Bechorot 36a ~ How Often do People Lie?

בכורות לו, א

מילתא דעבידא לאיגלויי לא משקרי בה אינשי

People do not lie about something that may later be revealed [as having been false]

Can a Cohen may be relied upon to testify that first-born animal in his possession has been declared by an expert to have a blemish (which would widen its permitted uses)? Rav Yehuda ruled (in the name of Rav) that the Cohen should indeed be believed. Since that expert could come forward and state that he issued no such ruling, the Cohen would not risk being discovered as having lied. In a small village or town of a few dozen to a few hundred families, this ruling is reasonable. To lie would expose the Cohen to the risk that his fraud might be exposed. But does Rav Yehuda’s no-lying rule make sense in today’s society?

It is important to point out at the outset that Rav Yehuda is not claiming that, as a rule, people do not lie. His point is that if they risk being discovered, they will not do so. So if there is no risk of the lie being detected, well, all bets are off.

“Most people lie often”

In 2002 Robert Feldman published a study demonstrating that 60% of people lied at least once during a 10-minute conversation and told an average of two to three lies. Now this cannot really be generalized, since it involved 121 pairs of undergraduate psychology students at a large state university who had to speak to a stranger for a period of time in a laboratory setting (and for their participation, received extra credit in their introductory psychology course). Although the researchers acknowledged that it would be “ hard to imagine that people lie almost three times per 10 min during most social interactions” the study was widely cited in the media, and is another example of journalists failing to take the time to understand what a scientist is actually claiming.

But there is a substantial and more reliable body of literature about the prevalence and psychology of lying. For example, there is the Principle of Veracity, first articulated by the philosopher and ethicist Sissela Bok. According to Bok, there is a moral asymmetry between truth and deception such that ‘‘truthful statements are preferable to lies in the absence of special considerations.” In other words people will be honest when the goals are attainable through honest means; absent a motive, honesty prevails. It sounds obvious, but that didn’t prevent three psychologists from Michigan State University to put this to the test. And not all lying is the same. People tell more lies to strangers than to close friends, and if people lie, they tell different lies to their close friends than to strangers: They tell more self-centred lies to strangers, more other-oriented lies to close friends, and more altruistic lies about close friends than about strangers.

“When social, psychological, and instrumental goals...can be accomplished without deception, then, absent psychopathology, people are honest. People do not deceive when the truth is equally efficacious. However, situations are sometimes such that the truth thwarts goal attainment. In these situations, people tacitly or actively consider deceit, and deceit is more or less probable depending on the importance of the goal, the difficulty of goal attainment absent deceit, and the probability of avoiding detection. ”

— Timothy R. Levine , Rachel K. Kim & Lauren M. Hamel (2010) People Lie for a Reason: Three Experiments Documenting the Principle of Veracity, Communication Research Reports, 27:4, 271-285,

Here is how the behavioral economist Dan Ariely summed up his comprehensive research on cheating and lying in his 2012 book The (Honest) Truth About Dishonesty:

Over the past decade or so, my colleagues and I have taken a close look at why people cheat, using a variety of experiments and looking at a panoply of unique data sets—from insurance claims to employment histories to the treatment records of doctors and dentists. What we have found, in a nutshell: Everybody has the capacity to be dishonest, and almost everybody cheats—just by a little. Except for a few outliers at the top and bottom, the behavior of almost everyone is driven by two opposing motivations. On the one hand, we want to benefit from cheating and get as much money and glory as possible; on the other hand, we want to view ourselves as honest, honorable people. Sadly, it is this kind of small-scale mass cheating, not the high-profile cases, that is most corrosive to society.

Unfortunately, I don’t know if any of these claims are true. Ariely has retracted a 2002 paper on procrastination and deadlines after signs of data tampering were discovered. And then came this:

A 2012 paper on dishonesty -published in the Proceedings of the National Academy of Sciences and coauthored by Harvard researcher Francesca Gino - was also retracted over concerns data in the study were fabricated. The authors of Data Colada were cited in that retraction notice for providing evidence questioning the validity of the data. 

That retraction brought attention to Ariely’s work. In 2024, another of Ariely’s papers on dishonesty, this one published in the Journal of Marketing Research in 2008, earned an expression of concern for concerns “about the replicability of the results.” A 2004 paper in Psychological Science on compensation in monetary versus social markets had received an expression of concern in July 2021, noting there was “uncertainty regarding the values of statistical tests reported in the article and the analytical approach taken.” (From here.)

Oy.

