Lifespan Development- Chapter 5

Diane, who is breast-feeding her infant daughter, had measles as a child. Her daughter is protected from the disease because of the _____ in Diane's breast milk.

antibodies

Vaccines protect against disease by injecting a small dose of inactive virus, which stimulates the same _____.

antibodies

Most infants begin to crawl between:

8 to 10 months after birth

In the twenty-first century, _____of people in the healthiest nations who survive the first month after birth live to age 15.

99.9%

At 2 years old, Maude is 2' 8" tall. Her height will likely be about _____ when she reaches adulthood.

5'6"

Lilly's facial expression tells the caregiver if she likes the taste or not. Historically, taste has been a very basic way for a newborn to determine if the food is safe to eat. To infants, desirable tastes are likely sweet foods full of energy while undesirable tastes are likely foods that have gone bad.

Hearing sensitivity improves over the first weeks of life. From their first moments, neonates respond to a wide variety of sounds. At birth, they can hear words spoken at a normal conversational level, but they cannot hear a whisper. They can distinguish among various sound pitches at birth, and their ability to distinguish small differences in tones gets better during the first year. One of the most impressive characteristics of newborns' hearing is how sensitive they are to small changes in human speech sounds. For example, they can hear differences in stressed syllables in a word, such as "ma-MA" versus "MA-ma." They can distinguish the difference between happy-sounding, sing-song speech, such as "Good baby, there you go," versus angry-sounding, staccato speech, such as "No! Stop that!" Interestingly, infants generally prefer a lullaby-type song to adult songs. Babies even notice variations in syllables differing in only one sound, such as "pa" versus "ba." This is an important skill because later when they learn to speak, we want babies to "pat," not "bat," the cat. Every spoken language is composed of speech elements called phonemes, such as the /p/ in "pat" or the /b/ in "bat." Becoming a native speaker and listener requires that the infant discriminate among these basic speech elements.

Infants sense touch, temperature changes, and position changes at birth. Taste and smell are also well developed from the start. For instance, infants show preferences for some smells. A newborn clearly does not like foul smells, such as vinegar, rotten eggs, or ammonia. He scrunches up his nose when exposed to these odors. Breastfed infants can recognize their own mothers by smell alone. When given a choice, they will turn their heads toward pads that were previously wiped under their mothers' armpits or breasts and away from pads with the smell of other breastfeeding mothers (Marlier, Schaal, & Soussignan, 1998). Sensitivity to odors is a two-way street since mothers also can tell their own babies from smell alone (Russell, Mendelson, & Peeke, 1983)

Infants seem to have a sweet tooth even before they have teeth! While taste is one of the most developed senses at birth, how individuals feel about different tastes does evolve over time. There are many tastes, such as certain vegetables, coffee, or tea, that infants and young children cannot stand but grow to like or even love as adults. Taste does appear to have had an evolutionary function, so its basic roots likely aided in survival at some point in human history.

What does a newborn experience in the first moments of life? This may seem like an impossible question to answer because, after all, babies cannot talk. However, research over the last 50 years has revealed that the sensory experiences of newborns, including sight, sound, taste, smell, touch, and the sensations that come from moving their own bodies, are vital tools for gathering information about the people and the world around them. Touch, smell, and taste function very well at birth. Hearing and vision are less well developed in newborns and need time outside of the mother's womb to reach their fullest potential.

Newborns are born with highly developed reflexes, many of which are designed to help them survive in their new world outside of their mothers' wombs. Some reflexes are stimulated by touch, such as the rooting reflex in which the baby turns her head toward the source of a touch on the cheek in hopes that it might be a nipple! Other reflexes are stimulated by a sense of the position of the body, such as the Moro reflex in which the baby reaches outward with his arms while arching his back in response to a sensation of being dropped. Just watch any newborn baby react to a needle prick during a medical examination, and you can see that, indeed, babies can feel pain. Newborns are sensitive to changes in temperature, touch, and movements of their own body from the very first day of life. These sensitivities increase over the next few days.

Michael and Diane, who celebrated their wedding anniversary with a bottle of champagne and some vodka shots, will be sharing their bed with their 2-month-old daughter. Doctors fear this situation could put the infant in danger of _____.

