Better decision-making for the planet

By Yasemin Saplakoglu

We might think we have control of the mix of decisions we make during the day. But it turns out that our brain gives us subconscious nudges, preferring some choices over others.

Elke Weber, the Gerhard R. Andlinger Professor in Energy and the Environment, studies how the science of human behavior can inform policies that encourage people to make good choices for the environment.

Elke Weber

Elke Weber studies the science of human behavior with the goal of encouraging environ-mentally responsible behavior.

“For far too long, we’ve assumed that people’s decisions are rational,” said Weber, who is also a professor of psychology and public affairs in the Woodrow Wilson School of Public and International Affairs. “My research asks, in what ways can we understand what goes on in the brain and use that knowledge to help us all make better decisions?”

Weber researches how to design solutions to society’s greatest problems, such as climate change. “It turns out we can do some psychological jiujitsu to convert seemingly negative choices into something positive,” Weber said. In the psychology field this is called “choice architecture.”

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For example, merely renaming a choice to avoid negative associations can make an impact on people’s decisions. Weber and colleagues found that airline passengers were far more willing to pay a surcharge to combat climate change if the fee was called a “carbon offset” instead of a “carbon tax.”

Another aspect of choice architecture comes into play when talking about present versus future activities. Climate change seems far off to many people. But people tend to make choices based on the present or the immediate future, which psychologists call presence bias. “We focus on the here and now, which makes evolutionary sense,” Weber said. “If you might not survive until tomorrow, what’s the point of planning for next year?”

One way to combat presence bias is by tapping into people’s desires to be remembered in a positive light, Weber and colleagues at Columbia University and the University of Massachusetts-Amherst found. If first prompted with questions about how they would like to be remembered, individuals are more likely to think about their future rather than their present selves, and therefore make pro-environmental choices. The research, funded in part by the National Science Foundation, was published in Psychological Science in 2015.

Then there’s our inability to concentrate on more than one option at a time when we are presented with a choice. Weber and her col-league Eric Johnson, a business and marketing professor at Columbia, coined the “query theory” to explain how people internally generate more arguments favoring the first option they consider, temporarily inhibiting arguments in favor of all other options.

When a “default” option is given, it becomes the option we think of first, which puts it at an advantage. Weber gives the example of a hypothetical electric utility company that offers customers the opportunity to switch to “green” energy. Typically, fossil fuel energy is the default option, and few customers end up switching to the cleaner though somewhat more expensive green power. In contrast, when in lab and field studies the company made it the default option to choose “green” energy, a large majority of customers did just that. “In terms of what influences people’s decisions, the million-dollar question is which option gets considered first,” Weber said.

Weber’s research demonstrates that changing the way choices are presented can play a role in conserving the environment through influencing people, the instigators of our warming planet.


How cancer stem cells evade the immune system

By Yasemin Saplakoglu

When Daniel D. Liu first encountered the world of research, he saw giants in white lab coats shaking flasks and squirting liquids into small vials. He was 4 years old, and his parents, both biochemists, would bring him to work and set him down with a book and instructions to keep quiet.

“I didn’t really understand what was happening, but I guess that was my first impression of what adults do,” said Liu, Class of 2018, who is majoring in molecular biology. It was no wonder that he went into the family business at a young age. During summer breaks in high school, he worked at the National Institutes of Health near his home in Potomac, Maryland.

At Princeton, Liu joined the laboratory of Yibin Kang, the Warner-Lambert/Parke-Davis Professor of Molecular Biology, where he focuses on breast cancer stem cells, which are a subset of cancer cells that can self-renew and cause tumors to spread or grow back after treatment.

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Daniel Liu

Undergraduate Daniel D. Liu co-authored a Nature Cell Biology study on the discovery of an RNA molecule that protects stem cells.

In a study published earlier this year in Nature Cell Biology, Liu helped identify a molecule that protects cancer stem cells by shielding them from the immune system. When the immune system cannot attack the cancer cells, the cells can spread to surrounding tissues, a process known as metastasis and a leading cause of cancer-related deaths.

The team found that when cells produce a lot of this molecule — actually a short strand of genetic information called microRNA-199a — both healthy and cancerous cells take on stem cell-like properties such as a heightened ability to regenerate breast tissue and to create spherical clumps of cells called mammospheres.

