TIME Science

You’re Not Fooling Anyone With Your Pretend Laughter

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A fake laugh is produced with a slightly different set of vocal muscles controlled by a different part of our brain

Why do we laugh? The obvious answer is because something is funny. But if we look closer at when and how laughter occurs in ordinary social situations, we see that it’s not so simple. Like most aspects of human behavior, laughter is complicated.

Scientists are learning about not only the ways in which people hear and categorize laughs, but also how human laughter relates to similar vocal behaviors across the animal kingdom. We have now uncovered many clues about the origins of this fascinating and ubiquitous behavior: While laughter might seem on the surface to be about jokes and humor, it turns out that it’s really about communicating affiliation and trust.

And then it gets tricky.

In one line of research in my Vocal Communication Lab at UCLA, we have been playing recorded laughs to listeners and asking them, is this laugh “real” or “fake”? Our recorded laughs were taken from real conversations between friends in a laboratory setting, or produced on command, also in the lab. Listeners were able to tell the “real” laughs from the “fake” laughs about 70 percent of the time. Why are people falling for the fake laughs? Before we can answer that, we need to address where laughter came from in the first place.

Laughter in humans likely evolved from play vocalizations in our primate ancestors. We see related vocal behaviors in many primate species today, as well as in rats and dogs. Scientists have described these play vocalizations as evolved from labored breathing during play. If one animal bites another, it could be taken as an attack—but if they signal while panting that they are just playing, the play can continue without being interrupted by an unnecessary real fight.

So how does this relate to human laughter? By comparing traits in different species, and then incorporating what is known about the evolutionary connection between those species, we can estimate how old a trait is, and how it has changed over evolutionary time. Our laughs have become longer, and the sound has more of a tone, including the stereotyped vowel sounds we all know: the human “hahaha.” Of course, human laughter can be composed of many sounds, including snorts, grunts, and hisses. But when we produce the classic “hahaha” sound, we are revealing the action of an ancient emotional vocal system shared with many species, and that has important consequences in how people appraise a laugh, and the laugher, at that moment.

Laughter triggers the release of brain endorphins that make us feel good, and it reduces stress. There is even evidence that we experience a temporary slight muscle weakness called cataplexy when we laugh, so we could be communicating that we are unlikely (or relatively unable) to attack. But laughter is not always made in fun, and can be quite hurtful (e.g., teasing). Laughter is a powerful signal with huge communicative flexibility.

We were laughing before we were talking, and crying, screaming, gesturing, and making other nonverbal signals. But we did eventually learn to talk, and developed fine control over our breathing to regulate it for speech, and better motor control over our larynx, lips, and tongue. These innovations afford us the ability to be vocal mimics. As this skill developed for speech production, the ability to imitate other non-speech sounds came rather quickly. Suddenly, the fake laugh was born.

A fake laugh is produced with a slightly different set of vocal muscles controlled by a different part of our brain. The result is that there are subtle features of the laughs that sound like speech, and recent evidence suggests people are unconsciously quite sensitive to them. For example, if you slow down a “real” laugh about two and half times, the result is strangely animal-like. But when you slow down human speech, or a “fake” laugh, it sounds like human speech slowed down.

The ability to be a good faker has its advantages, so there has likely been evolutionary pressure to fake it well, with subsequent pressure on listeners to be good “faker detectors.” This “arms race” dynamic, as it’s called in evolutionary biology, results in good fakers, and good fake detectors, as evidenced by many recent studies, including my own.

The reasons we laugh are as complicated as our social lives, and relate closely to our personal relationships and communicative strategies. One focus of researchers now is trying to decipher the relationship between specific sound features of our laughs—from loud belly laughs to quiet snickering—and what listeners perceive those features to mean. For someone studying the evolution of human communication, there are few things better to study. And it’s no joke.

Greg Bryant received his Ph.D. in psychology from UC Santa Cruz in 2004 and is now an associate professor in the Department of Communication at UCLA. He is interested broadly in the evolution of communication and cognition, and has published on a variety of topics exploring the role of the voice in social interaction. He wrote this for Thinking L.A., a partnership of UCLA and Zócalo Public Square.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME Research

Men Are Totally Hardwired by Evolution to Prefer Curvy Women, Study Finds

Human Spine
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And it's one curve in particular

A new University of Texas study has found that men express a clear preference for women who have a pronounced back-to-buttock curve.

