Ch4 Physical Development in Infancy and Toddlerhood

Speech Perception

-5 months infants become sensitive to syllable stress patterns -6-8 months they start to screen out sounds not used in their native tongue -Later they focus on larger speech segments and recognize familiar words and listen longer to speech with clear clause and phrase boundaries

Independent Movement and Depth Perception

-As infants discover how to avoid falling in different postures and situations, their understanding of depth expands -Crawling experience promotes other aspects of three dimensional understanding. Seasoned crawlers can remember an objects location and find hidden objects

Hearing

-Babies organize sounds into increasingly elaborate patterns over the first year -Between 4-7 months, infants display a sense of musical phrasing -6-7 months, they can distinguish musical tunes on the basis of variations in rhythmic patterns, including beat structure -End of first year, they can recognize the same melody in different keys -6-12 months can make comparable discrimination in human speech

Changes in Body Size and Muscle-Fat Make Up

-By the end of the first year an infants height is about 50% greater than at birth and 75% greater at 2 years. By 5 months weight has doubled, at 1 year it triples, at 2 years quadrupled -They grow in spurts, usually very irritable and hungry the day before -"Baby fat" peaks at about 9 months and helps the infant maintain a constant body temperature. They will slim down in the 2nd year. -Girls are slightly shorter and lighter than boys with a higher ratio of fat to muscle

Provide an example of classical conditioning, of operant conditioning, and of habituation/recovery in young infants. Why is each type of learning useful?

-Classical Conditioning: a neutral stimulus is paired with a stimulus that leads to a reflexive response. Once the baby's nervous system makes the connection between the two stimuli, the neutral stimulus produces the behavior itself. Classical conditioning helps infants recognize which events usually occur together in the everyday world, so they can anticipate what is about to happen next. Environment becomes more orderly and predictable. -Operant conditioning: infants act on the environment, and stimuli that follow their behavior change the probability that the behavior will occur again. Powerful tool for finding out what stimuli babies can perceive and which ones they prefer and plays vital role in the formation of social relationships. -Habituation/Recovery: Habituation is a gradual reduction in the strength of a response due to repetitive stimulation. A new stimulus causes responsiveness to return to a high level, called recovery. Habituation and recovery make learning more efficient by focusing our attention on those aspects of the environment we know least about. We rely on this more than any other learning capacity.

Nutrition and Growth

-Crucial the first 2 years -Infants energy needs are twice those of an adult. 25% of their caloric intake is devoted to growth

Face Perception

-Newborns prefer to look at photos and simplified drawings of faces with features arranged naturally or upright. They rely on outer features such as hairline and chin -They seem to look at photos of faces that adults find attractive longer -Newborns cant discriminate facial patterns -2 months they can combine pattern elements into an organized whole, babies prefer complex drawings of the human face and prefer their mothers face -3 months infants make fine distinctions among the features of different faces -5 months infants perceive emotional expression -Experience influences face processing leading babies to form group biases as young as 3 months

Motor Skill, Average Age Achieved, 90% of Infants Achieve the Skill

-When upright, holds head erect and steady: 6 weeks, 3 weeks-4 months -When prone, lifts self by arms: 2 months, 3 weeks-4 months -Rolls from side to back: 2 months, 3 weeks- 5 months -Grasps cube: 3 months 3 weeks, 2-7 months -Rolls from back to side: 4.5 months, 2-7 months -Sits alone: 7 months, 5-9 months -Crawls: 7 months, 5-11 months -Pulls to a stand: 8 months, 5-12 months -Plays pat-a-cake: 9 months 3 weeks, 7-15 months -Stands alone: 11 months, 9-16 months -Walks alone: 11 months 3 weeks, 7-15 months -Builds tower of 2 cubes: 11 months 3 weeks, 10-19 months -Scribbles vigorously: 14 months, 10-21 months -Walks up stairs with help: 16 months, 12-23 months -Jumps in place: 23 months 2 weeks, 17-30 -Walks on tiptoe: 25 months, 16-30 months

