Infant Capacities and the Process of Change

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





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


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


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.


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


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

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Infant Capacities and the Process of Change