Author: Lois Parshley

Millions of people around the world have forms of progressive retinal degeneration: These conditions cause blindness, slowly but surely. But a research team from the University of Pisa, Italy, just found a method to help adults retrain their brains to see again. Overturning old attitudes about the brain’s plasticity, their groundbreaking research, just published in the journal PLOS One, suggests that new visual prostheses can help these people restore visual signals to their brain.

The researchers Elisa Castaldi and Maria Concetta Morrone implanted the Argus II retinal prosthesis system in seven patients with retinitis pigmentosa, one of many retinal degenerative conditions that lead to blindness. The system sends small light pulses to the retina’s remaining cells, bypassing damaged photoreceptors, and stimulating the few remaining retinal cells. These cells then transmit this visual information along the optic nerve to the brain, allowing the person to perceive light patterns, and eventually see again. Before the surgery, all of the patients had been blind for 20 years. At the most, they had bare light perception.

“We tested the ability of our patients to detect big and high contrast shapes presented very briefly,” Elisa Castaldi, lead study author, and a post-doc in the Department of Translational Research on New Technologies in Medicine and Surgery at the University of Pisa, tells mental_floss. The subjects were asked to specify in which of two intervals—marked by two noises—there was a stationary, large, high-contrast visual stimulus. Then they had to verbally report whether it appeared in the first or second interval. “When using the prosthetic implant, they reached up to 90 percent accuracy in this task,” Castaldi says—a huge change from their normal vision.

The subjects were also hooked up to fMRI imaging that measured their brain activity by monitoring changes in their blood oxygen levels as their neurons fired, Castaldi explains. After implanting the system, the scientists found an increase of signals in a subcortical structure of the brain known as the lateral geniculate nucleus—the first relay station of visual information along the visual pathway before reaching the cortex.

Their remarkable results, however, were not immediate. The researchers found that the more time the patients spent training with the implant, the better their performance increased. In fact, most of these patients trained with their implant for months with a vision therapist at home, both to help them “localize” their physical world—interpreting the visual signals as doors, windows, and walls—as well as sitting in front of a computer and practicing recognizing “big, high-contrast shapes.”

“We observed that the recovery of vision depended on the amount of time and practice the subject experienced with the implant,” Castaldi says. Prior literature had shown that after many years of blindness, the brain reorganizes itself, and “the areas that were once used to process visual information are recruited for another purpose, like touch or hearing.” This study demonstrated that, in fact, the adult brain has greater “plastic potential” than research had previously shown, allowing people who had spent years without vision to learn to see using artificial visual input.

The results of this study, Castaldi says, are important “because it is often thought that the ability of our brain to reorganize itself and adapt to a new condition—a property called plasticity—is confined mainly to childhood.”

Now, combined with breakthroughs in visual prosthetics, research may be able to make significant strides to retrain adult brains to see again.

 
Anywhere from 60 to 100 tons of material falls to Earth every day. Most of it is in the form of dust and grain-sized particles and is harmless, but it’s a reminder that a lot of stuff is out there. The weathering on the International Space Station provides startling evidence of that.

So what do we do if a not-so-harmless object is hurtling towards us?

Although a doomsday asteroid is a frightening prospect, don’t worry—NASA has a plan. The agency actively monitors space for dangerous objects and has conducted research into the best way to repel or destroy a space invader. Today, it is actively developing missions to do just that, and even has a department to deal with the problem: the Planetary Defense Coordination Office. But just how fast could the agency deal with an actual catastrophe? Here’s an inside look into NASA’s emergency planning system.

FIRST WE FIND IT.

NASA has several ongoing projects to survey the solar system for new celestial objects. In 2009, the agency launched an infrared telescope called the Wide-field Infrared Survey Explorer (WISE). Its mission, run by NASA’s astrophysics division, was to create an infrared map of the entire sky. After the completion of its primary mission, NASA’s planetary science directorate asked to extend the life of the spacecraft, re-purposing it as an asteroid hunter in 2013. NEOWISE was born. Over the course of its life, what the spacecraft has found is terrifying―hundreds of new near-Earth objects, and scores of potentially hazardous ones. In other words, the solar system is a lot scarier than we thought. Here on Earth, there are several observatories that work together with a goal of discovering, tracking, and characterizing this population of renegade asteroids and comets.