Heredity and Physical Growth

-height, rate of growth, and weight are all influenced by genetics. However, environment (nutrition) plays a vital role as well. -Catch up growth: A return to genetically influenced growth path once conditions improve from negative environmental influences

Vision

-humans depends on vision more than any other sense -around 2 months babies can focus on objects as well as an adult -color comes at 4 months

Food Insecurity

21% of US children suffer from uncertain access to enough food for a healthy, active life. It is especially high among single parent families (35%), and low income ethnic minorities, Hispanic (25%) and African Americans (27%)

Brain Plasticity

A highly plastic cerebral cortex, in which many areas are not yet committed to specific functions, has a high capacity for learning. And if a part of the cortex is damaged, other parts can take over tasks it would have handled -Most plastic during first few years of life supported by an abundance of synaptic connections

Classical Conditioning

A neutral stimulus is paired with a stimulus that leads to a reflexive response. Once the baby's nervous system makes the connection between the two stimuli, the neutral stimulus produces the behavior itself. Classical conditioning helps infants recognize which events usually occur together in the everyday world, so they can anticipate what is about to happen next. Environment becomes more orderly and predictable.

Reinforcer

A stimulus that increases the occurrence if a response -sweet liquid reinforces the sucking response in newborns

Positron Emission Tomography (PET)

After injection or inhalation of a radioactive substance, the person lies on an apparatus with a scanner that emits fine streams of X-rays, which detect increased blood flow and oxygen metabolism in areas of the brain as the person processes particular stimuli. As with fMRI, the result is a computerized image of "online" activity anywhere in the brain. Not appropriate for children younger than age 5 or 6.

Binocular Depth Cues

Arise because our eyes have different perceptions of the visual field. The brain blends these, resulting in perception of depth -Emerge 2-3 months and develops rapidly

Programmed cell death

As synapses form, many surrounding neurons die, 20-80% depending on the brain region.

1. Unconditioned stimulus (UCS)

Before learning takes place UCS must consistently produce a reflexive, or unconditioned reflex (UCF) -Sweet breast milk (UCS) results in sucking (UCR)

Neurons

Brain has about 100 to 200 billion nerve cells that store and transmit info

Explain the benefits of breastfeeding over bottle-feeding in infancy. Why is breastfeeding particularly important in poverty-stricken countries?

Breastfeeding is ideally suited to babies needs. In poverty-stricken regions, babies who are breastfed are less likely to be malnourished. Breastfeeding helps protect against respiratory and intestinal infections, nursing mother is less likely to get pregnant again, helps increase spacing between siblings in nations with widespread poverty. -Benefits: provides correct balance of fat and protein, ensures nutritional completeness, helps ensure healthy physical growth, protects against diseases, protects against faulty jaw development and tooth decay, ensures digestibility, smooths transition to solid foods.

Statistical Learning Capacity

By analyzing the speech stream for patterns repeatedly occurring sequences of sounds, they acquire a stock of speech structures for which they will later learn meanings, long before they start to talk around age 12 months -Babies will listen for statistical regularities, by 10 months babies can detect words that start with weak syllables -ERP findings suggest that newborns perceive patterns in both sequences of speech syllables and sequences of tones

Kwashiokor

Caused by unbalanced diet low in protein. Body breaks down its own protein reserves which causes swelling and other symptoms. When diets improve, they tend to gain excessive weight, some catch-up in growth in height, but not head size because of a permanent loss is brain weight.

Ulnar Grasp- 3-4 months

Clumsy motion in which the fingers close against the palm. 4 months old adjust their grasp to the size and shape of an object which improves over the first year. 4-5 months they can hold in one hand and feel with the other and transfer object from hand to hand

Gross-Motor Development

Control over actions that help infants get around in the environment such as crawling, standing, and walking

Imitation

Copying the behavior of another person -According to Andrew Meltzoff, newborns imitate as much as older children and adults do by actively trying to match body movements they see with ones they feel themselves make

Cephalocaudal trend

During prenatal period, head develops faster than the rest of the body. At birth the head takes up 1/4 of body length, legs only 1/3, by age 2 the lower body catches up, head accounts for 1/5 and legs are 1/2.

