Seven and a Half Lessons About the Brain

by Lisa Feldman Barrett;

I should also note that scientists still debate how much attentional capacity infants are born with and what kind of attentional capacities they might be. Many scientists who study development think that infants are genetically programmed to attend to certain features of the world (such as whether something is alive or not) and that subsequent development scaffolds onto these innate abilities. See 7half.info/lantern.

  it’s far cheaper to eradicate poverty than to deal with its effects decades later: Childhood poverty costs society close to one trillion dollars per year, according to a 2019 report by the National Academies of Sciences, Engineering, and Medicine, A Roadmap to Reducing Child Poverty. The cost of lifting children out of poverty, the report states, is far less than the price paid for the consequences of poverty after the children grow up. My colleague psychologist Isaiah Pickens points out the irony that in our culture, we start to treat people as more responsible for their actions right around the time that the ill effects of poverty and adversity manifest themselves in more serious ways. See 7half.info/poverty.

  Lesson 4. Your Brain Predicts (Almost) Everything You Do

  a man who served in the Rhodesian army: Another take on this story appears in my 2018 TEDx Talk “Cultivating Wisdom: The Power of Mood,” which you can view at 7half.info/tedx.

  ambiguous scraps of sense data: Sense data is not only ambiguous but also incomplete. Information about the world and the body is lost when it’s processed by your retina, cochlea, and other sensory organs and sent to the brain. Scientists still debate just how much is lost, but everyone agrees that neurons convey less sense data from the world and the body than is available to be perceived. See 7half.info/incomplete.

  Your brain assembles these bits into memories: The idea that your brain uses past experiences to give incoming sense data meaning is in some ways similar to immunologist and neuroscientist Gerald Edelman’s proposal that your ongoing conscious experience is the “remembered present.” See 7half.info/present.

  line drawings: The three figures are a submarine going over a waterfall, a spider doing a handstand, and a ski jumper looking at spectators far below before pushing off.

  The figures are Droodles excerpted from The Ultimate Droodles Compendium​—​The Absurdly Complete Collection of All the Classic Zany Creations of Roger Price, © 2019 Tallfellow Press, Inc. Used by permission. All rights reserved. Captions for the Droodles are: SUBMARINE GOING OVER A WATERFALL; SPIDER DOING A HANDSTAND; SKI JUMP AND SPECTATORS SEEN BY JUMPER. Tallfellow.com.

  “the beholder’s share”: This idea about the perception of artwork originated with the art historian Alois Riegl, who called it “the beholder’s involvement.” The later term beholder’s share was coined by art historian Ernst Gombrich. See 7half.info/art.

  an everyday kind of hallucination: I referred to conscious perception and experience as an everyday hallucination for a number of years before discovering that philosopher Andy Clark eloquently makes the same point, calling conscious experience a “controlled hallucination.” See his book Surfing Uncertainty: Prediction, Action, and the Embodied Mind. Today, other scientists also describe experience in this way, notably the neuroscientist Anil Seth in his engaging TED Talk “Your Brain Hallucinates Your Conscious Reality.” See 7half.info/hallucination.

  who bears responsibility when you behave badly: Some material on this topic comes from my 2018 TED Talk “You Aren’t at the Mercy of Your Emotions​—​Your Brain Creates Them,” which you can view at 7half.info/ted.

  Lesson 5. Your Brain Secretly Works with Other Brains

  experiments that demonstrate the power of words: My lab’s research on the power of words, in which participants listened to scenarios and imagined them while having their brain scanned, is discussed in several papers. See 7half.info/words.

  many brain regions that process language also control the insides of your body: The brain regions that scientists call the “language network” overlap to a large extent with a network called the “default mode network,” particularly on the left side of the brain. The default mode network is part of a larger system that controls the internal systems of your body, including your autonomic nervous system (which controls your cardiovascular system, respiratory system, and other organ systems), immune system, and endocrine system (which controls hormones and metabolism). See 7half.info/language-network.

  This includes physical abuse, verbal aggression: Verbal aggression, at least the milder kind, depends on context. Not all profanity is verbal aggression. For example, women sometimes call each other bitch as a term of endearment or even empowerment. Likewise, words that are positive in one context can be aggressive in another. If you say something romantic to your partner who then responds, “Come here and say that,” your brain may predict that a kiss is in your future. If you stand up to a bully who then responds, “Come here and say that,” your brain may predict a threat. See 7half.info/aggression.

  a long period of chronic stress can harm a human brain: Studies show that chronic stress eats away at the brain and the body over the long term regardless of whether the stress stems from ongoing physical abuse, sexual abuse, or verbal aggression. Scientific results like these are surprising and unwelcome, so it’s helpful to consider the evidence in a bit of detail. I’ll share just a small portion here; more details are at 7half.info/chronic-stress.

  First of all, chronic stress causes brain atrophy. It reduces brain tissue, notably in parts of the brain that are important for body budgeting (allostasis), learning, and cognitive flexibility.