The Prevalence of Lying in America

A 2010 survey of 1,000 American adults found that 60% reported telling no lies at all over a 24 hour period. It also found that almost half of the lies are told by 5% of adults. In other words, most lies are told by a few rather prolific liars.

(A) The majority of Americans reported they did not lie in the past 24 hours (60%). (B) Percentage distribution by number of lies told; 32% told one to five lies and 8% reported telling six or more lies. From Serota K, Levine T and Boster F. The Prevalence of Lying in America: Three Studies of Self-Reported Lies. Human Communication Research 36 (2010) 2–25.

Over time, the researchers concluded, “most Americans probably lie at least occasionally. But the inference of pervasive daily lying, drawn from the statistical average of one to two lies per day, and reinforced by media coverage of corporate deception and political malfeasance, as well as pop culture portrayals of deception detectors, belies the basic honesty present in most people’s everyday communication.” So there is hope after all.

Those in the UK tell more lies

Using the same methodology, the same researchers surveyed almost 3,000 adults in the United Kingdom. As in the United States, most people in the UK reported lying relatively infrequently, but a few prolific liars had deceptive behavior that is both more pronounced (more big lies) and riskier in terms of the consequences of being caught. The U.K. mean was about one-and-a-half lies per day or more than double the U.S. mean of 0.70, providing some evidence that lying is more prevalent in the United Kingdom than in the United States. Make of that what you will.

Situations in which prolific and everyday liars consider it acceptable to lie. Data from the UK survey by Serota and Levine. A Few Prolific Liars: Variation in the Prevalence of Lying. Journal of Language and Social Psychology 2015, Vol. 34(2) 138–157/

If only it were so

People will lie even if there is a risk of being discovered, and will do so brazenly and without concern for others. Just ask Elizabeth Holmes. Actually, don’t ask her, since she’d probably lie you. Rav Yehuda’s rule that people will not lie if there is a risk of their lie being uncovered is at best aspirational. Sadly, it is no-longer an accurate description of social norms. (Perhaps it never really was.) But wouldn’t it be wonderful if it were so?

Bechorot 24a ~ Can a sheep suckle a pig?

בכורות כד, א

? יולדת מרחמת או אינה מרחמת

Might an animal that has given birth show mercy and suckle the young of another species?

On today’s daf we continue the vigorous argument between the rabbis and Rabban Shimon ben Gamliel over the following question: is it possible for a female of one species to adopt and nurse the young of an entirely different species? The rabbis (in the majority) believed that such a phenomena was entirely possible, while the great Rabban Shimon ben Gamliel believed that this does not occur. The rabbis were correct.

Animals as human wet-nurses

Let’s start with us. Unless you are lactose-intolerant, you probably are nourished from the milk of another species several times a day. But putting milk in our coffee is just the most recent manifestation of our being nursed by another species. There are myths and fables in many cultures in which a human infant is nursed by animals. In Rome, it was Romulus and Remus who were suckled by a wolf; this legend dates back to at least 350 BCE. In Greek mythology, Telephus the son of Hercules was (in most versions) suckled by a deer, but on the Telephos frieze from the first half of the second century BCE he is depicted suckling from a lioness. Another Greek myth tells of Zeus being suckled by a goat Amalthea.

The infant Telephos at the lioness’ breast, detail from the Telephos frieze. From here.

The Capitoline Wolf - La Lupa Capitolina. 11-12th century. The figures of Romulus and Remus were added in the 15th century.

In his 1976 essay “The Role of Animals in Infant Feeding,” Samuel Radbill noted that these common myths of a great leader being suckled by an animal owe their popularity to the belief that “mental, emotional and physical characteristics, as well as disease, can be transmitted through milk…” He continues:

The Persian Cyrus, raised by Cyno, a bitch, was thought to derive his name from the dog. Heiro of Syracuse was fed sweet food by the apes; Semiramus was fostered by birds. Midas was nourished by ants that put food into his mouth. Habia, king of the Tartessians, and Telphus, son of Hercules and Pelias in the greek myth were both suckled by deer. Paris and Orion by bears’ Aegisthus, by a goat; Rursus Sabdrocotto of India by a lio; Gordius of Lydia , by birds. Recently delivered mares refreshed the infants Croesus, Xerxes and Lysimachus. These extraordinary foster parents were portentous omens of future greatness.