Electroencephalogram (EEG)

Electrodes in a head cap record electrical brain wave activity in the brain's outer layers- the cerebral cortex. Today, researchers use a tool called a geodesic sensor net (GSN) to hold interconnected electrodes in place through a cap that adjusts to each person's head shape, yielding improved brain wave detection

Visual Acuity

Fineness of discrimination improves steadily reaching 20/80 by 6 months and 20/20 by 4 years -Scanning the environment and tracking moving objects improve over the first half year as infants better control their eye movements and build a organized perceptual world

Describe the development of speech perception, and explain how babies analyze the speech stream

First babies are sensitive to all speech sounds and around 6 months they narrow their focus, sensitivity to wide-ranging speech sounds, sensitive period is in the second half of the first year, learning is rapid across several domains. Infants have impressive statistical learning capacity. By analyzing the speech stream for patterns they acquire a stock of speech structures for which they will later learn in meanings, long before they start to talk around 12 months. They extract patterns from complex, continuous speech.

Motion

First depth cue to which infants are sensitive -3-4 weeks old babies blink their eyes rapidly if something gets too close

Synapses

Gap junctions where fibers from different neurons come close to one another by releasing neurotransmitters, which cross the synapse

Proximodistal trend

Growth proceeds from center of the body outwards. In prenatal period, head, chest, and trunk grow first, then arms, legs, hands and feet. During infancy and childhood the legs and arms continue to grow ahead of hands and feet.

Habituation/Recovery

Habituation is a gradual reduction in the strength of a response due to repetitive stimulation. A new stimulus causes responsiveness to return to a high level, called recovery. Habituation and recovery make learning more efficient by focusing our attention on those aspects of the environment we know least about. We rely on this more than any other learning capacity. -Recovery assesses newborns recent memory. Babies recover the familiar stimulus rather than a novel stimulus -Habituation can assess remote memory, memory for stimuli to which infant were exposed weeks or months earlier

3. Conditioned Stimulus

If learning has occurred, the neutral stimulus by itself produces a response similar to the reflexive response. The neutral stimulus becomes a conditioned stimulus (CS) and the response it elicits is called a conditioned response (CR) -Stroking the forehead outside the feeding situation (CS) results in sucking (CR) -If the CS goes without being paired with the UCS, the CR will go extinct

Operant conditioning

Infants act on the environment, and stimuli that follow their behavior change the probability that the behavior will occur again. Powerful tool for finding out what stimuli babies can perceive and which ones they prefer and plays vital role in the formation of social relationships.

Differentiation Theory (Gibson's)

Infants actively search for invariant features of the environment- those that remain stable- in a constantly changing perceptual world -Over time baby detects finer and finer invariant features among stimuli and this theory applies to depth perception

Pincer Grasp- 9 months

Infants use thumb and index finger opposably in a well coordinated pincer grasp. The ability to manipulate objects greatly expands

Amodal Sensory Properties

Info that overlaps two or more sensory systems, such as rate, rhythm, duration, intensity, temporal synchrony and texture and shape. Seems to be biologically primed -Newborns can perceive this by only one exposure to an object

Explain intermodal perception and its importance to perceptual development.

Intermodal perception allows enable babies to notice meaningful correlations between sensory inputs and rapidly make sense of their surroundings. It facilitates social and language processing and is another capacity that assists infants in their active efforts to build an orderly, predictable world.

List everyday experiences that support mastery of reaching, grasping, sitting, and crawling. Why should caregivers place young infants in a variety of waking-time body positions?

