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Do People Really Walk in Circles When They’re Lost?

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It’s a reliable movie trope: Our heroes are lost in the woods, and in their valiant effort to make a beeline out of the forest or back to camp or civilization, they inevitably get turned around and wind up back at the same spot where they began.

When a science television show approached Jan Souman, a research scientist at the Max Planck Institute for Biological Cybernetics, with a viewer’s question about the phenomenon, Souman wasn't sure if people actually did accidentally circle back. When lost, he thought, people would probably veer left or right randomly, but not actually circle back.

To find out, he and his research group gathered nine volunteers and stuck six of them in a German forest and the other three in the Tunisian desert. All of them were instructed to walk as straight as possible in one direction for several hours while wearing GPS receivers so that the researchers could analyze their routes.

Course Correction

Souman found that all of them eventually veered off course, and more than half did end up circling back to cross their own paths without realizing it. There was an interesting twist, though. The circling only happened with the four of the forest walkers who made their journeys in overcast conditions and the one desert walker who walked on a night with no visible moon. Those who could see the sun or moon managed to travel in straighter lines and, when they did lose their way, moved as Souman had predicted, veering left and right while generally going in the same direction and not crossing back on their route.

In a second experiment, the researchers had 15 volunteers try to walk in a straight line for an hour while blindfolded. When they couldn't see at all, the walkers circled back sooner, more often, and in tighter arcs, sometimes making a circle about the size of a basketball court.

The two experiments cast doubt on an older idea that this kind of disorientation comes from biomechanical asymmetries—like a differences in length or strength between the left and right legs—that create small but consistent directional bias. That would cause a person to consistently veer off in the same direction, especially when the person is blindfolded and without visual cues to compete with the bias. But only three of the walkers had a tendency to veer in one direction, while the others varied wildly in their circling, with their paths looking like a child had scribbled on a piece of paper. Walking in circles, Souman and his team think, isn’t caused by some physical bias, but an uncertainty about where straight ahead lies that increases over time.

Visual Clues

For the walkers in the first experiment, visual cues appeared to be very important. Those who could see some external reference point—the sun, the moon, a hill in the far distance—could use it to recalibrate their sense of direction and maintain a relatively straight path. (Interestingly, Souman notes that the volunteers in the first experiment walked for several hours, during which the sun moved about 50 to 60 degrees; rather than following a correspondingly bent path, they were able to correct for this, even if subconsciously.)

The volunteers who walked when it was cloudy or dark or while they were blindfolded didn’t have this luxury and walked in circles. Without a reference point to maintain their course, these subjects had to rely on other cues, like sounds and information from the vestibular system, which aids in movement, balance and spatial orientation. Small random mistakes in the processing of these cues, Souman and team think, add up over time, especially when the senses are limited. Eventually, the internal compass fails and “random changes in the subjective sense of straight ahead” lead a person off the straight and narrow path and right back where they started from.

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Big Questions
What Do Morticians Do With the Blood They Take Out of Dead Bodies?
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Zoe-Anne Barcellos:

The blood goes down the sink drain, into the sewer system.

I am not a mortician, but I work for a medical examiner/coroner. During an autopsy, most blood is drained from the decedent. This is not on purpose, but a result of gravity. Later a mortician may or may not embalm, depending on the wishes of the family.

Autopsies are done on a table that has a drain at one end; this drain is placed over a sink—a regular sink, with a garbage disposal in it. The blood and bodily fluids just drain down the table, into the sink, and down the drain. This goes into the sewer, like every other sink and toilet, and (usually) goes to a water treatment plant.

You may be thinking that this is biohazardous waste and needs to be treated differently. [If] we can’t put oil, or chemicals (like formalin) down the drains due to regulations, why is blood not treated similarly? I would assume because it is effectively handled by the water treatment plants. If it wasn’t, I am sure the regulations would be changed.

Now any items that are soiled with blood—those cannot be thrown away in the regular trash. Most clothing worn by the decedent is either retained for evidence or released with the decedent to the funeral home—even if they were bloody.

But any gauze, medical tubing, papers, etc. that have blood or bodily fluids on them must be thrown away into a biohazardous trash. These are lined with bright red trash liners, and these are placed in a specially marked box and taped closed. These boxes are stacked up in the garage until they are picked up by a specialty garbage company. I am not sure, but I am pretty sure they are incinerated.

Additionally anything sharp or pointy—like needles, scalpels, etc.—must go into a rigid “sharps” container. When they are 2/3 full we just toss these into one of the biotrash containers.

The biotrash is treated differently, as, if it went to a landfill, then the blood (and therefore the bloodborne pathogens like Hepatitis and HIV) could be exposed to people or animals. Rain could wash it into untreated water systems.

This post originally appeared on Quora. Click here to view.

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Why Does Asparagus Make Your Pee Smell Funny?
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The asparagus has a long and storied history. It was mentioned in the myths and the scholarly writings of ancient Greece, and its cultivation was the subject of a detailed lesson in Cato the Elder's treatise, On Agriculture. But it wasn't until the turn of the 18th century that discussion of the link between asparagus and odorous urine emerged. In 1731, John Arbuthnot, physician to Queen Anne, noted in a book about food that asparagus "affects the urine with a foetid smell ... and therefore have been suspected by some physicians as not friendly to the kidneys." Benjamin Franklin also noticed that eating asparagus "shall give our urine a disagreeable odor."

Since then, there has been debate over what is responsible for the stinky pee phenomenon. Polish chemist and doctor Marceli Nencki identified a compound called methanethiol as the cause in 1891, after a study that involved four men eating about three and a half pounds of asparagus apiece. In 1975, Robert H. White, a chemist at the University of California at San Diego, used gas chromatography to pin down several compounds known as S-methyl thioesters as the culprits. Other researchers have blamed various "sulfur-containing compounds" and, simply, "metabolites."

More recently, a study demonstrated that asparagusic acid taken orally by subjects known to produce stinky asparagus pee produced odorous urine, which contained the same volatile compounds found in their asparagus-induced odorous urine. Other subjects, who normally didn't experience asparagus-induced odorous urine, likewise were spared stinky pee after taking asparagusic acid.

The researchers concluded that asparagusic acid and its derivatives are the precursors of urinary odor (compared, in different scientific papers, to the smell of "rotten cabbage," "boiling cabbage" and "vegetable soup"). The various compounds that contribute to the distinct smell—and were sometimes blamed as the sole cause in the past—are metabolized from asparagusic acid.

Exactly how these compounds are produced as we digest asparagus remains unclear, so let's turn to an equally compelling, but more answerable question:

WHY DOESN'T ASPARAGUS MAKE YOUR PEE SMELL FUNNY?

Remember when I said that some people don't produce stinky asparagus pee? Several studies have shown that only some of us experience stinky pee (ranging from 20 to 40 percent of the subjects taking part in the study, depending on which paper you read), while the majority have never had the pleasure.

For a while, the world was divided into those whose pee stank after eating asparagus and those whose didn't. Then in 1980, a study complicated matters: Subjects whose pee stank sniffed the urine of subjects whose pee didn't. Guess what? The pee stank. It turns out we're not only divided by the ability to produce odorous asparagus pee, but the ability to smell it.

An anosmia—an inability to perceive a smell—keeps certain people from smelling the compounds that make up even the most offensive asparagus pee, and like the stinky pee non-producers, they're in the majority.

Producing and perceiving asparagus pee don't go hand-in-hand, either. The 1980 study found that some people who don't produce stinky pee could detect the rotten cabbage smell in another person's urine. On the flip side, some stink producers aren't able to pick up the scent in their own urine or the urine of others.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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