This stem cell-like property is necessary for normal breast tissue functioning, but it is also fuel for cancer cells to survive and duplicate, helping them to escape from the suppressive effects of immune cells.

The findings may shed light on the puzzle of why immunotherapy, a cancer treatment that spurs the immune system to attack tumors, is highly successful against some types of cancer patients but does not work well for others.

“Everyone is really banking on immunotherapy as a breakthrough in cancer treatment, but it only works really well for some types of cancers,” Kang said. “In breast cancer the response isn’t great, and we don’t really understand why.”

As a result of this study, made possible through funding from the National Institutes of Health and the U.S. Department of Defense, Kang now thinks the lack of response to immuno-therapy by some patients could, in part, be due to the microRNA’s role in protecting the cancer stem cells.

Since the team now understands what guards the cancer cells, Liu said, “perhaps we can target this pathway so as to sensitize cancer stem cells to immunotherapy.”

Liu’s contributions to the lab go beyond bench experiments. Recently, he coded a user-friendly program that enables the team to sift through large patient data sets quickly, improving upon the lab’s previous, manual approach. He also co-founded the Princeton Undergraduate Research Journal (see page 2) to help fellow students publish their work and learn firsthand about the peer-review process.

“Daniel not only does his own work but also makes life much easier for everyone in the lab,” Kang said. “It’s quite unusual for an undergraduate to make fundamental contributions to the lab that enable everyone to do research in a better way.”

Historian and neuroscientist team up for podcast

By Yasemin Saplakoglu

When history professor Julian Zelizer and neuroscientist Sam Wang started the podcast Politics and Polls prior to last year’s presidential election, they never dreamed it would still be going a year later. “We thought there wouldn’t be much to talk about after Hillary won,” Zelizer said.

Instead, the pair found themselves with plenty of new ground to cover. And Wang, who’d boasted on Twitter that he would eat a bug if Donald Trump won, found himself swallowing a cricket on national television.

Fast-forward to the present, and Zelizer and Wang continue to record weekly interviews with guests ranging from renowned journalists and politicians to playwrights. The podcast has become an influential source of commentary and analysis for policy-makers, journalists and the public. In the past year it has been downloaded 170,000 times on iTunes and it is ranked in the top 20 for political podcasts.

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The discussion resembles a dinner table conversation among friends trying to make sense of the political world around them. The hosts contemplate unfolding events such as the Trump-Russia story, or discuss the impact of gerrymandering on elections. Or they may talk about immigration with an expert in that field, or debate Brexit’s parallels to U.S. events.

Zelizer, who is also a commentator on CNN, said his background as a historian provides perspective on Trump’s victory.

Julian Zelizer and Sam Wang

Professors Julian Zelizer (left) and Sam Wang record the weekly podcast Politics and Polls at the University’s broadcast studio. PHOTO BY EGAN JIMENEZ

“I don’t tend to see partisanship as a product of 2017 as much as a product of 30 years of change in American politics, whose players I have been following closely,” said Zelizer, the Malcolm Stevenson Forbes, Class of 1941 Professor of History and Public Affairs in the Woodrow Wilson School for Public and International Affairs. “At the same time, I’m sensitive to the way in which certain individuals can make a huge difference in key moments, in ways that historical data may not be able to predict.”

The use of data to predict election outcomes is one of the areas of expertise that Wang, a professor of molecular biology and the Princeton Neuroscience Institute, brings to the podcast. In 2004, he started the Princeton Election Consortium, a blog that analyzes and predicts the outcomes of U.S. elections using polling data. While he stands behind statistical methods, he admits that the outcomes of the 2016 presidential election taught some new lessons.

“In news coverage and polling, there is this naive view that the way to find out what people think is to ask them,” he said. But many people don’t feel comfortable revealing information, he said, and it is useful to augment polling with information from people’s online searches, social media posts and other behaviors.

The podcast is produced by the Woodrow Wilson School. Additional research for each week’s episode is conducted by undergraduate Sophie Helmers, Class of 2019, who provides back-ground information on speakers and possible questions to ask.

As to the future direction of the podcast, Wang and Zelizer haven’t a clue — and they want to keep it that way. “I think it’s a virtue that there is no grand strategy for where this goes,” Zelizer said. “The election was so dramatic that it gave us an endless number of topics to talk about, and who knows what is going to happen next.”