After asking around 100 men to rank the attractiveness of images of various females, researchers found that men strongly preferred women with a back-to-buttock curve of 45.5 degrees, which they described as the “theoretically optimal angle of lumbar curvature.”

They theorized that, in ancient times, such an angle meant that women were more likely to carry out successful pregnancies.

“This spinal structure would have enabled pregnant women to balance their weight over the hips,” said researcher David Lewis.

“These women would have been more effective at foraging during pregnancy and less likely to suffer spinal injuries. In turn, men who preferred these women would have had mates who were better able to provide for fetus and offspring, and who would have been able to carry out multiple pregnancies without injury.”

Researchers conducted a second study to rule out if the spinal curvature preference was due to the buttock size rather than the spinal curvature angle itself. But they discovered that men repeatedly exhibited a preference for women with spinal-curvature angles closer to the optimum, even if the women had smaller buttocks.

“Beauty is not entirely arbitrary, or ‘in the eyes of the beholder’ as many in mainstream social science believed, but rather has a coherent adaptive logic,” Lewis added.

Read next: This App Alerts You When You’re Near a Spot Where a Woman Made History

Listen to the most important stories of the day.

TIME mating

Why Women Like War Heroes More than Any Other Kind of Guy

A stock image of a man in a military uniform lifting up a woman
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And why men don't find brave women attractive

In a study that could explain so much about the Brian Williams thing, it has been found that women are more sexually attracted to men who have been deemed heroic during conflict than men who have merely served in the armed forces. And—sorry, humanitarians—men who were deemed heroic during a non-war-related crisis didn’t have nearly the same game.

Meanwhile, women who were considered heroic for any reason were found to be less attractive to men than regular women. (You read that right. Less attractive.)

The findings are the result of three studies done by researchers in England and the Netherlands. First, the researchers established from archives that World War II veterans who were Medal of Honor winners had more kids on average (3.18) than other returned servicemen (2.72).

The number of offspring is not completely correlated with the frequency of springing into bed, however. So the researchers asked 92 female British students to rate how attracted they were to various profiles and the war hero came out as the No. 1 most dateworthy type. Military service was attractive to women generally, but interestingly, if the guy had no war honors, whether he had served overseas or never left home base made no difference to his magnetism. In other words, men who see more action don’t necessarily see more action.

In the third study, 159 women and 181 men studying in Holland were given various profiles to rate and again the decorated war veteran was the female favorite. Soldiers who had been honored for their work in disaster zones or humanitarian crises got no spike in interest. And, depressingly, guys were less interested in women who had done something amazingly brave than women who hadn’t, even though the participants in the study were the supposedly gender equal Dutch.

The researchers were looking at the impact of medals not to enhance the dating resumes of veterans, but to examine the effect of conflict and bravery on evolution. (Those who attract the most mating partners have the highest chance of passing on their genes.)

So why are women drawn to guys who are demonstrably willing to engage in life threatening behavior? Because they’ve proved their genetic hardiness, suggest the researchers.

“Raids, battles, and ambushes in ancestral environments, and wars in modern environments, may provide an arena for men to signal their physical and psychological strengths,” says Joost Leunissen, a psychologist at the University of Southampton and co-author of the study. The thinking is that those who have the clarity of thought to try something life-saving and the physical prowess to pull it off must be built to survive, and are therefore a good evolutionary bet.

Leunissen also seems to offer, perhaps unintentionally, some eggheady advice on whether women should be on the front lines. “In light of the physical dangers and reproductive risks involved,” he says, “participating in intergroup aggression might not generally be a viable reproductive strategy for women.” Translation: not if they want to have kids.

TIME Archaeology

Neanderthals May Have Used Tools, Making Them Smarter Than We Thought

A multipurpose bone tool dating back to before the Stone Age was discovered in France

A new discovery suggests that Neanderthals, the immediate ancestors of human beings, may not have been as technologically inferior to our species as previously thought.

