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Yahoo
21-07-2025
- General
- Yahoo
How to Be More Charismatic, but Not Too Much More
The Atlantic Daily, a newsletter that guides you through the biggest stories of the day, helps you discover new ideas, and recommends the best in culture. Sign up for it here. Want to stay current with Arthur's writing? Sign up to get an email every time a new column comes out. A special quality sets some people apart from the crowd. They are magnetic to be around, attractive to watch, hypnotic to listen to. They have, in a word, charisma. It seems like a divine grace—indeed, the word derives from the ancient Greek χάρισμα, meaning 'God's gift.' The word appeared in third-century B.C.E. Greek translations of the Hebrew Bible, and early Christians referred to charismata as blessings bestowed on believers such as prophecy, healing, and speaking in tongues. Our modern usage of charisma comes from the early-20th-century sociologist Max Weber, who called it a 'certain quality of an individual personality, by virtue of which he is set apart from ordinary men and treated as endowed with supernatural, superhuman, or at least specifically exceptional powers or qualities.' And today, the concept of charisma is having a moment in the abbreviated slang term rizz, which, in Generation Z vernacular, describes one's ability to charismatically court a romantic partner. It involves a notable power to impress others with smooth talk, confidence, or style—a skill we'd probably all like to have, beyond the domain of romance. Do you have charisma? Would your life be better if you had more? Or is it, like fame, a blessing that hides a curse? The idea of being more charismatic certainly seems appealing, but here's what science can tell you about whether this elusive rizz is a divine gift or a false friend. [From the September 2016 issue: The charisma effect] A number of psychologists have looked for charisma's seemingly magic ingredients. One of the most cited studies on the topic, from the Journal of Personality and Social Psychology in 2018, argues that charisma is actually a combination of two traits: influence (the ability to guide others with confidence and competence) and affability (the ability to make other people feel comfortable and at ease). Influence is judged based on qualities such as one's presence in a room, magnetism, and leadership ability. People see affability in, among other traits, frequency of smiling, approachability, and projection of positive energy. Leaders use their charisma to influence others in very specific ways. By analyzing speeches given by charismatic individuals, one helpful model shows a distinct, three-stage use of emotion. First, the speakers model and amplify the mood prevailing among their audience ('We are angry because those people over there are bad!'). Then they introduce a dissonant emotion that actually confuses people ('But you know what? I don't really care about that.'). Finally, they use that confusion to reframe the emotional environment and win over the audience to their view ('Because we should be happy that we are better people than they are!'). You will not be surprised to learn that charisma and professional success are strongly associated. Researchers following people's careers find that charisma early in life predicts a higher income 15 years later, as well as the managerial level a person achieves and the number of subordinates they have. However, this relationship appears to be curvilinear. Scholars in 2018 showed that people with a more charismatic personality are judged to be a more effective leader, but only up to about the 60th percentile. Beyond that point, perceived leadership effectiveness associated with charisma starts to decline. The authors of that study believed this was because extremely charismatic leaders tend to be strong on imparting a vision but weak on implementing it. Another possible reason why a very high level of charisma may lower the perceived effectiveness of a leader is the possible connection with narcissism. High charisma is specifically associated with people whom psychologists label 'agentic narcissists'; these people are extremely self-assured (whereas 'antagonistic narcissists' are mean and aggressive, and not perceived as charismatic at all). You can probably think of individuals whose charismatic qualities make them an effective leader up to a point, but tip over into being off-putting and arousing suspicion. [Tom F. Wright: The origin of vibes] In short, charisma might be a trait you'd want to increase—within reasonable limits. Of course, if charismatic individuals are simply born with the gift, this is a moot point. Some charisma, no doubt, is innate. We know, say, that attractive people are perceived as more charismatic than unattractive people; the same is true of more intelligent people. Charisma is also strongly correlated with personality traits, which are 40 to 60 percent heritable. Here, extroverts have the