SIDS

There is something about a baby's face that captures our attention, but did you know that faces also capture the attention of newborn babies? This surprising fact has been demonstrated in several experiments. When schematic drawings of a face are slowly moved from the center of a newborn's vision field to the side, newborns display the greatest amount of head and eye tracking movements in response to the more face-like drawings. A schematic face with scrambled features or a blank oval will also be tracked, but not with as much movement as the drawings with face-like features in their proper positions (Johnson, Dziurawiec, Ellis, & Morton, 1991). Does this mean that newborns have a built-in ability to recognize faces? It is probably more likely that their visual system is prepared at birth to respond to face-like elements, such as two blobs aligned horizontally with a single blob below all contained within an oval shape. This built-in response may ensure that infants spend time looking at faces and learning about them. After a few days of seeing, babies begin to prefer their mother's face to the face of an unfamiliar woman. During the first years, babies can discriminate some facial expressions, such as a happy face versus a sad face. By the end of the first year, infants seem to understand what some facial expressions mean, and as a result, newborns will look longer at a happy face than at an angry one.

The senses are a baby's connection to the world, and that connection is present from the first minutes of life. Touch, taste, smell, hearing, and vision (to a lesser-extent) are the tools with which the newborn begins to learn about objects in the world. What will a baby learn about in the first days of life? Babies seem to find some objects very interesting because they move, make special sounds, are close by, have a familiar odor, and contain intrinsically attractive visual features, such as two blobs in a horizontal row and a blob underneath. These objects, of course, are their caregivers, and the sensory systems help the baby first learn about important people and later, about important objects and places in the world. After watching the video for an overview of infant sensory development, describe some examples of how caregiver interaction helps to stimulate and activate a newborn's senses. Consider a newborn's response to touch, to being held and the position of her body, the sounds that she hears. When a newborn is held close to the caregiver, the baby more easily hears, sees, and smells that person. The soft, musical sounds that a caregiver makes attract a baby's attention and help the baby to become familiar with the sounds of language. Exaggerated expressions of the caregiver help the baby learn about people.

Young infants can discriminate most of the phonemes used in speech and miraculously can even discriminate sounds that are not used in their own native language for the first 6 months or so. Compared to older infants, children, and adults, newborns and young infants are sensitive to a broader set of phonemes (Eimas, 1985). Consider that this extra sensitivity helps infants learn any language no matter what phonemes are used. Over time, babies become fine-tuned to just those phonemes that they hear every day. How are researchers able to assess a newborn's ability to discriminate speech sounds? Researchers have used the habituation-dishabituation technique. Infants are given a special pacifier to suck. If they suck quickly, they will hear a repetitive series of sounds, such as "pa-pa-pa-pa-pa." Infants seem to enjoy turning on this new sound, but they get bored and demonstrate habituation as they tend to stop sucking quickly as if the sound is no longer stimulating. If, without warning, the sound changes from "pa-pa-pa-pa-..." to "ba-ba-ba-ba-...," infants tend to begin sucking quickly again as if their interest in the sound has been renewed. In this instance, their sucking demonstrates dishabituation as the introduction of a new sound has revived their interest. Click to the next screen to hear a simulation of this speech discrimination experiment.

Vision seems to be one of the least developed sensory systems in newborn babies. Newborns have very little color vision at birth. They probably can only distinguish among high contrast, bright colors, such as black and white. By 3 or 4 months of age, an infant can distinguish more colors and different shades of the same colors. The reason for such poor color and detail among newborns is the immaturity of the sensory cells in the retina of the eye and of the neurons of the vision centers in the occipital lobe of the cerebral cortex. As new synapses are formed and as these emerging brain circuits are sculpted by experience, vision will steadily improve over the first year. By their first birthday, infants may likely see as clearly as adults. Vision is not just about recognizing what objects are and where they are. Vision is one way to know what things are doing. Newborns are particularly interested in objects that move. They follow moving objects and lights and prefer to look at moving, rather than stationary, objects.

at birth

all the senses are functional.