A small body called TB145―the “Great Pumpkin asteroid“―exemplifies how the discovery of a potentially hazardous object works in practice. On October 10, 2015, the Panoramic Survey Telescope and Rapid Response System (PAN-STARRS) in Hawaii spotted an object approximately 600 meters across that was speeding perilously toward Earth. The Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia imaged it, and the Goldstone Deep Space Network telescope also took radar images. The Infrared Telescope Facility in Hawaii provided spectrometry. In a very short amount of time, scientists knew a lot about this scary new cosmic neighbor. The object was soon identified as the dead nucleus of a comet, its volatiles having been burned away. Moreover, scientists identified boulders several meters in size sitting on the object’s surface. Those boulders matter because they can help steer the object away from Earth. We weren’t in danger from it; its trajectory was well understood, and even at its closest pass, it was 300,000 miles away from the Earth.

THEN WE TRY TO MOVE IT.

 
Two of the rapidly maturing projects of the still very nascent asteroid deflection program are the Asteroid Impact Deflection Assessment and the Asteroid Redirect Mission. These programs use two different techniques to attempt to change the orbit of space objects, kinetic deflection, and enhanced gravity tractoring.

The Asteroid Impact & Deflection Assessment is a collaboration between NASA and the European Space Agency. It recently completed its concept study phase and has moved into design. The goal is to build a rendezvous spacecraft called the Asteroid Impact Monitor (AIM) that would fly to an asteroid called Didymos, which is easily reached from Earth but does not cross our orbital path. (In other words, if something goes terribly wrong with this experiment, we don’t risk creating the potentially hazardous object we want to deflect.) Didymos is about a half-mile in diameter, and even has its own small moon, informally called Didymoon. Then NASA will launch a spacecraft called the Double Asteroid Redirection Test (DART). DART is a “kinetic impactor”: It will plow into Didymoon and demonstrate how much energy can be imparted, and how much it changes the moon’s orbital period. The hope is to test the effectiveness of a technique called “kinetic deflection,” which would enable scientists to redirect an asteroid were it on an impact trajectory with Earth (provided they discovered the asteroid quickly enough).

Another such project in development is the Asteroid Redirect Mission, run by NASA’s Human Exploration and Operations directorate. That mission is an element of NASA’s “journey to Mars,” and will further the development of solar electric propulsion, a technology designed to push large masses around the inner solar system—things like Mars habitat modules and cargo and, as a bonus, asteroids.

 
In fact, the near-Earth object observation program of the Planetary Defense Coordination Office helped identify places to test out the Asteroid Redirect Mission’s capabilities. When it launches, a robotic spacecraft will fly to asteroid 2008 EV5, a potentially hazardous object close to Earth that has been tentatively selected as the mission’s target. The spacecraft will approach the asteroid’s surface and survey it for boulders. Once scientists identify a suitable boulder, the robot will touch down on the surface using long landing legs, and then deploy grappling arms to grab hold of the boulder. With the boulder firmly in hand, the spacecraft will lift off from the asteroid surface.

Before flying back to Earth’s orbit with the asteroid (for astronauts to study safely once it’s in a new, safe, lunar orbit), the spacecraft will first perform an “enhanced gravity tractor” maneuver—another kind of asteroid redirection. By flying near one side of the asteroid, the mass of the spacecraft and the tens-of-tons boulder will use gravity to gently and gradually alter the trajectory of the asteroid.

AND IF THAT DOESN’T WORK, WE BLOW IT UP.

In a pinch, there’s the nuclear option [PDF]. If scientists discover an asteroid on an impact course with Earth and find that there’s no time to build a spacecraft, study the object, and adjust its course with “slow push deflection/migration” techniques such as the gravity tractor, they can crack their knuckles and resort to “impulsive migration” techniques. The beauty of using a nuclear device on an asteroid is that you don’t need to know much about the asteroid in advance. In a time-sensitive situation, this is your go-to option, and there are four ways of deploying it.

A standoff nuclear detonation involves a flyby of a hazardous object and using a proximity sensor to detonate a nuclear device. The explosion would push the asteroid off course. This technique is orders of magnitude less effective than plowing the nuke into the asteroid and pressing the red button, but it has the advantage of not fragmenting the asteroid. Fragments are bad. Remember the meteorite explosion over Chelyabinsk, Russia?
 