advantage because they tend to be high in influence and affability, while introverts score low on both. Yet ample evidence exists that charisma can be cultivated. Last year, three Israeli researchers created a virtual-reality device called the 'Charismulator' to help people develop a more appealing communication style, both verbal and nonverbal. Subjects who trained for only a few minutes with the device were judged by others to have 17 percent more 'general charisma' than they'd had before the intervention. The nonverbal-communication training exposed the participants to emphatic body gestures that conveyed a message, warm facial expressions, and powerful voice inflections—all demonstrated by charismatic speakers. You can re-create this input easily by reading the words of famous orators (think Abraham Lincoln and Martin Luther King Jr.), and studying videos of great speakers on YouTube. I stumbled on my own version of this method of the Charismulator intervention early in my public-speaking career, by listening to audio recordings of great communicators. I took copious notes on the speakers I admired, and accepted every invitation to talk in order to practice what I was learning. (Your nephew's bar mitzvah in February in Fairbanks, Alaska? I'll be there!) Anyone can improve their charismatic presence by being conscious of using these physical gestures, but it takes practice to make learned charisma stick. The early feedback I got on my public speaking did not include the phrase incredible charisma. The first notes were more like 'paces like a caged animal' and 'terrifying amount of eye contact.' With time, I did get better at it—fortunately. [Read: The perils of charisma] One question I haven't answered yet—and given this column's remit, you might be thinking that was a strange oversight: Does possessing charisma make you happier? I have found no evidence that addresses this topic head-on. Although you might assume that charisma would deliver happiness, one line of research gives me pause. One human capacity that strongly predicts charisma but is most definitely not correlated with higher happiness is self-consciousness—that is, thinking frequently about yourself. Charismatic people do think about themselves a lot—and that characteristic, as I have previously discussed, usually brings unhappiness. When it comes to happiness, much can be said for accepting who you are, rather than constantly worrying about what impression you're making on others. So yes: You probably can get more rizz, but you might want to skip it and have more peace of mind instead. Article originally published at The Atlantic Solve the daily Crossword
Atlantic
17-07-2025
- General
- Atlantic
How to Be More Charismatic, but Not Too Much More
Want to stay current with Arthur's writing? Sign up to get an email every time a new column comes out. A special quality sets some people apart from the crowd. They are magnetic to be around, attractive to watch, hypnotic to listen to. They have, in a word, charisma. It seems like a divine grace—indeed, the word derives from the ancient Greek χάρισμα, meaning 'God's gift.' The word appeared in third-century B.C.E. Greek translations of the Hebrew Bible, and early Christians referred to charismata as blessings bestowed on believers such as prophecy, healing, and speaking in tongues. Our modern usage of charisma comes from the early-20th-century sociologist Max Weber, who called it a 'certain quality of an individual personality, by virtue of which he is set apart from ordinary men and treated as endowed with supernatural, superhuman, or at least specifically exceptional powers or qualities.' And today, the concept of charisma is having a moment in the abbreviated slang term rizz, which, in Generation Z vernacular, describes one's ability to charismatically court a romantic partner. It involves a notable power to impress others with smooth talk, confidence, or style—a skill we'd probably all like to have, beyond the domain of romance. Do you have charisma? Would your life be better if you had more? Or is it, like fame, a blessing that hides a curse? The idea of being more charismatic certainly seems appealing, but here's what science can tell you about whether this elusive rizz is a divine gift or a false friend. From the September 2016 issue: The charisma effect A number of psychologists have looked for charisma's seemingly magic ingredients. One of the most cited studies on the topic, from the Journal of Personality and Social Psychology in 2018, argues that charisma is actually a combination of two traits: influence (the ability to guide others with confidence and competence) and affability (the ability to make other people feel comfortable and at ease). Influence is judged based on qualities such as one's presence in a room, magnetism, and leadership ability. People see affability in, among other traits, frequency of smiling, approachability, and projection of positive energy. Leaders use their charisma to influence