2007 Thesis Excerpts

Ada Brunstein Eye to I

Will Dowd A Bright Idea?: The Promise and Peril of a Memory Drug

Katharine Stoel Gammon Changing Her Tune: How a Transsexual Woman Claims a New Identity Through Voice

B. Christine Hoekenga Mind Over Machine: What Deep Blue Taught Us About Chess, Artificial Intelligence, and the Human Spirit

Erica Naone The Dancer in Nature

Elizabeth Quill Eavesdroppers: How Scientists Are Learning to Listen In On the Animal Kingdom

Jocelyn Rice The Butterfly Clock: Illuminating the Molecular Myseteries of Monarch Migration


Eye to I
Ada Brunstein

The racy magazine Cosmopolitan has long served as a how-to manual for young love-struck women. One article claiming to help women answer the question “is he looking for love or sex,” quotes an expert: “ Holding intense eye contact for more than five seconds doesn’t happen naturally, so he may be using the look as a seduction technique to get you into bed.” Another Cosmo article entitled “The Silent Ways He Says I Love You” makes the opposite claim. If “you catch him staring at your eyes,” it means he loves you. “ Guys are guarded when it comes to showing emotion,” the article claims. “If they lock eyes for a full-tilt, unabashed stare, they’re lowering their shield to let you in. ‘I’d never hold that sort of eye contact with anyone else, but an intense gaze with my girlfriend reflects how comforted and captivated I am by her,’ says Chip, 29.”

Flirting advice stresses the importance of eye contact, though any pro knows that the real trick is the dance between looking towards and away from your object of affection with the timing of a prima ballerina.

Cosmo wisdom aside, eye gaze plays a big role in attraction and scientists have been trying to decode that mysterious link for decades. In 1970, Harvard psychologist Zick Rubin created a “love scale” on which couples reported how intensely they loved each other. He then measured how much eye contact they made while talking with each other and found that the more a couple reported to love each other, the more eye contact they made. Whether this study is convincing or not, it conjures up a persuasive array of bulletproof, laser-beam on-screen gazes that precede a long-awaited kiss. Images of new lovers locked in each other’s eyes are as wonderfully commonplace as images of long-time partners comfortably directing their gaze elsewhere, secure in the knowledge that out of sight does not mean out of mind.

More recently, in 1989, Art Aron, behavioral psychologist at the State University of New York at Stony Brook, conducted his own study. He asked people to write stories about what happened when they last fell in love. Aron found that eye contact played a surprisingly large role. Among those who fell in love at their first meeting “our eyes connected” was a major factor. He found a similar sense of connection in 1998 when he brought pairs of strangers into his lab and asked them to perform a series of tasks designed to help them get close to each other. In one task, pairs who had never met before looked into each others eyes without talking for 2 minutes. The couples reported that this exercise made them feel extremely close. One of the first couples who participated in this study later got married, Aron told me.

When I asked him why he thought the eyes had that much power he surprisingly said he never thought about it. Maybe, he speculated, eye contact represents honesty and openness. Maybe it indicates directness. “The single strongest most common indicator in accounts of falling in love is eye contact,” Aron said. People want to feel a reciprocal liking and eye contact often serves that role. I wondered if Kleck was right; love emerges when someone we think well of showers us with gazes.

The strong link between love and eye contact that Rubin, Aron and others have found, might be explained in part, with the findings of another research team at University College , London . In 2001, Knut Kampe, Chris Frith and colleagues found that when people looked at an image of an attractive face looking at them, this activated the same areas of the brain that release dopamine when we are rewarded. When the eyes of an attractive face looked away, fMRI measurements showed less activity in the reward systems of the brain. In other words, an attractive face that’s looking at us is a kind of gift.

Neil Macrae, professor of social cognition at the University of Aberdeen , pushed these findings even further. His question was, does gaze affect how attractive we find someone ?

In an article entitled The Look of Love, which appeared in Psychological Science in 2005, Macrae, along with colleagues, conducted two experiments. One asked the question, “How likable are you?” and the other asked, “How attractive are you?” In the first experiment, subjects looked at animated faces of attractive women, in some cases shifting their gaze towards the subject, in other cases shifting away. On a rating scale of 1-5 the subjects were asked to rate how likable the women were.

