Infant Capacities and the Process of Change
The Development of Children (5th ed.)
Cole, Cole & Lightfoot
Chapter 4
What does this mean?
““Babies control and Babies control and bring up their bring up their families as much as families as much as they are controlled they are controlled by them; in fact, we by them; in fact, we may say that the may say that the family brings up a family brings up a baby by being baby by being brought up by him.”brought up by him.”
““Babies control and Babies control and bring up their bring up their families as much as families as much as they are controlled they are controlled by them; in fact, we by them; in fact, we may say that the may say that the family brings up a family brings up a baby by being baby by being brought up by him.”brought up by him.” Erik Erikson in
Childhood and Society
Why is this the case?
Compared with many animals that are able to negotiate their environments at birth almost as well as their parents, human beings are born in a state of marked immaturity…. For many years, human offspring must depend on their parents and other adults for their survival.”
Compared with many animals that are able to negotiate their environments at birth almost as well as their parents, human beings are born in a state of marked immaturity…. For many years, human offspring must depend on their parents and other adults for their survival.”
Cole, Cole & Lightfoot, p. 114
Overview of the Journey
Brain development
Earliest capacities
Coordination with the social world
Mechanisms of development
First postnatal BSB shift
Brain development
Earliest capacities
Coordination with the social world
Mechanisms of development
First postnatal BSB shift
Brain Development
Neurons and Neural Networks
Experience and Development
The CNS and the Brain
1. Dendrite size and branching
2. Axon branching and myelination (speed)
1. Dendrite size and branching
2. Axon branching and myelination (speed)
At birth, the brain has all the cells it will have, yet it is ¼ the size of an adult brain. Why?
At birth, the brain has all the cells it will have, yet it is ¼ the size of an adult brain. Why?
Neural Networks in Postnatal Life
Experience and Development
Exuberant synapto-genesis
Synapticpruning
Rats Raised in Enriched Environments
Increased rates of learning in standard laboratory tasks, such as learning a maze
Increased overall weight of the cerebral cortex (the part of the brain that integrates sensory information)
Increased amounts of acetylcholinesterase, a brain enzyme that enhances learning
Larger neuronal cell bodies and glial cells (which provide insulation, support and nutrients to neuronal cells)
More synaptic connectionsRosenzweig, 1984
Active Interaction with the Environment
Rats were raised with an enriched environment but were housed singly in small cages so that could do no more than observe what was going on around them
The learning capacity of these rats differed in no way from that of the animals that were housed in individual cages away from the enriched environment
What might this imply for child-rearing? For teaching?
Brain Elements and Functions
Six Mammalian Species
Why the difference?
Why the difference?
Cortex Development Matures later than the
lower-lying areas of the CNS, spinal cord, brain stem
Primary motor area First area of the cortex to develop Responsible for voluntary (nonreflexive) movement Begins with raising head (1 month), control of arms and
trunk (3 months); leg control is last to develop Primary sensory areas
Begins with touch, then visual, then auditory By 3 months, all primary sensory areas are relatively mature
Frontal cortex (e.g., planning, decision-making) Begins to function in infancy but continues to develop
throughout childhood
Earliest Capacities
Sensory Processes
Response Processes
Sensory Processes
Normal full-term newborns enter the world with all sensory systems functioning, but not all of these systems have developed to the same level due to different developmental rates (i.e., heterochrony)
Indications of sensation Turning of the head, variation in brain waves,
changes in rate of sucking on a nipple Habituation: Becomes bored and stops attending Dishabituation: Interest is renewed after the
infant perceives a change in the stimulus
Hearing
Infants only minutes old will startle with a loud noise and may even cry
Will also turn their heads toward the source of a noise
Hearing
Infants can distinguish the sound of the human voice from other kinds of sounds, and seem to prefer it Are particularly interested in
speech with the high pitch and slow, exaggerated pronun-ciation (i.e., “baby talk”)
Evidence that by 2 days old, some babies would rather hear the language that has been spoken around them than a foreign language
Hearing Capacity
At 2 months of age: Present phoneme
(e.g., /pa/) Habituate (i.e.,
return to baseline sucking rate)
New phoneme(e.b., /ba/)
Dishabituate (i.e., sucking rate increases)
New Consonant
Both groups hear a consonant sound
Habituate Experimental
group hears a new consonant sound at time marked 0
Infants are able to distinguish consonant sounds
Auditory Discrimination and Culture
Infants can distinguish among language sounds that do not occur in their native language, but this capacity diminishes during the first year of life.
Infants’ Visual Capacity
Based on studies of infant eye movement when a striped visual field passes in front of the eyes, it is evident that visual capacity increases dramatically over the first few months of life.