others in very specific ways. By analyzing speeches given by charismatic individuals, one helpful model shows a distinct, three-stage use of emotion. First, the speakers model and amplify the mood prevailing among their audience ('We are angry because those people over there are bad!'). Then they introduce a dissonant emotion that actually confuses people ('But you know what? I don't really care about that.'). Finally, they use that confusion to reframe the emotional environment and win over the audience to their view ('Because we should be happy that we are better people than they are!'). You will not be surprised to learn that charisma and professional success are strongly associated. Researchers following people's careers find that charisma early in life predicts a higher income 15 years later, as well as the managerial level a person achieves and the number of subordinates they have. However, this relationship appears to be curvilinear. Scholars in 2018 showed that people with a more charismatic personality are judged to be a more effective leader, but only up to about the 60th percentile. Beyond that point, perceived leadership effectiveness associated with charisma starts to decline. The authors of that study believed this was because extremely charismatic leaders tend to be strong on imparting a vision but weak on implementing it. Another possible reason why a very high level of charisma may lower the perceived effectiveness of a leader is the possible connection with narcissism. High charisma is specifically associated with people whom psychologists label 'agentic narcissists'; these people are extremely self-assured (whereas 'antagonistic narcissists' are mean and aggressive, and not perceived as charismatic at all). You can probably think of individuals whose charismatic qualities make them an effective leader up to a point, but tips over into being off-putting and arousing suspicion. Tom F. Wright: The origin of vibes In short, charisma might be a trait you'd want to increase—within reasonable limits. Of course, if charismatic individuals are simply born with the gift, this is a moot point. Some charisma, no doubt, is innate. We know, say, that attractive people are perceived as more charismatic than unattractive people; the same is true of more intelligent people. Charisma is also strongly correlated with personality traits, which are 40 to 60 percent heritable. Here, extroverts have the advantage because they tend to be high in influence and affability, while introverts score low on both. Yet ample evidence exists that charisma can be cultivated. Last year, three Israeli researchers created a virtual-reality device called the 'Charismulator' to help people develop a more appealing communication style, both verbal and nonverbal. Subjects who trained for only a few minutes with the device were judged by others to have 17 percent more 'general charisma' than they'd had before the intervention. The nonverbal-communication training exposed the participants to emphatic body gestures that conveyed a message, warm facial expressions, and powerful voice inflections—all demonstrated by charismatic speakers. You can re-create this input easily by reading the words of famous orators (think Abraham Lincoln and Martin Luther King Jr.), and studying videos of great speakers on YouTube. I stumbled on my own version of this method of the Charismulator intervention early in my public-speaking career, by listening to audio recordings of great communicators. I took copious notes on the speakers I admired, and accepted every invitation to talk in order to practice what I was learning. (Your nephew's bar mitzvah in February in Fairbanks, Alaska? I'll be there!) Anyone can improve their charismatic presence by being conscious of using these physical gestures, but it takes practice to make learned charisma stick. The early feedback I got on my public speaking did not include the phrase incredible charisma. The first notes were more like 'paces like a caged animal' and 'terrifying amount of eye contact.' With time, I did get better at it—fortunately. One question I haven't answered yet—and given this column's remit, you might be thinking that was a strange oversight: Does possessing charisma make you happier? I have found no evidence that addresses this topic head-on. Although you might assume that charisma would deliver happiness, one line of research gives me pause. One human capacity that strongly predicts charisma but is most definitely not correlated with higher happiness is self-consciousness —that is, thinking frequently about yourself. Charismatic people do think about themselves a lot—and that characteristic, as I have previously discussed, usually brings unhappiness. When it comes to happiness, much can be said for accepting who you are, rather than constantly worrying about what impression you're making on others. So yes: You probably can get more rizz, but you might want to skip it and have more peace of mind instead.
