group. In general, if you have a symmetric object and you can do something to it that leaves it the same, then those symmetrical operations form a group.

It turns out that there are interesting connections between groups and dynamical systems. Dynamical systems are things that evolve and change over time—a machine and its moving gears, or an ecological system with a changing number of animals, or maybe a physical system of billiard balls that are bouncing around. You can ask a lot of abstract questions about how dynamical systems behave, and there are many connections to groups.

Tell us a little about yourself.

I was born in Israel, and raised part of the time in Israel, Germany, and Austria. I went to an international high school in Vienna, which was a great experience. I did my undergraduate education in Israel in physics and computer science. As an undergrad, my research was in astronomy, looking for exoplanets—planets outside of our solar system. After undergrad, I felt like I needed a break, so I went to work as a software developer for a few years. Then I went to grad school and got a master's and a PhD in math at the Weizmann Institute of Science—also in Israel. After that, I was a postdoc in the MIT math department and at the Microsoft Research lab in Cambridge, MA. And then I came here to Caltech.

What led you to make the transition from astronomy to economics?

My work in astronomy involved a lot of analyzing data, trying to find very faint signals in a lot of background noise. We were trying to come up with new statistical methods to get rid of that noise. I found that I really liked to do that, but I didn't care so much about studying the stars themselves. Later, as I was studying probability in graduate school, the things I was looking at overlapped a lot with economics. In mathematical terms, many economics problems are really questions in probability.

What do you like to do in your free time?

I have two kids so that's where a lot of my free time goes. I like running, and on the weekends we drive up to the mountains and go hiking.

What is it like to be in Southern California?

What I like about Caltech is that it has such a great spirit and culture. Everything is geared to help you do your research. It's exactly the kind of place you want to be in. But I'm still getting used to saying I live in LA… I'm still trying to develop the LA accent. 

Home Page Title: 
Why We Do What We Do
Listing Title: 
Why We Do What We Do: A Conversation with Omer Tamuz
Writer: 
Exclude from News Hub: 
No
Short Title: 
Why We Do What We Do
News Type: 
In Our Community
Exclude from Home Page: 
Home Page Summary: 
Omer Tamuz discusses economics, rational choices, and life as a new faculty member.

The Global History of Space Exploration

When talking about the history of space exploration, people are often quick to reference the Soviet and U.S. victories of the 1950s and 1960s, such as Sputnik and the Apollo program. However, these memorable advances are only a slice of a broader global history that includes significant contributions from dozens of nations, including many within the developing world. To science historian Asif Siddiqi—who specializes in the history of space exploration—these lesser-known stories of the global space race are just as interesting.

"For a long time, historians have said, 'Science is global!' but their claims were largely theoretical," Siddiqi says. "I'm interested in empirical examples of the global circulation of scientific knowledge and expertise, and one way I wanted to track this was through examples of leftover infrastructure from space exploration."

A professor of history at Fordham University, Siddiqi is this year's Eleanor Searle Visiting Professor of History at Caltech and The Huntington Library. The Searle visiting professorship is offered every year to a historian who wishes to conduct research in the Huntington's collections and teach courses in the Division of the Humanities and Social Sciences at Caltech.

"This professorship is a very wonderful opportunity for people in the middle of their careers to take a year off to start some new projects," he says.

Siddiqi has used this time, which continues until the end of the academic year, to focus his work on the history and impact of India's space program. "I'm interested in how developing nations allocated resources for very high-technology projects, despite their apparent social and economic problems. I wanted to look at India because it is a country with some obvious societal inequalities, but at the same time, they also prioritized this very modern technology. So I'm looking at the Indian space program through that lens," he says.

Siddiqi believes that one reason the Indian government initially became interested in space exploration was an urge to modernize after becoming independent from Great Britain in 1947. "Things like space exploration and nuclear energy were markers of the modern world, and they didn't want to have to spend 200 years trying to play catch up with the Western countries," he says. "That urge to 'leapfrog' over the West, often framed in terms of the modernization theory of the 1960s, gets manifested in a kind of fixation on certain things, and space was the most cutting-edge thing at the time."