To this list we might add our very own Moses, raised for future greatness in the house of Pharaoh himself. Except, of course, that the Torah made sure to distance Moses from any suggestion that he was suckled by an animal or an Egyptian wet nurse. Instead, Moses was suckled by his own mother, and in a Midrash the rabbis describe why:

“לְפִי שֶׁהֶחֱזִירַתּוּ לְמשֶׁה עַל כָּל הַמִּצְרִיּוֹת לְהָנִיק אוֹתוֹ וּפָסַל אֶת כֻּלָּן, וְלָמָּה פְסָלָן, אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא הַפֶּה שֶׁעָתִיד לְדַבֵּר עִמִּי יִינַק דָּבָר טָמֵא

Moses passed before all the wet nurses in Egypt, and rejected them all. And why did he reject them? The Holy One, Blessed be He said “should the mouth that will in the future speak to me suckle from that which is impure?””

— Shemot Rabba 1:25

Goats have been used as wet nurses for human infants for centuries. In her cultural history of milk, historian Deborah Valenze notes that during the syphilis plagues of the 1500s, “mothers bypassed infected wet nurses by employing goats. Similarly, eighteenth century abandoned children…received animal milk at the udder.” in 1900, a reference to animal wet nurses (in this case pigs) even made its way into the Philadelphia Medical Journal. Here it is in the original:

Philadelphia Medical Journal 1900;5: 236

More examples of Interspecies feeding

Beware of believing what you see on the Internet. But if these images are real, they are examples of interspecies feeding: camels nursing goats, goats nursing camels (at the same time as her own calf) pigs nursing tiger cubs But perhaps the most moving (and authenticated) story of interspecies care is that of the Kenyan lion that adopted a baby antelope. Six times. Take the time to watch the story here.

Tarzan, Raised by Apes

On this page of Talmud the rabbis stated that nursing females will suckle the young from another species, and they are certainly correct. Perhaps the best description of why this should be so is found in Tarzan of the Apes, the famous 1912 novel by Edgar Rice Burroughs. In the story, John Clayton II is one year old when he is snatched from his crib by Kala, an ape whose own infant had just died. As Kala took John

…she dropped the dead body of her own into the empty cradle; for the wail of the living had answered the call of universal motherhood within her wild breast which the dead could not still…Then hunger closed the gap between them and the son of an English lord and an English lady nursed at the breasts of Kala, the great ape.

Talmudology on the Parsha, Vezot Haberacha: Where Does Dew Come From?

דברים 32:13

וּלְיוֹסֵף אָמַר מְבֹרֶכֶת יְהֹוָה אַרְצוֹ מִמֶּגֶד שָׁמַיִם מִטָּל וּמִתְּהוֹם רֹבֶצֶת תָּחַת׃

And of Joseph he said:
Blessed of God be his land
With the bounty of dew from heaven,
And of the deep that couches below

In this penultimate chapter of the Torah, Moshe blesses each of the Tribes of Israel. On reaching the Tribe of Joseph, Moshe asks that they be blessed with “the bounty of the dew from heaven” - “מְבֹרֶכֶת ה׳ אַרְצוֹ מִמֶּגֶד שָׁמַיִם מִטָּל” Dew is not something we think about very often, and its appearance was long considered a mystery, until a British physician named William Charles Wells spent thirty years solving it.

Dew In the Talmud

The Talmud takes dew very seriously, and in tractate Taanit Rabbi Hanina makes a curious claim: dew never ceases to appear, and the winds never cease to blow - אָמַר רַבִּי חֲנִינָא: לְפִי שֶׁאֵין נֶעֱצָרִין. It is for this reason that there is no requirement to ask them of God in the silent prayer known as the Amidah, (although they may mentioned, for good measure).

But in the Book of Kings, Elijah tells the wicked King Ahab that God will withhold the rain and the dew:

מלאכים א, 17:1

וַיֹּאמֶר אֵלִיָּהוּ הַתִּשְׁבִּי מִתֹּשָׁבֵי גִלְעָד אֶל אַחְאָב חַי ה׳ אֱלֹהֵי יִשְׂרָאֵל אֲשֶׁר עָמַדְתִּי לְפָנָיו אִם יִהְיֶה הַשָּׁנִים הָאֵלֶּה טַל וּמָטָר כִּי אִם לְפִי דְבָרִי

And Elijah the Tishbite, who was of the settlers of Gilead, said to Ahab: As the Lord, the God of Israel, lives, before whom I stand, there shall be no dew or rain in these years but according to my word.