National Geographic
17-06-2025
- Science
- National Geographic
Use this ancient technique to remember (almost) anything
In Orlando, Florida, a dozen seniors gather in a YMCA twice a week. Some push walkers, others roll in on wheelchairs. After some light exercise and corny jokes, they get down to the real workout—flexing their memory muscles. Most are battling early-stage dementia, hoping to hold onto their memories a little longer. They're learning an ancient technique called the method of loci, which transforms any familiar space into a storage system for new information. Want to remember your grocery list? Link milk to your sister's senior photo in the living room—visually, and in a way that feels almost absurd. Maybe imagine it pouring out of her nose? Link apples to the window—a volley of Golden Delicious smashing through the pane. The Roman orator Cicero used the same method to memorize speeches two millennia ago. Today's competitive 'memory athletes' use it to cram thousands of data points into their brains. And now the ancient technique is helping people in surprising new ways —slowing cognitive decline, treating depression and PTSD, even aiding recovery from traumatic brain injury. As researchers are only just now discovering, this tool works in startlingly complementary ways with how our brains naturally function. The palace of the mind At the USA Memory Championship, seemingly ordinary people show off extraordinary recall. Competitors memorize hundreds of random words, dozens of strangers' life histories, and the order of shuffled card decks—all at lightning speed. These are the kinds of folks who might rattle off a thousand digits of pi without breaking a sweat. They all use variations on the method of loci, also known as the 'memory palace' or 'Roman room' method. The basics are straightforward: Make a mental map of a familiar place, then create associations between items and specific locations along a route. But is it easy? Not necessarily. The trick is using your imagination to make those mental connections memorable—the weirder, more vivid, and more outrageous, the better. Legend credits the method's invention to the ancient Greek poet Simonides of Ceos, who escaped a collapsing building in the fifth century B.C.E. As victims were pulled from rubble, Simonides identified them by remembering where each had sat around a banquet table. But indigenous cultures worldwide tapped into similar techniques long before. Native American pilgrimage trails, Australian Aboriginal songlines, and Pacific Islanders' ceremonial roads all follow a similar pattern: Elders would sing, dance, or tell stories at specific locations, making information stick by pairing information with location and context. 'It's shocking to me that this is so understudied when this was the dominant form of information storage for literally all of civilization, until the printing press,' says MIT neuroscientist Robert Ajemian, who has studied how the brain uses the method of loci. The event finalists are given instructions during the 2023 USA Memory Championship at Full Sail University, Winter Park, Florida. Photograph by Phanindra Pavuluri Why the memory palace works Neuroscience is catching up to what ancient cultures seemed to know instinctively. The method of loci taps our natural strengths in spatial navigation and visual memory—abilities that evolution has honed over thousands of generations. While almost no one is naturally great at remembering abstract information, like numbers or words, the human brain is built to remember what we've seen and where we've been. Recent brain-imaging studies show that using the method of loci creates more robust networks by linking multiple parts of the brain involved in memory: the prefrontal cortex, hippocampus, and visual cortex. Memory palace practitioners are literally rewiring their brains to be more efficient at memory. And after mastering the technique, they can develop elaborate systems of personalized imagery to represent, say, numbers, individual playing cards, or other hard-to-remember info. Despite their effectiveness, variations on the method of loci are neither widely taught nor widely researched, Ajemian