Researchers from the University of Montreal found a multipurpose bone tool in Burgundy, France, that dates back to the Neanderthal era, Science Daily reported.

“It proves that Neanderthals were able to understand the mechanical properties of bone and knew how to use it to make tools, abilities usually attributed to our species, Homo sapiens,” said Luc Doyon, a University of Montreal anthropologist who participated in the excavation.

The pre–Stone Age implement is the first of its kind ever discovered, and challenges a long-held assumption that Neanderthals did not have the cognitive ability to create tools. Marks on the artifact, supposedly fashioned from the left femur of a reindeer, indicate that it was used as a scraper, a sharpener for stone tools and a device to puncture meat.

[Science Daily]

TIME animals

Newly Discovered Fanged-Frog Gives Birth to Live Tadpoles

A newly discovered frog from the island of Sulawesi in Indonesia is the only known frog to give direct birth to tadpoles.
Jim McGuire—UC Berkeley A newly discovered frog from the island of Sulawesi in Indonesia is the only known frog to give direct birth to tadpoles.

As opposed to eggs, like most frogs

Scientists have discovered a rare frog in Indonesia that gives birth to live tadpoles, researchers report in a journal article published this week.

Herpatologist Jim McGuire found proof this summer that the frog, one of a group of roughly 25 species in Indonesia that have two fangs used for fighting, lays not eggs or even live froglets but live tadpoles. It’s the only frog species in the world to do so.

McGuire found the frogs on the Indonesian island of Sulawesi. He named to the species Limnonectes larvaepartus.

Jim McGuire—UC BerkeleyTwo tadpoles, each about 10 millimeters long, shortly after birth.

[Eureka]

TIME Science

Watch Bill Nye Explain Evolution Using Emoji

“We emojinized it.”

Bill Nye has never been known to teach science the way you learned it in school — unless, of course, your school taught you about water displacement by spoofing Sir Mix-a-Lot. The Science Guy is still infusing fun into science, this time spreading the gospel of evolution with the help of some emoji.

In the video, produced by Mashable as part of General Electric’s “Emoji Science” promotion, the major players in evolution get emoji matches: carbon is represented by the diamond, self-replicating molecules are interconnected faces and bacteria are represented by the purple alien monster. But despite his casual demeanor in this video, Nye takes the topic rather seriously. Back in February, he debated Ken Ham, a prominent proponent of creationism, in an attempt to win over creationists with the scientific evidence supporting evolution. In November, he released a book called Undeniable: Evolution and the Science of Creation, aimed at exposing young creationists to the scientific principles of evolution.

For those who don’t plan to read the book, the video offers a simplified version. “We shook it up with emoji, and then we told a story,” Nye says of the digital age approach to evolution. “The way you might do if you had too many, um, Jell-O shots.”

TIME

On Evolution Day, Remember That Darwin Knew He’d Meet Resistance

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Philippe Lissac—Godong / Getty Images A statue of Darwin in the Natural History Museum, London

Plus, TIME's original coverage of the anti-evolution arguments of the 1925 Scopes trial

Correction appended, Nov. 24, 2014, 5:49 p.m.

Time was, “Darwin” was just a guy’s name. It was not a noun (Darwinism) or an adjective (Darwinian). And it certainly wasn’t a flash point for debate between folks who prefer a Scriptural view of the history of life and those who take a more scientific approach. That started to change 155 years ago today, on Nov. 24, 1859, when Charles Darwin’s seminal work—On the Origin of Species—was published.

Darwin knew that by supporting an empirical theory of evolution as opposed to the Biblical account of Creation he was asking for trouble. Two weeks before the book’s publication, he sent letters to 11 prominent scientists of his day, asking for their support—or at least their forbearance—and acknowledging that for some of them, that would not be easy. To the celebrated French botanist Alphonse de Candolle he wrote:

Lord, how savage you will be, if you read it, and how you will long to crucify me alive! I fear it will produce no other effect on you; but if it should stagger you in ever so slight a degree, in this case, I am fully convinced that you will become, year after year, less fixed in your belief in the immutability of species.

