The riddle of zebras’ stripes


Why zebras have black and white stripes is a question that has intrigued scientists and spectators for centuries. A research team led by UC Davis, has now examined this riddle (in a very systematic way).

Many hypotheses for zebra stripes have been proposed since Alfred Russel Wallace and Charles Darwin debated the problem 120 years ago. These include:

  • A form of camouflage
  • Disrupting predatory attack by visually confusing carnivores
  • A mechanism of heat management
  • Having a social function
  • Avoiding ectoparasite attack, such as from biting flies

After analyzing the five hypotheses, the scientists ruled out all but one: avoiding blood-sucking flies. The scientists found that biting flies (such as horseflies and tsetse flies) are the evolutionary driver for zebra stripes.

Why would zebras evolve to have stripes whereas other hooved mammals did not? The study found that, unlike other African hooved mammals living in the same areas as zebras, zebra hair is shorter than the mouthpart length of biting flies, so zebras may be particularly susceptible to annoyance by biting flies.

Yet in science, one solved riddle begets another: Why do biting flies avoid striped surfaces?

Read more →

Building robots to land on Saturn’s moons

Building robots to land on Saturn’s moons

Landing an unmanned robot on another planet can be quite a feat and can end up being quite a complex process.  Scientists want to make this process easier but also allow us to explore worlds that are currently too difficult to land on.

UC Berkeley professor Alice Agogino is working with doctoral students to build what are known as tensegrity robots.  Essentially, these are robots built with a series of rods and tension wires that protect the delicate scientific instruments in the middle.

The structure allows for both flexibility and strength while navigating a rugged environment — for example, landing on a planet’s rocky surface. These robots can explore places that are currently inaccessible to wheeled rovers such as rocky cliffs, which are rich in geological data due to the exposed rock.

Currently, NASA researchers are working on a prototype to one day land on places such as Titan – one of Saturn’s moons.  Scientists are interested in this moon because it has a thick atmosphere with flowing liquids on the surface and is often referred to being the most earthlike world in our solar system.

Read more about this technology 

She loves you, she loves you not

Whether in fiction or history, women have often gotten a bad rap for being fickle. But it may just be evolution. A landmark meta-analysis suggests that ovulating women have evolved to prefer mates who display ‘sexy traits’ (think muscular build, dominant behavior, symmetrical facial features). UCLA psychologist Martie Haselton, who is one of a handful of pioneers in research on behavioral changes at ovulation, explains that sexy traits are not typically desired in long-term mates.

“Women who were partnered with men, who at one point in the study they rated them as very satisfying long-term partners, but not the sexiest guys around –  those women experienced increases in attraction to men other than their partner on fertile days of the cycle. So, it’s as if women on fertile days place a premium on male partners’ sexiness and if their male partner isn’t sexy, then women start to notice other men.”

While these findings may seem depressing, Haselton argues that just understanding this can help couples improve their relationships when in conflict.

“Once you understand how your mind works, what the mechanisms are that might otherwise be passing under the radar of conscious awareness, you can ‘mind hack’ and do things to achieve whatever your goals are – so, to maintain a happy relationship with your partner, or maybe it’s to have a wild sex life, but whatever it is, if women understand that there are these patterned changes across the cycle, then they can probably make better sexual decisions.”

The mere notion that a woman’s mate preferences could shift at high fertility has been a source of debate since the late 1990s, when the first studies that hinted at such a change began to appear. Since then, several papers failed to replicate the early studies’ results, casting doubt on the hypothesis.

“Until the past decade, we all accepted this notion that human female sexuality was radically different from sexuality in all of these other animal species – that, unlike other species, human female sexuality was somehow walled off from reproductive hormones. Then a set of studies challenged conventional wisdom.”

One hypothesis for why this mate preference shift occurs is that it may be an evolutionary adaptation that served our ancestors’ reproductive interests long before modern medicine, nutrition and sanitation greatly reduced infant and child mortality rates.

A Powerful Eye into Deep Space

The Thirty Meter Telescope (TMT) —which has been spearheaded by UC and the California Institute of Technology since 2003— will be built and run by a consortium of universities and scientific organizations from around the world.

Special adaptive optics will correct for the blurring of Earth’s atmosphere, enabling the TMT to study the universe as clearly as if the telescope were in space (In fact, it has 12 times the resolution of the Hubble Space Telescope).

Once finished, the new telescope will allow astronomers to see faint objects clearer than ever before:

It will be able to focus on and identify extremely distant structures that currently appear as blurry smudges in the Hubble Deep Field. As yet, no one knows what these objects are.