says—much to his frustration. We've been too quick to dismiss it as a neat trick, he argues, instead of regarding it as a valuable learning tool that's sustained human knowledge for millennia. Perhaps nowhere is its potential more poignant than in the fight against dementia. New hope for aging minds For Michael Dottino, memory is the family business. His father founded the USA Memory Championship, and Michael trained businesspeople and students in memory techniques. Then the local Jewish Community Center asked him to try something new: develop a class for seniors with early-stage dementia. The Memory Institute program he created meets twice a week at the Dr. P. Phillips YMCA in Orlando. The four-hour sessions combine memory training with physical activity, social interaction, and cognitive exercises like using the method of loci. The goal, Dottino says, is to slow participants' rates of decline. Three years in, he finds the program's results encouraging. Some of the earliest participants are still showing up twice a week, keeping up the regimen. Dottino calls out one of them, Karen Vourvopoulos, who has retained all of her cognitive function. 'The class has given my mother a new lease on life,' says Matina Vourvopoulos, Karen's daughter. 'She's more energized, inspired, creative, and enthusiastic about life. I wish there was a Memory Institute for every senior in every community.' Clinical neuropsychologist Erica Weber is putting similar approaches through rigorous clinical trials. Memory programs are few and far between, she says, and patients often pay out of pocket. But if such strategies can be proven genuinely effective, insurance companies might start covering them. One current challenge, Weber says, is that the main sources of funding for rehabilitation research—the U.S. Department of Defense and the National Institute on Disability, Independent Living and Rehabilitation Research—are facing large cuts (and, in the latter case, outright elimination). But so far, the research looks promising. One massive study, funded by the National Institutes of Health, showed that cognitive training can help healthy older adults maintain and improve their mental skills. Though there's no need to wait until retirement age to put memory strategies like the method of loci to use. 'Try to practice using the strategies before you need to rely on them,' Weber advises. Think of it as a cognitive gym membership—better to start lifting mental weights before the muscle gets weak. Applications beyond aging Which is to say, seniors aren't the only ones who can benefit. Weber adapts the method of loci to help people with traumatic brain injuries—suffered in car accidents or falls, for example—to recover cognitive function. What she calls the modified Story Memory Technique breaks down memory palaces into simpler components, like transforming verbal information into mental imagery. The range of patients she works with keep expanding, including those suffering from multiple sclerosis, HIV-related cognitive impairment, and spinal cord injuries that impact brain function. Perhaps most intriguingly, mental health experts are exploring the memory palace as a therapy tool. People with depression or PTSD might create palaces filled with positive memories, mental refuges to revisit during tough times. The concept makes intuitive sense: if you can train your brain to efficiently store and retrieve any information using spatial memory, why not train it to access calm, positive states when you need them most? In our smartphone age, when we've outsourced so much memorization to Google and GPS, ancient mnemonics are reminders of what our remarkable brains can do. As MIT neuroscientist Ajemian puts it, engaging these techniques is 'fundamental cognitive exercise, in the same way that aerobics is fundamental physical exercise.' Our ancestors carried entire libraries in their heads. With a little practice, we can at least make sure to pick up the milk. This article is part of Your Memory, Rewired, a National Geographic exploration into the fuzzy, fascinating frontiers of memory science—including advice on how to make your own memory more powerful. Learn more.
