Episode AI notes
- Babies are born with limited abilities to engage with the world and their behavioral repertoire skews toward the negative and involuntary. It takes weeks before babies first smile unambiguously, marking the beginning of their engagement with the social world.
- The origins and meaning of smiles remain mysterious despite extensive research. Smiles are often associated with light, warmth, and attention-grabbing qualities. A smile involves the contraction of specific muscles and genuine smiles include eye crinkles.
- The authenticity of facial expressions, including smiles, is still debated. Facial expressions may not solely reflect internal emotions but can be tools for influencing others. Smiles during activities can be more social responses than direct reflections of happiness.
- Smiling is a universal human behavior, but there is variability in who smiles and when. Women tend to smile more than men, and smilingness varies across countries based on migration history. Smiling behaviors have also changed across history, becoming more acceptable and associated with play and pleasure.
- The evolution of smiling and laughing suggests a continuum of integrating signals. Smiles and laughter have origins in primate displays associated with submissiveness and playfulness. Laugh-like vocalizations have been observed in other mammals and birds, indicating a common trait across species.
- The nature and power of smiles remain intriguing. Smiles can activate reward centers in the brain and elicit positive responses from others, even in babies. Smiles may serve as a means for babies to solicit care and protection when they are most vulnerable. (Time 0:00:00)
The Dawn of a Baby’s Smile Babies are born with limited abilities to engage with the world, mostly exhibiting negative and involuntary behaviors. It takes weeks before they first smile unambiguously, despite making smiling movements from birth or even before birth. The genuine smile marks the beginning of their engagement with the social world. Transcript: Speaker 1 Hope you enjoyed your fall and your holidays. Thanks so much for joining us. We’re super excited to be kicking off a brand new season of the Many Minds podcast. We thought we’d get things started this year with an audio essay, one partly inspired by some musings and mullings from my parental leave. Hope you enjoyed, folks. And we’ll see you again in a couple weeks with our first interview of 2024. Without further ado, on to Dawn of the Smile. Enjoy. When my daughter was born this past August, it felt like a long wait was finally over. But soon after she came into the world, wriggling and wailing, another wait began. Babies are born notoriously helpless, and they’re not particularly happy. Their behavioral repertoire at first skews toward the negative and involuntary. They cry, they furrow their brows, they sneeze and hiccup and yawn. But at some time before they actually start to engage with the social world, it’s weeks before one day, out of the blue, they look at you and smile. Our daughter first really smiled unambiguously in her sixth week. I say really because babies do from day one, actually even while they’re in utero, form their mouths into the shape of a smile. They make this face while they’re sleeping or drowsy. (Time 0:00:27)
The Power and Mystery of Smiles A baby’s first smiles can be big and goofy, reminiscent of a switch being flipped, before becoming more fine-tuned over time. The expression of a smile is often associated with light, warmth, and attention-grabbing qualities. Despite extensive research, the origins and meaning of smiles remain mysterious, even 150 years after Charles Darwin’s observations of his own children’s smiles. Transcript: Speaker 1 You might think that a baby’s first real smiles would be tentative. A testing of the social waters. Not necessarily. Our daughter’s early social smiles, according to notes I took at the time, were big and goofy. They tended to come on fast as if a switch had been flipped. Slowly, they became more fine-tuned. Now at four months, her smiles are on more of a smooth dimmer switch. Some are subtle, others are broad and beaming. Invariably, the largest smiles we get all day are the first ones of the morning, around dawn, when she wakes up cooing and squirming, her face one big cuddle me beacon. It’s no accident that we talk about smiles in terms of light. We speak of radiant smiles, incandescent smiles, high wattage smiles. We say that someone’s smiling eyes sparkle, or twinkle. There’s just something about the expression that seizes our attention and somehow warms us. When Charles Darwin described the first smiles of his own children, bright around that six-week mark, he noted that, as they smiled, their eyes became, decidedly bright. The smile is such a powerful and primordial expression. It’s ubiquitous and universal, and so readily understood. You’d be forgiven for assuming we’ve long since figured out what smiles mean, and why. But the truth is, despite 150 years of research since Darwin, the origins of the smile remain swaddled in mystery. (Time 0:02:07)