The Talmud explains that there are two kinds of dew: regular dew that appears every day, and a second dew that only appears as a blessing. It was this second kind of dew, which helps the crops to grow, that was being witheld as a punishment. But, rather sneakily, the two dews are indistinguishable, so when God ended the drought of rain, he did not re-introduce the second type of dew, since its presence is imperceptible. In other words, a blessing that you cannot tell from the background is a blessing that does not need announcing. Or something like that.

תענית ג ב

אֲפִילּוּ טַל בְּרָכָה נָמֵי לָא אָתֵי ... מִשּׁוּם דְּלָא מִינַּכְרָא מִילְּתָא

Elijah told Ahab that even the dew of blessing would not come... [and God did not restore it afterward] because the matter is not recognizable. (Taanit 3b)

So Where does the dew come from?

For many centuries, the origin of dew was completely mysterious. The answer took a long time to arrive. Aristotle believed that there was a kind of dew equivalent of the rain cycle. As outlined in his Meteorolgy (Book I, 9-11), the sun's heat lifts moisture from the earth as vapor. Some of the vapor does not rise high during the day, because the heat lifting it is weak relative to the amount of moisture. When it cools and descends at night, it is called dew.

For all his fame, Aristotle’s claims were usually wrong. This one was no different, although it stayed around for a couple of millennia; until 1814 to be precise. The man who finally settled the question was not a meteorologist. He was a physician named William Charles Wells, who practiced St. Thomas's Hospital in London, and in 1812 he began, in his own words, to study dew “with great patience.” In 1814 he published An Essay on Dew, and Several Appearances Connected with It, which won him the Royal Society's Rumford Medal. The physicist John Tyndall later called it "a model of wise enquiry and lucid exposition," and it has been described as the “first foundational paper in modern climate science.”

“If, in the course of the night, the weather, from being calm and serene, should become windy and cloudy, not only will dew cease to form, but that which had previously formed, will either disappear, or diminish considerably.”

— William Charles Wells. An Essay on Dew. London 1815, 5-6.

Wells' Experiments

Armed with thermometers, wool, paper, string, wood shavings and a friend's suburban lawn, Wells set out to discover how dew forms. He concluded that it is neither invisible rain falling from heaven nor sweat from plants. Rather, it is condensation from air in contact with objects that have cooled by radiating their heat into a cloudless night sky. It forms best on calm, clear nights. Clouds interrupt the radiation, and cloud cover reduces or stops dew. Dark materials and poor conductors of heat collect more dew than pale ones and good conductors. Fine shavings of wood collected more dew than a thick piece of the same wood. Metals, which cool slowly, attract much less.

So rain and dew are intimately connected. Rain needs clouds; dew needs their absence. The Talmud noticed that dew behaves differently from rain, even if it lacked a mechanism to explain why. Strictly speaking, dew is not "never withheld." It depends on clear, still nights, and it will not form under cloud cover or in wind. But look at what the Gemara actually does. It places dew in the same category as wind and groups both with things that are not withheld. And it distinguishes dew from clouds, which it says can be withheld in the later part of the rainy season.

And what of the verse's claim that dew comes "from heaven"? Wells showed that dew does not fall. Rather, it forms in place, from the moisture in the air at ground level. But that is a physicist's quibble. The sky is what cools the ground, so perhaps, after all, the dew does come from heaven.

A Note on Gideon's Fleece

Readers of the ספר שופטים (The Book of Judges) will recall Gideon's famous test. While rallying the Tribes of Israel to join his fight against Ba’al, Gideon asks God for a sign he will be victorious: that a fleece left outside be wet with dew while the ground stays dry. And that’s what happens. Wells's finding that different materials collect very different amounts of dew makes that outcome easy to imagine for a woolly object. Not satisfied, Gideon asks for a different (harder?) miracle: that the fleece now remain dry while the ground became wet with dew. Now that’s much harder to explain, and so, I suppose, it was a really convincing sign.

שופטים 6:36-40

וַיֹּאמֶר גִּדְעוֹן אֶל־הָאֱלֹהִים אִם־יֶשְׁךָ מוֹשִׁיעַ בְּיָדִי אֶת־יִשְׂרָאֵל כַּאֲשֶׁר דִּבַּרְתָּ׃

הִנֵּה אָנֹכִי מַצִּיג אֶת־גִּזַּת הַצֶּמֶר בַּגֹּרֶן אִם טַל יִהְיֶה עַל־הַגִּזָּה לְבַדָּהּ וְעַל־כל־הָאָרֶץ חֹרֶב וְיָדַעְתִּי כִּי־תוֹשִׁיעַ בְּיָדִי אֶת־יִשְׂרָאֵל כַּאֲשֶׁר דִּבַּרְתָּ׃

