by Alex Boese
Space Invaders in the Loo
A man sits in a stall at a public lavatory on a college campus. He has been there for well over an hour. At his feet is a stack of books, and hidden among these books is a small periscope he is using to peer beneath the door and watch a man standing at a urinal, going to the bathroom. Through his periscope the stall-sitter can see the stream of urine trickling down the porcelain into the drain. The urine stops, and he immediately presses a button on a stopwatch he holds in his hand.
The man in the stall was not a Peeping Tom. He was actually a reputable researcher conducting a scientific experiment. At least that was his story, and he was sticking to it.
The location of this peculiar scene was “a men’s lavatory at a midwestern U.S. university.” The date was sometime in the mid-1970s. Let’s momentarily follow a hypothetical person, probably a student at the university, who wandered into the lavatory and unwittingly became a participant in the stall-sitter’s experiment. We’ll call him Joe.
Feeling some pressure in his bladder, Joe ducks into the toilets. He sees two stalls and three urinals that extend up from the floor. One of the stalls is occupied by someone who has piled his books at his feet—the covert watcher. But Joe ignores the stalls and heads straight for the urinals. A man is standing at the middle urinal, and a sign hanging on the rightmost urinal reads, “Don’t use, washing urinal.” So Joe walks up to the leftmost one.
He stands next to the other man—sixteen inches away from him, to be exact—and unzips his fly. Unbeknownst to him, at that moment the man sitting in the stall presses a button on his stopwatch.
Joe can sense the presence of the guy standing next to him. He is, perhaps, a little too close for comfort. But Joe really has to go, so he concentrates, tuning out the thought of the stranger’s proximity. At last his bladder muscles relax and the urine starts to flow.
Peering through his periscope, the researcher in the stall sees the stream of urine begin to trickle downward. He presses another button on the stopwatch.
Eighteen seconds later Joe is finished. (The watcher in the stall presses another button.) Joe zips up his fly and walks to the sink to wash his hands. He notices the man at the middle urinal still hasn’t finished. “Poor guy,” he thinks, “must be having trouble going.” Then he dries his hands and leaves, blissfully unaware that he just took part in an experiment.
This scene, with a few variations, played out sixty times at the midwestern university, as different unwitting subjects wandered in and out of the restroom.
The purpose of all this clandestine loo activity was to determine whether “decreases in interpersonal distance lead to arousal as evidenced by increases in micturition delay and decreases in micturition persistence.” Translated into plain English: Do guys have more difficulty peeing when they feel crowded? On a nonscientific level, most men would say yes, obviously this is true. Pop culture offers a variety of terms to describe the phenomenon—“choking at the bowl” or “stage fright.” But the researchers wanted empirical data, not hearsay. If they could establish a connection between crowding and “onset of micturition,” this would demonstrate, they believed, that the body reacts with signs of stress when strangers get too close or invade our personal space.
The experimenters manipulated conditions in the lavatory to force subjects to urinate while standing at varying distances from a stranger. In the “close distance condition,” one of the experimenters pretended to use the middle urinal while the DON’T USE sign hung on the rightmost one, forcing subjects to use the one immediately to the experimenter’s left. In the “moderate distance condition,” he stood at the right-most urinal with the “don’t use” urinal between him and the subjects. In the control condition, signs hung on two of the three urinals, allowing people to pee in relative privacy. Meanwhile the researcher in the stall timed how long subjects took to start urinating, and the duration of their urination.
The results revealed that “closer distances led to increases in micturition delay and decrease in micturition persistence.” When guys had to stand shoulder to shoulder with a stranger, they waited, on average, 8.4 seconds before their urine started to flow. They were done 17.4 seconds later. At a moderate distance they fared slightly better—a 6.2-second wait and a 23.4-second duration. But in the control condition, the wait lasted only 4.9 seconds and subjects enjoyed a leisurely 24.8-second pee. This means that for a guy with a full bladder, a crowded bathroom can mean 3.5 extra seconds before the arrival of relief. And sometimes those 3.5 seconds seem like a loooong time.