The enigmatic nature of smiles Smiles are a powerful and universal expression, yet their origins remain a mystery despite years of research. Anatomically, a smile involves the contraction of the zygomaticus major muscles, resulting in the curving up of the lips. The genuine Duchenne smile includes the contraction of the orbicularis oculi muscles, leading to eye crinkles. The enigmatic nature of smiles continues to elude complete understanding. Transcript: Speaker 1 There’s just something about the expression that seizes our attention and somehow warms us. When Charles Darwin described the first smiles of his own children, bright around that six-week mark, he noted that, as they smiled, their eyes became, decidedly bright. The smile is such a powerful and primordial expression. It’s ubiquitous and universal, and so readily understood. You’d be forgiven for assuming we’ve long since figured out what smiles mean, and why. But the truth is, despite 150 years of research since Darwin, the origins of the smile remain swaddled in mystery. Anatomically speaking, the smile is to pull back the corners of the mouth. This movement is a contraction of the zygomaticus major muscles, bands of muscle that run diagonally up our cheeks. The result, visually, is that telltale curving up of the lips. This is the essence of the smile. It’s cinequanon. But the simple mouth-only version of the expression often gets upgraded with contractions of another group of muscles, the orbicularis oculi. These constrict the eyes and lead to those crinkles that are sometimes called crow’s feet. Smiles that include the eyes like this are known as douche-shen smiles. After the 19th century French anatomist Guillaume Duchin, he thought there was something more genuine at work in these cases. (Time 0:02:55)
Anatomy of a Smile The smile is anatomically characterized by the contraction of the zygomaticus major muscles, resulting in the telltale curving up of the lips. Additional contractions of the orbicularis oculi muscles can lead to the appearance of crow’s feet around the eyes, known as douche-shen smiles. These smiles were thought by a French anatomist to be brought into play by true feeling. The meaning of smiles, even the basic ones, is contested, but the folk view sees facial expressions as a way of broadcasting emotions through distinct facial features such as curved lips, widened eyes, furrowed brows, and wrinkled noses. Transcript: Speaker 1 Anatomically speaking, the smile is to pull back the corners of the mouth. This movement is a contraction of the zygomaticus major muscles, bands of muscle that run diagonally up our cheeks. The result, visually, is that telltale curving up of the lips. This is the essence of the smile. It’s cinequanon. But the simple mouth-only version of the expression often gets upgraded with contractions of another group of muscles, the orbicularis oculi. These constrict the eyes and lead to those crinkles that are sometimes called crow’s feet. Smiles that include the eyes like this are known as douche-shen smiles. After the 19th century French anatomist Guillaume Duchin, he thought there was something more genuine at work in these cases. Such smiles, quote, do not involve the will, he wrote, but are, quote, brought into play by true feeling, end quote. There’s little question that douche-shen smiles are more intense than simple smiles, but whether they’re actually truer is up for debate. In fact, the meaning of even the most basic smiles is still surprisingly contested. We all intuitively recognize a smile as a sign of happiness, of pleasure, of joy. We see those up-curved lips as telling us something about the smile’s inner state, about how they’re feeling. This in a nutshell is the folk view of smiling. On this view, facial expressions are a way of broadcasting our emotions, those curved lips, but also widened eyes, furrowed brows, and wrinkled noses, all correspond to distinct Inner feelings. (Time 0:03:31)
Insights into the Contested Nature of Facial Expressions Facial expressions such as douche-shen smiles are often attributed to genuine feelings, but their authenticity is still debated. The folk view of smiling sees facial expressions as a reflection of inner emotions, while the basic emotions theory, associated with psychologist Paul Ekman, has long dominated research in this area. However, there is a newer theory gaining traction that challenges the idea of facial expressions as simply broadcasting internal feelings. Transcript: Speaker 1 These constrict the eyes and lead to those crinkles that are sometimes called crow’s feet. Smiles that include the eyes like this are known as douche-shen smiles. After the 19th century French anatomist Guillaume Duchin, he thought there was something more genuine at work in these cases. Such smiles, quote, do not involve the will, he wrote, but are, quote, brought into play by true feeling, end quote. There’s little question that douche-shen smiles are more intense than simple smiles, but whether they’re actually truer is up for debate. In fact, the meaning of even the most basic smiles is still surprisingly contested. We all intuitively recognize a smile as a sign of happiness, of pleasure, of joy. We see those up-curved lips as telling us something about the smile’s inner state, about how they’re feeling. This in a nutshell is the folk view of smiling. On this view, facial expressions are a way of broadcasting our emotions, those curved lips, but also widened eyes, furrowed brows, and wrinkled noses, all correspond to distinct Inner feelings. This account of facial expressions is not just a folk theory. It’s also a well-respected academic position, sometimes called the basic emotions theory. It’s most strongly associated with the work of the psychologist Paul Ekman. It has for some time dominated research on facial behavior, but there’s also a newer theory in town, one that’s quickly gaining traction. According to this alternative, facial expressions are not about publicizing our private feelings. (Time 0:03:58)