And to American Asa Gray, another botanist, he conceded:

Let me add I fully admit that there are very many difficulties not satisfactorily explained by my theory of descent with modification, but I cannot possibly believe that a false theory would explain so many classes of facts as I think it certainly does explain.

But the whirlwind came anyway. Speaking of Darwin in 1860, the Bishop of Oxford asked: “Was it through his grandfather or his grandmother that he claimed his descent from a monkey?” The battle raged in the U.S. in the summer of 1925, with the trial of John Scopes, a substitute school teacher charged with violating a Tennessee statute forbidding the teaching of evolution in schools.

But Darwin and his theory of evolution endured, so much so that Nov. 24 is now recognized as Evolution Day. As if serendipity and circumstance were conspiring to validate that decision, it was on another Nov. 24, in 1974, that the fossilized remains of Lucy, the australopithecus who did so much to fill in a major gap in human evolution, were found in Ethiopia.

In honor of Lucy and Evolution Day and Darwin himself, check out TIME’s coverage of the florid anti-evolution closing argument of prosecuting attorney and three-time presidential candidate William Jennings Bryan during the Scopes trial, as quoted in the magazine’s Aug. 10, 1925 issue:

“Darwin suggested two laws, sexual selection and natural selection. Sexual selection has been laughed out of the class room, and natural selection is being abandoned, and no new explanation is satisfactory even to scientists. Some of the more rash advocates of Evolution are wont to say that Evolution is as firmly established as the law of gravitation or the Copernician theory.

“The absurdity of such a claim is apparent when we remember that any one can prove the law of gravitation by throwing a weight into the air and that any one can prove the roundness of the earth by going around it, while no one can prove Evolution to be true in any way whatever.”

Bryan died mere days after the trial ended but, as the historical record shows, his strenuous efforts paid off—sort of. Scopes was duly convicted. His sentence for teaching what most of the world now accepts as science: $100.

Read the full text of that story, free of charge, here in the TIME archives, or in its original format, in the TIME Vault: Dixit

Correction: The original version of this article misstated the date of Darwin Day. Darwin Day is typically celebrated on February 12.

TIME Science

What You Didn’t Know About William Jennings Bryan. What You Should Know About Darwin

Bryan
AP William Jennings Bryan, center, arrives at Dayton, Tenn., in 1925.

Enthusiasm for improving the human race could have negative consequences

History News Network

This post is in partnership with the History News Network, the website that puts the news into historical perspective. The article below was originally published at HNN.

The action of the North Carolina legislature to pay compensation to victims of a forced sterilization program brings attention to an almost forgotten chapter of American history. It may also provide an opportunity to set the infamous Scopes trial in a broader light and do justice to the much-maligned William Jennings Bryan for his role in that case.

The sterilizations that were carried out in so many American states were a direct result of Charles Darwin’s writing on the theory of evolution, writings which alarmed William Jennings Bryan and led him to campaign against it being taught in American schools. Bryan was no theologian but an intensely practical man concerned with consequences. His goal in life was to make the world a better place and he believed that teaching evolution would not do that. In one area at least he was right.

Darwin followed up his publication of The Origin of Species in 1859 with a second book, The Descent of Man, published in 1871. Bryan had prepared a long statement for the Scopes trial but the trial came to an end before he could enter it in the record. In his statement, he quoted from The Descent of Man, in which Darwin had written:

With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilized men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed and the sick: we institute poor laws and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands who from a weak constitution would formerly have succumbed to smallpox. Thus the weak members of civilized society propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race; but, excepting in the case of man himself, hardly anyone is so ignorant as to allow his worst animals to breed.45

Bryan was appalled. Darwin, he wrote,

. . . reveals the barbarous sentiment that runs through evolution and dwarfs the moral nature of those who become obsessed with it. Let us analyze the quotation just given. Darwin speaks with approval of the savage custom of eliminating the weak so that only the strong will survive, and complains that “we civilized men do our utmost to check the process of elimination.” How inhuman such a doctrine as this! He thinks it injurious to “build asylums for the imbecile, the maimed and the sick” or to care for the poor. Even the medical men come in for criticism because they “exert their utmost skill to save the life of everyone to the last moment.” And then note his hostility to vaccination because it has “preserved thousands who, from a weak constitution would, but for vaccination, have succumbed to smallpox!” All of the sympathetic activities of civilized society are condemned because they enable “the weak members to propagate their kind.” . . . Could any doctrine be more destructive of civilization? And what a commentary on evolution! He wants us to believe that evolution develops a human sympathy that finally becomes so tender that it repudiates the law that created it and thus invites a return to a level where the extinguishing of pity and sympathy will permit the brutal instincts to again do their progressive (?) work! . . . Let no one think that this acceptance of barbarism as the basic principle of evolution died with Darwin. ( Memoirs, p. 550)

