discussion/lifespan chapter4, 5 and 6
dbrown83
psyc2314_ppt_ch04.pptxLIFE-SPAN DEVELOPMENT 17e
John W. Santrock
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Physical Development in Infancy
Chapter 4
©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.
Chapter Outline
Physical Growth and Development in Infancy
Motor Development
Sensory and Perceptual Development
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Physical Growth and Development in Infancy
Patterns of growth
Height and weight
The brain
Sleep
Nutrition
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Patterns of Growth
Cephalocaudal pattern
Developmental sequence in which the earliest growth always occurs at the top—the head—with physical growth and differentiation of features gradually working their way down from top to bottom.
Proximodistal pattern
Sequence in which growth starts at the center of the body and moves toward the extremities
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Changes in Proportions of the Human Body During Growth
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Height and Weight
The average American newborn is 20 inches long and weighs 7.6 pounds.
Most of the newborns are 18–22 inches long and weigh between 5 and 10 pounds.
Babies grow about 1 inch per month during the first year.
By 2 years of age
Infants weigh approximately 26–32 pounds
Average 32–35 inches in height
Growth is episodic.
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The Brain (1 of 6)
Courtesy of Vanessa Vogel Farley
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The Brain (2 of 6)
Brain’s development
Rapid and extensive growth through infancy and later
Brain very vulnerable to shaken baby syndrome
Noninvasive tools that measure brain activity:
Electroencephalogram (EEG)
Functional near-infrared spectroscopy (fNRIS)
Mapping the brain:
Forebrain—portion farthest from the spinal cord—includes the cerebral cortex and structures beneath it.
Brain has two hemispheres containing four lobes.
Lateralization: Specialization of function in one hemisphere of the cerebral cortex or the other; both needed for complex functions.
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The Brain (3 of 6)
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The Brain (4 of 6)
Changes in neurons during first years of life:
Myelination
Increased connectivity among neurons creates new neural pathways
Changes in regions of the brain:
Blooming and pruning vary by brain region
Peak of synaptic overproduction in the visual cortex followed by a gradual retraction
Heredity and environment influence the timing and course
Pace of myelination varies
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The Brain (5 of 6)
Early experience and the brain
Children in deprived environment such as Romanian orphanage may have depressed brain activity.
Brain demonstrates both flexibility and resilience.
Michael Rehbein’s right hemisphere and other areas reorganized to take over language functions and process speech after his left hemisphere was removed due to uncontrollable seizures.
Courtesy of The Rehbein Family
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The Brain (6 of 6)
Neuroconstructivist view
Interactions between experience and gene expression in the brain’s development are important.
Biological processes and environmental conditions influence the brain’s development.
Brain has plasticity and is context dependent.
Development of the brain and the child’s cognitive development are closely linked.
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The Brain: Four Lobes
Frontal lobes are involved in voluntary movement, thinking, personality, and intentionality or purpose.
Occipital lobes function in vision.
Temporal lobes have an active role in hearing, language processing, and memory.
Parietal lobes play important roles in registering spatial location, attention, and motor control.
Damage to the lobes results in aphasia or language ability loss.
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Early Deprivation and Brain Activity
Courtesy of Dr. Harry T. Chugani, Children’s Hospital of Michigan
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Sleep (1 of 4)
Why Do We Sleep?
Evolutionary perspective
Necessary for survival
Replenishes and rebuilds the brain and body
Restorative function
Clearing out waste in neural tissue
Critical for brain plasticity
Increases synaptic connections between neurons
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Sleep (2 of 4)
Typical newborn sleeps approximately 18 hours a day.
Infant sleep-related problems affect 15–25 percent of infants.
Night-time waking
Linked to separation distress and anxiety
Cultural variations influence infant sleeping patterns.
Infants sleep with their mothers in the Kipsigis culture in Kenya.
REM sleep—Eye movement under closed lids
Half of an infant’s sleep is REM sleep, the most in one’s life span.
REM sleep may promote infant brain’s development.
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Sleep (3 of 4)
Shared sleeping
Varies within cultures
Safety concerns in the United States
Sleeping parent may roll over onto infant.