When published in the prestigious Journal of Personality and Social Psychology, this study was not universally well received. Gerald Koocher of the Harvard Medical School wrote in, blasting it as “laughable and trivial.” He also expressed fear that its publication would encourage a “veritable flood of bathroom research.” We can now say that this fear was unjustified. It has, in fact, been more of a slow but steady trickle of research, inhibited perhaps by all those strangers standing close by, waiting and watching.
Middlemist, R. D., E. S. Knowles, & C. F. Matter (1976). “Personal Space Invasions in the Lavatory: Suggestive Evidence for Arousal.” Journal of Personality and Social Psychology 33: 541–46.
Communal Peeing in Ants
The rain begins to fall in the Malaysian rain forest. Water droplets tumble through the thick, humid air, onto the lush vegetation below. Leaves shake as the downpour hits. Giant bamboo stalks sway with the force of the storm. Inside the internodes of the giant bamboo, the rain is flooding a nest that ants from the species Cataulacus muticus have spent years building. The nest must be saved. The worker ants mobilize, squeezing their bodies into the entrances, blocking the water with their heads. But it’s not enough. Water still leaks in. Luckily, the others know what to do. Hours later the rain has passed, and the nest is bone dry.
After studying ants in the Malaysian rain forest for years, Joachim Moog and Ulrich Maschwitz thought they knew a lot about ant behavior. But Cataulacus muticus was a puzzle to them. How did this ant get the water out of its nest?
Many ant species transport water by holding it in their mouths, then spitting it out. Other ants carry droplets on their backs. But Moog and Maschwitz didn’t observe this behavior. Something else seemed to be going on. Something far weirder.
To solve the mystery, the researchers brought a Cataulacus muticus ant colony back to their lab at Frankfurt University and subjected it to experimental flooding. They injected two milliliters of yellow-dyed water directly into the nest. Like students at a party, the ants immediately began to drink as much of the yellow liquid as they could. Twenty minutes later they exited the nest en masse. Moog and Maschwitz then observed:
They moved sideward for several centimeters and raised their gasters steeply. Immediately a clear droplet appeared at the gaster tip which rapidly grew and fell down within a few seconds.
The ants were peeing the water away. To make sure they were seeing this correctly, the researchers repeated the experiment, with the same results. They calculated that 3,030 pee runs were required to dry out the nest.
Such “cooperative peeing behavior” had never before been observed in ants. Moog and Maschwitz tested other species, but found none that employed the same strategy. Cataulacus muticus appears to be the only ant species that uses its bladder for flood control.
The communal peeing of Cataulacus muticus truly is a wonder of evolution. That an ant species developed such an ingenious nest-saving technique boggles the mind. Unfortunately, the same cannot be said of the communal peeing of students.
Maschwitz, U., & J. Moog (2000). “Communal Peeing: A New Mode of Flood Control in Ants.” Naturwissenschaften 87: 563–65.
The Sweet Smell of Diapers
Feces are disgusting. People don’t like coming into contact with them, and will in fact go to great lengths to avoid them. This disgust protects us from bacterial infection. But why, psychologists Trevor Case, Betty Repacholi, and Richard Stevenson wondered,
doesn’t disgust prove to be more of an obstacle to child care? Babies may be cute and lovable, but they’re also prodigious poop machines. Why don’t mothers recoil in loathing at the thought of getting up close and personal with another person’s excrement? Perhaps, the researchers theorized, some kind of “source effect” modifies the disgust reaction. Perhaps feces (and other unpleasant substances) inspire less disgust if they come from sources familiar to us, such as our own child.
To test this theory, the researchers recruited thirteen mothers to participate in a “Baby Smell Study.” This description was slightly euphemistic. The task asked of each subject was actually to sniff dirty diapers, both of her own baby and a stranger’s baby, and rate which she found less offensive.
