Sleeping, eating, and crying are easy to observe; but suppose you could time-travel back to your first days of life. What would you experience through your senses?

One sense is definitely operational before we leave the womb. Using ultrasound, researchers can see startle reactions in fetuses in response to noise, showing that rudimentary hearing capacities exist before birth. Recall from the previous chapter that the basics of vision may also be in place by about the seventh month of fetal life.

Table 3.6 lists other interesting facts about newborn senses. Now, let’s focus on vision because the research in this area is so extensive, the findings are so astonishing, and the studies devised to get into babies’ heads are so brilliantly planned.

Imagine you are a researcher who wants to figure out what a newborn can see. What do you do? As might be logical, you put the baby into an apparatus, present images, and watch her eyes move. Specifically, researchers use the preferential-looking paradigm—the principle that human beings are attracted to novelty and look selectively at new things. They also draw on a process called habituation—the fact that we naturally lose interest in a new object after some time.

You can notice preferential looking and habituation in operation right now in your life. If you see or hear something new, you look up with interest. After a minute, you habituate and return to reading this book.

By showing newborns small- and large-striped patterns and measuring preferential looking, researchers have found that at birth our ability to see clearly at distances is very poor. With a visual acuity score of roughly 20/400 (versus our ideal adult 20/20), a newborn would qualify as legally blind in many states (Kellman & Banks, 1998). Because the visual cortex matures quickly, vision improves rapidly, and by about age 1, infants see just like adults.

What visual capacities do we have at birth? A century ago, the first American psychologist, William James, described the inner life of the newborn as “one buzzing, blooming confusion.” Studies exploring face perception (making sense of human faces) offer scientific data about the truth of James’ ideas.

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Focusing on Faces

Actually, when we emerge from the womb, we are primed to selectively attend to the social world. When presented with the paired stimuli in Figure 3.6, newborns spend more time looking at the face pattern than at the scrambled pattern. They follow that facelike stimulus longer when it is moved from side to side (Farroni, Massaccesi, & Simion, 2002; Slater and others, 2010).

The story gets more interesting. Newborns can make amazing distinctions. During their first week of life, they prefer to look at a photo of their mother compared to one of a stranger (Bushnell, 1998). Newborns prefer attractive-looking people too!

Researchers selected photos of attractive and unattractive women, then took infants from the maternity ward and measured preferential looking. The attractive faces got looked at significantly longer—61 percent of the time (Slater and others, 2010). By 3 to 6 months of age, babies preferentially look at good-looking infants and children. They even prefer handsome men and pretty women of different racial groups (Slater, 2001). Unhappily, our tendency to gravitate toward people for their looks seems somewhat biologically built in. (In case you are interested, more symmetrical faces tend to be rated as better-looking.)

We also seem prewired to gravitate to relationships. Newborns look longer at faces when the “eyes” are gazing directly at them (Frischen, Bayliss, & Tipper, 2007). They can mimic facial expressions that an adult makes, such as sticking out the tongue (Meltzoff & Moore, 1977). So if you have wondered why you get uncomfortable when someone stares at you, or have agonized at your humiliating tendency to mimic everyone else’s gestures and facial tics, this research offers answers. It’s not a personal problem. It’s built into our human biology, beginning from day one!

With experience, our sensitivity to faces—and the emotions they reveal—markedly improves. But fascinating research suggests that early experience also shapes what we learn not to see (Slater and others, 2010).

Developmentalists tested European American babies at different points during their first year of life for their ability to discriminate between different faces within their own racial group and those belonging to other ethnicities (African American, Middle Eastern, and Chinese). While the 3-month-olds preferentially looked at “new faces” of every ethnicity, showing they could see the differences between individuals in each group, by 9 months of age, the babies could only discriminate between faces of their own ethnicity.

Why did this skill disappear? The cause, as you may have guessed, is cortical pruning—the fact that unneeded synapses in our visual system atrophy or are lost (Slater and others, 2010). So if you have wondered why other races look more alike (compared to your own ethnic group, of course!), it’s a misperception. You learned not to see these differences during your first year of life!

This tantalizing research suggests that spending our first years of life in a racially homogenous environment might promote prejudice because the resulting neural atrophy could blunt our ability to decode the emotions of other ethnic groups. Amazingly, in testing U.S. teens adopted from Eastern European or Asian orphanages (places where infants are only exposed to caregivers of their ethnicity), scientists discovered that this was true. The longer a child lived in an orphanage, the less sensitive that adolescent was at picking up facial expressions of people from other races. Moreover, fMRI recordings showed an unusual spike in the amygdala (our brain’s fear center) when these young people viewed “foreign” faces. Therefore, simply being born in a multicultural city, such as New York or Chicago, might make us more tolerant because that experience prewires us visually to be more sensitive to the feelings of other races (Telzer and others, 2013)!

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The main conclusion, however, is that William James was wrong. Newborns don’t experience the world as a “blooming, buzzing confusion.” We arrive in life with a built-in antenna to tune into the human world. But also, visual skills change as we mature, in sometimes surprising ways.

Now let’s trace another visual capacity as it comes on-line—the ability to see and become frightened of heights.

Seeing Depth and Fearing Heights

Imagine you are a researcher facing a conundrum: How can I find out when babies develop depth perception—the ability to “see” variations in heights—without causing them harm? Elinor Gibson’s ingenious solution: Develop a procedure called the visual cliff. As Figure 3.7 shows, Gibson and her colleague placed infants on one end of a table with a checkerboard pattern while their mothers stood at the opposite end (Gibson & Walk, 1960). At the table’s midpoint, the checkerboard design moved from table to floor level, so it appeared to the babies that if they crawled beyond that point, they would fall. Even when parents encouraged their children to crawl to them, by 8 months of age, babies refused to venture beyond what looked like the drop-off—showing that depth perception fully comes on-line, but only about this age.