La teoría de la sonrisa como herramienta social Transcript: Speaker 1 According to this alternative, facial expressions are not about publicizing our private feelings. They’re about doing things in the social world. They’re about influencing others. They are in short tools of manipulation. Proonents of this social tools view usually reject the term facial expression altogether. They don’t like the metaphor it implies, that to make a face is to push out a feeling, like expressing oil from a seed. Instead, they speak of smiles, frowns, and the like as facial displays or facial configurations. Researchers in the social tools camp emphasize that we smile because we want to affiliate with others, not necessarily because we’re happy. A range of studies support this interpretation. In one, psychologists, armed with binoculars, went to a local bowling alley and watched people’s faces as they bold. If smiles are expressions of happiness, they reasoned, you’d expect a bowler to smile when they bold well. But this is not quite what they observed. People were more likely to smile, not after rolling a good ball and still facing the pins, but moments later, once they turned around, to face their friends. The same researchers also reported that people bowling alone don’t smile much at all. Similar studies have been conducted with hockey fans and judo athletes, and all point to a similar conclusion. (Time 0:05:16)
definición evolución función sonrisa
función sonrisa evolución definición
The Social Motivation of Smiles Studies show that smiles during activities like bowling are more likely to be a social response than a direct reflection of happiness. Research with various activities and across cultures supports the idea that smiles have a social motivation rather than purely emotional. This challenges the traditional view that smiles simply mean “I’m happy” and leans towards the interpretation of smiles as a signal for social affiliation. Furthermore, cross-cultural research suggests that smiling is a universal human behavior, seen in diverse cultures and even in blind individuals, supporting the idea that smiling is a fundamental aspect of human communication and social interaction. Transcript: Speaker 1 In one, psychologists, armed with binoculars, went to a local bowling alley and watched people’s faces as they bold. If smiles are expressions of happiness, they reasoned, you’d expect a bowler to smile when they bold well. But this is not quite what they observed. People were more likely to smile, not after rolling a good ball and still facing the pins, but moments later, once they turned around, to face their friends. The same researchers also reported that people bowling alone don’t smile much at all. Similar studies have been conducted with hockey fans and judo athletes, and all point to a similar conclusion. Smiles don’t have a purely emotional motivation. They have a social one. So in short, the basic emotions view sees the meaning of a smile as I’m happy. The social tools view, by contrast, sees the meaning of a smile as let’s affiliate. Now, the debate between these views is complex. It rages on, and the relevant body of research is too vast to summarize here. But personally, I incline toward the social tools view. It feels intuitively right to me, and as I think it jives better with what we know about facial displays in other species. But before we get to those other species, first a bit more about our own. Smiling appears to be a universal human birthright. Cross-cultural research has documented this basic display in countless far-flung cultures. It’s produced by blind people, and emerges in blind infants at around the same time it does in sighted infants. (Time 0:05:59)
Teoría de la sonrisa como herramienta social y algunos ejemplos. Transcript: Speaker 1 So in short, the basic emotions view sees the meaning of a smile as I’m happy. The social tools view, by contrast, sees the meaning of a smile as let’s affiliate. Now, the debate between these views is complex. It rages on, and the relevant body of research is too vast to summarize here. But personally, I incline toward the social tools view. It feels intuitively right to me, and as I think it jives better with what we know about facial displays in other species. But before we get to those other species, first a bit more about our own. Smiling appears to be a universal human birthright. Cross-cultural research has documented this basic display in countless far-flung cultures. It’s produced by blind people, and emerges in blind infants at around the same time it does in sighted infants. But beyond this universal core, there’s some curious variability. In particular variability in who smiles and when. A robust literature, for instance, has documented that women smile more than men. This is not an essential difference due to biological sex, but rather a difference due to, as one study put it, rules and roles. Smilingness also varies across countries. A major predictor of this variation turns out to be the history of migration to the region. In countries with a long history of migration, places like the US and Canada, people tend to smile more than in countries with little historical migration, places like Japan or Indonesia. One reason for this could be that in a more heterogeneous society, it’s important to wield obvious signs of friendliness. (Time 0:06:38)
