In other experiments, Provine has proven that yawning has nothing to do with oxygen or carbon dioxide intake. When he pumped pure oxygen into subjects, for example, their frequency of yawning did not change.
Provine’s research also supports the relationship between boredom and yawning. Considerably more subjects yawned while watching a thirty-minute test pattern than while watching thirty minutes of rock videos (although he didn’t poll the subjects to find out which viewing experience was more bearable—we wouldn’t yawn while watching and listening to thirty minutes of fingernails dragged across a blackboard, either). Did the subjects yawn for psychological reasons (they were bored) or for physiological reasons (boredom made them sleepy)?
When Provine asked his students to fill out diaries recording their every yawn, certain patterns were clear. Yawning was most frequent the hour before sleep and especially the hour after waking. And there was an unmistakable link between yawning and stretching. People usually yawn when stretching, although most people don’t stretch every time they yawn.
Yawning is found throughout the animal kingdom. Birds yawn. Primates yawn. And, when they’re not sleeping, fish yawn. Even human fetuses have been observed yawning as early as eleven weeks after conception. The child psychologist Piaget noted that children seemed susceptible to yawning contagion by the age of two. It was clear to Provine that yawning was an example of “stereotyped action pattern,” in which an activity once started runs out in a predictable pattern. But what’s the purpose of this activity?
Although Provine is far from committing himself to an answer of why we yawn, he speculates that yawning and stretching may have been part of the same reflex at one point (one could think of yawning as a stretch of the face). Bolstering this theory is the fact that the same drugs that induce yawning also induce stretching.
The ubiquity of yawning epidemics was obvious to all the people who sent in this Imponderable. Provine told Imponderables, “Virtually anything having to do with a yawn can trigger a yawn,” and he has compiled data to back up the contention:
55% of subjects viewing a five-minute series of thirty yawns yawned within five minutes of the first videotaped yawn, compared to the 21% yawn rate of those who watched a five-minute tape of a man smiling thirty times.
Blind people yawn more frequently when listening to an audiotape of yawns.
People who read about yawning start yawning. People who even think about yawning start yawning. Heck, the writer of this sentence is yawning as this sentence is being written.
If we are so sensitive to these cues, Provine concludes that there must be some reason for our built-in neurological yawn detectors. He concludes that yawning is not only a stereotyped action pattern in itself, but also a “releasing stimulus” that triggers another consistently patterned activity (i.e., another yawn) in other individuals. Yawns have the power to synchronize some of the physiological functions of a group, to alter the blood pressure and heart rate (which can rise 30% during a yawn).
Earlier in our evolution, the yawn might have been the paralinguistic signal for members of a clan to prepare for sleep. Provine cites a passage in I. Eibl-Eibesfeldt’s Ethology, in which a European visitor to the Bakairi of Central Brazil quickly noted how yawns were accepted behavior:
If they seemed to have had enough of all the talk, they began to yawn unabashedly and without placing their hands before their mouths. That the pleasant reflex was contagious could not be denied. One after the other got up and left until I remained…
Yet, Provine is not willing to rule out our evolutionary theory either. Perhaps at one time, the baring of teeth sometimes apparent in yawning could have been an aggressive act. Or more likely, combined with stretching, it could have prepared a group for the rigors of work or battle. When bored or sleepy, a good yawn might have revivified ancient cavemen or warriors.
So even if Dr. Provine can’t yet give us a definitive answer to why yawning is contagious, it’s nice to know that someone out there is in the trenches working full-time to stamp out Frustability. If Dr. Provine finds out any more about why yawning is contagious, we promise to let you know in the next volume of Imponderables.