San Francisco Chronicle
11-06-2025
- Science
- San Francisco Chronicle
Solstices brought Mayan communities together, using monuments shaped by science and religion – and kingly ambitions, too
Eds: This story was supplied by The Conversation for AP customers. The Associated Press does not guarantee the content. Gerardo Aldana, University of California, Santa Barbara (THE CONVERSATION) K'ahk' Uti' Witz' K'awiil knew his history. For 11 generations, the Mayan ruler's dynasty had ruled Copan, a city-state near today's border between Honduras and Guatemala. From the fifth century C.E. into the seventh century, scribes painted his ancestors' genealogies into manuscripts and carved them in stone monuments throughout the city. Around 650, one particular piece of architectural history appears to have caught his eye. Centuries before, village masons built special structures for public ceremonies to view the Sun – ceremonies that were temporally anchored to the solstices, like the one that will occur June 20, 2025. Building these types of architectural complexes, which archaeologists call 'E-Groups,' had largely fallen out of fashion by K'ahk' Uti' Witz' K'awiil's time. But aiming to realize his ambitious plans for his city, he seems to have found inspiration in these astronomical public spaces, as I've written about in my research on ancient Mayan hieroglyphically recorded astronomy. K'ahk' Uti' Witz' K'awiil's innovations are a reminder that science changes through discovery or invention – but also occasionally for personal or political purposes, particularly in the ancient world. E-Groups were first constructed in the Mayan region as early as 1000 B.C.E. The site of Ceibal, on the banks of the Pasión River in central Guatemala, is one such example. There, residents built a long, plastered platform bordering the eastern edge of a large plaza. Three structures were arranged along a north-south axis atop this platform, with roofs tall enough to rise above the rainforest floral canopy. Within the center of the plaza, to the west of the platform, they built a radially symmetric pyramid. From there, observers could follow sunrise behind and between the structures on the platform over the course of the year. At one level, the earliest E-Group complexes served very practical purposes. In Preclassic villages where these complexes have been found, like Ceibal, populations of several hundred to a few thousand lived on 'milpa' or 'slash-and-burn' farming techniques practices still maintained in pueblos throughout Mesoamerica today. Farmers chop down brush vegetation, then burn it to fertilize the soil. This requires careful attention to the rainy season, which was tracked in ancient times by following the position of the rising Sun at the horizon. Most of the sites in the Classic Mayan heartland, however, are located in flat, forested landscapes with few notable features along the horizon. Only a green sea of the floral canopy meets the eye of an observer standing on a tall pyramid. By punctuating the horizon, the eastern structures of E-Group complexes could be used to mark the solar extremes. Sunrise behind the northernmost structure of the eastern platform would be observed on the summer solstice. Sunrise behind the southernmost structure marked the winter solstice. The equinoxes could be marked halfway between, when the Sun rose due east. Scholars are still debating key factors of these complexes, but their religious significance is well attested. Caches of finely worked jade and ritual pottery reflect a cosmology oriented around the four cardinal directions, which may have coordinated with the E-Group's division of the year. Fading knowledge K'ahk' Uti' Witz' K'awiil's citizenry, however, would have been less attuned to direct celestial observations than their ancestors. By the seventh century, Mayan political organization had changed significantly. Copan had grown to as many as 25,000 residents, and agricultural technologies also changed to keep up. Cities of the Classic period practiced multiple forms of intensive agriculture that relied on sophisticated water management strategies, buffering the need to meticulously follow the horizon movement of the Sun. E-Group complexes continued to be built into the Classic period, but they were no longer oriented to sunrise, and they served political or stylistic purposes rather than celestial views. Such a development, I think, resonates today. People pay attention to the changing of the seasons, and they know when the summer solstice occurs thanks to a calendar app on their phones. But they probably don't remember the science: how the tilt of the Earth and its path around the Sun make it appear as though the Sun itself travels north or south along the eastern horizon. United through ritual During the mid-seventh century, K'ahk' Uti' Witz' K'awiil had developed ambitious plans for his city – and astronomy provided one opportunity to help achieve them. He is known today for his extravagant burial chamber, exemplifying the success he eventually achieved. This tomb is located in the heart of a magnificent structure, fronted by the 'Hieroglyphic Stairway ': a record of his dynasty's history that is one of the largest single inscriptions in ancient history. Eying opportunities to transform Copan into a regional power, K'ahk' Uti' Witz' K'awiil looked for alliances beyond his local nobility, and he reached out to nearby villages. Over the past century, several scholars, including me, have investigated the astronomical component to his plan. It appears that K'ahk' Uti' Witz' K'awiil commissioned a set of stone monuments or 'stelae,' positioned within the city and in the foothills of the Copan Valley, which tracked the Sun along the horizon. Like E-Group complexes, these monuments engaged the public in solar observations. Taken together, the stelae created a countdown to an important calendric event, orchestrated by the Sun. Back in the 1920s, archaeologist Sylvanus Morley noted that from Stela 12, to the east of the city, one could witness the Sun set behind Stela 10, on a foothill to the west, twice each year. Half a century later, archaeoastronomer Anthony Aveni recognized that these two sunsets defined 20-day intervals relative to the equinoxes and the zenith passage of the Sun, when shadows of vertical objects disappear. Twenty days is an important interval in the Mayan calendar and corresponds to the length of a 'month' in the solar year. My own research showed that the dates on several stelae also commemorate some of these 20-day interval events. In addition, they all lead up to a once-every-20-year event called a 'katun end.' K'ahk' Uti' Witz' K'awiil celebrated this katun end, setting his plans for regional hegemony in motion at Quirigua, a growing, influential city some 30 miles away. A round altar there carries an image of him, commemorating his arrival. The hieroglyphic text tells us that K'ahk' Uti' Witz' K'awiil 'danced' at Quirigua, cementing an alliance between the two cities. In other words, K'ahk' Uti' Witz' K'awiil's 'solar stelae' did more than track the Sun. The monuments brought communities together to witness astronomical events for shared cultural and religious experiences, reaching across generations. Coming together to appreciate the natural cycles that make life on Earth possible is something that – I hope – will never fade with fashion.