  What exactly causes atrophy in a stressed brain? And how are these brain changes related to an increased likelihood of physical illness and a shorter life span? Scientists are still studying the biological details. One tricky bit is that we can’t view the microarchitecture of a living human brain in enough detail to know exactly what changes occur. This is why scientists study the impact of stress on nonhuman animals and then carefully generalize to humans where possible. For example, see the research of neuroendocrinologist Bruce McEwen.

  Chronic verbal abuse in childhood has long-lasting effects. For example, in a study of 554 young adults, scientists asked the participants to rate their exposure to verbal abuse from parents and peers when they were children. The scientists found that people who reported exposure to verbal abuse in childhood were more likely to experience anxiety, depression, and anger during young adulthood. Incredibly, these associations were larger than those observed for people who reported physical abuse by a family member and comparable to those observed for people who reported sexual abuse by someone outside the family. These findings are consistent with the hypothesis that chronic verbal abuse in childhood predisposes people to mood disorders in young adulthood. However, an alternative interpretation is that people who suffer from mood disorders remember more abuse, including verbal abuse. That’s why it’s important to have other studies to help us determine which of these two hypotheses is more likely to be correct.

  In one such study, scientists measured the biological impact of growing up in a harsh or chaotic family with a lot of verbal criticism and conflict. Researchers measured a marker of inflammation (interleukin 6) and a marker of metabolic dysfunction (cortisol resistance) in 135 female adolescents. Participants were interviewed four times during an eighteen-month period. Participants who reported a harsher family environment with more verbal aggression showed more immune dysfunction and more metabolic dysfunction as time went on, whereas participants with average exposure showed no change in these markers, and those with the lowest exposures were healthier. Other studies find similar results​—​swimming in a sea of sustained aggression places adolescents on a developmental trajectory that can lead to physical and mental illness.

  An increasing number of studies consistently reveal a link between sustained social stress, usually involving verbal aggression, and an increased incidence of psychiatric and physical disease. For example, there is evidence that verbal aggression can alter the immune response sufficiently to reactivat
e latent herpes viruses, reduce the benefits of common vaccines, and slow the healing of wounds. These are not studies of vulnerable people but of average people who were drawn from across the political spectrum. I should also point out that these findings hold whether or not test subjects report experiencing intense stress. See 7half.info/chronic-stress.

  the effects of stress on eating: I mentioned two studies on stress and how your body metabolizes food. Both studies are by psychologist Janice K. Kiecolt-Glaser and her colleagues. The figure of eleven pounds per year assumes that you’re stressed before one meal each day​—​104 calories times 365 days divided by 3,500 calories per pound. I like to offer up these scientific tidbits when I am at a flagging dinner party that needs a bit of livening up. See 7half.info/eat.

  Lesson 6. Brains Make More than One Kind of Mind

  When people from the island of Bali in Indonesia are afraid, they fall asleep: I borrowed this example from the psychologists Batja Mesquita and Nico Frijda. They cite an ethnology, Balinese Character, published in 1942, in which anthropologists Gregory Bateson and Margaret Mead observed that people who lived in Bali would often fall asleep when faced with events that were unfamiliar or frightening. Their interpretation was that the people were avoiding something scary, like you might do by closing your eyes during a gruesome or suspenseful movie. According to Bateson and Mead, sleeping was a socially approved response to fear; the Balinese called it takoet poeles, which translates to “in a fright sleep.” See 7half.info/sleep.

  Thunberg’s mind is on the autism spectrum: Greta Thunberg describes herself as having Asperger’s syndrome, but the proper diagnostic term today is autism spectrum disorder. See 7half.info/thunberg.

  Hildegard of Bingen: Hildegarde of Bingen believed that her visions, which she called “the Shade of the Living Light,” were instructions from God. Over the years, she documented her visions in words and artwork. Just to be clear, I am not diagnosing Hildegard of Bingen with schizophrenia or any other mental illness. Rather, I am making a general point that one person’s mystical experience can be another person’s symptom of illness, depending on the historical or cultural context. A number of scholars have retrospectively diagnosed Hildegard of Bingen with various disorders, but this sort of activity should be done with extreme caution. See 7half.info/bingen.

  the sort of mind that might emerge from Pocketknife Brain: When applied to the mind (instead of the brain), the clash of Pocketknife versus Meatloaf is perhaps best known as nativism versus empiricism. This philosophical debate is about whether knowledge is inborn or learned from experience, and it has raged for thousands of years. Psychologists sometimes call this debate faculty psychology versus associationism. See 7half.info/nativism.

  variation is a prerequisite for natural selection to work: In his book On the Origin of Species, Charles Darwin proposed that variation among individuals in a species is a prerequisite for natural selection during the course of evolution. A species is a diverse group of individuals, and those who are most suited to a particular environment are more likely to survive and pass their genes to their offspring (who also will be more likely to survive and breed). Darwin’s idea about variation, known as population thinking, is one of his greatest innovations, according to the evolutionary biologist Ernst Mayr. For a primer, see Mayr’s book What Makes Biology Unique, and for a more thorough treatment, see his book Toward a New Philosophy of Biology. See 7half.info/variation.