The ratings were higher when the target faces were turned towards the rater, giving the appearance that the faces were paying attention to them. When the rater was ‘engaged’, the rating was more favorable than when he or she wasn’t. The authors concluded that gaze shifts affect how we evaluate others. Translation: we find people more likable when we think they like us!

In the second study, the male participants rated the images of women who were looking at them as more attractive than the women who weren’t looking at them. The female participants, on the other hand, did not experience this bias. Whereas likeability is a factor that was relevant to both the men and the women in the study, attractiveness was only relevant to the men. The female participants were not affected by gaze shifts when asked to rate the attractiveness of women’s faces. The simple gesture of direct eye contact seems to play a role in how we see people in contexts that are socially relevant to us.

These studies of love in the lab seemed to all support the same claim. Whether we observe behavior or the brain, narcissism fuels love – we are deeply affected when someone takes enough of an interest to look at us.

Read Ada’s entire thesis on MIT’s DSpace


A Bright Idea?: The Promise and Peril of a Memory Drug
Will Dowd

On an early Saturday morning in November, Sarah Holguin, a petite, fourth-year graduate student, was harvesting brains.

It was “Sac Day” in the lab of MIT neuropharmacologist Richard Wurtman and, judging by an incessant clamor from the cages, the dozens of laboratory rodents slated to be “sacrificed” seemed to know what was coming.

Holguin, who looked like she could be twelve-years-old in her oversized lab coat, was jovial and industrious. She plucked gerbils two at a time from their bed of wood shavings, or else a single Chihuahua-sized rat, and dropped them in a glass container. A tube, snaking from a nearby tank, pumped in a suffocating flow of carbon dioxide. The gerbils and rats threw their heads back as if howling, then collapsed. Holguin slid the limp rodents one-by-one into a guillotine the size of a large paper cutter and, with a tiny leap, brought all her weight down on the blade. The bodies were discarded in a shopping bag at her feet (“My bag of horrors,” she called it). The heads, and the all-important brains, were passed down the long metal table, a make-shift assembly line, to three undergraduate assistants.

While steeled to the task at hand, the undergrads were less cheerful than Holguin. They looked up regularly from the steady stream of heads to take in the view: the tortuous, almost byzantine pipes sprouting from the nearby power plant; a sheer steeple rising from Cambridge’s Central Square, its apex just visible from the fifth floor animal surgery room of the Picower Institute for Learning and Memory.

It was the undergraduates’ job to cut away the rodents’ scalps with miniature scissors, crack and peel away the skull like a peanut shell, and spoon out the brain. With a razor blade, they easily sliced apart the left and right hemispheres of the brains, separating them like lobes of cauliflower. Wrapped in a square of tinfoil, each half was deposited in a bucket filled with chips of dry ice. Once collected, all the brains were moved to an industrial freezer to be preserved for later analysis.

These rodent brains, each a mere 2 grams of pale tissue, were handled like precious stones. Over the past few months, half of the rodents had received Dr. Wurtman’s new drug, a cocktail of dietary supplements including uridine, choline, and an omega-3 fatty acid called DHA. Holguin studied the behavioral effects of the cocktail, putting the rodents through a series of mazes that tested learning and memory. Rodents that received the drug performed better than those that received a placebo. In one test, they quickly paddered down the correct arm of a radial maze to retrieve a food pellet, rarely if ever doubling back to paths they’d already explored.

Holguin’s tests suggest that the cocktail enhances the rodents’ ability to learn and remember. Under the staid surface of Wurtman’s lab, there is growing excitement that this cocktail could do the same in humans.

