1. Invitation to the Life Span
Chapter 3- The First Two Years
Body and Brain
2. Body Changes
Height and Weight
• Average weight at birth: 7.5 pounds
• Average length: 20 inches
• These numbers are norms, an average
measurement.
3. Body Changes
Well-baby checkup
• Doctor or nurse measures baby’s growth:
height, weight, and head circumference.
• Abnormal growth may indicate physical or
psychological problems.
• Headsparing- 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.
5. Body Changes
Brain Development
• Neuron- nerve cell. Billions in the central
nervous system.
• Cortex- the outer layers of the brain.
• Axon- a fiber that extends from a
neuron and transmits
electrochemical impulses from
that neuron to the dendrites of
other neurons.
6.
7. Body Changes
• Dendrite- a fiber that extends from a neuron
and receives electrochemical impulses
transmitted from other neurons via their
axons.
• Synapse- the intersection between the axon
of one neuron and the dendrites of other
neurons.
• Neurotransmitter- a brain chemical that
carries information from the axon of a
sending neuron to the dendrites of a
receiving neuron.
9. Body Changes
• Neurons and synapses proliferate (increase rapidly in
number) before birth. This increase continues at a
fast pace after birth, but soon an opposite
phenomenon occurs: the elimination, or pruning, of
unnecessary connections.
• The last part of the brain to mature is the prefrontal
cortex, the area for anticipation, planning, and
impulse control.
• Shaken baby syndrome- a life-threatening injury that
occurs when an infant is forcefully shaken back and
forth, a motion that ruptures blood vessels in the brain
and breaks neural connections.
10.
11. Body Changes
• Newborns baby sleep about 17 hours a day, in
one- to three-hour segments.
• Newborns’ sleep is primarily active sleep: 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.
• Quiet sleep: slow brain waves and slow breathing
• Newborns have a high proportion of REM (rapid
eye movement) sleep, with flickering eyes and
rapid brain waves.
12. Moving and Perceiving
Motor Skills
• The first movements are not skills but
reflexes, involuntary responses to a
particular stimulus.
13. Moving and Perceiving
Some reflexes help insure survival: breathing, thrashing,
shivering, sucking, rooting, swallowing, spitting up.
Other reflexes are signs of normal functioning:
• Babinski reflex. When infants’ feet are stroked, their toes fan
upward.
• Stepping reflex. When infants are held upright with their feet
touching a flat surface, they move their legs as if to walk.
• Swimming reflex. When they are laid horizontally on their
stomachs, infants stretch out their arms and legs.
• Palmar grasping reflex. When something touches infants’ palms,
they grip it tightly.
• Moro reflex. When someone startles them, perhaps by banging on
the table they are lying on, infants fling their arms outward and then
bring them together on their chests, as if to hold on to something,
while crying with wide-open eyes.
14. Moving and Perceiving
• Gross motor skills- Physical abilities
involving large body movements, such as
walking and jumping.
• Fine motor skills- Physical abilities
involving small body movements,
especially of the hands and fingers, such
as drawing and picking up a coin.
16. Moving and Perceiving
Sensation and Perception
• Sensation- The response of a sensory
system (eyes, ears, skin, tongue, nose)
when it detects a stimulus.
• Perception- The mental processing of
sensory information when the brain
interprets a sensation.
• Sensory development- typically precedes
intellectual and motor development.
17. Moving and Perceiving
The sense of hearing develops during the
last trimester of pregnancy and is already
quite acute at birth; it is the most advanced of
the newborn’s senses.
Vision is the least mature sense at birth.
– Newborns focus only on objects between 4 and
30 inches away.
– Binocular vision, the ability to coordinate the two
eyes to see one image, appears at 3 months.
– Sensation is essential for the visual cortex to
develop normally.
19. Surviving in Good Health
Preventing Sudden Infant Death Syndrome
• In 1990, about 5,000 babies died of sudden
infant death syndrome (SIDS) in the United
States.