וַיֹּאמֶר גִּדְעוֹן אֶל־הָאֱלֹהִים אַל־יִחַר אַפְּךָ בִּי וַאֲדַבְּרָה אַךְ הַפָּעַם אֲנַסֶּה נָּא־רַק־הַפַּעַם בַּגִּזָּה יְהִי־נָא חֹרֶב אֶל־הַגִּזָּה לְבַדָּהּ וְעַל־כל־הָאָרֶץ יִהְיֶה־טָּל׃

וַיַּעַשׂ אֱלֹהִים כֵּן בַּלַּיְלָה הַהוּא וַיְהִי־חֹרֶב אֶל־הַגִּזָּה לְבַדָּהּ וְעַל־כל־הָאָרֶץ הָיָה טָל׃

וַיְהִי־כֵן וַיַּשְׁכֵּם מִמחֳרָת וַיָּזַר אֶת־הַגִּזָּה וַיִּמֶץ טַל מִן־הַגִּזָּה מְלוֹא הַסֵּפֶל מָיִם׃

And Gideon said to God, “If You really intend to deliver Israel through me as You have said, here I place a fleece of wool on the threshing floor. If dew falls only on the fleece and all the ground remains dry, I shall know that You will deliver Israel through me, as You have said.” And that is what happened. Early the next day, he squeezed the fleece and wrung out the dew from the fleece, a bowlful of water. Then Gideon said to God, “Do not be angry with me if I speak just once more. Let me make just one more test with the fleece: let the fleece alone be dry, while there is dew all over the ground.” God did so that night: only the fleece was dry, while there was dew all over the ground.

William Charles Wells. An Essay on Dew. London 1815, 149.

חג שמח from Talmudology

עד הנצחון

Want more on Wells and dew? Have a read here and here.

From the Talmudology Archives: The Vilna Gaon’s Sleepless Nights over Sukkot

In honor of Sukkot, here is a Talmudology encore presentation about the Vilna Gaon’s refusal to sleep in prison over Sukkot.

Let’s start with the Talmud in Nedarim, the tractate that deals with vows.

נדרים טו א

והא"ר יוחנן שבועה שלא אישן שלשה ימים מלקין אותו וישן לאלתר

...Rabbi Yochanan said "An oath that I will not sleep for three days" - we lash him [since he took an oath in vain] and he may sleep immediately...(Nedarim 15a)

How long can you go without sleep? If you are like me, staying awake for just one night can be very challenging.  I worked my share of night shifts in the emergency department for over fifteen years (amounting to hundreds of overnight shifts) but it never got any easier with time. We all push ourselves when we need to, but is there a physiological limit to the amount of time that you can stay awake?

The World Record for Staying Awake

The world record for staying awake is an amazing eleven days. Eleven days – that’s 264 hours (and 24 minutes to be precise) without sleep. It was set in 1965 by Randy Gardner, who was then seventeen years old. Gardner seems to have suffered little if any harm by his marathon period of sleep deprivation. But don’t try and beat the record. The Guinness Book of Records no longer has an entry for staying awake – because it is considered too dangerous an ordeal to undertake. (You can hear a review of sleep deprivation stunts in general and a wonderful interview with Gardner himself here.)

The Health Risks of Sleep Deprivation

A 1970 study of four volunteers who stayed awake for 205 hours (that’s eight and a half days!) noted some differences in how the subjects slept once they were allowed to do so, but follow-up testing of the group conducted 6-9 months after the sleep deprivation showed that their sleep patterns were similar to the pre-deprivation recordings.

Although Randy Gardner and these four volunteers seem to have suffered no long-term health consequences of staying awake for over a week, scientists have long noted that sleep deprivation is rather bad for the body. Or to be more precise, the bodies of unfortunate laboratory rats who are not allowed to sleep. In these animals, prolonged sleep deprivation causes the immune system to malfunction. This results in infection and eventual lethal septicemia. The physiologist who kept these rats awake noted that there are “far-reaching physical implications resulting from alterations in immune status [which] may explain why sleep deprivation effects are risk factors for disease and yet are not well defined or specifically localized.” In other words, sleep deprivation makes rats really sick, but we don’t know how, or why…

One possible explanation was suggested in a 2013 by a group from the University of Rochester Medical Center. They demonstrated that during sleep, the space between the cells of the brain (the interstitial space) increased by up to 60%, allowing toxic metabolites to be cleared. This raises the question of whether the brain sleeps in order to expel these toxic chemicals, or rather it is the chemicals themselves that drive the brain to switch into a sleep state.