Read William’s entire thesis on MIT’s DSpace


Changing Her Tune: How a Transsexual Woman Claims a New Identity Through Voice
Katharine Stoel Gammon

One January evening in downtown San Francisco, the front hall of the Regency Ballroom was filled with people dressed in floor-length gowns. Sequins were particularly popular. A woman in a rhinestone-covered strappy number walked by, even her hair glimmering in sparkles. Other dresses dipped dangerously low in the back, revealing toned muscles, or cascaded in the front to expose buxom cleavage. Tightly laced corsets created slim waistlines and hourglass shapes. Splendidly styled heads with big curls and plentiful hairspray bobbed through the crowded marble corridor. Flashbulbs popped as the most celebrated participants walked into the room, their stiletto heels clacking against the cold stone floor. A buzz suffused the chamber, similar to the sound of a flock of geese collecting near a lake. The event was a black-tie gala, themed “A Return to Elegance,” which drew a few hundred members of TransGender San Francisco. Each year, its cotillion is a chance for new members of the transgender community to have a “coming out,” to walk debutante-style across the stage, and to meet other members of the city’s transsexual and transgender population.

The women continued to arrive, and a few men as well. Despite the mild San Francisco weather, many wore elegant heavy furs and were already sweating as they dropped them at the coat check. Heavy floral perfume saturated the air. Voices glissando-ed to falsetto and back. The elongated vowels were striking: It’s so gooooood to seeeeeee yooooouu! What are you doooooooing these daaays? What a beeeeeeaaaauuuuutiful dress you are wearing!

Some of the gala attendees were clearly in the early stages of male-to-female transition or perhaps transvestites—choosing to live as men and dress as women for pleasure in their personal lives. A young woman moved through the crowd in a tight lacy black cocktail dress and a tiny, feathered pillbox hat. She looked completely “biological”—naturally female, lacking the broad shoulders and big hands that some transsexuals bemoan cannot be altered with surgery. Others stared at her in envy and whispered to each other as she passed.

As the show began, Allison Laureano, the president of TransGender San Francisco, wearing a dress inspired by Lara Turner and a hairstyle reminiscent of Rita Hayworth, took the front stage. After some opening jokes and banter, she introduced the candidates for Miss Transgender 2007. Later a rotund transwoman performer named Tommi Rose sang about a friend who had passed away from cancer years before. “She once said not to cremate her body because silicon doesn’t burn and it would be a bad, bad sight for everyone nearby,” said Rose, wearing a royal blue dress with so much sparkle that the ballroom’s walls were bathed in an underwater glow.

Among the attendees, there were those who had undergone sexual reassignment surgery to give them the genitals of their desired gender, those who had changed their faces to be more feminine, and those who had added breasts. Others had their facial hair lasered away or their Adam’s apples shaved off. But the one thing that seemed to make the most difference in establishing their new identity was the way they used their voices.

Tommi Rose possessed an amazingly versatile voice; she could reach into her upper registers easily and then smoothly transition back down to a bass to speak to her audience in an intimate-sounding way. Her glittery performance, full of jokes and poignant anecdotes, was observed by hundreds of transwomen and some transmen, munching on pasta salad at linen-covered tables. Alone on the stage under the spotlight, Tommi Rose represented the entire spectrum from man to woman; her voice was an acoustic medley of the struggles transgendered people go through as they move from one way of being in the world to another.


Mind Over Machine: What Deep Blue Taught Us About Chess, Artificial Intelligence, and the Human Spirit
B. Christine Hoekenga

On the other side of the board sat one of the members of the IBM research team that had built and fine-tuned Deep Blue. Various members of the team stood this post as the games progressed, but whoever sat in the chair was a stand in – a set of eyes to observe the board and a set of hands to relay information via keyboard to Deep Blue and to move pieces on the computer’s behalf. Four-year-old Deep Blue had its own cache of imposing weapons: the support of a six-person team of crack IBM programmers who drew on 50 years of computer chess innovation and 480 custom chess chips distributed among 30 processors working in parallel to allow the computer to examine an average of 200 million moves per second.

The competitors were not strangers. They had sat across the board from one another in Philadelphia the year before when Kasparov defeated an earlier version of Deep Blue with a record of 4 – 2. A few months later, the parties agreed to a rematch, and the IBM researchers set to work updating and enhancing their machine. The Association of Computing Machinery agreed to officiate, and IBM organized the match, put up a purse of $700,000 for the winner and $400,000 for the loser, and made sure the event was well publicized.