• The actual cause of SIDS is still unknown: low
birthweight, heavy clothing, soft bedding,
teenage parenthood, and, particularly, maternal
smoking are risk factors.
• Putting infants to sleep on their backs reduces
the risk but does not eliminate it.
20. Surviving in Good Health
Adequate Nutrition
• For every infant disease (including SIDS),
breast-feeding reduces risk and malnutrition
increases it, stunting growth of body and
brain.
• Breastfed babies are less likely to develop
allergies, asthma, obesity, and heart disease.
• As the infant gets older, the composition of
breast milk adjusts to the baby’s changing
nutritional needs.
21. Infant Cognition
Piaget
• sensorimotor intelligence
– Piaget’s term for the way infants think—by using their senses
and motor skills—during the first period of cognitive
development.
• assimilation
– Piaget’s term for a type of adaptation in which new experiences
are interpreted to fit into, or assimilate with, old ideas.
• accommodation
– Piaget’s term for a type of adaptation in which old ideas are
restructured to include, or accommodate, new experiences.
• object permanence
– The realization that objects (including people) still exist when
they can no longer be seen, touched, or hear.
23. Infant Cognition
Information-processing Theory
• A perspective modeled on computer
functioning.
• Information-processing theorists believe that
a step-by-step description of the mechanisms
of thought adds insight to our understanding
of cognition at every age.
• Information-processing research has
overturned some of Piaget’s conclusions—
including the concept of object permanence.
24. Infant Cognition
• The visual cliff was designed to provide
the illusion of a sudden dropoff between
one horizontal surface and another.
• Mothers were able to urge their 6-month-
olds to wiggle forward over the supposed
edge of the cliff, but 10-month-olds
fearfully refused to budge.
25. Infant Cognition
Early Memory
• According to classic developmental theory,
infants store no memories in their first year.
• Developmentalists now agree that very young
infants can remember if the following
conditions are met:
– Experimental conditions are similar to real life.
– Motivation is high.
– Special measures aid memory retrieval.
26. Language Learning
Early Communication
• Child-directed speech- The high-pitched,
simplified, and repetitive way adults speak to
infants. (Also called baby talk or
motherese.)
• Babbling- The extended repetition of certain
syllables, such as ba-ba-ba, that begins when
babies are between 6 and 9 months old.
• Naming explosion- A sudden increase in an
infant’s vocabulary, especially in the number
of nouns, that begins at about 18 months of
age.
27. Language Learning
First Words
• At about 1 year, babies speak a few
words.
• Spoken vocabulary increases gradually
(about one or two new words a week).
• Once spoken vocabulary reaches about
50 words, it builds quickly, at a rate of 50
to 100 words per month.
28. Language Learning
Cultural Differences in Language Use
• Holophrase- A single word that is used to
express a complete, meaningful thought.
– All new talkers say names and utter
holophrases.
• Infants differ in their use of various parts of
speech, depending on the language they
are learning, e.g. more nouns and fewer
verbs.
29. Language Learning
Acquiring Grammar
• Grammar includes all the devices by
which words communicate meaning:
sequence, prefixes, suffixes, intonation,
loudness, verb forms, pronouns,
negations, prepositions, and articles.
• Worldwide, people who are not yet 2 years
old already use language well.
30. Language Learning
Hypotheses About Language Development
Learning Approach
• Infants need to be taught
• B. F. Skinner (1957) noticed that spontaneous
babbling is usually reinforced.
• Parents are expert teachers, and other caregivers
help them teach children to speak.
• Frequent repetition of words is instructive,
especially when the words are linked to the
pleasures of daily life.
• Well-taught infants become well-spoken children.
31. Language Learning
Language Learning is Innate
• Language acquisition device (LAD)-
Chomsky’s term for a hypothesized mental
structure that enables humans to learn
language, including the basic aspects of
grammar, vocabulary, and intonation.
32. Language Learning
Social Impulse Toward Communication
• Infants communicate in every way they
can because humans are social beings,
dependent on one another for survival,
well-being, and joy.