evolución función sonrisa teoría
evolución función sonrisa teoría
Variability of Smiling: From Culture to History Smiling behaviors emerge universally in infants but vary in frequency and timing among different groups, such as women and men. This variability is attributed to cultural and societal factors, as evidenced by differences in smiling across countries with varying histories of migration. Additionally, historical shifts in the perception of smiling, from being unbecoming to being associated with play and pleasure, have been documented through a big data analysis of yearbook photos. Transcript: Speaker 1 It’s produced by blind people, and emerges in blind infants at around the same time it does in sighted infants. But beyond this universal core, there’s some curious variability. In particular variability in who smiles and when. A robust literature, for instance, has documented that women smile more than men. This is not an essential difference due to biological sex, but rather a difference due to, as one study put it, rules and roles. Smilingness also varies across countries. A major predictor of this variation turns out to be the history of migration to the region. In countries with a long history of migration, places like the US and Canada, people tend to smile more than in countries with little historical migration, places like Japan or Indonesia. One reason for this could be that in a more heterogeneous society, it’s important to wield obvious signs of friendliness. Smilingness also varies across history. In the west, we’re accustomed to putting on a toothy grin for photos, but this wasn’t always the case. In an earlier time, a big open mouth smile was considered unbecoming. People sitting for photos were instructed to say not cheese, but prunes to keep their mouth small. The cultural historian Christina Coache-Madova has argued that the shift began in the 1900s, when Kodak launched a campaign to associate photography with play and pleasure. A big data analysis of yearbook photos bears this timeline out. (Time 0:07:17)
La sonrisa en las fotos es resultado de una campaña de Kodak. Transcript: Speaker 1 In the west, we’re accustomed to putting on a toothy grin for photos, but this wasn’t always the case. In an earlier time, a big open mouth smile was considered unbecoming. People sitting for photos were instructed to say not cheese, but prunes to keep their mouth small. The cultural historian Christina Coache-Madova has argued that the shift began in the 1900s, when Kodak launched a campaign to associate photography with play and pleasure. A big data analysis of yearbook photos bears this timeline out. Smiling in portraits steadily increased over the course of the 20th century. (Time 0:08:08)
fotografía historia sonrisa
Idea sobre los orígenes evolutivos de la risa. Transcript: Speaker 1 Van Hoof argued that human smiles and laughter originated in two different primate displays. The source of the smile, he suggested, is the silent, beared, teeth display. A common signal of submissiveness. Meanwhile, the source of the laugh is the relaxed open-mouth display, often known more simply as the playface. The playface is thought to be rooted in the mock gnawing or mock biting that accompanies physical play. Van Hoof further argued that, though drawn from these two separate sources, smiling and laughing eventually converged in humans to form a continuum of positive, affiliative displays. (Time 0:10:50)
risa sonrisa
Evolution of laughter and its acoustic properties in primates and other mammals Smiling and laughing in humans have evolved from separate sources to form a continuum of positive, affiliative displays. Research on the acoustic properties of laughter in great apes found that each species has its own distinctive flavor of laughter. Humans primarily laugh while breathing out, while other apes laugh during both inhalation and exhalation. This initial ape-like stage in human infants may explain the awkwardness of their first chuckles. The taxonomy of primate laughter matches the known primate taxonomy from genetic analysis. Furthermore, laughter-like vocalizations have been observed in other mammals such as rats and birds, suggesting that positive vocalizations during play and social interaction may be a common trait across species. Transcript: Speaker 1 Van Hoof further argued that, though drawn from these two separate sources, smiling and laughing eventually converged in humans to form a continuum of positive, affiliative displays. A bunch of work since Van Hoof has followed up on these ideas. Much of it has zoomed in on laughter, and specifically on its acoustic properties. The comparative psychologist Marina de Villa Ross, for instance, has examined laughter across the great apes. In one study, she and her colleagues systematically tickled orangutans, gorillas, chimpanzees, banobos, and human infants and