Bryan’s concern was with practical outcomes, not “What do Christians believe?” but “What difference does it make?” Evolution seemed to him to be making the wrong kind of difference, and in his time it often did. The development of what is now called “Social Darwinism” is far too complex to be dealt with fairly in this brief article, but German militarism in World War One seems to have been influenced by it and the Turkish genocide of Armenians was justified by some on the same grounds.

The same enthusiasm for improving the human race called “eugenics” led a majority of the states to pass laws allowing the sterilizing and castrating of selected populations, typically prisoners and those with reduced mental abilities. California, in particular, carried out thousands of sterilizations. Unnoticed at the time of the Scopes trial was the publication in the same year, 1925, of Mein Kampf in which Adolf Hitler called for the improvement of the race by the elimination of inferior people: Jews, gypsies, homosexuals, the mentally retarded, and others. Once the full significance of that program became visible at the end of World War Two, eugenics and social Darwinism took on a different appearance and the interest in improving the human race by those methods withered away.

The ongoing struggle over the teaching of evolution in American classrooms and courthouses seems now to be confined to a conflict between what scientists believe and what some Christians believe but unfortunately William Jennings Bryan’s role in the Scopes trial is caricatured in those same terms. Undoubtedly Bryan had a simplistic view of the Bible, but the cause Bryan was championing was one with which most Americans today would probably agree: human beings are not to be treated as mere tools in some gigantic experiment. Human progress is created when societies find new and better ways to incorporate the weakest and most handicapped as fully as possible in the life of their community. The North Carolina legislature has taken an important step in recognizing a wrong turn in its past and has set an example for many other states to follow.

Perhaps it is time also to rescue William Jennings Bryan’s reputation from the stain of the Scopes trial. He was not a brilliant and original thinker but he was a man who consistently worked for the weaker members of society and set the Democratic party on the side of those who were being left behind in the free-for-all evolutionary struggle of the age of industrialization.

Christopher L. Webber is an Episcopal priest and author of some thirty books including “American to the Backbone,” the biography of the fugitive slave and abolition leader, James W.C. Pennington. He is a graduate of Princeton University and the General Theological Seminary who has served parishes in Tokyo, Japan, and the New York area and currently lives in San Francisco. The work of William Jennings Bryan is dealt with more fully in Christopher Webber’s book, “Give Me Liberty: Speeches and Speakers that Shaped America,” Pegasus, 2014.

TIME animals

Scientists Discover Why Mosquitos Love Human Blood

mosquitoes blood sucking
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You get mosquito bites because of your smell

Scientists have discovered the reason that mosquitos switched from feeding on animals to humans: the smell of a chemical vapor on human skin.

The chemical, called sulcatone, has a unique scent that mosquitos learned to associate with food, The Independent reports.

“It was a really good evolutionary move,” said Leslie Vosshall of Rockefeller University in New York, who led the study published in the journal Nature, “We provide the ideal lifestyle for mosquitoes. We always have water around for them to breed in, we are hairless and we live in large groups.”

Researchers found that mosquitos that still feed on animals do not respond to the presence of sulcatone, but those that prefer humans are drawn to the scent.

TIME space

Why the First Comet Landing Matters

This mission may be our most informative one yet

Philae lander touched down Wednesday on the comet Churyumov-Gerasimenko, also known as 67p, after a 10 year journey that cost as much as $1.3 billion. You might be wondering why the European Space Agency spends so much time and resources on a frozen lump of ice millions of miles away. But this mission, which successfully landed the first ever probe onto our solar system’s most primitive material, will give us valuable information about the origins of our solar system and how it evolved.

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