This new resolution will provide insights into the both dark matter and dark energy. And it will widen the search for planets orbiting stars outside our solar system. For the first time, we will be able to routinely image direct light from these exoplanets, garnering information on their atmospheric chemistry and dynamics.

The new TMT will also be able to see further back in time than any previous telescope, all the way back to the formation of the first stars and galaxies that followed the universe’s “Dark Ages.”

Read more about the project at →

Trilobites can tell us how animals evolved

The trilobitewhich became extinct millions of years ago, is commonly known as one of the first complex forms of life on earth.  Their fossils can be found in many parts of the world and are often collected for their interesting shapes and varieties. (There’s even a vacuum cleaner designed after this creature…)

In fact there are actually 20,000 known varieties of this arthropod. They even ranged in sizes from ones that could fit inside your pocket to being as large as your sofa (!!!?!).

UC Riverside’s Dr. Nigel Hughes explains:

“They can have scoops or shovels, be fantastically spiny or beautifully streamlined and diverged to really explore their evolutionary space, but they still maintain that common body plan.”

Scientists study trilobite fossils to understand how today’s animals have evolved to the present.  This can be everything from how mating habits developed to how a species can protect itself from predators.

Dr. Hughes not only studies the trilobite, but even sings about them.


This is a declarative sentence?

“Men don’t think they do it, but they do,” explains Amanda Ritchart, a linguistics grad student at UCSD.

‘It’ is uptalk, the oft-mocked conversational style that uses a rising pitch at the end of utterances. Here’s a classic example:

A coffee shop barista asks a person for his or her name. The person says their name almost as if it were a question (Mike?, Isabelle?), even though we know that this person is not actually questioning his or her name.

Although it’s associated with the caricature of valley girls (as seen in the 1995 movie Clueless)some linguists date it to the 1950s, while others argue it is centuries old.

To investigate the phenomena of uptalk, Ritchart and Amalia Arvanti gathered 23 undergraduates (who were native speakers of SoCal English*) and gave them two tasks:

  • Use a map to give directions to a listener.
  • Describe a sitcom clip they had just watched. (Scrubs and How I Met Your Mother were the chose sitcoms, in case you were wondering…)

“For young speakers in Southern California, no matter the gender, the ethnicity, the socioeconomic background, everyone uses uptalk,” Ritchart says.  The researchers found that uptalk could also serve a strategic purposes such as confirmation (“are you following me on this?”):

When giving directions, a non-uptalker would use a declarative sentence, without a rising inflection. But uptalkers did use rises, as if they were implicitly asking the listener to confirm that they were being understood: “Go all the way to the right in the middle where it says Canyon Hills?” Both the men and women in the study used uptalk 100 percent of the time in these so-called “confirming” statements.

In such instances, uptalk suggests confidence or paternalism (maybe even coercion).  Another technique the researchers identified was ‘floor-holding’ — where a speaker, anticipating being interrupted by the listener, tries to fight it off by using a rising tone at the end of the statement:

In the study, women spoke with the floor-holding rise nearly 60 percent of the time: “O.K., so go toward Warren” (pronounced as a high-rising “Waa—REN?”). Men used it only 28 percent of the time, tending instead to maintain steady voices, in a plateau. Amalia Arvaniti, a co-author of the study who is now head of the English language and linguistics department at the University of Kent in England, said, “It could indicate that young women were generally interrupted more than men and so it’s a defense mechanism.”

It’s easy to dismiss uptalk as the language of airheads, but in fact, it appears that it can be quite useful.

Arvanti added that the research doesn’t imply that Uptalk doesn’t happen outside of Southern California or that young men have only recently picked up uptalk:  ”The primary motivation was to document the form and function of uptalk in SoCal because there was so little systematic research on this particular variety compared to, say, Australian and New Zealand English uptalk and even UK varieties that uptalk.”

*11 male and 12 female. 15 monolingual and 8 bilingual. 12 self-identified as Asian, six as Hispanic, 5 as White.  Using the MacArthur Scale, the speakers were grouped into socioeconomic status classes: Lower (4), Middle (13), and Upper (6).


Happiness hyped, ethnic competition and power poses

Aiming for happiness can stress you out. White and Asian students feel at a disadvantage in college admissions. And striking powerful poses before a job interview (hands on hips, feet spread, chin up) can make you come across as more hirable.