 
That rock was a dinky 20 meters in diameter. If we created a sustained bombardment of such asteroid fragments, we would be in for a pretty bad time.

The standoff technique also allows for a progressive adjustment of an asteroid’s course. We wouldn’t be limited to launching a single nuke; we would launch several. (It’s not like we’re running low on nuclear weapons.) Rather than correct the asteroid’s course in a single dramatic blast, we could more precisely adjust its course with a series of detonations.

Other nuclear use tactics are surface, subsurface, and delayed. A nuclear surface is like dropping a nuke on the asteroid. When it touches the asteroid’s surface, it detonates. Subsurface is like the DART half of the Asteroid Impact Deflection Assessment mission―the impactor drives a nuclear explosive deep into the asteroid, and it detonates. A delayed nuclear technique is just that: The nuke is landed on the asteroid and waits for scientists to detonate it when the time is right.

All of this can be done with conventional explosives as well, though it’s unlikely that conventional explosives would pack enough punch to make much of a difference.

Last month, paleontologists announced a new species of ancient pinniped—a group that includes modern seals, sea lions, and walruses. The animal lived off the coast of what is now Washington state about 10 million years ago and probably fished like seals do, relying on the power of its oversized eyes to track its prey. Robert Boessenecker, an adjunct lecturer who works for College of Charleston’s department of geology and environmental sciences, recently presented a study on the newfound fossil at the annual Society of Vertebrate Paleontology meeting in Salt Lake City.

Discovered in Washington’s Grays Harbor County in the 1980s, the incomplete skeleton consists of neck vertebrae, a well-preserved ribcage, a partial sternum, and a skull with jawbones. It was encased in exceptionally hard rock that took scientists prepping the fossil two decades to clear away. Judging by the available remains, the animal was more than 8 feet long—about the size of an adult male California sea lion. 

Boessenecker and his team were able to classify the creature as a new species of Allodesmus, a pinniped genus whose members once roamed coastal Japan and North America’s western seaboard. Although a species name has been chosen for the animal, it has yet to be made public. “We plan on naming [it] after a beloved colleague who has contributed extensively to pinniped paleontology,” Boessenecker tells mental_floss. “But we’re going to keep that under wraps for now.”

The newly discovered animal hailed from a marine mammal family known as the desmatophocids, which evolved around 23 million years ago. From the neck down, they looked very much like today’s seals and walruses, both of which sport a combination of enlarged front flippers and well-developed hind limbs. But the skulls contained a mix of features seen in a variety of pinnipeds today—and some evidence suggests that they had trunk-like noses similar to modern elephant seals.

Notably, the new Allodesmus also features proportionally huge eye sockets, each of which could house a poolroom eight ball. Their dimensions suggest it had exceptionally keen eyesight, allowing the animal to function as a deep-diving predator. Because the ocean gets darker the farther you get from the surface, the size of its eyes would have allowed it to absorb large quantities of light far beneath the waves. While navigating through the inky depths, it would’ve most likely hunted down such game as fish and squid.

Boessenecker’s team closely studied the skeleton to see what they could learn about its life. With the exception of some seals, most pinnipeds are strongly sexually dimorphic: Their relative body size, in other words, makes it easy to distinguish their gender. Fossil evidence reveals that the same was true of this Allodesmus species; the skeleton’s size and the thickness of its canines suggest it was male.

It’s also obvious that the Grays Harbor specimen was nibbled on after it died. “Fossil dogfish teeth were found around the skeleton of our Allodesmus, and numerous bite marks are present [as well],” Boessenecker says. Then, as now, a marine mammal’s corpse must’ve looked like an irresistible banquet to the ocean’s many opportunists.

At about 10 million years old, the animal is the youngest-known desmatophocid specimen on record. Its relative youth may reveal quite a bit about the evolution and ultimate disappearance of this pinniped group. “Truth is, we have no idea why desmatophocids died out,” Boessenecker says. “Perhaps our new species was in a very specialized niche, surviving as long as possible [until it was] eventually snuffed out, a possibility that remains for our most charismatic extant pinniped.” 