Fantz Looking Chamber (1960s)
Demonstrated that babies less than 2 days old can distinguish among visual forms
Tend, however, to focus on areas of high contrast, such as lines and angles
Development of Visual
Scanning
Due to brain maturationDue to brain maturation
Perception of Faces
Infants show a preference for patterned stimuli over plain stimuli
Babies as young as 9 minutes old will look longer at a schematic moving face than a scrambled one
Visual Preferences
of Infants
Expressions of Various Tastes
(a) Neutral stimulus (water)
(b) Sweet stimulus
(c) Sour stimulus
(d) Bitter stimulus
Early Sensory Capacities
Sense Capacity
Hearing Ability to distinguish phonemesPreference for native language
Vision Slightly blurred at birthColor vision by 2 months
Distinguish patterned stimuli from plainPreference for facelike stimuli
Smell Ability to differentiate odors well at birth
Taste Ability to differentiate tastes well at birth
Touch Response to touch at birth
Temperature Sensitivity to temperature changes at birth
Position Sensitivity to changes in position at birth
Response Processes
Reflexes Automatic (involuntary)
responses to specific types of stimulation…
Emotions Two basic emotions,
contentment (+) & distress (-), split into primary emotions (e.g., joy, anger, fear) at 3-6 months…
Temperament Individual modes of responding to the environment
that appear to be consistent across situations and stable over time…
Reflexes Present at Birth
Reflex Description
Babinski When the bottom of the baby’s foot is stroked, the toes fan out and then curl
Crawling When the baby is placed on his stomach and pressure is applied to the soles of his feet, his arms and legs move rhythmically
Moro If the baby is allowed to drop unexpectedly while being held or if there is a loud noise, she will throw her arms outward while arching her back and then bring her arms together as if grasping something
Rooting The baby turns his head and opens his mouth when he is touched on the cheek
Sucking The baby sucks when something is put in her mouth
Grasping Reflex
When a finger or some other object is pressed against the baby’s palm, the baby’s fingers close around it
Disappears in 3-4 months; replaced by voluntary grasping
Stepping Reflex
When the baby is held upright over a flat surface, he makes rhythmic leg movements
Disappears in first 2 months, but can be reinstated in special contexts (e.g., when partially submerged in water)
Infant Expression of Emotions
Joy Anger Sadness Disgust
Distress Interest Fear Surprise
Infant Expression of Emotions
Joy Anger Sadness Disgust
Distress Interest Fear Surprise
Joy Anger Sadness Disgust
Distress Interest Fear Surprise
Temperaments
Three broad categories Easy babies: Playful,
regular in their biological functions, adapt readily to new circumstances
Difficult babies: Irritable, irregular in their biological functions, often respond intensely and negatively to new situations or try to withdraw from them
Slow-to-warm-up babies: Low in activity level, responses are typically mild, tend to withdraw from new situations, require more time than easy babies to adapt to change
Moderate temperamental stability over first 8 years of childhood Impact of both genetic and environmental components
Coordination with the Social World
Sleeping
Feeding
Crying
Sleep Patterns in Infants
NREM Sleep REM Sleep
During first 2-3 months of life, infants begin their sleep with active (REM) sleep and then fall into quiet (NREM) sleep. Subsequently, the sequence reverses and shifts toward the adult pattern.
During first 2-3 months of life, infants begin their sleep with active (REM) sleep and then fall into quiet (NREM) sleep. Subsequently, the sequence reverses and shifts toward the adult pattern.
Pattern of Sleep/Wake Cycles
Newborns sleep ~16½ hours /day, but the longest period of sleep is only 3-4 hours.
Newborns sleep ~16½ hours /day, but the longest period of sleep is only 3-4 hours.
Feeding
When fed “on demand”, majority of newborns preferred a 3-hour schedule
Interval gradually increased to 4-hour schedule by 2 ½ months
By 7 or 8 months, 4x/day
Nursing Behavior
Later attempts become much more coordinated resulting in nursing – an evidence of learning.