The room where the games took place was not a room at all, but a television set designed to look like a professor’s study, complete with bookshelves and wing-backed chairs, a model sailboat, and an oriental rug. The table at the center of the stage was outfitted with a chessboard and a pair of flags (one Russian, one American), and a computer terminal used for communicating with Deep Blue. The computer’s brain, made up of two refrigerator-sized towers from the IBM RS/6000 supercomputer series, was stored in a locked room down the hall. Several cameras broadcast close-ups of the players, the board, and the clock to a pressroom and an auditorium in the basement where three grandmasters offered commentary to an audience of 500 while they watched the action on three large projections screens. Hourly updates were broadcast on CNN, and IBM posted a play-by-play webcast that was followed by millions.

Kasparov won the first game handily and commented that the computer played just as he had expected it to. Having competed against an early version of Deep Blue in 1996 as well as a number of other chess programs, Kasparov remained confident that he would prevail by playing in an “anticomputer” style. Conventional wisdom among chess players held that because computers do not have an overall sense of strategy, they typically play best when lines of attack are out-in-the-open and obvious. If, for example, an opponent’s rook is directly threatening the computer’s king, the machine will likely be able to counter that by capturing the rook or protecting its king. But, if a human can line up an attack in a roundabout way, such as behind a row of his or her own pawns, the computer will not develop a long-term strategy to neutralize that attack the way a human player would. In essence, it will play planlessly – an Achilles heel that Kasparov planned to exploit for the remaining five games.

But in game two, Deep Blue shocked the champion with some very unexpected moves. By the computer’s 16 th move, the board was in a “closed position” where pawns are blocking many of the pieces capable of controlling long stretches of the board, such as bishops. This is precisely the type of position that usually favors human players, but Deep Blue continued to make good moves and eventually worked its way to a slight advantage. Because of the way chess computers are typically programmed, they tend to capture opponents’ unprotected pieces right away. Knowing this, Kasparov purposely offered a pawn as a sacrifice. He expected that Deep Blue would immediately jump on it like a cat distracted by a mouse and allow him to regain some strength. But the computer didn’t take the bait and instead continued with its line of attack.

To Kasparov and many who watched from the sidelines, this was eerily human. The computer appeared to be playing with a long-term strategy that outweighed its impulse to capture pieces. Kasparov was shaken and resigned the game, believing he could not win.

The jubilant IBM team was the center of attention at the post-game press conference where they had previously been ignored by an audience rooting for Kasparov. Another blow rocked Kasparov’s confidence the next day when fans following the match on the Internet showed how the game could have been played to a draw had he not resigned.

Psychologically, Kasparov was in shambles. He no longer felt confident that he could gauge the computer’s abilities. And although there was no real evidence to support it, another, more insidious thought began to haunt him: could there have been human interference in the computer’s play? He demanded printouts of Deep Blue’s analytical processes, but the IBM team declined. Later, Joel Benjamin, a grandmaster who worked with the team to program Deep Blue, explained that a human opponent would not be expected to discuss his strategy and reveal every variation he had considered in the middle of a competitive match.

Whatever had gone on inside Deep Blue’s circuitry to secure its victory, the second game became a pivotal point in the match. Kasparov never recovered from the defeat and continued demanding printouts and insinuating that something had not been kosher during game two. He joked bitterly about it later at press conferences and his attitude about the whole endeavor changed. The day after the match ended, IBM gave Kasparov the printouts he wanted, but he remained disgruntled, upset that the logs didn’t reveal why the computer chose a line of play, only the various lines it considered.

In a piece that appeared in Time a couple of weeks later, Kasparov described the atmosphere of the match as “hostile” and said that he believed that “competition had overshadowed science.” A few years later, in a documentary film, Kasparov commented that he had originally believed the match was in the spirit of science and would benefit chess, computer science, and society, but that he had played right into IBM’s hands. He proffered a scenario by which a human might have helped Deep Blue, and his agent, Owen Williams, said Kasparov hadn’t realized at the outset that they were trying to “kill him at all costs.”

Despite the uproar surrounding game two, games three through five passed without incident. They were all draws, strongly played by Kasparov, but not strongly enough to defeat the computer. Going into the sixth and final game, the score stood even. Kasparov needed a victory in order to keep his reputation as the strongest chess playing entity in the world.