To Boessenecker, the “most charismatic extant pinniped” is the walrus. In fact, the rise of walruses might have been a factor in the disappearance of pinnipeds like the Grays Harbor animal, because they may have gradually outcompeted Allodesmus and its kin between 13 and 8 million years ago. Back then, the walrus family was a large and diverse group whose members included such oddballs as the four-tusked, mollusk-eating Gomphotaria pugnax. But today, there’s only one remaining species of walrus—and it’s currently at risk of becoming endangered. Boessenecker and his team hope that by learning more about the Grays Harbor Allodesmus, we’ll be able to better understand and protect pinnipeds today.

The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy part by part. Think of it as a mini digital encyclopedia with a dose of wow.

The brain is arguably the one organ that makes you who you are—and the largest part of the brain is the neocortex. Taking up a vast amount of space in your skull, the neocortex is what allows you to do many things you take for granted, such as write and speak, have social interactions, and muse philosophically about the meaning of life. But you might not have known these nine crucial facts about this critical part of your brain.

1. IT’S THE “NEWEST” ADDITION TO YOUR BRAIN.

You might have guessed that, considering the name. The origin of the neocortex is surprisingly recent, evolutionarily speaking. It dates back to reptiles of the Carboniferous Period, about 359 million years ago. It emerged then as “a uniform, six-layered sheet consisting of radially deployed neurons” in the first small mammals who appeared during the transition of the Triassic and Jurassic periods.

2. IT TAKES UP MOST OF THE SPACE IN YOUR BRAIN.

The human neocortex accounts for a whopping 76 percent of your gray matter.

3. YOU WON’T FIND IT IN BIRDS OR REPTILES.

 
The reason birds, lizards, and frogs can’t do much more than attend to the basic functions of survival, and certainly will never write a poem or perform a piece of theater, may be due to the fact that they lack a neocortex. And yet some birds are incredibly clever. The term bird brain is turning out to be quite the misnomer.

4. THE NEOCORTICES OF EARLY MAMMALS WERE MUCH SMALLER.

The fossil record tells us that early mammals were typically small—generally somewhere between mouse- and cat-sized. They likely had small brains with much smaller neocortices [PDF].

5. YOUR NEOCORTEX CAN DEVELOP NEW NEURONS IN ADULTHOOD.

In 1999, contrary to previous theories, scientists were surprised to discover that the adult neocortex can in fact experience neurogenesis—the growth of new neurons. This helped develop a theory about plasticity in the brain—the idea that even adult brains can be retrained and strengthened after adulthood.

6. IT MAY BE THE SEAT OF CONSCIOUSNESS.

 
The neocortex controls language and consciousness, among other things. It is also involved in higher functions such as sensory perception, motor commands, spatial reasoning, and conscious thought.

7. CORTICAL NEURONS ARE NOT BORN IN THE NEOCORTEX.

As the cortex develops in mammalian species, its neurons are not generated within the area, but migrate from neighboring “transient proliferative embryonic zones” near the surface of the cerebral lateral ventricles.

8. THE NEOCORTEX BUILDS CONNECTIONS BETWEEN PARTS OF THE BRAIN.

A team at Yale’s Kavli Institute for Neuroscience found that the human brain is “like a neighborhood”—better defined by the community living within its borders than its buildings. The team writes, “The neighborhoods get built quickly and then everything slows down and the neocortex focuses solely on developing connections, almost like an electrical grid.”

9. INJURY TO THE NEOCORTEX MAY COST YOU THE ABILITY TO COMMUNICATE.

 
If the neocortex is injured through accident, surgery or head trauma, patients may lose any number of cognitive abilities including speech, space recognition, eyesight, motor control, the ability to recognize social cues and more. Wear your helmets!

 
Nature hasn’t been nice to Europe recently. While the United States continues to enjoy calm and warm weather that’s anything but usual for autumn, parts of Europe have been plagued by a string of natural disasters, including earthquakes, a relatively rare tropical cyclone in the Mediterranean Sea, and a tornado outbreak in Italy.

THE MEDICANE

While hurricanes are a frequent visitor to most oceans around the world, there are a few large bodies of water where these spiraling windstorms are noticeably absent. The southern parts of the Pacific and Atlantic Oceans are characteristically empty of tropical storms and hurricanes, due to cold water and strong winds that fill the sky above them. (Only occasionally is there a tropical or subtropical storm that manages to briefly spin to life off the coast of Brazil near Rio de Janeiro.)