Infant’s nostrils are blocked while he/she is attempting to feed
This elicits a head-withdrawal reflex that interferes with feeding
Early feeding attempts are rather uncoordinated
Crying
Increases from birth to about 6 weeks and then starts to decrease
At a few months of age, infants begin to cry voluntarily (“crying on purpose”) as the cerebral cortex becomes involved
Crying helped by nursing, holding baby to shoulder, rocking, patting, cuddling, swaddling (reduces over-stimulation from uncontrolled limb movements)
Mechanisms of Developmental Change
Biological-Maturation Perspective
Environmental-Learning Perspective
Constructivist Perspective
Cultural-Context Perspective
Mechanisms of Developmental Change
Biological-MaturationPerspective
Reflex Coordination
Early, simple reflexes arise from the brain stem
More complex, coordinated reflexes result from the maturation of the cerebral cortex
Early Attention to Human Speech
In 1-month-old baby born without a cerebral cortex
On first exposure to sound of human speech, there is a marked decrease in heart rate, indicating attention
After 5 additional presentations of the sound, the infant has habituated
Mechanisms of Developmental Change
Environmental-LearningPerspective
Classical Conditioning
(a) Sight of a light (CS) elicits no particular response
(b) Loud sound of gong (UCS) causes baby to blink (UCR)
(c) Sight of light (CS) is paired with sound of gong (UCS), which evokes an eyeblink (UCR)
(d) Sight of light (CD) is sufficient to cause the baby to blink (CR), evidence that learning has occurred
Operant Conditioning An organism will tend to
repeat behaviors that lead to rewards and will tend to give up behaviors that fail to produce rewards or lead to punishment
Requirement: Behavior must occur before it can be reinforced
Operant Conditioning
After only 25 occasions on which the head turning was reinforced with the pacifier, most of the babies had tripled the rate at which they turned their heads.
Conversely, those infants who were rewarded with a pacifier for holding their heads still, learned to move their heads less during the course of the experiment.
Mechanisms of Developmental Change
ConstructivistPerspective
(Piaget)
Piaget’s Theory of Developmental Change via Schemas
EquilibrationEquilibration
AssimilationAssimilation(Incorporated into an(Incorporated into an
existing schema)existing schema)
AccommodationAccommodation(Modification of a(Modification of a
prior schema)prior schema)
Leads to developmental stages…
Piaget’s Stages of Cognitive Development
Age (Yrs) Stage Description
Birth – 2 Sensori-motor
Achievements consist largely of coordinating sensory perceptions and simple motor behaviors. Come to recognize the existence of a world outside themselves and begin to interact with it in deliberate ways.
2 – 6 Preopera-tional
Can use symbols, including mental images, words, and gestures. Often fail to distinguish their point of view from that of others, become easily captured by surface appearances, and are often confused about causal relationships.
6 – 12 Concrete Operational
Become capable of mental operations that allow them to combine, separate, order, and transform objects and actions. There are still carried out, however, in the presence of the objects and events being thought about.
12 – 19 Formal Operational
Acquire the ability to think systematically about all logical relations within a problem. Display keen interest in abstract ideas and in the process of thinking itself.
Sensorimotor Substages
Sub Age (M) Description
1 0 – 1 ½ Reflex schemas exercised: Involuntary rooting, sucking, grasping, looking
2 1 ½ – 4 Primary circular reactions: Repetition of actions that are pleasurable in themselves
3 4 – 8 Secondary circular reactions: Dawning awareness of the effects of one’s own actions on the environment, and that extended actions can produce interesting change in the environment
4 8 – 12 Coordination of secondary circular reactions: Combining schemas to achieve a desired effect (earliest form of problem solving)
5 12 – 18 Tertiary circular reactions: Deliberate variation of problem-solving means, with experimentation to see what the consequences will be
6 18 – 24 Beginning of symbolic representation: Images and words come to stand for familiar objects, accompanied by the invention of new means of problem solving through symbolic combinations
Mechanisms of Developmental Change
Cultural-ContextPerspective
Reciprocal Relationships
Presence of milk stimulates infant sucking, which in turn triggers the release of hormones that increase milk production and release
Developmental Change Incorporates Cultural Variations
Additional sources of developmental change Active contribution
of other people in the child’s community
Cultural “designs for living” accumulated over the history of the larger social group
Case in PointBottle-feeding vs. Breast-feeding
Case in PointBottle-feeding vs. Breast-feeding
First PostnatalBio-Social-Behavioral Shift
Occurs at 2½ Months
Social Smiling!
BSB Shifts & Subsequent Periods
Shift Point Developmental Period
Conception Prenatal period
Birth Early infancy
2 ½ months Middle infancy
7-9 months Late infancy
24-30 months Early childhood
5-7 years Middle childhood
11-12 years Adolescence
19-21 years Adulthood
Characteristics of the Shift
Biological Myelination of cortical and subcortical neural pathways Increased cortical control of subcortical activity Increased diversity of brain cells Increase in amount of wakefulness Decrease in proportion of active (REM) sleep Quiet (NREM) sleep begins to come first
Social New quality of coordination and emotional contact between infants and caretakers
Beginning of “crying on purpose”
Behavioral Better retention of learning Increased visual acuity and better visual scanning Onset of social smiling Decreased fussiness and crying Visually initiated reaching visually guided reaching