Listen to the Politics and Polls podcast at or download via iTunes, Soundcloud or other podcast services

Egyptian translation highlights the beauty of hieroglyphs

By Catherine Zandonella

Since he was in fourth grade, Tom Hare has been fascinated with Egypt. Although his career as a professor of comparative literature has focused mainly on Japanese works, he never forgot his love for the images and symbols of ancient Egyptian culture.

Now, Hare has written and illustrated a new book that brings the picture-based writing of ancient Egypt to audiences in an experimental way, as a “graphic translation” of a 4,000-year-old Egyptian fable. In the slim volume called Sinuhe: Flight and Homecoming, Hare weaves hieroglyphs and prose to create a narrative that retains the rich and colorful beauty of the symbols. “It bothered me that translations of Egyptian works took these beautiful hieroglyphs and converted them into text,” said Hare, the William Sauter LaPorte ’28 Professor in Regional Studies. “The result is that you’ve lost the visual character of the original language.”

The book tells the story of Sinuhe, a nobleman who flees Egypt during a period of unrest that follows a pharaoh’s death. He finds a new and prosperous life in a land to the east, and returns home in his later years, uncertain of his reception from the new king.

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The story was written during the age of the Middle Kingdom, which spanned from 2030 B.C.E. to 1700 B.C.E. It was preserved across the ages on two papyrus scrolls and on pieces of broken pots, and today is a well-known fable in the region.

One of the challenges of creating the graphic translation was choosing which hieroglyphs to include, Hare said. Many hieroglyphs have a literal translation. For example, the cow represents livestock, so when the story says that Sinuhe amassed a fortune in livestock, Hare included several columns of cows. Other hieroglyphs are less literal but still evocative, like the dead goose that represents fear. Some hieroglyphs represent sounds, like the horned viper that represents the sound “f” but can also mean “he,” “his” or “him.”

Still other symbols were part of a Middle Egyptian form of cursive called hieratic. The latter half of the book contains notes on the translation, including discussions of where experts have disagreed on the exact meaning of a passage.

While preparing the book, Hare found that the visual nature of the volume demanded a great deal of experimentation on where to put the hieroglyphs and text, leading him to self-publish a limited number of copies. He is now editing it and eventually plans to seek a publisher.

Hare hopes the story of Sinuhe presented in this graphic format will help people channel their inner 10-year-old and learn to read hieroglyphs. “The visual elements make it possible for people today to get insight into what Egyptian culture was like,” he said. “This is important given the foundational role of Egyptian culture in Western civilization.”

Discovery provides a path to safe, clean, plentiful energy

By John Greenwald

Fusion — the energy-producing reaction that powers our sun and most stars — can be a safe, clean and virtually limitless source for generating electricity on Earth, ending reliance on fossil fuels and curbing greenhouse-gas emissions. In the sun, gravity traps particles inside an ultra-hot charged cloud of gas known as plasma, forcing them to fuse and release their energy. On Earth, we use powerful magnets to force plasma particles to fuse and release their power at temperatures many times hotter than the center of the sun.

At the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), which is managed by Princeton University, scientists have been making great strides in determining how to trap those particles in doughnut-shaped facilities called “tokamaks” — fusion devices that confine the plasma in magnetic fields in place of gravity.

Now, PPPL scientists have for the first time reproduced the key elements that double the tokamak’s ability to prevent heat and energy loss that could slow or halt fusion reactions. Finding the factors that enable a doubling of the confinement of particles inside a plasma marks a major advance on the path to fusion energy and to creating an artificial sun on Earth to help power the world.

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“This discovery provides understanding of a path to improved plasma performance,” said Michael Zarnstorff, deputy director for research at PPPL. “It will enable physicists to predict with confidence the heating power required to keep plasma well-confined and to provide energy for the world.”

This doubling of confinement, which has been poorly understood, is vital to current and future fusion devices, sometimes called “star jars,” on the planet. The new understanding stems from a computer simulation that shows how a barrier can form to prevent the escape of heat and energy in plasmas.

ITER fusion facility

The construction of a major new experimental fusion facility called ITER in Cada-rache, France, will enable researchers to test the feasibility of fusion power. A Princeton Plasma Physics Laboratory discovery could help the giant reactor achieve success.