Similarly, the Mediterranean Sea is typically quiet. The Mediterranean’s water is usually too cold and regional weather patterns too hostile for hurricanes to form, but they do happen from time to time. Tropical cyclones that form in the Mediterranean are unofficially called “Medicanes.” Medicanes are typically small, and generally not more intense than tropical storm strength (39–73 mph winds). Tropical cyclones form so infrequently in the Mediterranean that no weather agency officially tracks these storms when they do form, leaving these uncommon systems without the standard tracking maps we’re accustomed to using.

What we do know about the Medicane that formed in the final days of October is that it came to life off the southern coast of Italy near the island of Malta, forming from a non-tropical low-pressure system. It was able to get organized when it moved over abnormally warm sea waters. The unnamed tropical storm tracked east toward Greece, producing a 60-mph wind gust and widespread street flooding on the island of Crete.

ITALIAN TORNADOES

Just one week after the Medicane, and days after a series of powerful earthquakes struck central Italy, a separate potent (but non-tropical) storm swept over southern Europe—producing more damage than the photogenic storm that preceded it.

A severe thunderstorm spawned a powerful tornado in the small coastal town of Ladispoli, Italy, which sits about 20 miles to the west of Rome. The tornado was particularly strong and long-lived, causing damage from the coast to the town of Cesano, 16 miles to the northeast. The storm reportedly killed two people and injured many more as it destroyed buildings and uprooted trees from the ground.

While the United States and Canada jointly see the vast majority of the tornadoes that touch down each year, other parts of the world aren’t immune from these ferocious whirlwinds. Tornadoes are common in places like Australia, South Africa, Bangladesh, and most of Europe. These are all areas where severe thunderstorms are capable of tapping into strong wind shear—a vital ingredient required for the development of tornadoes. But hopefully there aren’t more such storms in store for Europe this year.

Synesthesia is a condition in which the brain links a person’s senses together in a rare manner, prompting unusual sensory responses to stimuli. People with synesthesia, for example, might see a certain color in response to a certain letter of the alphabet. Those who experience synesthesia “hear colors, feel sounds, and taste shapes” in a remarkably consistent fashion. For example, someone who sees “1” as burnt orange will always see “1” as burnt orange—unlike, say, someone who hallucinates colors while on LSD.

Scientists still disagree as to what causes synesthesia. Some claim it is a series of learned responses, but most point to a neurological foundation. Some studies reveal unusual connections in synesthetes’ adjacent brain regions, similar to those in babies; in fact, it is believed that all babies have synesthesia until they are about four months old, when the synaptic pruning process normally severs those neural connections.The condition, which occurs in about 4 percent of the population, is more common in women than in men, and appears to be genetic. Though it can manifest in many ways, the most common are grapheme-color, in which numbers or letters produce colors, and chromesthesia (sound-color), in which sounds produce colors or shapes. Unsurprisingly, synesthetes are eight times more likely to work in a creative capacity—and quite a few talented artists through history have had it.

1. VLADIMIR NABOKOV

Occupation: Author

Type of synesthesia: Grapheme-color

 
A writer of novels, poems, and short stories, Nabokov was not the only one in his family to experience synesthesia—his mother and son, Dmitri, also had chromesthesia. Nabokov’s descriptions of his condition are as captivating and well-written as any of his works, and in his memoir Speak, Memory, he describes his condition: “As far back as I remember … I have been subject to mild hallucinations. Some are aural, others are optical, and by none have I profited much … In the brown group, there are the rich rubbery tone of soft g, paler j, and the drab shoelace of h … among the red, b has the tone called burnt sienna by painters, m is a fold of pink flannel, and today I have at last perfectly matched v with ‘Rose Quartz’ in Maerz and Paul’s Dictionary of Color.”

Nabokov even mentions the moment he and his mother learned of their shared synesthesia, writing, “We discovered that some of her letters had the same tint as mine, and that, besides, she was optically affected by music notes.”