Before the experiment began, the mothers submitted diapers freshly soiled by their babies. The experimenters had stockpiled dirty diapers from a control baby. These were stored in a refrigerator to keep them fresh, but were taken out two hours before the test and allowed to warm to room temperature. By the time the sniffing began, they were good and rank.
To ensure the mothers couldn’t identify the diapers by sight, the experimenters placed each diaper in a covered plastic bucket. The aroma wafted up through a hole in the lid. Mothers put their noses right up to the hole and took a good whiff.
The mothers participated in a total of three trials. In the first trial the diaper-bearing buckets were unmarked. In the second and third trials they bore labels identifying the diapers either as those of the mother’s child or of “someone else’s baby.” However, in one of the trials these labels were incorrect.
After smelling the stinky diapers, the mothers rated each odor on how disgusting they thought it was. The results were unequivocal. Mothers preferred the smell of their own baby’s poop. In all three of the conditions—unlabeled, correctly labeled, and incorrectly labeled—the mothers rated the odor of their own baby’s dirty diapers as less offensive than that of the other diapers. Surprisingly, this preference was most pronounced in the blind trial, where the mothers had no clue which diaper was which.
The preference was so clear-cut the experimenters briefly worried that the control baby’s diapers might have been unusually stinky. But the experimenter who handled and prepared the soiled diapers assured them this was not the case. He insisted the odor of all the diapers was “similarly intense and overpoweringly unpleasant.”
The experimenters offered two reasons why a mother prefers the smell of her own baby’s poop. Either they become used to the smell through repeated contact, or they are able to detect “some quality that signals relatedness.” Case, Repacholi, and Stevenson left it to future researchers to provide further clarification.
This experiment ultimately offers a reassuring message: No matter how stinky, ugly, or disgusting we are, one person will always think we’re great—our mother.
Case, T. I., B. M. Repacholi, & R. J. Stevenson (2006). “My Baby Doesn’t Smell as Bad as Yours: The Plasticity of Disgust.” Evolution and Human Behavior 27: 357–65.
Fart-ology
Sometime in the early stone age, the first joke is about to be told.
A small group of cavemen creeps through a forest, clubs in hand. Danger lurks everywhere. They must constantly be on guard. Suddenly the caveman in the lead stops and signals his companions to be silent. They all freeze in place, straining to hear any noises made by a predator. The leader looks slowly back and forth. He signals the others to listen. And then he lets one rip. Caveman guffawing ensues.
As the story of the flatulent caveman illustrates, farts have always been the butt of jokes (so to speak). The merriment that surrounds them has tended to inhibit serious research. However, there are people who make a living studying farts. In vain they point out that excessive flatulence causes extreme discomfort and distress. Someone has to study the problem, no matter how amusing it seems to everyone else. To paraphrase a joke of more recent vintage, for most a fart is just a fart, but for fart doctors it’s their bread and butter.
As a sign of the slow advance of fart studies, not until 1991 did researchers precisely determine the normal amount of flatulence produced by healthy subjects in one day. A study conducted at the Centre for Human Nutrition at the University of Sheffield recruited ten volunteers (five men and five women) each willing to live with a “flexible gas impermeable rubber tube” inserted forty millimeters into his or her anus for twenty-four hours. The tube, held in place by surgical tape, led to a plastic bag, from which no gas could escape. The researchers made sure of this:
The competence of this gas collection system was validated in two volunteers who submerged the lower parts of their bodies in warm water for an hour during which time there were no detectable leaks (bubbling) and gas was collected in the bags.
The subjects ate a normal diet supplemented by two hundred grams of baked beans, to ensure flatus production. Whenever the need to defecate arose, subjects closed off their bag, removed the tube, did their business as quickly as possible, and reinserted the tube. After a day of collection, the gas volume was measured. The median volume came out to 705 milliliters. An average of eight episodes of flatulence were reported. This translated to a median volume of 90 milliliters per episode. The women and men expelled equivalent amounts, proving the equality of the sexes, at least in this matter.