The extracellular (interstitial) space in the cortex of the mouse brain, through which cerebral spinal fluid moves, increases from 14% in the awake animal to 23% in the sleeping animal, an increase that allows the faster clearance of metabolic waste products and toxins. From Suzana Herculano-Houzel. Sleep it out. Science 2013: 342; 316

Not having any sleep is bad for your health - but so too is going without enough sleep. Chronic restriction of sleep to six hours or less per night can produce cognitive performance deficits equivalent to up to two nights of total sleep deprivation. So be sure to get a full night's rest.

How long did the Vilna Gaon stay awake?

And now, with this background, we can turn to Sukkot. In his book on the Vilna Gaon, Eli Stern reviewed an episode in which the Gaon (d. 1797) was jailed on charges of kidnapping. (It’s a long story, but the Vilna Gaon was involved in the kidnapping of a young Jewish man who had converted to Christianity.) This episode occurred in January 1788, after which the Gaon was arrested and held for over a month.  The case was later tried, and on September 15, 1789 (sic) the Gaon of Vilna (together with others involved in the kidnapping) was sentenced to twelve weeks in jail.  Although it is unclear how long he was imprisoned, he was there over Sukkot, and the Lithuanian authorities were hardly in the practice of providing imprisoned Jews with a sukkah.  But since one is not permitted to sleep outside of the sukkah, what was the Gaon to do?  Simple.  He’d stay awake, and by doing so he would not transgress the prohibition of sleeping outside the sukkah.  Here’s how the episode is described in the work Tosefet Ma’aseh Rav published in 1892. 

Our Leader, teacher and Rabbi may he rest in peace, when he was imprisoned on Sukkot, tried with all his strength, and walked from one place to another, and held his eyelids open, and made an extraordinary effort not to sleep outside the sukkah – not even a brief nap – until the authorities released him to a sukkah.

We don’t know for how long the sixty-nine year-old Elijah stayed awake, but any suggestion that he was awake for the entire holiday of Sukkot seems to be far fetched (though as we have seen, not entirely impossible).

Hard, But Not Impossible

As we read in the Talmud, Rabbi Yochanan ruled that since it impossible to stay awake for more than three days, any vow to do so is considered to have been a vow made in vain – and punishment follows swiftly.  Here is how the ArtScroll Talmud explains this ruling, (based on the explanation of the Ran).

Since it is impossible for a person to go without sleep for three days, the man has uttered a vain oath. Hence, he receives lashes for violating the prohibition (Exodus 20:7): לא תשא את שם ה׳ אלוקיך לשוא, You shall not take the Name of Hashem, your God, in vain. And since the oath -being impossible to fulfill -has no validity, he is not bound by it at all and may sleep immediately.

We have seen however, that while it’s not a good idea to do so on any kind of regular basis, it is certainly possible to stay up for longer than three days. (Back in the 1970s, some volunteers would even do so for as little as $100). Maimonides codified this law and also assume that it is impossible to stay awake for three consecutive days. 

רמב"ם הלכות שבועות פרק ה הלכה כ

נשבע שלא יישן שלשת ימים, או שלא יאכל כלום שבעת ימים וכיוצא בזה שהיא שבועת שוא, אין אומרין יעור זה עד שיצטער ויצום עד שיצטער ולא יהיה בו כח לסבול ואח"כ יאכל או יישן אלא מלקין אותו מיד משום שבועת שוא ויישן ויאכל בכל עת שירצה

Based on what we've reviewed, Rabbi Yochanan was incorrect when he stated that it was impossible to stay awake for three days. It's certainly not impossible, but that hardly means it's a good idea to try. 

“Sleep deprivation reduces learning, impairs performance in cognitive tests, prolongs reaction time, and is a common cause of seizures. In the most extreme case, continuous sleep deprivation kills rodents and flies within a period of days to weeks. In humans, fatal familial or sporadic insomnia is a progressively worsening state of sleeplessness that leads to dementia and death within months or years. ”

— Lulu Xie et al. Sleep Drives Metabolite Clearance from the Adult Brain. Science 2013. 342.317

This may explain the teaching of Rabbi Chaninah ben Chachina'i in Masechet Avot  (3:4) who taught that one who stays awake at night "will forfeit with his life."  Now that's a warning to heed.

רבי חנינא בן חכינאי אומר הנעור בלילה ... הרי זה מתחייב בנפשו

Happy Sukkot from Talmudology