2. TORI AMOS

Occupation: Musician

Type of synesthesia: Unspecified

 
Amos experiences an unusual type of synesthesia in which sounds produce different images of lights. When commenting on her synesthesia in her book Piece by Piece, Amos said, “The song appears as light filament once I’ve cracked it … I’ve never seen a duplicated song structure. I’ve never seen the same light creature in my life. Obviously similar chord progressions follow similar light patterns, but try to imagine the best kaleidoscope ever.”

3. GEOFFREY RUSH

Occupation: Actor

Type of synesthesia: Grapheme-color, spatio-temporal synesthesia

 
In an interview, Rush said his synesthesia goes back to his toddler days: “When I was in school, in the very early days, we would learn the days of the week. And for some reason the days of the week just instantly had strong color associations. Monday for me is kind of a pale blue …. Tuesday is acid green, Wednesday is a deep purple-y darkish color. Friday’s got maroon and Saturday is white and Sunday is a sort of pale yellow.

Rush experiences several types of synesthesia, another of which, spatio-temporal, he describes by explaining, “I can say to my wife, ‘That play opened on Tuesday, May the 8th back in 1982.’ I can remember it had a position in my mind where 1982 is and where May is within that. It’s a kind of series of hills and dales so if someone says King Charlemagne lived in 800 A.D., there is a very definite place where I see that.”

4. DUKE ELLINGTON

Occupation: Musician

Type of synesthesia: Chromesthesia

In Sweet Man: The Real Duke Ellington, author Don George recounts Ellington’s statements on how his synesthesia affected his music: “I hear a note by one of the fellows in the band and it’s one color. I hear the same note played by someone else and it’s a different color. When I hear sustained musical tones, I see just about the same colors that you do, but I see them in textures. If Harry Carney is playing, D is dark blue burlap. If Johnny Hodges is playing, G becomes light blue satin.”

5. BILLY JOEL

Occupation: Musician

Type of synesthesia: Chromesthesia, grapheme-color

 
Joel is fond of his synesthetic experiences, in which songs create worlds of color. As he told Psychology Today writer Maureen Seaberg, “When I think of different types of melodies which are slower or softer, I think in terms of blues or greens … When I have a particularly vivid color, it’s usually a strong melodic, strong rhythmic pattern that emerges at the same time. When I think of (those) certain songs, I think of vivid reds, oranges, or golds.”

On his grapheme-color synesthesia, Joel commented, “Certain lyrics in some songs I’ve written, I have to follow a vowel color.” He associates strong vowel endings—such as –a, –e, or –i—with “a very blue or very vivid green … I think reds I associate more with consonants, a t or a p or an s; something which is a harder sound.”

6. DEV HYNES

Occupation: Singer, composer

Type of synesthesia: Chromesthesia

 
Though synesthesia can be overwhelming and unpleasant for some, Hynes, a.k.a. Blood Orange, also seems to appreciate his condition. As he told NPR, “When I was younger, I wanted to just, like, throw the whole paint can onto the canvas and just see what would happen … Whereas now, I’m kind of enjoying it and exploring the interesting scientific part of it as much as I can, and trying to celebrate it and invite other people to enjoy it.”

7. ARTHUR RIMBAUD

Occupation: Poet

Type of synesthesia: Grapheme-color

 
It’s not definitively known whether Rimbaud had synesthesia, but his poem Vowels strongly suggests as much, assigning color values to different vowels:

A Black, E white, I red, U green, O blue: vowels,
I shall tell, one day, of your mysterious origins:
A, black velvety jacket of brilliant flies
Which buzz around cruel smells,

Gulfs of shadow; E, whiteness of vapours and of tents,
Lances of proud glaciers, white kings, shivers of cow-parsley;
I, purples, spat blood, smile of beautiful lips
In anger or in the raptures of penitence;

U, waves, divine shudderings of viridian seas,
The peace of pastures dotted with animals, the peace of the furrows
Which alchemy prints on broad studious foreheads;

O, sublime Trumpet full of strange piercing sounds,
Silences crossed by Worlds and by Angels:
O the Omega, the violet ray of Her Eyes!

8. PATRICK STUMP

Occupation: Musician

Type of synesthesia: Grapheme-color, chromesia

 
Fall Out Boy’s Stump addressed his synesthesia directly in a blog post in 2011. He stated that “most letters and numbers feel like a color. Music also can have colors associated with them (but this is a lot less pronounced than my grapheme-color associations). I’ve talked to a lot of musicians though and the more I talk to [them] the more I’m finding out that this is fairly common.” Stump is right about that—musicians with synesthesia are quite common.