Kicking, rocking on all fours, being held upright, control of head and upper chest, stairs. It broadens their understanding of behaviors and of the range of actions that can be performed on various objects. It helps with central nervous system development, the body's movement capacities, the goals the child has in mind, and environmental supports for the skill. Change in any element make the system less table and the child starts to explore and select new, more effective motor patterns. -Reaching may play the greatest role in infant cognitive development because infants learn sights, sounds, and feel of objects

Prefrontal Cortex

Lies in front of the areas controlling body movement, is responsible for thought. In particular, consciousness, inhibition of impulses, integration of information, use of memory, reasoning, planning, and problem solving strategies

Glial Cells

Make up about half the brain's volume which are responsible for myelination, the coating of neural fibers with an insulating fatty sheath (myelin) that improves the efficiency of message transfer. They multiply rapidly until about 2 years, then slow down in middle childhood and pick back up again in adolescence. -Responsible for gain in overall size of the brain

Dynamic Systems Theory of Motor Development

Mastery of motor skills involves acquiring increasingly complex systems of action. When motor skills work as system, separate abilities blend together, each cooperating with others to produce more effective ways of exploring and controlling the environment -Control of head and upper chest combine into sitting with support. -Each new skill is a joint product of central nervous system development, the body's movement capacities, the goals the child has in mind, and environmental supports for the skill -Behaviors are softly assembled, allowing for different paths to the same motor skill

Are chubby babies at risk for later overweight and obesity?

Most chubby babies thin out during toddlerhood and early childhood. They can eat nutritious foods without risk of becoming overweight. Recent studies show a correlation between rapid weight gain in infancy and adult obesity. This may be because obese parents tend to feed their children in the same patterns that they eat, promoting unhealthy eating habits. -Avoid: foods loaded with sugar, salt, and saturated fats, and excessive TV viewing -Breastfeeding until 6 months is associated with slower early weight gain

Pattern Perception

Newborns prefer to look at patterned rather than plain stimuli. As infants get older they prefer more complex patterns

Experience-Dependent Growth

Occurs throughout our lives. It consists of additional growth and refinement of established brain structures as a result of specific learning experiences that vary widely across individuals and cultures

Perceptual Narrowing Effect

Perceptual sensitivity that becomes increasingly attuned with age to info most often encountered.

Visual cliff

Plexi glass covered table with a platform at the center, a "shallow" side and "deep" side with a checkerboard several feet below the glass and one just under the glass. Crawling babies usually went over the shallow side but reacted with fear to the deep side. Meaning that crawling babies have depth perception

Prereaching-Newborn

Poorly coordinated swipes or swings toward an object in front of them, but because of poor arm and hand control they rarely contact the object. Drops out around 7 weeks of age

Changing States of Arousal

Rapid brain growth means that the organization of sleep and wakefulness changes substantially between birth and 2 years. Avg 2 yr old needs 12-13 hours of sleep/day. Periods of sleep and wakefulness become fewer and longer and they begin to sleep at night more. -Also affected by cultural beliefs. US parents belief the sleep schedule is naturally coming from the baby. Western parents try to get babies to sleep through the night which may be at odds with development -Melatonin doesn't emerge until the middle of the first year -Babies who sleep with their parents average consistently at three hours from 1 to 8 months until end of first year when REM declines

Right Hemisphere

Receive info from the left side of the body, responsible for spatial abilities and negative emotions -Processes info in a holistic, integrative manner, ideal for making sense of spatial info and regulating negative emotion

Left Hemisphere

Receives info from the right side of the body, responsible for verbal abilities and positive emotion. -Better at processing info in a sequential, analytic way, a good approach for dealing with communication

Experience-Expectant Brain Growth

Refers to the young brain's rapidly developing organization, which depends on ordinary experiences - opportunities to explore the environment, interact with people, and hear language and other sounds -occurs early and naturally

Punishment

Removing a desirable stimulus or presenting an unpleasant to decrease the occurence of a response

Synaptic pruning

Returns neurons not needed at the moment to an uncommitted state so they can support future development. ~40% of neurons in childhood are pruned -Stimulation is vital during periods in which the formation of synapses is at its peak

Fine-Motor Development

Smaller movements such as reaching and grasping

Lateralization

Specialization of the two hemispheres -The process of acquiring language and other skills promotes lateralization

Mirror Neurons

Specilized cells in motor areas of the cerebral cortex that fire identically when you hear or see an action and when it carries out that action on its own (can be found around 6 months) -Believed to be biological base of imitation, empathy, and understanding other's intentions

Pictorial Depth Cues

Starts 2-3 months, improves rapidly 5-7 months, 3 dimensional. Ex: receding lines, texture change, overlapping objects, shadows

Cerebral Cortex

Surrounds the rest of the brain, resembling half of a shelled walnut. It is the largest brain structure, accounting for the 85% of the brain's weight and containing the greatest number of neurons and synapses.