Probably in an effort to avoid scenarios that the IBM team had programmed Deep Blue to handle well, Kasparov played an opening sequence he had not used since 1982. His attempt to mix things up led him to stumble on his seventh turn and move a piece out of order. After his 17 th move, Kasparov picked up his watch from the table and put it back on. The commentators were confused. This was usually a symbol that the game was wrapping up. And indeed, after Deep Blue’s 19 th move, Kasparov resigned, immediately leaving the table and heading straight for the elevator.


The Dancer in Nature
Erica Naone

On a visit I made last October to Streb’s studio in Brooklyn, called the SLAM Action Laboratory, Newton’s Third Law ruled like a tyrant over every dance, even the ones that weren’t about one body straining against another. I walked into the “laboratory,” a warehouse that used to be a mustard factory, and saw Nelson suspended from the ceiling, a harness belted to her pelvis. Dancer Ami Ipapo lifted and lowered her by working the controls on an industrial hoist, and Nelson’s body swung in circles, the cord that held her up winding and unwinding around a pole in the center of the dance floor.

Streb called this “flying,” and talked about putting Nelson on “new ground” – the pole, not the earth, became the floor. But Nelson’s face turned redder and redder, and she grunted, gasped, and cried out, until dancer Terry Dean Bartlett asked if he could let her down.

“How come?” Streb asked, looking up placidly from the choreographic notes she had been scribbling. “What’s going on?”

“She’s been hanging upside down for 15 minutes,” he said.

“Oh,” Streb said. “Of course.”

Nelson, once released from the harness, came over to where I sat with Streb. She panted, her face, neck and chest still pink from increased bloodflow. Short and well-muscled, brown hair sharply cut to stay out of her face, Nelson looked too thick and powerful to have been the “prima ballerina” for anyone but Streb. She pulled down the waistband of her pants and showed me the raw welt the harness left on her right hip.

As her body pressed down against the harness, the harness pressed back up into her hip. Whichever direction Nelson’s feet may have been pointing, her blood was never confused about which way was down.

Later, Streb told me her dances “are about surviving in a mean world riddled with physical truths.”

“What are you really doing in normal dancing?” she said. “It’s…geared to make me impressed – it’s an issue of demonstrating privilege. The dancer has a straight back – it’s aristocratic. …My dances are working class – so it’s hard. …It may not look elegant, because I want to show that it’s not elegant.”

She sometimes calls these inelegant movements “experiments,” though they are experiments in the sense that a child may experiment with a hot stove. They are experiments in classical physics, exploring the consequences of crashing, jumping, colliding, and flinging a (human) projectile. Her experimental equipment are a series of contraptions she engineers and builds: the hoist that lifted Nelson; an arrangement of swinging concrete blocks; a human sized hamster wheel; and “Tip,” a hollow half-wheel that rocks back and forth on its round side while Streb’s dancers balance on the flat surface above. They are simple machines – wheels, levers, pulleys and pendulums – that Streb uses as a sort of physics class for the hard-headed.

At the Boston show, it’s time for the finale. The speakers play the theme from the movie 2001 , and the human sized hamster wheel is revealed. Screens rise away from a picture window behind the wheel and sunlight floods the dark auditorium, while glittering shards of it dance over Boston Harbor, spreading out wide and blue just beyond.

The dancers board the wheel in inadvisable ways, leaping on and off as it spins. They flatten themselves inside so it seems only centrifugal force holds them in place. They run on top of the wheel, or cling flattened to the outside through full rotations.

A crowd gathers on the other side of the window, peering into the darkness at the strange sight, becoming part of the show for the audience inside. Streb couldn’t have planned it better – the confusion and wonder on their faces testify to the craziness of the whole idea of Streb, and also to her appeal. Though she presents herself as a rebel against the forces of nature, and uses her art to highlight the effort in humanity’s struggle, the sight of the wheel against the backdrop of sun and ocean and wondering humans drives home the point that Streb’s dancers only accomplish what they do with nature as a partner. For all that I feel sympathetic pains each time a dancer smacks against the floor or a moving object, only the predictability of the laws of classical physics makes Streb’s work safe at all. Nature is her partner, not her enemy, and her dancers triumph only so much as they are parts of nature moving exactly as predicted, as simple machines obeying simple laws.