9. PHARRELL WILLIAMS

Occupation: Musician

Type of synesthesia: Chromesthesia

In coming years, leaf peepers might still able to enjoy a road trip through fall foliage—but the display might not look the same. While foliage is notoriously difficult to predict, researchers suggest climate change may dull autumn’s vibrant red and yellow hues.

According to Nicole Cavender, vice president of science and conservation for Illinois’s Morton Arboretum, unpredictability caused by climate change—including extreme droughts and floods—could reduce the number of leaves on a tree, hindering the spectacle of foliage colors. One bad storm can change the entire year’s outlook for fall foliage.

Another effect will be the timing of the leaf change: Warmer temperatures generally cause trees to change colors later in the season. A group of researchers recently studied the effects of climate change on autumn phenology, or seasonal changes, and found that 70 percent of their study area (the Northern Hemisphere) experienced delayed foliage. Only the arid and semi-arid regions stayed unchanged.

Of course, Cavender notes, fall foliage doesn’t hinge on climate alone. Factors like the genetics of a tree, environmental conditions such as wind and strong rains, and the tree’s overall health all play an integral part.

While specifics remain up in the air, Cavender predicts that the growing number of frost-free days anticipated in the next 50 years will definitely dull the colors of some of the United States’ most popular fall trees.

The sugar maple, for example, known for its vibrant shades of yellow, orange, and red, is expected to decrease in abundance in America’s natural forests by 2100. It’s also one of many species whose natural habitats will shift north due to warming temperatures. The sugar maple isn’t alone: The yellow birch, beloved for its bright yellow fall leaves, will also migrate north—possibly above the Canadian border by the early 22nd century, according to National Geographic.

Trees aren’t the only species which will move as a result of changing climate: The range of insects are also predicted to dramatically change. The ash tree, which typically has yellow, red and even purple leaves in the fall, is particularly sensitive to insect-borne diseases. One such insect, the emerald ash borer in North America, has been decimating ash trees—although cold winters could help control the epidemic by reducing the insect population, very cold days have decreased by more than 30 percent in the last century, according to NOAA’s National Centers for Environmental Information.

These somewhat dire predictions have already changed this fall’s display: This year’s extended summer temperatures caused foliage delays in popular leaf peeping spots from Massachusetts to Indiana, among other locations.

But there are some things—besides reducing greenhouse gas emissions—that we can do to help. Fall foliage effects—such as colors, vibrancy, and longevity of those colors—varies by type of tree. Cavender says that by planting a diverse assortment of tree species, we can pave the way for colorful autumns well into the future.

“As the climate changes, it’s critical to plant the right tree in the right environmental conditions,” Cavender tells mental_floss. “The more tree diversity you have, the more likely you are to get fall colors every year.”

The phrase “survival of the fittest” makes it tempting to think of natural selection as an unequivocal engine of progress, one that only makes humans stronger and healthier specimens. But, in reality, the process is more complicated.

“I preach about this in my classes all the time,” Karen Rosenberg, a paleoanthropologist at the University of Delaware, tells mental_floss. “We think of ‘fit’ to mean aerobically fit, or able to run far, but in evolutionary biology, ‘fit’ means being reproductively successful.” In other words, you just need to be able to survive long enough to pass on your genes to the next generation.

To achieve reproductive success, natural selection sometimes makes compromises, and as a result, humans have developed some traits that pose real challenges to our health today. From back injuries to difficult childbirth, here are six downsides of being human that you can blame on evolution.

1. WE HAVE BACK PAIN.

The birth of bipedalism was a high point in human evolution. Standing upright allowed us to travel long distances and freed up our hands to use tools and carry food, but it also came at a cost.

In chimpanzees and our other quadrupedal cousins, the vertebral column acts like a suspension bridge. “But if you take that horizontally stable structure and tilt it vertically, it loses its stability,” Jeremy DeSilva, a paleoanthropologist at Dartmouth College, tells mental_floss.

