41–60 of 61
As we look ahead, we see these three trends not only accelerating but also evolving. For instance, new research by David Autor and David Dorn has put an interesting twist on the SBTC story. They find that the relationship between skills and wages has recently become U-shaped. In the most recent decade, demand has…
Man has two conditions of existence in the body. Hardly two creatures can be less alike than an infant and a man. The whole fetal state is a preparation for birth ... The human brain, in its earlier stage, resembles that of a fish: as it is developed, it resembles more the cerebral mass of a reptile; in its increase…
We make models in science, but we also make them in everyday life. Model-dependent realism applies not only to scientific models but also to the conscious and subconscious mental models we all create in order to interpret and understand the everyday world. There is no way to remove the observer—us—from our perception…
Past experiments have shown persuasively that exercise spurs the birth of new mitochondria in muscle cells and improves the vigor of the existing organelles. This upsurge in mitochondria, in turn, has been linked not only to improvements in exercise endurance but to increased longevity in animals and reduced risk for…
Many well-meaning moms and dads think their child’s brain is interested in learning. That is not accurate. The brain is not interested in learning. The brain is interested in surviving. Every ability in our intellectual tool kit was engineered to escape extinction. Learning exists only to serve the requirements of…
The brain’s chief job description—yours, mine, and your hopelessly adorable children’s—is to help our bodies survive another day. The reason for survival is as old as Darwin and as young as sexting: so we can project our genes into the next generation. Will a human willingly overcome self-interest to ensure the…
Two types of cells are important here. The first type, glial cells, make up 90 percent of the brain cells inside your child’s head. They give the brain its structure and help the neurons correctly process information. It’s a good name; glial is a Greek word for glue. The second type of cell is the familiar neuron…
The opening cast members of the baby-making play are simply a sperm and an egg and a saucy Marvin Gaye song. Once these two cells are joined, they begin producing lots of cells in a small space. The human embryo soon looks like a tiny mulberry. (Indeed, one early development stage is called the morula, Latin for…
In fact, babies do improve their motor skills much as adults do—as a result of diligent practice. New skills, such as walking independently, don't suddenly emerge out of nowhere but gradually build out of prior, simpler abilities—kicking, standing, and walking with support—after weeks or months of trying. The only…
One trick our brains use to figure out the location of a sound is to compare the time it takes to reach each ear. For example, sound waves emanating from a wind chime located to your right will reach your right ear a few milliseconds earlier than they reach your left ear, and the brain uses this small timing…
Beginning about four months of age, the perception of detail takes another leap forward with the emergence of hyperacuity: the ability to discriminate features that are up to ten times finer than the size of the photoreceptors should theoretically permit. It is this ultrafine discrimination that allows us, for…
Nonetheless, our early touch experiences determine the extent of possible tactile sensitivity. They also play a surprisingly potent role in the overall quality of brain development. We have already seen in Chapter 2 how rats raised in a highly enriched environment develop a thicker cerebral cortex and are actually…
Brain wiring begins with the outgrowth of axons. Once a newborn neuron has migrated, planting its cell body in a permanent position, it sends out a fine axon shoot with an enlarged tip known as a growth cone. At the end of the growth cone are about a dozen long tentacles that shoot out in all directions and act like…
The real obstetrical dilemma came long after Lucy and her colleagues became extinct, when there was a sudden upsurge in brain expansion. About 1.5 million years ago, die adult hominid brain went from the Australopithecine size of 400 cubic centimeters to 750 cubic centimeters in a species called Homo habilis, the…
Not all babies are the same. Human babies are rather helpless, interested mostly in food, sleeping, eating, defecating, and comfort. Compare human babies with newborn deer. When fawns are born, they immediately stand up and soon are able to run away from danger. Scientists call these two types of babies in the animal…
Once you know about sitters and rovers, you see them everywhere, especially among young children. Drop in on your local Mommy and Me music class: there are the sitters, intently watching the action from their mothers’ laps, while the rovers march around the room banging their drums and shaking their maracas. Relaxed…
Let me suggest a new axiom: juxtaposition is the spice of life. Humanity’s biggest talent, unique to us, is juxtaposing, finding and operating novel relationships between things or ideas... Recent ideas on neural activity suggest that the brain operates in a very associative way, with small neuron clusters containing…
I prefer sociobiologist E. O. Wilson's view of us as unfortunate tribal carnivores that have acquired intelligence. Our evolution is more like that of social insects; the advances in knowledge and understanding that we prize are more a property of the human nests we call civilization than of its individual members…
We already know that our use of technology changes how our brains work. Reading and writing are cognitive tools that, once acquired, change the way in which the brain processes information. When psychologists use neuroimaging technology, like MRI, to compare the brains of literates and illiterates working on a task…
Consider, for example, the fact that the size of military units has not changed materially in thousands of years, even though our communication technology (from signal fires to telegraphy to radio to radar) has. The basic unit in the Roman army (the “maniple”) was composed of 120-130 men, and the size of the analogous…