compared the vocalizations they made. What they found, through close acoustic analysis, is that each of these species has its own distinctive flavor of laughter. Humans, for instance, are the only one that primarily laughs while breathing out. From these analyses, de Villa Ross and her team built a taxonomy of primate laughter, and they found that it matches the actual primate taxonomy known from genetic analysis. Another research team followed up on these findings. They showed that human infants go through an initial stage where they laugh more like other apes, with vocalization during both exhalation and inhalation. This ape-like stage may account for the ungainliness of those first chuckles. Additional work has broadened out beyond primates, examining laugh-like vocalizations in other mammals, and even in birds. Rats, it turns out, produce repetitive, ultrasonic vocalizations during play and while tickled. Kia, the parrots of New Zealand, seem to emit positive warbles that infect other Kia. (Time 0:11:15)
The Nature of Smiles The nature of smiles is a subject of interest, with some research suggesting that open-mouthed smiles in babies are associated with physical play, and adults are more likely to make open-mouthed smiles during playful activities. The smile is seen by some as a display of submissiveness, while others view it as a signal of playfulness. Additionally, there is a suggestion that smiles have an acoustic origin, linked to making vocalizations sound less threatening. Despite the mystery surrounding the ultimate origins of the smile, its power is evident. Baby grins activate reward centers in their mother’s brains, and carrying a smiling baby elicits positive reactions from others. Transcript: Speaker 1 Intriguingly, some infant researchers have found it useful to distinguish basic smiles with the mouth closed from open-mouthed smiles that more obviously resemble the primate Playface. Babies tend to make these open-mouthed smiles more often during physical play. Open-mouthed smiles may have a similar shading in adults, too. An analysis in the bowling study described earlier found that people were more likely to make open-mout smiles while being particularly playful, for example when hamming it up. So, in summary, some see the smile as rooted in a display of subisiveness. Others see it as fundamentally a signal of playfulness, but importantly, these aren’t the only accounts out there. Another suggestion is that the smile has an acoustic origin. When we pull back our lips, it makes our vocalizations sound higher-pitched, and thus less threatening. And so the mystery persists. Questions linger. For example, if smiles are fundamentally playful, why do babies smile long before they can play? Could there be something to the fact that a smile is a fundamentally visual signal while a laugh is a fundamentally acoustic one? And why is it that sometimes when we laugh or experience extreme joy, we also shed tears? The ultimate origins of the smile may remain in doubt, but its power does not. When we see a smile, in fact, even when we simply hear a smile in someone’s voice, we smile too. Baby grins are known to activate reward centers in their mother’s brains. And those little curved mouths aren’t just rewarding for caregivers. Walk around with a smiling baby in your arms, and people will stop in their tracks. (Time 0:13:30)
The Power and Origin of Smiles The smile may have an acoustic origin, making vocalizations sound less threatening. Despite the mystery surrounding the fundamental playfulness of smiles, the power of a smile is undeniable. Smiles can activate reward centers in the brain and elicit positive responses from others, even in babies. The potency of smiles may have developed as a means for infants to solicit care and protection when they are most vulnerable, despite their helplessness. Transcript: Speaker 1 Another suggestion is that the smile has an acoustic origin. When we pull back our lips, it makes our vocalizations sound higher-pitched, and thus less threatening. And so the mystery persists. Questions linger. For example, if smiles are fundamentally playful, why do babies smile long before they can play? Could there be something to the fact that a smile is a fundamentally visual signal while a laugh is a fundamentally acoustic one? And why is it that sometimes when we laugh or experience extreme joy, we also shed tears? The ultimate origins of the smile may remain in doubt, but its power does not. When we see a smile, in fact, even when we simply hear a smile in someone’s voice, we smile too. Baby grins are known to activate reward centers in their mother’s brains. And those little curved mouths aren’t just rewarding for caregivers. Walk around with a smiling baby in your arms, and people will stop in their tracks. Some of these people, in my experience, will actually thank you. The potency of smiles can’t be an accident. A baby, again, is utterly helpless. At six weeks of age, infants are still in the so-called fourth trimester. They can’t chew, they can’t walk or crawl, they can barely hold their heads up and don’t seem to realize they have hands, and get they wield the most powerful tool in the social world. Perhaps they needed those early smiles to solicit care and deter aggression, to protect them when they’re still at their most vulnerable. (Time 0:14:05)