Chapter 3 Flashcards
Average weight of baby at birth vs. at 24 months
Growth in infancy
At birth: 7 pounds
At 24 months: 28 pounds
Average length of baby at birth vs. at 24 months
Growth in infancy
At birth: 20 inches
At 24 months: 34 inches
Eat and Sleep
Growth in infancy
Babies need to be fed day and night, so the rate of increasing weight in the first weeks of life is high
– Most 1-month-old girls who weigh 10 pounds should be at least 25 pounds by age 2.
– Females weigh less than males on average over their lifespan
Sleep specifics vary because of…
Infant Sleep
biology and the social environment.
How much and how often do newborns sleep?
Infant Sleep
Newborns sleep about 15-17 hours a day, in one- to three-hour segments.
Active sleep
Infant Sleep
Newborns’ sleep is primarily active sleep, or quiet sleep: slow brain waves and slow breathing
– Often dozing, able to awaken if someone rouses them, but also able to go back to sleep quickly if they wake up, cry, and are comforted
REM [rapid eye movement] sleep
Infant Sleep
Newborns have a high proportion of REM sleep, with flickering eyes and rapid brain waves.
Very deep sleep, dreaming
Variation
Infant Sleep
Particularly apparent in the early weeks. As reported by parents, 1 new baby in 20 sleeps 9 hours or fewer per day and 1 in 20 sleeps 19 hours or more.
Where should babies sleep?
Opposing perspectives
Decision to co-sleep or bed-share linked to culture, age of infant, mother’s education level, depressive state, and father involvement.
– U.S. middle class infants sleep separated from parents
– Asian, African, and Latin American infants co-sleep or bedshare.
– Asian and African mothers worry more about separation; European and North American mothers worry more about lack of privacy.
Head-sparing
Brain Development
a biological mechanism that protects the brain when
malnutrition disrupts body growth.
The brain is the last part of the body to be damaged by malnutrition.
Brain Development
Prenatal and postnatal brain growth (measured by head circumference) is crucial for later cognition.
Neuron
Brain Basics
NERVE CELLS in the central nervous system (CNS), especially in the brain
Axon
Brain Basics
Fiber that extends from a neuron and TRANSMITS electrochemical impulses from that neuron to the dendrites of other neurons.
Cortex
Brain Basics
Outer layers of the brain where most thinking, feeling, and sensing occurs.
Prefrontal cortex
Brain Basics
Area of the cortex at the very front of the brain that specializes in anticipation, planning, and impulse control.
Dendrite
Brain Development
Fiber that extends from a neuron and RECEIVES
electrochemical impulses transmitted from other neurons via their axons.
Synapses
Brain Development
Intersection between the axon of one neuron and the
dendrites of other neurons.
Neurotransmitter
Brain Development
Brain chemical that carries information from the axon of a sending neuron to the dendrites of a receiving neuron.
Connecting
neurons grow axons and dendrites to each other’s neurons.
Throughout life, those fragile dendrites will grow or disappear as the person continues thinking.
Experience, expansion and pruning
Brain Development
• Specifics of brain structure and growth depend on genes and maturation but even more on experience.
– Expansion and pruning of dendrites occur for every aspect of early experience.
Transient exuberance
Brain Development
The great but temporary increase in the number of dendrites that develop in an infant’s brain during the first two years of life.
– exuberant because growth is rapid; transient because some growth is temporary
Pruning and sculpting
Brain Development
Pruning - When applied to brain development, the process by which unused connections in the brain atrophy and die.
Unused dendrites whither (through pruning) to allow space between neurons in the brain, allowing more synapses and thus more complex thinking (sculpting)
Experience-expectant
Brain Development
Brain functions that require certain basic common experiences (which an infant can be expected to have) in order to develop normally.
Experience-dependent
Brain Development
Brain functions that depend on particular, variable experiences and therefore may or may not develop in a particular person.
EEG research
- Research has found that babies respond to language long before they speak.
- Experiences of all sorts connect neurons and grow dendrites.
Infants need stimulation
Implications for Caregivers
• Playing, allowing varied sensations, and encouraging movement
– Patterns, not moments, of neglect or maltreatment harm the brain.
Shaken baby syndrome
Implications for Caregivers
• A life-threatening injury that occurs when an infant is forcefully shaken back and forth.
– This motion ruptures blood vessels in the brain and breaks neural connections.
Sensory development
Moving and Perceiving
Is the gradual process by which an infant’s senses begin to grow. These senses are sight, taste, touch, smell and hearing. Sensory development begins during GESTATION
• Typically precedes intellectual and motor development yet are present in utero
• At birth, infants possess functional sensory systems;
– vision is somewhat organized
– audition (hearing), olfaction (smell), and touch are fairly mature
Sensation
Moving and Perceiving
Response of a sensory system (eyes, ears, skin, tongue, nose) when it detects a STIMULUS
– A physical feeling or perception resulting from something that happens to or comes into contact with the body.
Perception follows sensation
Moving and Perceiving
The mental processing of sensory information when the brain interprets a sensation (from stimulus)
• Infants’ brains are especially attuned to their own repeated social experiences, and perception occurs
• Infant brain and auditory capacity to hear sounds in the usual speech range
• The parts of the cortex dedicated to the senses develop rapidly.
Sense of hearing
Moving and Perceiving: Hearing
- Develops during the LAST TRIMESTER of pregnancy
- Most advanced of the newborn’s senses
- Speech perception by four months after birth
What area of the brain produces speech?
Moving and Perceiving: Hearing
BROCA’S AREA (like “boca”)
• Note that a person could hear but not understand OR understand but not speak if Broca’s area is damaged.
Damage of Wernicke’s area is concerned with the…
Moving and Perceiving: Hearing
COMPREHENSION of language
Damage causes Wernicke’s aphasia, characterized by superficially fluent, grammatical speech but an inability to use or understand more than the most basic nouns and verbs.
Sense of Sight (Vision)
Moving and Perceiving: Seeing
- Least mature sense at birth
- Newborns focus between four and 30 inches away
- Experience and maturation of visual cortex improve shape recognition, visual scanning, and details