Newborns' eyes are not sensitive to low light levels and do not respond well to many different colors. Newborns' vision is very blurry especially for distant objects. With vision rated at 20/400, babies can see an object at 20 feet no better than an adult with perfect vision could see the same object at 400 feet. Newborns are very nearsighted. Throughout the first year, infants' abilities to see distant objects gradually improve. How do we know anything about infants' eyesight? And furthermore, how do we know that infants' eyesight is so poor? One research technique is based on the fact that the human eye will move reflexively to follow movements. If you show humans of any age a moving pattern of stripes, the person's eyes will follow the movement, dart back to the center, and repeat the cycle over and over again. These movements are a type of visual reflex that will occur as long as the visual system can "see" the stripes (Kellman & Banks, 1998). Click on the picture to start just such a moving pattern of stripes, and consider the visual reflexes of a baby younger than one year.

When the researcher makes the moving stripes progressively smaller, an infant's eyes stop moving indicating that the infant can no longer "see" the pattern. This experiment reveals that an infant's visual system lacks: the ability to see fine details in images.

Colostrum is:

a thick, high-calorie fluid secreted by the woman's breasts for about the first three days following the birth of her child.

Dr. Miller measured 1-year-old Roy's head circumference and found that it increased 25 percent since birth. He is concerned about Roy's _____.

brain growth

Neurotransmitters are

chemical messengers in the nervous system.

In the sequence of interpretation of stimuli, perception comes after sensation but before _____.

cognition

The high-calorie fluid women's breasts secrete for about the first three days following birth is called _____.

colostrum

Over the first few months of infancy, the amount of time spent in REM (rapid eye movement) sleep:

decreases Newborns exhibit a very high proportion of REM sleep.

Sensation is to perception as:

detecting a stimulus is to making sense of a stimulus.

By the fourth month, an infant's weight typically:

doubles

Alice lives in a house with cold, rough floors. She went from scooting to standing without crawling. An explanation for this leap may be that crawling is _____ and not necessary for normal development.

experience-dependent

Walking and jumping are NOT:

fine motor skills

According to Jean Piaget, the sensorimotor stage is the _____ period of cognitive development.

first

Large body movements, such as walking and jumping, are:

gross motor skills

A process that stimulates the body's immune system to defend against attack by a particular contagious disease is:

immunization

Perception is the mental procession of sensory information when the brain _____ a sensation.

interprets

A sign of brain _____ is when infants develop from kicking alternate legs to deliberate leg action.

maturation

crawling depends on

maturation

Improvements to public health are the primary reason that childhood _____ has declined over the decades

mortality

The three factors that allow toddlers to walk are brain maturation, _____, and practice.

muscle strength

Janna, who just gave birth to a son, has a concern about sudden infant death syndrome (SIDS). Jenna's doctor is likely to tell her that she should:

place the baby on his back when the baby sleeps.

Crawling depends on maturation and _____.

practice

The last part of the brain to mature is the _____.

prefrontal cortex

Dead-heading a flower refers to the elimination of a dead bloom to make way for new growth. This is similar to the process in the brain called _____, when unused neurons and misconnected dendrites die to enable new brain activity.

pruning

The primary reason childhood mortality has declined over the decades is because of improvements in _____.

public health

One study found that a primary factor in reducing the likelihood of wasting and stunting in Niger and Gambia was a mother's _____ education.

secondary

In the sequence of interpretation of stimuli, perception comes after _____, but before cognition.

sensation

Perception refers to the mental processing of sensory information when the brain interprets a(n) _____.

sensation

The response of a sensory system when it detects a stimulus is called:

sensation

The sequence of interpretation of stimuli by the human perceptual apparatus is BEST described by which order?

sensation > perception > cognition

The Internet's information superhighway is not unlike the brain's neural system. Instead of computers, servers, nodes, and transmission lines, in the brain neurotransmitters carry information from the axons of sending neurons across the _____ to the dendrites of receiving neurons.

synapse

Donald loves to smell roses; he thinks they are the most beautiful flower. Which part of his brain is he using to experience the rose?

the cortex

Dale smiles as he touches the rattle hanging above him as he lies on his back on the floor. However, his efforts to grab the rattle fail. Dale is MOST likely about _____ months old.

three

Stephen is 6 months old and loves to make stepping movements when taking a bath. He does not perform this movement when he is on the floor. This may be explained by Stephen's _____ leg muscles.

underdeveloped

Vaccines protect against disease by injecting a small dose of the _____ , which stimulates antibodies to prevent recurrence of the disease.

virus