Can heterosexual men and women ever be “just friends”? Few other questions have provoked debates as intense, family dinners as awkward, literature as lurid, or movies as memorable. Still, the question remains unanswered. Daily experience suggests that non-romantic friendships between males and females are not only possible, but common—men and women live, work, and play side-by-side, and generally seem to be able to avoid spontaneously sleeping together. However, the possibility remains that this apparently platonic coexistence is merely a façade, an elaborate dance covering up countless sexual impulses bubbling just beneath the surface.

New research suggests that there may be some truth to this possibility—that we may think we’re capable of being “just friends” with members of the opposite sex, but the opportunity (or perceived opportunity) for “romance” is often lurking just around the corner, waiting to pounce at the most inopportune moment.

In order to investigate the viability of truly platonic opposite-sex friendships—a topic that has been explored more on the silver screen than in the science lab—researchers brought 88 pairs of undergraduate opposite-sex friends into…a science lab.  Privacy was paramount—for example, imagine the fallout if two friends learned that one—and only one—had unspoken romantic feelings for the other throughout their relationship.  In order to ensure honest responses, the researchers not only followed standard protocols regarding anonymity and confidentiality, but also required both friends to agree—verbally, and in front of each other—to refrain from discussing the study, even after they had left the testing facility. These friendship pairs were then separated, and each member of each pair was asked a series of questions related to his or her romantic feelings (or lack thereof) toward the friend with whom they were taking the study.

The results suggest large gender differences in how men and women experience opposite-sex friendships. Men were much more attracted to their female friends than vice versa. Men were also more likely than women to think that their opposite-sex friends were attracted to them—a clearly misguided belief. In fact, men’s estimates of how attractive they were to their female friends had virtually nothing to do with how these women actually felt, and almost everything to do with how the men themselves felt—basically, males assumed that any romantic attraction they experienced was mutual, and were blind to the actual level of romantic interest felt by their female friends. Women, too, were blind to the mindset of their opposite-sex friends; because females generally were not attracted to their male friends, they assumed that this lack of attraction was mutual. As a result, men consistently overestimated the level of attraction felt by their female friends and women consistently underestimated the level of attraction felt by their male friends.

Men were also more willing to act on this mistakenly perceived mutual attraction. Both men and women were equally attracted to romantically involved opposite-sex friends and those who were single; “hot” friends were hot and “not” friends were not, regardless of their relationship status.  However, men and women differed in the extent to which they saw attached friends as potential romantic partners.  Although men were equally as likely to desire “romantic dates” with “taken” friends as with single ones, women were sensitive to their male friends’ relationship status and uninterested in pursuing those who were already involved with someone else.

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  • Caffeine For Imprisoned Twins

    In the late 18th century, King Gustavus III of Sweden was rumored to have carried out a strange experiment to determine the harmful health effects of coffee. Two identical twins who had been condemned to death had their sentences commuted to life in prison on the condition that one would drink three pots of coffee per day, and the other three pots of tea, for the rest of their lives. The only problem was that the doctors assigned to monitor the cases died before either of the patients did, their observations lost--as the story goes, the tea drinker died first, and there's no record of the coffee-drinker's death. The experiment proved nothing, suffering from a lack of rigor (to say the least). Source: Uppsala University, "Coffee - rat poison or miracle medicine?"

  • Simulated Anthrax On The Subway

    In June 1966, the U.S. Army's Special Operations Division secretly dispersed harmless bacteria in the New York Subway system to model the effects of an outbreak of more harmful germs. According to Army reports, "Test results show that a large portion of the working population of New York City would be exposed to disease if one or more pathogenic agents were disseminated covertly in several subway lines at a period of peak traffic." Source: Deadly Cultures: Biological Warfare Since 1945. Wheelis, Rózsa, and Dando. Harvard University Press, 2006.

  • Weaponized Fleas In The Desert

    Operation Big Itch, 1954, was an attempt to discover the potential of weaponized fleas. The operation, part of the Cold War-era United States biological weapons program, took place at Dugway Proving Ground in Utah. According to "Using the flea as weapon," an article in the Army Chemical Review, "In the United States, the plague flea concept was competing against the use of mosquitoes, flies, ticks, and lice. Of these concepts, the United States put most of its energies behind weaponizing yellow fever in combination with the Aedes aegypti mosquito."

  • Food Through A Hole In The Stomach

    U.S. Army Surgeon William Beaumont (above) found an extraordinary patient in Alexis St. Martin, a Canadian trapper who was injured in a hunting accident and left with a hole in his belly that led directly into his stomach. Beaumont attached a string to various foods, including oysters and rare roast beef, and introduced them into the wound to observe the rates of digestion. Despite the unorthodox techniques, this research would later lead to the discovery of the importance of stomach acid in digestion, earning Beaumont the epithet "father of gastric physiology." Source: Experiments and observations on the gastric juice, and the physiology of digestion. Beaumont, Martin and Combe. Maclachlan & Stewart, 1838

  • Candy For Mental Patients

    In 1945, Sweden's new National Dental Service commissioned research, now known as the Vipeholm experiments, in which researchers gave subjects large amounts of sticky sugary candy in order to study the development of cavities. This might not have been so controversial, except that the subjects couldn't give consent to their participation: "The use of mentally handicapped subjects was criticized in the Swedish press and all studies on mentally handicapped individuals were stopped in 1954," according to Topics In Dental Biochemistry by Mark Levine (Springer, 2010).