Submitted by Mrs. Elaine Murray of Los Gatos, California. Thanks also to Esther Perry of Clarks Summit, Pennsylvania; Julie Zumba of Ocala, Florida; Jo Ellen Flynn of Canyon Country, California; Hugo Kahn of New York, New York; Steve Fjeldsted of Huntington Beach, California; Frank B. De Sande of Anaheim, California; Mark Hallen of Irvington, New York; Raymond and Patricia Gardner of Morton Grove, Illinois; Jim White of Cincinnati, Ohio; Renee Nank of Beachwood, Ohio; and many others.
A free book goes to Christine Dukes of Scottsdale, Arizona, for being the first to direct us to Dr. Provine.
FRUSTABLE 5: Why Do We Give Apples to Teachers?
This Frustable has remained remarkably resistant to reasoned replies. Although few readers could supply hard evidence to back their claims, a lot of people sure seemed to think they knew the answer to this one.
Two theories predominated. The most popular answer was the Biblical explanation. In Genesis, the forbidden fruit comes from the tree of knowledge. Although the forbidden fruit is never specified, the apple has over time been given that distinction. As Lou Ann M. Gotch of Canton, Ohio, puts it:
the apple has come to signify knowledge. Perhaps by giving an apple to the teacher our children are admitting that they’re little devils. Or perhaps they are intimating that the teachers could use a little more knowledge.
The second camp traces the custom to early rural America, when teachers were given free room and board but little pay. Students and their families traditionally brought something to contribute to the school and/or the teacher, be it wood for a fire or fruit for consumption.
But why an apple? As Georgette Mattel of Lindenhurst, New York, points out, apples were cheap and plentiful. Donald E. Saewert adds that the apple is the only fruit that can be stored for long periods of time without canning. In the winter, it might have been the only fresh fruit that was available in many areas. And Ann Calhoun of Los Osos, California, closes this argument with an impressive volley: “Sure would beat dragging a twelve-foot stalk of corn to school.”
Both of these arguments are plausible but certainly not proven. Two readers sent us evidence of other possible solutions to this Frustable.
Ann Calhoun mentions that perhaps the apple-teacher connection was made up by an illustrator in one of the nineteenth-century illustrated magazines (“Every illustration I’ve seen…includes a very pretty young teacher, a blushing hayseed boy of nine, and a classroom of giggling sniggerers.”)
Calhoun speculates that the boy gives the teacher an apple not as a symbol of knowledge but as a symbol of beauty. For according to ancient Greek legend, the highly prized golden apples that grew in the Garden of the Hesperus were awarded for beauty at the Judgment of Paris. Calhoun continues:
In every Rockwellian illustration of this theme…the teacher is young and beautiful. Since older generations were heavily schooled in the classics (as ours is not) the teacher and kids would get the reference immediately. And yes, there are satiric variations with the teacher depicted as old, fat, gray, ugly, and scowling. The reason for her sour expression is that she also knows the original reference, knows the satiric content of the gesture and is about to send that little hypocritical, mendacious, miscreant presenter out behind the barn for a thrashing he so richly deserves…. I truly can’t imagine a spindly young cleric presenting his medieval monkish tutor with an apple for beauty. Such impertinence would only earn him a thrashing outside the castle walls. So when and where did all this apple presenting and polishing start?
Good question. We’ve heard from only one person who dares to speculate on this. We received a fascinating letter from Henry C. Hafliger, member of the Board of Trustees of the San Jacinto Unified School District. He traces the custom back to Switzerland and cites the book Bauerspiegel, written by Jeremiah Gotthelf in the early nineteenth century. Gotthel
f was a disciple of Johann Pestalozzi, the Swiss educator and reformer who had a tremendous influence on American education in the nineteenth century.
In effect, Bauerspiegel chronicles a Swiss equivalent to our rural explanation for the custom. Hafliger summarizes:
when education was first offered to all classes of children in Switzerland, salaries of teachers were subsistence at best. Parents would supplement teachers’ salaries with food, and one of the easiest foods to bring to school was the apple. Farmers would keep apples in their cellars all year long because in those days apples were not considered a dessert but a staple. Gotthelf writes that children soon learned that the child who brought the apple received the least amount of swats with the pointer or switch that the teacher always carried. The children from the poor families, some of whom did not have enough food themselves, were at a distinct disadvantage.