  Myers-Briggs Type Indicator: The MBTI and various other personality tests have no more scientific validity than horoscopes. Years of evidence show that the MBTI does not live up to its claims and does not consistently predict job performance. Nonetheless, these kinds of personality tests lure otherwise capable managers into making decisions that benefit neither their employees nor their company. Why do the test results seem so true when you receive them? Because the test asks what you believe about yourself. The results summarize those beliefs and give them back to you, and wow, they fit so well! The bottom line is this: You can’t measure behavior by asking people their opinions about their behavior. You have to observe that behavior in multiple contexts. (Furthermore, the same people may be honest in some contexts and dishonest in others, introverted in some contexts and extroverted in others, and so on.) See 7half.info/mbti.

  Feelings of affect range from pleasant to unpleasant, from idle to activated: Affect is described by a mathematical structure depicted in the figure on page 105, called a circumplex, which was first discussed by the psychologist James A. Russell. A circumplex represents relations using the geometry of a circle; in this case, the relations among affective feelings. The term circumplex means “circular order of complexity” to indicate that the feelings in question are characterized simultaneously by at least two basic psychological features. The circle maps how similar the feelings are to one another, and the two dimensions describe the properties of similarity. See 7half.info/circumplex.

  an app or a smart watch to regulate your body budget: This analogy also appears in my 2018 TEDx Talk “Cultivating Wisdom: The Power of Mood,” which you can view at 7half.info/tedx2.

  Lesson 7. Our Brains Can Create Reality

  The boundary between social reality and physical reality is porous: This porous boundary is easily revealed by experiments about the sense of taste, such as the studies I mention in this lesson about wine and coffee. A more serious example can be found in lesson no. 3, where we discussed the vicious cycle of poverty. Societal attitudes toward people in poverty, which are social reality, affect the physical reality of brain development, which then increases the likelihood that those little brains will grow to become adults who live in poverty. See 7half.info/porous.

  a suite of abilities that I’ll call the Five Cs: The Five Cs is my own term for a collection of characteristics that evolve together to reinforce one another and that give humans the capacity to create social reality on a large scale. Four of these Cs​—​creativity, communication, copying, and cooperation​—​are inspired by research from evolutionary biologist Kevin Laland, and my account draws heavily from his book Darwin’s Unfinished Symphony: How Culture Made the Human Mind. Laland does not discuss the role of social reality in human evolution, but he discusses the related concept of cultural evolution. See 7half.info/5C.

  explorers in the 1800s: The example of explorers who cooperated with indigenous people to survive comes from the anthropologist Joseph Henrich’s book The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter. See 7half.info/explore.

  You also need the fifth C, compression: Compression occurs in many parts of the brain. Here, we’re discussing the compression that occurs in the cerebral cortex, particularly in layers 2 and 3. The human brain has souped-up wiring in these critical layers, which enhances compression.

  A big, complex brain with the capacity to compress, however, is probably not sufficient on its own for small bits of social reality to cohere into a civilization. You also need the right metabolic conditions, including agriculture, to supply enough energy to build and maintain a human brain with its souped-up wiring. For a useful discussion, see Kevin Laland’s book Darwin’s Unfinished Symphony. Also see evolutionary biologist Richard Wrangham’s book Catching Fire: How Cooking Made Us Human. See 7half.info/metabolic.

  sense data from your eyes, ears, and other sense organs: Sense data is collected by various sense organs in your body, such as your eyes, ears, nose, and so on, and converted into neural signals that the brain can use. Sense data usually passes through several way stations before reaching the brain. For example, in vision, the cells in your retina (the thin layer that lines the back of your eyeball) are called photoreceptors and they convert light energy to neural signals. These neural signals travel along a bundle of nerve fibers called the optic nerve. A majority of your optic nerve fibers arrive at a cluster of neurons called the lateral geniculate nucleus, which is part of a brain structure called the thalamus; this structure’s main job
is to relay the sense data from your body and the surrounding world to your cerebral cortex. From there, the neural signals make their way to neurons at the very back of your cortex, in the occipital lobe, also known as your primary visual cortex. A small number of axons branch away from your optic nerve and travel to other parts of the subcortex, including your hypothalamus, which is a subcortical brain structure that is important for regulating the internal systems of your body.

  Most of your sensory systems work in a similar way, except for the system that gives you your sense of smell, known as the olfactory system. The cells that convert chemicals in the air into neural signals are located in a structure called the olfactory bulb. These cells send information directly to the cerebral cortex, bypassing the thalamus. The neural signals bring olfactory sense data to your primary olfactory cortex, which is part of a brain region called the insula, which itself is a portion of the cerebral cortex between the temporal and frontal lobes. See 7half.info/sense-data.

  compression makes it possible for your brain to think abstractly: Scientists are still working out the details of how the brain compresses information and how compression leads to abstraction. There is a long and vigorous debate about how much sensory and motor information remains in highly compressed abstractions. Some scientists propose that abstractions are multimodal, meaning they include information from all senses; others propose that abstractions are amodal, meaning they include no sense data. My view is that the evidence favors the multimodal hypothesis. For example, the most compressed summaries are created in areas of the cerebral cortex that neurologists and neuroanatomists call heteromodal, meaning that those areas manage information from multiple senses as well as motor information.