The most obvious way to make a structurally sound spine in an upright creature would be a straight stack of vertebrae. But this arrangement would block the birth canal, and clearly you need to have babies to ensure the survival of your species. So the human spine had to evolve into the “curved mess” that it is today to make way for our big-brained babies to be born, DeSilva says. The price we pay is back pain—and prevalent injuries like slipped disks and spontaneous compression fractures.

2. WE HAVE WEIRD APEY FEET.

If you look at the most high-tech prosthetic feet available today, their structure is more like an ostrich’s foot. They don’t replicate human anatomy because the anatomically correct human foot is sort of awkward.

“Humans were not designed from scratch,” DeSilva says. “We’ve inherited a lot of the anatomies we have from our ape ancestry, and the foot is a wonderful example.”

When we starting walking on two feet, we no longer needed the flexible feet that our ape ancestors required to climb trees and grab branches. In order to give us more stability and allow us to better push off the ground, evolution took a “paper clips and duct tape” approach, DeSilva says. But because we walk around on modified ape feet that can twist and roll quite easily, we sprain and break our ankles. We get shin splints, plantar fasciitis, and collapsed arches. This isn’t just a modern phenomenon; scientists even see some of these common foot injuries in the fossil record.

“It works well enough, and that’s all you really need in evolution,” DeSilva says. “What we have as a consequence of a just-good-enough foot is a billion-dollar podiatry industry.”

3. CHILDBIRTH IS TRICKY.

Compared with other apes, humans experience very difficult childbirth. That’s largely because the human pelvis is very narrow relative to the big heads and broad shoulders of our babies.

“The pelvis serves two conflicting functions in humans: allowing us to walk on two legs and allowing us to give birth to big-brained babies,” Rosenberg says. The shape of the pelvis is a compromise between those two things.

But humans have come up with an interesting cultural answer to the problem of long and painful birth. While birth is a solitary event for most mammals, Rosenberg pointed out that virtually all human mothers seek delivery assistance from relatives, midwives, or doctors.

In a paper in the British Journal of Obstetrics and Gynaecology, Rosenberg and her colleague Wenda Trevathan wrote that natural selection likely favored the behavior of seeking assistance during birth. This probably wasn’t a conscious decision by expectant mothers. Rather, seeking help might have been driven by fear, anxiety, and pain, but over time, this led to reduced mortality.

4. WE CRAVE JUNK FOOD.

There’s a good reason it’s hard to give up fast food and candy. Sugar is a basic form of energy, and excess sugar is stored as fat to get us through times of hardship. Before the rise of agriculture and industrialization, when food sources were scarce or unreliable, a taste for sugar was necessary for survival. But now that processed sugar is readily available in grocery stores, humans are overdoing it. As a result, we’re facing an obesity epidemic and a rise in conditions like diabetes and high blood pressure.

“The food industry has made a fortune because we retain Stone Age bodies that crave sugar but live in a Space Age world in which sugar is cheap and plentiful,” Harvard evolutionary biologist Daniel Lieberman wrote in an op-ed in The New York Times a few years ago. (He was arguing at the time that New York City’s proposed ban on big sodas might actually help restore the healthy constraints of a hunter-gatherer world.)

5. A LOT OF US HAVE MENTAL ILLNESS.

Natural selection didn’t weed out potentially harmful conditions like schizophrenia and depression, even though many of these disorders are associated with lower birth rates. Some scientists have theorized that the unaffected siblings of the people with mental disorders might be responsible, as they may pass the mutations on to their own children, keeping these disorders in the gene pool. Other scientists have looked at the origins of mental disorders, showing that while devastating, some of these illnesses seem connected to an evolutionary advantage.

For example, while some symptoms of depression can be debilitating, some researchers have argued that the condition can also promote an analytical style of thought that can be very productive at solving problems. Other research has shown that schizophrenia-related genes may have helped humans achieve complex cognition.

6. OUR THIRD MOLARS ARE A PAIN.

After humans started walking upright, we underwent another major transformation: Our brains got much bigger. To accommodate a larger brain, the shape of our faces changed, and our jaws had to become narrower. But for many people, this means that their third molars, or wisdom teeth, once vital for chewing, have no room to erupt through the gums, so they become impacted. If these impacted teeth are not extracted, they can become extremely painful or cause infections.

But natural selection is still at work: A genetic mutation that stops wisdom teeth from forming has been spreading, and more people today are born without third molars.