Could be linked to sudden infant death syndrome (SIDS):
Infant suddenly dies without an apparent cause
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Sleep (4 of 4)
Sleep and Cognitive Development
Sleep may be positively linked to cognitive development.
Likely occurs because of sleep’s role in brain maturation and memory consolidation.
Better memory, language, and executive function
Lower quality of sleep linked with distractibility and behavioral problems.
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SIDS: Findings (1 of 2)
SIDS is likely in infants
With abnormal brain stem functioning involving the neurotransmitter serotonin
With heart arrhythmia
With sleep apnea and low birth weight
Who do not use a pacifier when they go to sleep
Whose siblings have died of SIDS
Of lower socioeconomic groups
Who are passively exposed to cigarette smoke, maternal smoking
Who share the same bed with parents or sleep on soft bedding
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SIDS: Findings (2 of 2)
SIDS is less common in infants who
Are breast fed
Sleep in a bedroom with a fan
Sleep on their backs
African American and Eskimo infants are four to six times as likely as all others to die of SIDS.
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Developmental Changes in REM and Non-REM Sleep
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Nutrition (1 of 5)
Nutritional needs and eating behavior
Infants should consume approximately 50 calories per day for each pound they weigh.
As motor skills improve, infants’ eating changes
From using suck-and-swallow to chew-and-swallow movements
As they can eat semisolid and then complex foods
Need to have a varied diet
Introduce fruits and vegetables early
Most common “vegetable” fed to 15-month olds are French fries.
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Nutrition (2 of 5)
Breast versus bottle feeding
Breast feeding is better for baby’s health.
Benefits of breast feeding and outcomes for the child
Fewer gastrointestinal infections
Fewer respiratory tract infections
Protects against wheezing in babies but may or may not be linked to preventing asthma
Fewer ear, throat, and sinus infections
Reduced infant hospitalizations for various infections
Not linked to reduced risk of developing allergies
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Nutrition (3 of 5)
Infant less likely to
Develop middle ear infection.
Become overweight or obese in childhood, adolescence, and adulthood
Develop type 1 diabetes in childhood or adult type 2
Suffer from SIDS
Maternal benefits of breast feeding:
Lower incidence of breast cancer and ovarian cancer
Reduced rate of type 2 diabetes
©JGI/Getty Images
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Nutrition (4 of 5)
Mother should not breast feed
When infected with HIV or other infectious disease
If she has active tuberculosis
If she is taking any drug
Additional issues
Breast feeding can be physically difficult.
Not all studies imply causality between health benefits and breast feeding; most studies are correlational.
Evidence of psychological differences between breast-fed and bottle-fed infants is inconclusive.
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Nutrition (5 of 5)
Infant malnutrition, chronic malnutrition, and protein deficiency is a worldwide problem.
It is very problematic in developing countries lacking clean water and milk.
Increasing number of HIV-positive mothers impairs breast feeding.
It is linked to impaired physical, cognitive, and social development.
Attention deficits are caused by severe protein malnutrition during infancy persists to middle age.
Cognitive development in those malnourished as infants can benefit from psychosocial interventions.
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Motor Development
The dynamic systems view
Reflexes
Gross motor skills
Fine motor skills
©Di Studio/Shutterstock
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Dynamic Systems View
Dynamic systems theory: Infants assemble motor skills for perceiving and acting.
Motor skills are developed by
Maturation and development of the nervous system
The body’s physical properties (e.g., physical strength) and its potential for movement, (e.g., motor control)
The child’s motivation to reach a goal, create new motor behavior (e.g., walking)
Environmental support for the skill
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Reflexes (1 of 3)
Built-in reactions to stimuli that govern the newborn’s movements
Are automatic and beyond the newborn’s control
Rooting reflex: occurs when the infant’s cheek is stroked or the side of the mouth is touched
Turns his or her head in an effort to find something to suck
(Top) ©Petit Format/Science Source; (bottom) ©Stockbyte/ PunchStock
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Reflexes (2 of 3)
Sucking reflex: occurs when newborns automatically suck an object placed in their mouth
Enables newborns to get nourishment before they have associated a nipple with food
Serves as a self-soothing mechanism
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Reflexes (3 of 3)
Moro reflex: a neonatal startle response that occurs in reaction to a sudden, intense noise or movement
Infant throws head back, flings out arms and legs, and arches back, then contracts movements
Believed to be a way of grabbing for support while falling
Grasping reflex: occurs when something touches the infant’s palms
Responds by grasping tightly
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Gross Motor Skills (1 of 3)
Involve large-muscle activities, such as walking
Development of posture
Posture: dynamic process linked with sensory information in the skin, joints, and muscles, which tell us where we are in space
Learning to walk, babies can stand by 10–12 months and can
Alternate leg movements and balance on one leg without falling
Learn safe places and surfaces to walk on and avoid unsafe places
Utilize perceptual-motor coupling in the development of new motor skills
Practice their new motor skills
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Gross Motor Skills (2 of 3)
The first year: Motor development milestones and variations
Developmental milestones include grasping, rolling, sitting, and crawling; standing and walking.