Even more shocking, it was not until 1998 that science identified the exact gases responsible for flatus odor. Dr. Michael Levitt of the Minneapolis Veterans Affairs Center used the same rectal-tube-and-bag system as the 1991 study to collect flatus from sixteen healthy subjects who ate pinto beans the night before to enhance production. Samples were then drawn from the bags via syringe and given to two judges to rate for intensity:
In an odour-free environment, the judges held the syringe 3 cm from their noses and slowly ejected the gas, taking several sniffs. Odour was rated on a linear scale from 0 (“no odour”) to 8 (“very offensive”).
And you think your job sucks.
Odor intensity correlated with high levels of sulfur gases: hydrogen sulfide, methanethiol, and dimethyl sulfide. These gases were isolated and presented individually to the judges, who described them, respectively, as “rotten eggs,” “decomposing vegetables,” and “sweet.” Therefore Levitt could positively identify hydrogen sulfide as the gas that causes real stinkers. The sickly sweet kind of wiffies, by contrast, are due to an excess of dimethyl sulfide.
Intriguingly, Levitt’s study did find a difference between men and women. The women’s farts “had a significantly higher concentration of hydrogen sulfide (p<0.01) and a greater odour intensity (p<0.02) than did that of men.” But the men held their own by producing a greater volume of gas overall. So, for now, we can still call this battle of the sexes a draw.
Suarez, F. L., J. Springfield, & M. D. Levitt (1998). “Identification of gases responsible for the odour of human flatus and evaluation of a device purported to reduce this odour.” Gut 43: 100–4.
CHAPTER NINE
Making Mr Hyde
Human nature has two sides—good and evil. What causes one side to grow stronger than the other? For Robert Louis Stevenson’s character Dr. Henry Jekyll, it was a salt containing an “unknown impurity.” When Jekyll mixed this salt into a solution and drank it, he transformed into the murderous Mr. Hyde. Many real-life researchers have shared Jekyll’s—and Stevenson’s—fascination with humankind’s wicked ways. They have studied what causes people to become rude, antisocial, overly aggressive, and cruel. Unnervingly, the answers they come up with rarely involve anything as elaborate as crystalline salts. Scientists have discovered that to bring out the worst in a person, it usually suffices to place him or her in the right situation. As Philip Zimbardo, whom we shall meet later in this chapter, once observed, “Any deed that any human being has ever done, however horrible, is possible for any of us to do—under the right or wrong situational pressures.” Of course, the same is true in reverse. Given the right situation, any person can be turned into a sa
int. And many researchers do study the causes of altruistic behavior. But let’s be honest—the villains are always more interesting.
Shocking Obedience
A nervous-looking man in a tight-fitting white T-shirt leans forward and speaks into the microphone. “Learner, what is your answer?”
There is no reply. After a few seconds, the man repeats the question more forcefully, “Learner, what is your answer?”
Suddenly a voice shouts through the wall, “I refuse to answer. Let me out of here.”
“You’ve got to answer, otherwise you get a shock.”
“I won’t answer. You can’t hold me here. Get me out. Get—me—out—of—here.”
The man turns in his chair and gazes imploringly at the lab-coat-wearing researcher seated behind him. “I don’t think he’s going to answer.”
The researcher calmly replies, “If the learner doesn’t answer in a reasonable time, consider the answer wrong.”
“But he’s yelling in there. He wants out.”
“Please continue.”
“Maybe we should check in on him. He said that he had a weak heart.”
“The experiment requires that you continue.”
The man sighs and turns back around. He stares at the instrument panel in front of him. The panel displays a row of thirty switches. Each switch is marked with a voltage level, from 15 volts on the far left, progressing upward in increments of 15 to 450 volts on the far right. Beneath the switch marked 315 volts is a warning: EXTREME INTENSITY SHOCK. The man carefully places his finger on this switch. Then he removes it. Once again he turns to face the researcher.