Hafliger’s theory, then, was that the fruit was originally given on the premise that “an apple a day keeps the switch away.”
Submitted by Malinda Fillingion of Savannah, Georgia. Free books go to Ann Calhoun of Los Osos, California; and Henry C. Hafliger of San Jacinto, California.
FRUSTABLE 6: Why Does Looking up at the Sun Cause Many People to Sneeze?
Of all the Frustables, we came closest to getting a definitive solution to number six. Most of the people who responded were sun-sneezers themselves, and some said that just looking up at a bright light or even at the reflection from a car bumper was enough to set off the achoo mechanism.
The more than one hundred letters we received on this topic almost all carried some variation of the same theme. After a little digging, we found out that the most popular explanation was far from the only possible one.
We do know this much: Somewhere between 25 to 33% of the population is afflicted with “photic sneeze reflex.” It is almost certainly a hereditary condition. Reader Margy D. Miller of DeKalb, Illinois, reports that she and all four of her children all sneeze when they first step out of doors into the bright sun.
The most accepted explanation for the photic sneeze reflex is that light signals that should irritate the optic nerves somehow trigger receptors that play a part in the sneezing process. The neural tracts for the olfactory and optic sensory organs lie adjacent to each other and have close (but not identical) insertion points in the brain.
When some people with this particular genetic predisposition encounter a bright light for the first time, the pupils do not contract as rapidly as they should, and the eyes are irritated. Somehow—neurologists we spoke to could not specify how—the olfactory and neural tracts cross-circuit.
The result: The nerves fool the brain into thinking that there is a foreign irritant in the nasal mucosa. The brain does what comes naturally; it tries to rid the sinuses of the phantom dust or pollen. The brain sends out a sneeze reflex.
Case closed?
Not quite. Reader John W. Lawrence, M.D., who specializes in internal medicine and rheumatology, gave us a variation of the above. He concurs that the original cause of the sneeze is eye irritation, but believes that the tears caused by the irritation actually trigger the sneeze:
Many people develop eye sensitivity to light. This sensitivity results in a lacrimal outburst (making of excess tears) in response to the irritation. The excess tears then run off down the lacrimal duct, which is present for this purpose. The lacrimal duct empties into the back of the nasopharynx. A drippage of liquid into the back of the nose triggers the sneeze.
Only when tearing exceeds the lacrimal duct’s capacity to carry runoff do tears overflow and “run down the cheeks.”
William J. Dromgoole, a reader from Somerdale, New Jersey, sent us a newspaper clip indicating that scientists at Scripps Clinic and Research Foundation in La Jolla, California, have found evidence that certain allergy treatments for runny noses can cause photic sneeze reflex. Simply switching medications has rid some people of this mildly vexing problem.
Several readers have written to ask why they always seem to sneeze a particular number of times (sometimes twice, but usually three times). ENT specialists we talked to pooh-poohed it. Anyone have a theory to explain this phenomenon?
Submitted by Rick Stamm of Redmond, Washington. Thanks also to William Debuvitz of Bernardsville, New Jersey; and Lisa Madsden of Minneapolis, Minnesota.
A free book goes to James Miron, R.N., of Republic, Michigan.
FRUSTABLE 7: Why Does the First Puff of a Cigarette Smell Better than Subsequent Ones?
As we indicated in Why Do Clocks Run Clockwise?, the research departments of the major cigarette companies couldn’t (or wouldn’t) answer this Imponderable. Similarly, the Tobacco Institute and the Council For Tobacco Research—U.S.A., Inc., claimed that although much research has been conducted on the sensory awareness of cigarette smoke, this phenomenon was neither universal nor verifiable.