Depth Perception

The ability to judge the distance of objects from one another and from ourselves. Important for understanding the layout of the environment and for guiding motor activity

Skeletal Age

The best estimate of a child's physical maturity, a measure of bone development determined by X-rays of the long bones of the body to see the extent to which soft, pliable cartilage has hardened into bone

Describe the development of voluntary reaching and grasping, and explain why they are important for cognitive development.

They start out as gross, diffuse activity, and move towards mastery of fine movements. Prereaching suggests the babies are biologically prepared to coordinate hand with eye in the act of exploring. It broadens their understanding of behaviors and of the range of actions that can be performed on various objects.

2. Neutral Stimulus

To produce learning, a neutral status that does not lead to the reflex is presented just before or at about the same time as the UCS -Stroked the forehead before each nursing period began, stroking was paired with taste of milk (UCS)

Event-Related Potentials (ERPs)

Using the EEG, the frequency and amplitude of brain waves in response to particular stimuli are recorded in multiple areas of the cerebral cortex. Enables identification of general regions of stimulus induced activity

Near-infrared Spectroscopy (NIRS)

Using thin, flexible optical fibers attached to the scalp through a head cap, infrared light is beamed at the brain; its absorption by areas of cerebral cortex varies with changes in blood flow and oxygen metabolism as the individual processes particular stimuli. The result is a computerized moving picture of active areas in the cerebral cortex. Unlike fMRI and PET, NIRS is appropriate for infants and young children, who can move within limited range.

Deprived Early Environments

Usually, if a baby is deprived of environmental stimulation and if given environmental stimulation before 6 months, they usually catch up in cognitive function. If it is longer than 6 months then they show serious intellectual deficits, usually displaying inattention, over activity, unruly behavior, and autistic like symptoms -also shown is a decrease in activity in the cerebral cortex, especially the prefrontal cortex, and neural fibers which are involved in control of emotion, disrupts brain's capacity to manage stress, and left cerebral hemisphere activity is diminished

Marasmus

Wasted condition of the body caused by a diet low in all essential nutrients. Usually when mother is too malnourished to produce enough breast milk and bottle feeding is also inadequate. Baby becomes thin and is in danger of dying. -Suffer lasting damage to brain, heart, liver, and other organs, can disrupt appetite control centers in the brain, learning and behavior are effected, display more intense stress response to fear -When diets improve, they tend to gain excessive weight, some catch-up in growth in height, but not head size because of a permanent loss is brain weight.

Intermodal Perception

We make sense of these running streams of light, sound, tactile, odor, and taste info, perceiving them as integrated wholes. We know, for example that an object's movements are closely coordinated with the sound of a voice and that dropping a rigid object on a hard surface will cause a sharp, banging sound -3-4 months can match faces with voices -4-6 months infants can perceive and remember unique voice pairings of unfamiliar adults -Crucial for perceptual development, social and language processing

Functional Magnetic Resonance Imaging (fMRI)

While the person lies inside a tunnel-shaped apparatus that creates a magnetic field, a scanner magnetically detects increased blood flow and oxygen metabolism in areas of the brain as the individual processes particular stimuli. The scanner typically records images every 1 to 4 seconds; these are combined into a computer moving picture of activity anywhere in the brain (not just the outer layers). Not appropriate for children younger than age 5 to 6, who cannot remain still during testing.

Contrast Sensitivity

contrast refers to the difference in the amount of light between adjacent regions in a pattern. If babies are sensitive to the contrast in two or more patterns, they prefer the one with more contrast. -In early weeks of life babies respond to separate parts of a pattern, and stare at a single, high contrast feature, around 2-3 months they thoroughly explore a patterns features, pausing briefly to look at each part -around 4 months they can perceive subjective boundaries -12 months they can complete an uncompleted image in their mind