In sum, the sick feeling you have when leaning over a balcony—“Wow, I’d better avoid falling into that space below”—emerged when you started moving into the world and needed that fear to protect you from getting hurt. How does mobility unfold?

Our brain may expand dramatically after birth. Still, it’s out-paced by the blossoming of the envelope in which we live. Our bodies grow to 21 times their newborn size by the time we reach adulthood (Slater, 2001). This growth is most dramatic during infancy, slows down during childhood, and increases in velocity again during the preadolescent years. Still, looking at overall height and weight statistics is not that revealing. This body sculpting occurs in a definite way.

Imagine taking time-lapse photographs of a baby’s head from birth to adulthood and comparing your photos to snapshots of the body. While you would not see much change in the overall size and shape of the head, the body would elongate and thin out. Newborns start out with tiny “frog” legs timed to slowly straighten out by about month 6. Then comes the stocky, bowlegged toddler, followed by the slimmer child of kindergarten and elementary school. So during childhood, growth follows the same principle as inside the womb: Development proceeds according to the cephalocaudal sequence—from the head to the feet.

Now think of Mickey Mouse, Big Bird, and Elmo. They, too, have relatively large heads and small bodies. Might our favorite cartoon characters be enticing because they mimic the proportions of a baby? Did the deliciously rounded infant shape evolve to seduce adults into giving babies special care?

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Actually, all three growth principles spelled out in the previous chapter—cephalocaudal, proximodistal, and mass-to-specific—apply to infant motor milestones, the exciting progression of physical abilities during the first year of life. First, babies lift their head, then pivot their upper body, then sit up without support, and finally stand (the cephalocaudal sequence). Infants have control of their shoulders before they can make their arms and fingers obey their commands (proximodistal sequence, from interior to outer parts).

But the most important principle programming motor abilities throughout childhood is the mass-to-specific sequence (large before small and detailed). From the wobbly first step at age 1 to the home run out of the ballpark during the teenage years—as the neurons myelinate—big, uncoordinated movements are honed and perfected as we move from infancy to adult life.

Variations (and Joys) Related to Infant Mobility

Charting these milestones does not speak to the joy of witnessing them unfold—that landmark moment when your daughter masters turning over, after those practice “push-ups,” or first connects with the bottle, grasps it, and awkwardly moves it to her mouth. I’ll never forget when my own son, after what seemed like years of cruising around holding onto the furniture, finally ventured (so gingerly) out into the air, flung up his hands, and, yes, yes, took his ecstatic first step!

The charts don’t mention the hilarious glitches that happen when a skill is emerging—the first days of creeping, when a baby can only move backward and you find him huddled in the corner in pursuit of objects that get farther way. Or when a child first pulls herself to a standing position in the crib, and her triumphant expression changes to bewilderment: “Whoops, now tell me, Mom, how do I get down?”

Actually, rather than viewing motor development in static stages, researchers now stress the variability and ingenuity of babies’ passion to get moving into life (Adolph, 2008). Consider the “creeping” or belly-crawling stage. Some babies scoot; others hunch over or launch themselves forward from their knees, roll from side to side, or scrape along with a cheek on the floor (Adolph & Berger, 2006). And can I really say that there was a day when my son mastered walking? When walking, or any other major motor skill first occurs, children do not make steady progress (Adolph & Berger, 2006). They may take their first solo step on Monday and then revert to crawling for a week or so before trying, oh so tentatively, to tackle toddling again.

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But suppose a child is behind schedule. Let’s say your son is almost 15 months old and has yet to take his first solo step? And what about the fantasies that set in when an infant is ahead? “Only 8 months old, and he’s walking. Perhaps my baby is special, a genius!”

What typically happens is that, within weeks, the worries become a memory and the fantasies about the future are shown to be completely wrong. Except in the case of children who have developmental disorders, the rate at which babies master motor milestones has no relation to their later intelligence. Since different regions of the cortex develop at different times, why should our walking or grasping-an-object timetable predict development in a complex function such as grasping the point of this book?

But even if a baby’s early locomotion (physically getting around) does not mean he will end up an Einstein, each motor achievement provokes other advances.

Motor Milestones Have Widespread Effects

Consider, for instance, that landmark event: reaching. Because it allows babies to physically make contact with the world, the urge to grasp objects propels sitting, as a child will tolerate plopping over in her hunger to touch everything she can (Harbourne and others, 2013).

Now consider how crawling changes the parent–child bond (Campos and others, 2000). When infants crawl, parents see their children as more independent—people with a mind of their own. Many say this is the first time they discipline their child. So as babies get mobile, our basic child-rearing agenda emerges: Children’s mission is to explore the world. A parent’s job, for the next two decades, lies in setting limits to that exploration, as well as giving love.

Question 3.10

You are using a kind of preferential-looking paradigm; the scientific term for when your baby loses interest is habituation.

Question 3.11

Both Tania and Thomas are right. In support of Tania’s “dramatic improvement” position, while newborns are legally blind, vision improves to 20/20 by age 1. (Another example is the visual cliff research.) Thomas is also correct that in some ways vision gets worse during infancy. He should mention the fact that by 9 months of age we have “unlearned” the ability to become as sensitive to facial distinctions in people of other ethnic groups.

Question 3.12

The roots of adult prejudice may begin during the second 6 months of life.

Question 3.13

At 8 months of age, the child should be frightened of the cliff.

Question 3.14

Your answers might include installing electrical outlet covers; putting sharp, poisonous, and breakable objects out of a baby’s reach; carpeting hard floor surfaces; padding furniture corners; installing latches on cabinet doors; and so on.