Luckily, Imponderables readers aren’t as reticent as the professionals in the field. We don’t have a definitive answer to this Frustable, but readers supplied us with three plausible explanations.
The Physiological Theory. Richard H. Hawkins, D.D.S., president of Medical Innovators of North America, argues that the first puff of a cigarette smells best because the olfactory nerve endings within the nasal cavity are able to interpret the smell sensation only after a rest period. “With repeated puffs, the olfaction perception goes to zero.” This argument might explain why a smoker derives increasingly less satisfaction from subsequent puffs, but doesn’t explain why nonsmokers, who might find cigarette smoke irritating and obnoxious, find the aroma of the first puff pleasant.
Reader Albert Wellman of Santa Rosa, California, speculates that the difference between first puffs and subsequent ones is the physical process of burning the tobacco leaves. “I suspect that once the major portion of the chemical responsible for the ‘good smell’ of cigarette smoke has been vaporized by the first puff of smoke, there is not enough left in the tobacco to provide a comparable olfactory experience from the remainder of the cigarette.”
Wellman also hypothesizes that perhaps the olfactory nerves are temporarily blocked by some other active biochemical agent in the smoke. This theory is bolstered somewhat by research that indicates that although olfactory organs are easily fatigued, the fatigue is limited to one particular flavor. Usually, the nose will respond to a new or different smell, and there are 685 different chemical compounds found in leaf tobacco smoke.
Most of the (little) hard research we have been able to find on the sensory response to cigarette smoke doesn’t corroborate these physiological explanations. Dr. William S. Cain, of the departments of Epidemiology and Public Health and Psychology at Yale University, argues that smokers don’t really “taste” cigarettes in the conventional sense. The four tastes—sweet, sour, salty, and bitter—don’t play much of a role in cigarette enjoyment; of the four, only the bitter is perceived by the smoker.
But Cain argues that the sense of smell is not very important either, and in the last words of the following, hints at the problem posed in this Frustable:
it matters little for smoking enjoyment whether the smoke is exhaled through the nose or through the mouth. Smell may play a role at the moment the smoker lights up, but adaptation rapidly blunts olfactory impact.
The Tobacco as Filter Theory. Reader Jack Perkins of San Francisco, California, writes:
As a long-time heavy smoker, I can tell you that the first puff not only smells better, it’s milder. The reason for this is that the tobacco acts as a filter catching tars, nicotine, and chemicals. The further down you smoke, the greater the build-up of these substances, resulting in harsher smoke.
Rev. David C. Scott, of Bethany Presbyterian Church in Rochester, New York, agrees, adding, “The first puff has the advantage of being filtered both by the longest filter and cleanest filter…. Each subsequent puff both shortens the filter and dirties even more what remains. Andrew F. Garruto of Kinnelon, New Jersey, compares smoking the stub of a cigarette to making
a pot of coffee through used grains.
All of these arguments explain why the purity of taste and smell deteriorate as a cigarette has been smoked. But none explains to the nonsmoker why the first puff smells fine but then deteriorates immediately.
The Burning Wood, Sulfur, and Butane Theory. Even if we can’t confirm any of these theories for sure, we like this modest explanation the best. Perhaps the reason why the first puff smells better is that the aroma of the lighting agent, not the tobacco, is what we are responding to. We received this letter from Allison Rosenthal, of Rancho Palos Verdes, California:
People have always loved the smell of burning wood. By burning tree branches, pine needles, and pine cones, many not only warm their houses but improve the smell therein. If you have ever gone for a walk in Mammoth [California] in the winter, you would surely be familiar with this wonderful scent. A burning match smells much the same, maybe even a little better. Not only do you have a form of wood on a match but also sulfur, which is very pleasing when mixed with wood smoke. If you use a large ‘Diamond’ wood match and pull on the cigarette hard enough when lighting it, you can actually taste the sulfur and wood mixture. Even though it doesn’t taste so good, it does smell nice.
When Do Fish Sleep? Page 19