Linked to reaching motor milestones earlier:
Infants who are larger at birth
Overall size increasing over the first year
Being breast fed
Timing of reaching milestones varies by 2–4 months.
Experiences can modify the onset of these accomplishments.
Caregiver participation enhances all new skill development in a real-world environment with objects, surfaces, and planes.
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Gross Motor Skills (3 of 3)
Development in the second year
Toddlers become more skilled and mobile
By 13–18 months, toddlers can
Pull a toy and climb steps
By 18–24 months, toddlers can
Walk quickly and run short distance
Balance on their feet while squatting
Walk backward and stand and kick a ball
Stand and throw a ball
Jump
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Milestones in Gross Motor Development
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(Photo credit left to right) ©Barbara Penoyar/Getty Images; ©StephaneHachey/Getty Images; ©Image Source/Alamy; ©Victoria Blackie/Getty Images; ©Digital Vision; ©Fotosearch/Getty Images; ©Corbis/PictureQuest; ©amaviael/123RF
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Fine Motor Skills
Involve more finely tuned movements, such as finger dexterity
Types of grasps
Palmer grasp
Grasping with the whole hand
Pincer grip
Grasping small objects with thumb and forefinger
Perceptual-motor coupling is necessary for the infant to coordinate grasping.
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Sensory and Perceptual Development
What are sensation and perception?
The ecological view
Visual perception
Other senses
Intermodal perception
Nature, nurture, and perceptual development
Perceptual-motor coupling
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What Are Sensation and Perception?
Sensation: occurs when information interacts with sensory receptors
Eyes, ears, tongue, nostrils, and skin
Perception: Interpretation of what is sensed.
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The Ecological View
Perception brings us into contact with the environment so we can interact with and adapt to it.
Perception is designed for action, that is, gives people information such as when to put up your hands up to catch something.
Affordances: Opportunities for interaction offered by objects that fit within our capabilities to perform functional activities.
We sense information from the environment and get feedback from our bodies about how to interact with the world.
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Methods to Study Infant Perception (1 of 2)
Visual preference method: determines whether infants can distinguish one stimulus from another by measuring the length of time they attend to different stimuli
Habituation and dishabituation
Habituation: decreased responsiveness to a stimulus after repeated presentations of the stimulus
Dishabituation: recovery of a habituated response after a change in stimulation
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Fig 17 and 18
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Methods to Study Infant Perception (2 of 2)
High-Amplitude Sucking
Assess infant’s attention to sound measured via sucking rate
When infants habituate to sound, stop sucking, start again with new sounds
The Orienting Response and Eye-Tracking Headgear
Turning head toward a sight or sound
Equipment precisely assesses aspects of infant looking, gaze, attention, memory, and face processing, all part of perceptual and cognitive development
Helps to understand atypically developing infants, that is, autistic children
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Fig 17 and 18, 19
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Visual Perception (1 of 3)
Visual acuity and human faces
Newborn’s vision is estimated at 20/240 on Snellen chart.
Vision clarity improves from fuzzy at 1 month to clear at 1 year.
Within hours of birth, newborns prefer looking at faces over other objects.
Color vision
By 4–8 weeks color vision develops, and by 4 months, babies prefer saturated colors.
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Visual Perception (2 of 3)
Perceptual constancy: develops so infants can perceive world as stable.