The Indian government was also motivated by the introduction of technologies, developed by NASA, that the American government gave to other countries—such as India—in an effort to gain allies during the Cold War, Siddiqi says. The countries could keep these millions of dollars of scientific equipment and materials at no cost, allowing them to build an infrastructure for space exploration, with one unspoken but implicit caveat: they had to agree that, politically speaking, they would side with the U.S. against the Soviet Union.

Siddiqi also wanted to investigate how India's commitment to space exploration had an impact on those people not involved with science or politics. For instance, the Searle professorship allowed Siddiqi to travel to a small fishing village on the southern tip of India, to see how the space race impacted the local community.

"It turns out that this village's location intersects with a particular cosmic ray phenomenon that only happens around the magnetic equator," he says. The phenomenon, called the equatorial electrojet, results when solar winds cause an intensification of the Earth's magnetic field in a small patch directly above equatorial regions, including the Indian Ocean.

Because of this phenomenon, top scientists from around the world wanted to build an observatory in the village to study it. The Indian government got behind the plan, insisting that the international scientists leave behind all of their expensive equipment when they left, infrastructure which was later used for their space program. However, making room for the observatory also meant that the entire local fishing village would have to be packed up and relocated.

"One of my goals in this project was to recover the history of the Catholic fishing community that lived there for centuries, but had to be moved," Siddiqi says.

He was also interested in what it was like for the international community of scientists that was created on the former site of the fishing village. "It was 1963—the height of the Cold War—and there were scientists from the U.K., America, Russia, Germany, Japan, and all over the world working in this remote village," he notes, pointing out how unusual such a collaboration was during the Cold War.

The observatory only lasted a few decades, as expanding capabilities of satellites eventually made the ground-based technologies obsolete for these types of studies. But it had a lasting impact.

"The cosmic phenomenon above this Indian fishing village was a total accident of geography, and that's what was interesting about that story," Siddiqi says. "However, there are many more stories like that across the global landscape. Our narrative of the space race is mostly about astronauts and the moon, and maybe a little bit of deep-space exploration, such as Mars. But in my work, I hope to shed some light on some of these other types of contributions on the earth that are largely forgotten."

Siddiqi recently presented a summary of this work in a lecture at The Huntington Library titled, "A Different Space: NASA in the Postcolonial World."

Home Page Title: 
The Global History of Space Exploration
Writer: 
Exclude from News Hub: 
No
News Type: 
Research News
Exclude from Home Page: 

Gift to Spark Powerful New Projects

Caltech leaders announced today two new funds that will provide flexible resources to support top priorities and launch bold academic endeavors.

These endowments—The Ronald and Maxine Linde Center for New Initiatives and the Ronald and Maxine Linde Leadership Chair in the Division of the Humanities and Social Sciences (HSS)—were created with money allocated from one of the largest single gifts ever pledged to Caltech, made public last year: the $50 million commitment by Ronald (MS '62, PhD '64) and Maxine Linde.

Read the full story at giving.caltech.edu.

Home Page Title: 
Gift to Spark Powerful New Projects
Exclude from News Hub: 
No
News Type: 
In Our Community
Teaser Image: 
Exclude from Home Page: 
Monday, May 23, 2016
Brown Gymnasium – Scott Brown Gymnasium

Animal magnetism

Monday, February 29, 2016
Brown Gymnasium – Scott Brown Gymnasium

Animal magnetism

Monday, April 11, 2016
Dabney Hall, Lounge – Dabney Hall

Jazz Waltz Recital

Thursday, May 26, 2016
Avery House – Avery House

The Mentoring Effect: Conference on Mentoring Undergraduate Researchers

Is Risk-Taking Behavior Contagious?

Why do we sometimes decide to take risks and other times choose to play it safe? In a new study, Caltech researchers explored the neural mechanisms of one possible explanation: a contagion effect.

The work is described in the March 21 online early edition of the Proceedings of the National Academy of Sciences.

