Lesson No. 3 Little Brains Wire Themselves to Their World
Many animals emerge from the egg or womb with brains that are more fully wired to control their bodies, but little human brains are born under construction. (Location 534)
A baby’s wiring instructions come not only from the physical environment but also from the social environment, (Location 548)
desarrollo vínculo cita infancia favorite cerebro adaptación cultura
Tuning means strengthening the connections between neurons, (Location 555)
If we think again of neurons as little trees, tuning means that the branch-like dendrites become bushier. It also means that the trunk-like axon develops a thicker coating of myelin, a fatty “bark” that’s like the insulation around electrical wires, which makes signals travel faster. Well-tuned connections are more efficient at carrying and processing information than poorly tuned ones and are therefore more likely to be reused in the future. (Location 556)
“Neurons that fire together, wire together.” (Location 560)
Meanwhile, less-used connections weaken and die off. This is the process of pruning, the neural equivalent of “If you don’t use it, you lose it.” (Location 561)
A human embryo creates twice as many neurons as an adult brain needs, and infant neurons are quite a bit bushier than neurons in an adult brain. Unused connections are helpful at the outset. They enable a brain to tailor itself to diverse environments. But over the longer term, unused connections are a burden, metabolically speaking—they don’t contribute anything worthwhile, so it’s a waste of energy for the brain to maintain them. The good news is that pruning these extra connections makes room for more learning—that is, for more useful connections to be tuned. (Location 563)
cerebro desarrollo poda neuronal cita favorite
Buds that aren’t tuned disappear within a couple of days. (Location 569)
Your adult brain can effortlessly focus on one thing and ignore others, similar to a spotlight in the darkness. That’s because your brain network contains smaller communities of neurons whose main job is to focus on certain details as important and ignore other details as irrelevant. Your brain focuses its spotlight of attention continually and automatically, and often you’re unaware that it’s happening. (Location 590)
The newborn brain doesn’t have a spotlight. It has more of a lantern, illuminating a wide area in its physical environment. Newborn brains don’t know what’s important and what’s not, so they cannot focus as adults do. (Location 594)
cerebro desarrollo bebés atención cita
Little by little, sharing attention teaches an infant which parts of the environment matter and which parts don’t. (Location 600)
In the first few months of life, babies are bathed in all kinds of sounds, including the sound of people speaking. Newborns, with their lantern of attention, take in all the sounds around them. When tested in a lab, newborns can distinguish a wide range of language sounds, including those that they don’t hear very often. But over time, tuning and pruning will wire the baby’s brain based on the vocal sounds he hears more regularly. Sounds that are frequent cause certain neural connections to be tuned, and the baby’s brain starts to treat those sounds as part of its niche. Sounds that are rare are treated as noise to be ignored, and eventually, related neural connections fall out of use and are pruned away. (Location 608)
Sensory integration itself is tuned and pruned as babies grow. A newborn at first can’t recognize his mother by her face, because he hasn’t learned what a face is, and his visual system isn’t fully formed. He might know a bit about how his mother sounds, and he can smell her breast milk. If you put a newborn on his mother’s belly, he will wriggle up to her breast by following the aroma. Soon, he learns to recognize his mother by different combinations of all his senses together. His little brain absorbs each pattern of sight, smell, sound, touch, and taste, plus sensations from inside his body, and learns its meaning: the person who regulates his body budget is here. Sensory integration conjures his first feeling of trust. It’s part of the neural foundation for attachment. (Location 626)
The scientific evidence is clear on this point. You can’t just feed and water babies and expect their brains to grow normally. You must also meet their social needs with eye contact and language and touch. If these needs go unmet, the seeds of illness may be planted very, very early. (Location 662)
This arrangement helps our cultural and social knowledge flow efficiently from generation to generation. Each little brain becomes optimized for its particular environment, the one it developed in. Caregivers curate a baby’s physical and social niche, and the baby’s brain learns that niche. When the baby grows up, he perpetuates that niche by passing his culture to the next generation through his words and actions, wiring their brains in turn. This process, called cultural inheritance, is efficient and frugal because evolution doesn’t have to encode all our wiring instructions in genes. It off-loads much of the job to the world around us, including the other humans in that world. We unknowingly wire the knowledge of our culture into our offspring after birth, for better or worse. (Location 683)