Size constancy: recognition that an object remains the same even though the retinal image of the object changes as you move toward or away from the object
Shape constancy: recognition that an object’s shape remains the same even though its orientation changes
Perception of Occluded Objects
First 2 months of postnatal development, infants don’t perceive occluded objects as complete; instead, they perceive only what is visible.
Beginning at about 2 months of age, infants develop the ability to perceive that occluded objects are whole.
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Visual Perception: Occluded Objects (3 of 3)
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Visual Acuity During the First Months of Life
©Kevin Peterson/Getty Images; Simulation by Vischek
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Examining Infants’ Depth Perception on the Visual Cliff
©Mark Richard/PhotoEdit
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Other Senses
Hearing
Changes in hearing
As infants age, sensitivity increases to
Loudness
Pitch
Localization
Newborns are sensitive to
Touch and pain
Smell
Taste
(a) ©McGraw Hill Companies/Jill Braaten, Photographer; (b) Courtesy of Dr. Melanie J. Spence
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Intermodal Perception
Involves integrating information from two or more sensory modalities.
Vision and hearing
In the first 6 months, infants have difficulty connecting sensory input from different modes, but in the second half of the first year, they show an increased ability to make this connection mentally.
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Nature, Nurture, and Perceptual Development
Nativists—Nature proponents
The ability to perceive the world in a competent, organized way is inborn or innate.
A completely nativist view of perceptual development no longer is accepted in developmental psychology.
Empiricists—Emphasis on learning and experience
Taking an extreme nativist or empiricist view is now seen as unwarranted.
A full portrait of newborns’ perceptual development includes the influence of nature, nurture, and a developing sensitivity to information through perception and coalescing accumulated experiences.
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Perceptual-Motor Coupling
Infants learn new perceptual-motor couplings by assembling skills for perceiving and acting.
New perceptual-motor coupling is accomplished by the infant actively developing a skill to achieve a goal within the constraints set by the infant’s body and the environment.
Perceptual-motor coupling is necessary for the infant to coordinate grasping.
Perception and action are not isolated but are coupled.
Children perceive in order to move and move in order to perceive.
Perceptual and motor development do not occur in isolation from each other but instead are coupled.
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Accessibility Content: Text Alternatives for Images
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The Brain (3 of 6) Text Alternative
A neuron is a nerve cell that handles information processing. Axons and dendrites extending from the neuron’s cell body. Axons carry signals away from the cell body, and dendrites carry signals toward it. A myelin sheath encases and insulates many axons, helping electrical signals travel faster down the axon. Myelination is also involved in providing energy to neurons and in communication. At the end of the axon are terminal buttons, which release chemicals called neurotransmitters into synapses, which are tiny gaps between neurons’ fibers. Chemical interactions in synapses connect axons and dendrites, allowing information to pass from neuron to neuron.
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Milestones in Gross Motor Development Text Alternative
Specific motor skills develop in infants between ages 0 and 16 months. From newborn to 1 month, babies can lift their head lying on their stomach or in the prone position. Between 2 and 4 months, babies can lay in the prone position, and lift their chest up, using arms for support. Between 2 and 5 months, babies can roll over. By 3–6 months, babies can support some weight with their legs. They can sit without support from about 5 to 8 months. They can stand with support between 5 and 10 months and can pull themselves to a standing position by 6–10 months. Babies walk using furniture for support between 7 and almost 13 months and can stand alone at just under 10 to around 14 months. Babies can walk alone easily between 11 and 14 months. Overlap in motor skill development is normal.
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Visual Perception: Occluded Objects (3 of 3) Text Alternative
To study an infant’s ability to perceive occluded objects, researchers presented 5- to 9-month-old babies with a ball disappearing and reappearing behind a partition. Researchers observed the baby’s ability to track the moving ball disappearing gradually behind a partition or gradual occlusion. They also observed their tracking of abrupt occlusion or the ball disappearing abruptly. Finally, they observed imploding, or the ball quickly shrinking as it approached a partition, and reappearing larger the other side of the occluding partition. Overall, infants were more likely to accurately predict the reappearance of the moving object when it disappeared gradually than when it vanished abruptly or imploded.
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