In the study led by John O'Doherty, professor of psychology and director of the Caltech Brain Imaging Center, 24 volunteers repeatedly participated in three types of trials: a "Self" trial, in which the participants were asked to choose between taking a guaranteed $10 or making a risky gamble with a potentially higher payoff; an "Observe" trial, in which the participants observed the risk-taking behavior of a peer (in the trial, this meant a computer algorithm trained to behave like a peer), allowing the participants to learn how often the peer takes a risk; and a "Predict" trial, in which the participants were asked to predict the risk-taking tendencies of an observed peer, earning a cash prize for a correct prediction. Notably in these trials the participants did not observe gamble outcomes, preventing them from further learning about gambles.

O'Doherty and his colleagues found that the participants were much more likely to make the gamble for more money in the "Self" trial when they had previously observed a risk-taking peer in the "Observe" trial. The researchers noticed that after the subjects observed the actions of a peer, their preferences for risk-taking or risk-averse behaviors began to reflect those of the observed peer—a so-called contagion effect. "By observing others behaving in a risk-seeking or risk-averse fashion, we become in turn more or less prone to risky behavior," says Shinsuke Suzuki, a postdoctoral scholar in neuroscience and first author of the study.

To look for indications of risk-taking behavior in specific brain regions of subjects participating in the trials, the Caltech team used functional magnetic resonance imaging (fMRI), which detects brain activity.

By combining computational modeling of the data from the "Self" behavioral trials with the fMRI data, the researchers determined that a region of the brain called the caudate nucleus responds to the degree of risk in the gamble; for example, a riskier gamble resulted in a higher level of observed activity in the caudate nucleus, while a less risky gamble resulted in a lower level of activity. Additionally, the more likely the participants were to make a gamble, the more sensitively activity in the caudate nucleus responded to risk. "This showed that, in addition to the behavioral shift, the neural processing of risk in the caudate is also altered. Also, both the behavioral and neural responses to taking risks can be changed through passively observing the behavior of others," Suzuki says.

The "Predict" behavioral trials were designed to test whether a participant could also learn and predict the risk-taking preferences of an observed peer. Indeed, the researchers found that the participants could successfully predict these preferences—with the learning process occurring even faster if the participant's risk-taking preferences mirrored those of the peer. Furthermore, the fMRI data collected during the "Observe" trial showed that a part of the brain called the dorsolateral prefrontal cortex (dlPFC) was active when participants were learning about others' attitudes toward risk.

The researchers also found differences among participants in functional connectivity between the caudate nucleus and the dlPFC that were related to the strength of the contagion effect—meaning that these two brain regions somehow work together to make a person more or less susceptible to the contagiousness of risk-taking behavior. The work provides an explanation of how our own risk-taking behaviors can be influenced simply by observing the behaviors of others. This study, Suzuki says, is the first to demonstrate that a neural response to risk is altered in response to changes in risk-taking behavior.

"Our findings provide insight into how observation of others' risky behavior affects our own attitude toward risk," Suzuki says—which might help explain the susceptibility of people to risky behavior when observing others behaving in a risky manner, such as in adolescent peer groups. In addition, the findings might offer insight into the formation and collapse of financial bubbles. "The tendency of financial markets to collectively veer from bull markets to bear markets and back again could arise, in part, due to the contagion of observing the risk-seeking or risk-averse investment behaviors of other market participants," he says.

"The findings reported in this paper are part of a broader research goal at Caltech, in which we are trying to understand how the brain can learn from other people and make decisions in a social context," O'Doherty says. "Ultimately, if we can understand how our brains function in social situations, this should also enable us to better understand how brain circuits can go awry, shedding light on social anxiety, autism, and other social disorders."

The paper is titled, "Behavioral contagion during learning about another agent's risk-preferences acts on the neural representation of decision-risk." In addition to Suzuki and O'Doherty, other Caltech coauthors include instructional assistant Emily Jensen and visiting associate in finance Peter Bossaerts. The work was funded by a Japan Society for the Promotion of Science Postdoctoral Fellowship for Research Abroad and the Caltech Conte Center for the Neurobiology of Social Decision Making, which is supported by the National Institute of Mental Health.

Home Page Title: 
Is Risk-Taking Behavior Contagious?
Writer: 
Exclude from News Hub: 
No
News Type: 
Research News
Exclude from Home Page: 
Home Page Summary: 
The neural processing of risk in our brain is changed when we observe the risk-taking behaviors of others, Caltech study says.

Pages