We have the kind of nature that requires nurture. (Location 689)
Lesson No. 4 Your Brain Predicts (Almost) Everything You Do
Scientists used to believe that the brain’s visual system operated sort of like a camera, detecting the visual information “out there” in the world and constructing a photograph-like image in the mind. Today we know better. Your view of the world is no photograph. It’s a construction of your brain that is so fluid and so convincing that it appears to be accurate. But sometimes it’s not. (Location 708)
your brain recreates the past from memory by asking itself, The last time I encountered a similar situation, when my body was in a similar state and was preparing this particular action, what did I see next? What did I feel next? The answer becomes your experience. In other words, your brain combines information from outside and inside your head to produce everything you see, hear, smell, taste, and feel. (Location 730)
So what do you see? A bunch of black lines and a couple of blobs? Let’s see what happens when we give your brain some more information. Turn to pages 153–54 of the appendix, read the entry for line drawings, and then come back and look at the drawings again. (Location 740)
you don’t sense with your sensory organs. You sense with your brain. (Location 752)
your brain also constructs what you feel inside your body. Your aches and jitters and other inner sensations are some combination of what’s going on in your brain and what’s actually happening within your lungs and heart and gut and muscles and so on. Your brain also adds information from your past experiences to guess what those sensations mean. (Location 755)
In this situation, the stuff inside and outside his head didn’t match, and the inside stuff prevailed. (Location 762)
Have you ever seen a friend’s face in a crowd, but when you looked again, you realized it was a different person? Have you ever felt your cell phone vibrate in your pocket when it didn’t? Have you ever had a song playing in your head that you couldn’t get rid of? (Location 765)
ejemplo predicción alostasis cerebro función
Neuroscientists like to say that your day-to-day experience is a carefully controlled hallucination, constrained by the world and your body but ultimately constructed by your brain. (Location 767)
Tal como propone el psicoanálisis entonces, todas estas experiencias idiosincráticas DICEN ago sobre la estructuración subjetiva de quien la experimenta.
neurociencia favorite cerebro alucinación cita control constraints
The same is true for moment-to-moment changes in your body—your brain begins to sense them before the relevant data arrives from your organs, hormones, and various bodily systems. (Location 773)
Como el juego en el que se avanza caminando con los dedos por el antebrazo.
cerebro nota predicción percepción
Think of the last time you were thirsty and drank a glass of water. Within seconds after draining the last drops, you probably felt less thirsty. This event might seem ordinary, but water actually takes about twenty minutes to reach your bloodstream. Water can’t possibly quench your thirst in a few seconds. So what relieved your thirst? Prediction. (Location 775)
cerebro cita favorite ejemplo predicción
Scientists have had hints for more than a century that brains are predicting organs, though we didn’t decipher those hints until recently. You might have heard of Ivan Pavlov, the nineteenth-century physiologist who famously taught his dogs to salivate upon hearing a sound (usually described as a bell, but it was really a ticking metronome). Pavlov played that sound right before his dogs ate each meal, and eventually the dogs salivated when they heard the sound even when they weren’t fed. Pavlov won a Nobel Prize for discovering this effect, which became known as Pavlovian or classical conditioning, but he didn’t realize that he was discovering how brains predict. (Location 782)
Condicionamiento clásico como predictive coding.
condicionamiento predicción conductismo cerebro cita
You can try a similar experiment right now. Picture your favorite food in your mind. (For me, it’s a morsel of dark chocolate with sea salt.) Imagine its smell, its taste, and how it feels in your mouth. Are you salivating yet? I am, just writing this, and no metronome is required. (Location 788)
In a very real sense, predictions are just your brain having a conversation with itself. A bunch of neurons make their best guess about what will happen in the immediate future based on whatever combination of past and present that your brain is currently conjuring. Those neurons then announce that guess to neurons in other brain areas, changing their firing. Meanwhile, sense data from the world and your body injects itself into the conversation, confirming (or not) the prediction that you’ll experience as your reality. (Location 794)
Definición de predictive coding en palabras sencillas.