Read Erica’s entire thesis on MIT’s DSpace


Eavesdroppers: How Scientists Are Learning to Listen In On the Animal Kingdom
Elizabeth Quill

On a balmy night in late May 1985, thousands of migratory sparrows and hundreds of cuckoos called out of the Minnesota sky. Their staccato “tweeps” and repetitive “woops” emanated in all directions as they communicated among themselves. The sound also moved downward, toward the ground. Bill Evans, an amateur birder turned ornithologist, had just returned to his campsite on a bluff by the St. Croix River when he noticed the chorus. “I enjoyed just hearing it,” Evans says years later. “I thought, ‘There is an enormous amount of information up there, and there has to be a way of extracting it.’”

Determined to document the voices, Evans purchased a VCR. A two- or three-dollar VHS tape would last all night in extended play mode, and the audio quality, though admittedly not perfect, was OK. He rented a Sennheiser microphone, the top-of-the-line kind, and ran a power cord into the field. This is when Evans’s obsession began. He wanted to know what creatures were passing in the darkness out of sight, above the trees. Since then, he has never missed a migration. He set up monitoring sites across the country, committing himself to identify every night migrating land bird in eastern North America. Excluding shore birds like plovers and sandpipers, most birds land in this group. For Evans, night flight calls were like the pieces of a giant, dynamic puzzle. If he could identify the birds, then he could understand the patterns of their movement and he could educate others. “Once you have the recordings, you can hand them down,” Evans says, like a packrat with a mission. “The sounds are changing all the time.”

If scientists want to study animals in the wild they rely on field observations. If they want to track those species to know where they are and where they are going, then researchers typically capture and tag them. These methods, however, are difficult if not impossible for rare and hard-to-see species like whales in the oceans, elephants under a forest canopy, or birds at night. Sound gives scientists a new way of knowing what is swimming, roaming, and flying where. And if scientists understand these things, the habitats animals need to survive can be located and protected. The nocturnal flight calls, according to Evans, provide a simple and straightforward first cut of the information conservationists need.

Evans thought nothing of flyway protection 25 years ago. A student at Oberlin College, he did not know where his life would lead. “I was floundering,” he says. When he heard the migrating birds in 1985, he began thinking about John James Audubon’s accounts of hoards of migrating passenger pigeons darkening the skies of southern Ohio.

“The air was literally filled with pigeons; the light of noon-day was obscured by an eclipse, the dung fell in spots, not unlike melting flakes of snow, and the continued buzz of wings had a tendency to lull my senses to repose,” Audubon wrote about an autumn day in 1813. The birds were hunted for food and shot for pleasure. They sold for two cents a pair in New York City. The last passenger pigeon died in the Cincinnati Zoo in 1914.

“I was sad I would never see it,” Evans says. “But I realized change is happening all the time.”

Ornithologists have been counting the calls of migratory birds since the 1890s, and Audubon , the magazine of the National Audubon Society, first published tallies of calls in the 1950s. Late in the same decade, Richard Graber and Bill Cochran, leading ornithologists working at the Illinois Natural History Survey, began a nocturnal flight call study in the state. Graber and Cochran lugged around 15-pound reel-to-reel decks and pulled wagons loaded with amplifiers. Only in the past two decades have better and cheaper microphones, computers, and software provided a way for researchers to acquire, sort, store, and analyze thousands of hours of sound, turning curiosity into science and descriptive detail into data. “Now you can just stick your laptop out in the field for an entire season,” Evans says. “Technology has opened the sky.”

Read Elizabeth’s entire thesis on MIT’s DSpace


The Butterfly Clock: Illuminating the Molecular Myseteries of Monarch Migration
Jocelyn Rice

For the most part people have just looked at monarch migration and called it a mystical event,” says Steven Reppert, a neurobiologist with a soft spot for insects. Reppert staunchly rejects the idea that there’s anything magical about the butterflies’ yearly trek. “There’s a biological basis for it,” he says. Coming from Reppert, this statement is anything but dismissive. “It’s spectacular biology,” he adds.