Yahoo
11-06-2025
- Science
- Yahoo
How was the wheel invented? Computer simulations reveal the unlikely birth of a world-changing technology nearly 6,000 years ago
Imagine you're a copper miner in southeastern Europe in the year 3900 B.C.E. Day after day you haul copper ore through the mine's sweltering tunnels. You've resigned yourself to the grueling monotony of mining life. Then one afternoon, you witness a fellow worker doing something remarkable. With an odd-looking contraption, he casually transports the equivalent of three times his body weight on a single trip. As he returns to the mine to fetch another load, it suddenly dawns on you that your chosen profession is about to get far less taxing and much more lucrative. What you don't realize: You're witnessing something that will change the course of history – not just for your tiny mining community, but for all of humanity. Despite the wheel's immeasurable impact, no one is certain as to who invented it, or when and where it was first conceived. The hypothetical scenario described above is based on a 2015 theory that miners in the Carpathian Mountains – now Hungary – first invented the wheel nearly 6,000 years ago as a means to transport copper ore. The theory is supported by the discovery of more than 150 miniaturized wagons by archaeologists working in the region. These pint-sized, four-wheeled models were made from clay, and their outer surfaces were engraved with a wickerwork pattern reminiscent of the basketry used by mining communities at the time. Carbon dating later revealed that these wagons are the earliest known depictions of wheeled transport to date. This theory also raises a question of particular interest to me, an aerospace engineer who studies the science of engineering design. How did an obscure, scientifically naive mining society discover the wheel, when highly advanced civilizations, such as the ancient Egyptians, did not? It has long been assumed that wheels evolved from simple wooden rollers. But until recently no one could explain how or why this transformation took place. What's more, beginning in the 1960s, some researchers started to express strong doubts about the roller-to-wheel theory. After all, for rollers to be useful, they require flat, firm terrain and a path free of inclines and sharp curves. Furthermore, once the cart passes them, used rollers need to be continually brought around to the front of the line to keep the cargo moving. For all these reasons, the ancient world used rollers sparingly. According to the skeptics, rollers were too rare and too impractical to have been the starting point for the evolution of the wheel. But a mine – with its enclosed, human-made passageways – would have provided favorable conditions for rollers. This factor, among others, compelled my team to revisit the roller hypothesis. The transition from rollers to wheels requires two key innovations. The first is a modification of the cart that carries the cargo. The cart's base must be outfitted with semicircular sockets, which hold the rollers in place. This way, as the operator pulls the cart, the rollers are pulled along with it. This innovation may have been motivated by the confined nature of the mine environment, where having to periodically carry used rollers back around to the front of the cart would have been especially onerous. The discovery of socketed rollers represented a turning point in the evolution of the wheel and paved the way for the second and most important innovation. This next step involved a change to the rollers themselves. To understand how and why this change occurred, we turned to physics and computer-aided engineering. To begin our investigation, we created a computer program designed to simulate the evolution from a roller to a wheel. Our hypothesis was that this transformation was driven by a phenomenon called 'mechanical advantage.' This same principle allows pliers to amplify a user's grip strength by providing added leverage. Similarly, if we could modify the shape of the roller to generate mechanical advantage, this would amplify the user's pushing force, making it easier to advance the cart. Our algorithm worked by modeling hundreds of potential roller shapes and evaluating how each one performed, both in terms of mechanical advantage and structural strength. The latter was used to determine whether a given roller would break under the weight of the cargo. As predicted, the algorithm ultimately converged upon the familiar wheel-and-axle shape, which it determined to be optimal. During the execution of the algorithm, each new design performed slightly better than its predecessor. We believe a similar evolutionary process played out with the miners 6,000 years ago. It is unclear what initially prompted the miners to explore alternative roller shapes. One possibility is that friction at the roller-socket interface caused the surrounding wood to wear away, leading to a slight narrowing of the roller at the point of contact. Another theory is that the miners began thinning out the rollers so that their carts could pass over small obstructions on the ground. Either way, thanks to mechanical advantage, this narrowing of the axle region made the carts easier to push. As time passed, better-performing designs were repeatedly favored over the others, and new rollers were crafted to mimic these top performers. Consequently, the rollers became more and more narrow, until all that remained was a slender bar capped on both ends by large discs. This rudimentary structure marks the birth of what we now refer to as 'the wheel.' According to our theory, there was no precise moment at which the wheel was invented. Rather, just like the evolution of species, the wheel emerged gradually from an accumulation of small improvements. This is just one of the many chapters in the wheel's long and ongoing evolution. More than 5,000 years after the contributions of the Carpathian miners, a Parisian bicycle mechanic invented radial ball bearings, which once again revolutionized wheeled transportation. Ironically, ball bearings are conceptually identical to rollers, the wheel's evolutionary precursor. Ball bearings form a ring around the axle, creating a rolling interface between the axle and the wheel hub, thereby circumventing friction. With this innovation, the evolution of the wheel came full circle. This example also shows how the wheel's evolution, much like its iconic shape, traces a circuitous path – one with no clear beginning, no end, and countless quiet revolutions along the way. This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Kai James, Georgia Institute of Technology Read more: Disaster evacuations can take much longer than people expect − computer simulations could help save lives and avoid chaos The horse bit and bridle kicked off ancient empires – a new giant dataset tracks the societal factors that drove military technology The mysterious biomechanics of riding – and balancing – a bicycle Kai James receives funding from The National Science Foundation.