So, your brain issues predictions and checks them against the sense data coming from the world and your body. What happens next still astounds me, even as a neuroscientist. If your brain has predicted well, then your neurons are already firing in a pattern that matches the incoming sense data. That means this sense data itself has no further use beyond confirming your brain’s predictions. What you see, hear, smell, and taste in the world and feel in your body in that moment are completely constructed in your head. By prediction, your brain has efficiently prepared you to act. (Location 802)
cita favorite predicción cerebro
But in the real story, the soldier’s brain made the wrong prediction. It predicted a posse of guerrilla fighters with machine guns when really he faced a shepherd boy with a herding staff and a bunch of cattle. In that situation, his brain had two options. One option was to incorporate the sense data from the outside world, update his predictions, and construct a new, corrected experience of a boy and his cows. This new prediction would seed the soldier’s brain and improve prediction next time. Scientists have a fancy name for this option. We call it “learning.” (Location 810)
Now here’s the final nail in the coffin of common sense: All this predicting happens backward from the way we experience it. You and I seem to sense first and act second. You see an enemy and then raise your rifle. But in your brain, sensing actually comes second. Your brain is wired to prepare for action first, like moving your index finger onto a trigger and making body-budgeting changes to support that movement. It’s also wired to route these predictions to your sensory systems, which predict the feeling of cold steel on your fingertip and your racing heartbeat. In the case of our soldier friend, his brain heard rustling leaves, moved his hands on the gun, and guided itself to see enemies that weren’t present. (Location 818)
Think about the last time you acted on autopilot. Maybe you bit your nails. Maybe your brain-to-mouth connection was too well oiled and you muttered something regrettable to a friend. Maybe you looked away from an engaging movie and discovered that you’d downed an entire jumbo bag of red Twizzlers. In these moments, your brain employed its predictive powers to launch your actions, and you had no feeling of agency. Could you have exercised more control and changed your behavior in the moment? Maybe, but it would have been difficult. Were you responsible for these actions? More than you might think. The predictions that initiate your actions don’t appear out of nowhere. If you hadn’t chomped on your nails as a kid, you probably wouldn’t bite them now. If you’d never learned the regrettable words you tossed at your friend, you couldn’t say them now. If you’d never developed a taste for licorice … you get the idea. Your brain predicts and prepares your actions using your past experiences. If you could magically reach back in time and change your past, your brain would predict differently today, and you might act differently and experience the world differently as a result. (Location 830)
here’s the thing: a hammering heartbeat is not necessarily anxiety. Research shows that students can learn to experience their physical sensations not as anxiety but as energized determination, and when they do, they perform better on tests. (Location 843)
Aplicaciones para la clínica.
cita sentido interpretación ansiedad favorite
It’s also possible to change predictions to cultivate empathy for other people and act differently in the future. An organization called Seeds of Peace tries to change predictions by bringing together young people from cultures that are in serious conflict, like Palestinians and Israelis, and Indians and Pakistanis. The teens participate in activities like soccer, canoeing, and leadership training, and they can talk about the animosity between their cultures in a supportive environment. By creating new experiences, these teens are changing their future predictions in the hopes of building bridges between the cultures and, ultimately, creating a more peaceful world. (Location 847)
Algo similar se podría ha er con grupos en conflicto en Chile.
More control also means more responsibility. If your brain doesn’t merely react to the world but actively predicts the world and even sculpts its own wiring, then who bears responsibility when you behave badly? You do. Now, when I say responsibility, I’m not saying people are to blame for the tragedies in their lives or the hardships they experience as a result. We can’t choose everything that we’re exposed to. I’m also not saying that people with depression, anxiety, or other serious illnesses are to blame for their suffering. I’m saying something else: Sometimes we’re responsible for things not because they’re our fault, but because we’re the only ones who can change them. (Location 868)
When you were a child, your caregivers tended the environment that wired your brain. They created your niche. You didn’t choose that niche—you were a baby. So you’re not responsible for your early wiring. (Location 874)
Lesson No. 5 Your Brain Secretly Works with Other Brains
This co-regulation has measurable effects. Changes in one person’s body often prompt changes in another person’s body, whether the two are romantically involved, just friends, or strangers meeting for the first time. When you’re with someone you care about, your breathing can synchronize, as can the beating of your hearts, whether you’re in casual conversation or a heated argument. This sort of physical connection happens between infants and their caregivers, between therapists and their clients, and among people taking a yoga class or singing in a choir together. We often mirror each other’s movements in a dance that neither of us is aware of and that is choreographed by our brains. One of us leads, the other follows, and sometimes we switch. In contrast, when we don’t like or trust each other, our brains are like dance partners who step on each other’s toes. (Location 901)
When you have empathy for other people, your brain predicts what they’ll think and feel and do. The more familiar the other people are to you, the more efficiently your brain predicts their inner struggles. (Location 927)
Una de las características que añadieron fitness evolutivo a los homíninos, ya que les permite sostener niveles de colaboración cada vez más complejos.