PPPL scientists used a sophisticated computer code to show how the formation of the barrier occurs and reduces the turbulence at the edge of the plasma that produces such losses. The simulation took three days and 90 percent of the capacity of Titan, the fastest U.S. supercomputer, which can perform 27,000 trillion calculations per second.

“After 35 years, the fundamental physics has been simulated, thanks to the rapid development of the computational hardware, software and detailed physics understanding,” said Choong-Seock Chang, managing principal research physicist at PPPL and leader of the nationwide team that developed the sophisticated code and produced the model.

Full understanding of the spontaneous transition to this mode, called high confinement, or H-mode, is essential for the demonstration of the feasibility of fusion power planned for a new international fusion facility known as ITER under construction in France. Operators of the seven-story, 23,000-ton machine must achieve H-mode to reach the goal of producing 10 times more energy than ITER will consume.

Understanding the transition will allow operators to predict the heating power needed to reach H-mode. The goal: to have predictions that are more accurate than projections based on today’s tokamaks, since conditions inside ITER, the largest and most powerful fusion facility so far conceived, will be significantly different.

Coming enhancements of the code will be part of the Exascale Computing Project, a nationwide program to develop computers that will run up to 50 times faster than Titan, improving U.S. security, economic competitiveness and scientific capability. PPPL leads an initiative that will develop the first complete model of an entire fusion plasma that could fuel a promising new era of energy production.

Professor reflects on growing up undocumented and the power of books

By Jamie Saxon

When Dan-el Padilla Peralta was 4, he and his parents left the Dominican Republic and traveled to the United States for better medical care for his mother. Although his father returned to Santo Domingo, Padilla Peralta and his mother overstayed their temporary visas, subsisting partly on the public assistance funds received by Padilla Peralta’s younger brother, who was born in the United States. The family spent a year in the New York City shelter system.

Photos taken at age 9 and recently

Dan-el Padilla Peralta, age 9, reads a book in spring 1994 in the Bushwick Family Center, one of the shelters he lived in with his mother and brother. Right: Padilla Peralta on campus in the fall of 2016.

With support from a scholarship, Padilla Peralta attended a private high school, and he graduated from Princeton in 2006 as salutatorian with a degree in classics and a certificate in the Woodrow Wilson School of Public and International Affairs. After earning a master’s degree in classics at the University of Oxford and a Ph.D. at Stanford University, Padilla Peralta was a postdoctoral fellow at Columbia University. His memoir, Undocumented: A Dominican Boy’s Odyssey from a Homeless Shelter to the Ivy League, was published in 2015.

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Padilla Peralta, undocumented no longer, joined Princeton as an assistant professor of classics in 2016. In this excerpt from the University’s “What I Think” faculty interview series, he reflects on his childhood inspirations and his current area of inquiry.

Growing up, I drew sustenance from books. Books provided me with the raw material I needed to construct a vision of what not only my future but my family’s future, my community’s futures, should look like.

One of the most salient memories I have of the first shelter we stayed in was the smell of the bathroom; it was rank and overpowering. It was very loud in the hallways. In the shelter’s library, I discovered the book How People Lived in Ancient Greece and Rome.

I started reading The Odyssey in middle school, and it spoke to me. Initially, Telemachus’ constant negotiation of the challenges of adolescence and young adulthood and his acute feeling of loss from not having a father figure resonated with my own experiences.

I’m fascinated by the influence of ancient Greek on rap music. Jay-Z raps in one song on the album “Watch the Throne” he made with Kanye West, “Is pious pious ’cause God loves pious?” This is a pretty unmistakable reference to Plato’s Euthyphro, in which one of the questions raised by Socrates and Euthyphro is, “Is the pious known as the pious because the divinity has defined it as pious?”

I’m challenging my students to do some serious thinking about the long history of exclusion. For example, Romans understood their own cultural history as being pluralistic, yet they repeatedly defined themselves by excluding certain others. You have a culture that is, on the one hand, preoccupied with targeting and expelling certain communities and yet at the same time is aware of the degree to which its own origins are implicated in cultural difference, in migration, in mobility — this is the scope of the paradox that I want my students to appreciate.
–By Dan-el Padilla Peralta