Reppert’s office at the University of Massachusetts Medical School in Worcester, Massachusetts, is probably best described as L-shaped. But with a little imagination the legs of the L could be the outspread wings of a butterfly. We’re sitting at a round table—a spot on the right wing. And we’re leaning over his sleek little MacBook—itself a pair of unfolded wings. It’s easy, in Reppert’s presence, to see butterflies everywhere.

Reppert gestures towards a map on the screen of his laptop. It’s the familiar shape of North America, shaded red wherever eastern monarchs spend their springs and summers. The United States is more red than not. The western border of the red zone roughly traces the continental divide, following the Rocky Mountains northward from New Mexico up through Montana; the eastern border is the Atlantic Ocean. Red surges into Canada, from Quebec to Alberta, with the tiniest, northernmost finger jutting up into British Columbia.

But what’s most remarkable on Reppert’s map, pinched from a monarch-themed website, is not the dizzying expanse of red. It’s a miniscule spot of yellow, which I have to squint to see. This spot marks the monarchs’ overwintering grounds, the endpoint of their yearly migration—remote oyamel pine groves in the mountains of central Mexico. Each year, the entire eastern monarch population crowds into those groves to weather the cold season. As fall cools into winter, hundreds of millions of butterflies funnel southward from the red zone into the yellow: from well more than three million square miles into just three hundred. There, they huddle in tight clusters until spring arrives. The microclimate in these montane forests is like Goldilocks’ porridge: just right. It’s cool but not too cold; damp but not drenched; the conditions are perfect to keep monarchs alive through the winter.

In early March, when winter begins to wane, the sun coaxes the overwintering monarchs out of the trees. By then these winter butterflies, in monarch terms, are Methuselahs; at seven months or so, they are far older than any summer monarch will ever be. They live so long in part because nature pressed the pause button on their sexual development. Winter held them in limbo, in a state known as reproductive diapause. But as spring approaches, for the first time in their lives, they are stirred by the urge to mate—and they do so, in a massive flurry of color, countless orange wings against crisp blue sky.

Meanwhile, each butterfly’s internal compass has rotated, its needle drawn in a new direction. Whereas in the fall they were compelled to fly south, now they are drawn irresistibly to the north. It’s time to find milkweed, the only plant on which monarchs will lay eggs. As soon as they emerge from their chrysalides, these newborn summer monarchs are ready to mate, unlike the southward migrators. Their life cycle is short and efficient: they hatch, metamorphose, take wing, mate, lay eggs, and die—all within the span of about two months. This northward leg of the annual migration is a relay race, each short generation handing the torch to the next. In this fashion, the butterflies burst forth from their overwintering sites and fan out into their summer range, repopulating that wide red swath on Reppert’s map.

The first northbound summer generation, hatched from eggs laid by the butterflies that flew south and wintered in Mexico, begets a second. The second may even beget a third. So when fall arrives, a monarch emerging from its chrysalis at the northern edge of its range is the grandchild or great-grandchild of those that flew south the previous fall. Its impending trek to Mexico will be its maiden voyage. “You’re talking about butterflies that are three generations removed—the ones that make the journey from the ones that were there before,” Reppert explains.

If someone dropped you off in Canada, could you find your way to Michoacán, Mexico? What if you had never been there before, or even heard of the place? What if you had no map, and no one to guide you? What if your brain was no bigger than the head of a pin?

This is exactly what monarch butterflies do each fall. They journey toward Mexico for the first time in their lives, with no parents to show them the way. “They really are traveling there for the first time, and there’s nobody who’s telling them how to get there,” he says, a slow smile spreading across his face. Because of that, he says, “there has to be a genetic program that is underlying the vast majority of what these animals are doing.” If they can’t learn the route from their parents, they must learn it from their genes. That fantastic funneling, from the vast red smear across North America to the tiny yellow dot in Mexico, must somehow be imprinted in their DNA. And Reppert wants to figure out how.

Read Jocelyn’s entire thesis on MIT’s DSpace