homininos empatía colaboración evolución
This may be one reason why people sometimes fail to empathize with those who look different or believe different things than they do and why it can feel uncomfortable to try. It’s metabolically costly for a brain to deal with things that are hard to predict. (Location 930)
Humans are unique in the animal kingdom, however, because we also regulate each other with words. (Location 937)
Words, then, are tools for regulating human bodies. Other people’s words have a direct effect on your brain activity and your bodily systems, and your words have that same effect on other people. Whether you intend that effect is irrelevant. It’s how we’re wired. (Location 959)
Evidencia a favor de que el trabajo de psicoterapia realmente moviliza afectos a través de la conversación.
comunicación alostasis efectos argumento psicoterapia lenguaje
If you constantly struggle in a simmering sea of stress, and your body budget accrues an ever-deepening deficit, that’s called chronic stress, and it does more than just make you miserable in the moment. Over time, anything that contributes to chronic stress can gradually eat away at your brain and cause illness in your body. This includes physical abuse, verbal aggression, social rejection, severe neglect, and the countless other creative ways that we social animals torment one another. (Location 967)
the human brain doesn’t seem to distinguish between different sources of chronic stress. (Location 971)
Simply put, a long period of chronic stress can harm a human brain. Scientific studies are absolutely clear on this point. When you’re on the receiving end of ongoing insults and threats, for example, studies show that you’re more likely to get sick. Scientists don’t understand all the underlying mechanisms yet, but we know it happens. (Location 976)
No se conocen completamente los mecanismos que vinculan el estrés crónico con problemas de salud, pero el efecto es real.
Your brain already burns 20 percent of your body’s entire metabolic budget, making it the most “expensive” organ in your body. (Location 1020)
Nota para esta idea.
costo metabolismo nota cerebro
Lesson No. 6 Brains Make More than One Kind of Mind
WHEN PEOPLE FROM the island of Bali in Indonesia are afraid, they fall asleep. (Location 1041)
if you are from a Western culture, like I am, your mind has features called thoughts and emotions, and the two feel fundamentally different from each other. But people who grow up in Balinese culture, as well as in the Ilongot culture in the Philippines, do not experience what we Westerners call cognition and emotion as different kinds of events. They experience what we would call a blend of thinking and feeling, but to them it’s a single thing. (Location 1047)
This variation in mind types should not, at this point in our lessons, come as a surprise. We have learned that humankind has a single brain architecture—a complex network—and yet each individual brain tunes and prunes itself to its surroundings. (Location 1063)
Cerebro viene preparado para adaptarse.
cerebro adaptación desarrollo evolución estrategia cita
a particular human brain in a particular human body, raised and wired in a particular culture, will produce a particular kind of mind. There is not one human nature but many. (Location 1067)
We come into the world with a basic brain plan that can be wired in a variety of ways to construct different kinds of minds. (Location 1074)
Think about it: If there’s a huge change in the environment, like a catastrophic drop in the food supply or a big increase in temperature, a species without much variation might be completely wiped out. (Location 1077)
Sadly, the MBTI’s scientific validity is pretty dubious. This test and its many cousins typically work by asking what you believe about yourself, which research suggests may have little to do with your actual behavior in daily life. (Location 1090)
Common sense isn’t much use when it comes to understanding how a brain works. (Location 1102)
Muy en la línea de Buzsaki.
An especially useful feature of the mind, and one of the closest things we have to a universal mental feature, is mood—the general sense of feeling that comes from your body. Scientists call it affect.* Feelings of affect range from pleasant to unpleasant, from idle to activated. Affect is not emotion; your brain produces affect all the time, whether you’re emotional or not and whether you notice it or not. (Location 1113)
Your brain summarizes what’s going on with your body in the moment, and you feel that summary as affect. (Location 1126)
Nuevamente la conciencia como el correlato de lo que busca hacer sentido.
emociones cognición cerebro cita
Scientists are still puzzling out how your brain’s body-budgeting activities, which are physical, become transformed into affect, which is mental. Hundreds of studies from laboratories around the world, including mine, observe that it happens, yet this transformation from physical signals to mental feelings remains one of the great mysteries of consciousness. It also reaffirms that your body is part of your mind—not in some gauzy, mystical way but in a tangible, biological way. (Location 1133)