UC Berkeley psychologist Iris Mauss has found that the pursuit of happiness can backfire
UC Berkeley psychologist Iris Mauss has found that the pursuit of happiness can backfire

These are among the UC Berkeley findings that psychologists will share at this week’s annual meeting of the Society for Personality and Social Psychology in Austin, Texas. More than 3,500 scientists and scholars have registered for the Feb. 12-15 conference that is popular with UC Berkeley psychology faculty, researchers and students.

A key theme at this year’s conference is the growing relationship between psychology, big data and social media. Speakers on that topic will include Facebook social psychologist Adam Kramer, Microsoft computer scientist Eric Horvitz and Google and Harvard University data researcher Jean Baptiste.

“Some of the most exciting and important discoveries about social and personality psychology are now the domain of computer science, engineering, and communication,” says the promo for the event’s Presidential Symposium. “Rather than marvel on the sidelines, it’s time to jump into the fray and work with colleagues in computer sciences, engineering, and other disciplines.”

The downside of the pursuit of happiness

On the more fundamental topic of how we manage emotions, UC Berkeley psychologist Iris Mauss and fellow researcher Maya Tamir of Hebrew University will present their newest findings on the paradoxical question of why aiming for happiness can be detrimental to one’s sense of well-being.

In two previous studies published in the journal, Emotion, the researchers found that people who placed a higher premium on happiness reported higher rates of stress, discontent and even depression than those who did not set a happiness goal. The results suggest that the proverbial pursuit of happiness can actually heighten awareness of how one is falling short of that goal. Their newest research expands on this irony.

“People who strive for greater happiness will evaluate their own emotions more negatively, even if they are relatively happy,” Mauss said. “Conversely, people who accept their own emotions for what they are will evaluate them less negatively, even if they are relatively unhappy. ”

Ethnic competition in admissions

As for the pursuit of diversity, Victoria Plaut, a social psychologist at UC Berkeley’s School of Law, will present findings on how bringing up diversity on university admission applications can intensify a sense of ethnic competition.

In an experiment, Plaut and fellow researchers Michelle Rheinschmidt of UC Berkeley and Kimberly Rios of Ohio University directed more than 430 white, Asian and Latino undergraduates to fill out mock graduate school applications. While some wrote about student diversity, others wrote about personal creative influences. The students then rated the applications according to how much they felt they favored or handicapped their own particular ethnic group.

The results suggest that when whites were more attuned to diversity (by writing an essay about it), they perceived themselves to be at a greater disadvantage in the admissions process than both Asian and Latino applicants. Asian students sensed that Latino students had an edge over them in admissions while Latino students thought the application was equally fair to all applicants. Surprisingly, white students were more likely to support diversity initiatives after writing about the issue.

“The finding that students are reading advantage or disadvantage to their racial group into these applications, based simply on a diversity essay prompt, reflects our larger societal sensitivity about these issues,” Plaut said.

Power poses can help land a job

Another intriguing area of research to be presented at the conference is how striking “power poses” can enhance one’s performance in a job interview, among other stressful situations.

In one study — conducted by UC Berkeley assistant business professor Dana Carney, Harvard social psychologists Amy Cuddy and Carolyn Wilmuth Maarten and MIT’s Andy J. Yap — subjects prepared for a mock job interview, with half adopting  expansive poses (hands on hips, feet apart, chin up), and the other half keeping their gestures constrained.

Next, they were videotaped as they delivered  speeches, and their presentations were rated for overall performance and hireability. As predicted, those who prepared for the job interview by adopting expansive poses performed better and were more likely to be chosen for the job.

Into the Wildfire

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Researchers at Los Alamos National Laboratories and elsewhere are investigating other aspects of fire propagation, like how big fires create their own weather — a process that has contributed to some of the most devastating fires in recent years.

The setup in the photo above is known as a “fire-whirl generator” and is used to better understand the physics of a flame.

Read more about fire science here

A whole new meaning to “Deadhead”

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Above is a representation of former Grateful Dead drummer Mickey Hart’s brain.  It will be used on his upcoming tour as both a visual and as a way for his mind to power the stage’s lighting.  Hart explains:

“I was just looking at it and watching it fire, and you see the colors moving and the different rhythm patterns and realizing, that’s me!”

We specify “representation” because the visuals are part of a collaboration between Hart and UCSF researcher Adam Gazzaley.  Gazzaley is quick to say that the images are stylized for the sake of special effects, but the method in which to read Hart’s brain in real time has much larger scientific and medical implications.

Read more here