INFANCY AND TODDLERHOOD

CEPHALOCAUDAL AND PROXIMODISTAL PATTERNS

1. Cephalocaudal - sequence in which the earliest growth always occurs at the top, beginning with the head

2. Proximodistal -- sequence in which growth starts at the center of the body and moves toward the

extremities.

    The Brain

• Cerebral cortex covers the forebrain like a wrinkled cap

• Two halves, or hemispheres, based on ridges and valleys in the cortex

• Four main areas, lobes, in each hemisphere

• frontal lobes, occipital lobes, temporal lobes, parietal lobes

• Lateralization specialization of function in one hemisphere or the other

    Parts of the neuron

• Axon carries signals away from the cell body

• Dendrites carry signals toward it

• Myelin sheath -- a layer of fat cells -- provides insulation and helps electrical signals travel faster down the axon

• At the end of the axon are terminal buttons, which release chemicals called neurotransmitters into synapses

• Synapses - tiny gaps between neurons' fibers

   Changes in Neurons

• Chemical interactions in synapses connect axons and dendrites, allowing information to pass from neuron to neuron

• The pace of myelination also varies in different areas of the brain

• The infant's brain is waiting for experiences to determine how connections are made

   Changes in Regions of the Brain

• Both heredity and environment influence synaptic overproduction and subsequent retraction

• "Blooming (development) and pruning" vary considerably by brain region

• Pruning -- unused connections are replaced by other pathways or disappear

• Prefrontal cortex -- the area of the brain where higher-level thinking and self- regulation occur

    Sleep

• Considerable individual variation in how much infants sleep

• Typical newborn sleeps 16 to 17 hours a day

SIDS

• Sudden infant death syndrome (SIDS) -- condition that occurs when infants stop breathing, usually during the night, and die suddenly without an apparent cause

• SIDS is the highest cause of infant death in the United States

• Risk of SIDS is highest at 2 to 4 months of age

Risk Factors for SIDS

• SIDS decreases when infants sleep on their backs

• More common in low birth weight infants

• Infants who are passively exposed to cigarette smoke are at higher risk

• More frequent in infants who sleep in soft bedding

• Less likely in infants who use a pacifier when they go to sleep

    When Mother Should Not Breast Feed

• • • If she is infected with AIDS or any other infectious disease that can be transmitted through her milk

    •  If she has active tuberculosis

    • If she is taking any drug that may not be safe for the infant

   Nutritional Needs

• • • Nutritionists recommend that infants consume approximately 50 calories per day for each pound they weigh

    • This is more than twice an adult's requirement per pound

    Dynamic  systems theory 

• Infants assemble motor skills for perceiving and acting, which are coupled together

• When infants are motivated to do something, they might create a new motor behavior

• Mastering a motor skill requires the infant's active efforts to coordinate several components of the skill

•  Mastering a New Skill

• The infant is motivated by a new challenge

• Partially accomplishes the task

• "Fine tunes" movements to make them smoother and more effective

• "Tuning" is achieved through repeated cycles of action and perception of the consequences of that action

Reflexes

• Reflexes -- built-in reactions to stimuli

• Genetically carried survival mechanisms

• automatic

• Involuntary

• Allow infants to respond adaptively to their environment

Gross Motor Skills

• Skills that involve large-muscle activities

• Sitting with support-2 months

• Sitting upright without support - 6 to 7 months of age Pull themselves up and hold on to a chair -- 8 months

• Stand alone - 10 to 12 months

• With experience, babies learn to avoid risky situations, integrating perceptual information with the development of a new motor behavior

• Toddlers become more mobile

13-18 months

• can pull a toy attached to a string

• use their hands and legs to climb up a number of steps

18-24 months

• toddlers can walk quickly or run stiffly

• walk backwards without losing their balance

• stand and kick a ball without falling and stand and throw a ball

• jump in place

Fine Motor Skills

• Finely tuned movements

• At birth, infants have very little control over fine motor skills

• During the first two years of life, infants refine how they reach and grasp

• Perceptual-motor coupling is necessary for the infant to coordinate grasping

• Experience plays a role in reaching and grasping

Sensory and Perceptual Development

• Sensation occurs when information interacts with sensory receptors -- the eyes, ears, tongue, nostrils, and skin

•  Perception is the interpretation of what is sensed

• Our perceptual system can select from the rich information that the environment provides

• We directly perceive information that exists in the world around us

Studying the Infant's Perception

• Perception brings us into contact with the environment in order to interact with and adapt to it

• Visual Preference Method -- Infants look at different things for different lengths of time

•  Orienting response to determine if an infant can see or hear a stimulus 

• Habituation-decreased responsiveness to a stimulus after repeated presentations of the stimulus

• Dishabituation -- is the recovery of a habituated response after a change in stimulation

Visual Acuity and Color

• Newborn's vision is estimated to be 20/600 on the well-known Snellan eye examination chart

• By 6 months of age -- vision is 20/40 or better

• By about the first birthday, the infant's vision approximates that of an adult

• By 8 weeks, possibly even by 4 weeks, infants can discriminate among some colors

Perception of Pattern and Depth

• Infants prefer to look at a normal human face rather than one with scrambled features

• Depth perception -- visual cliff

• Infants develop the ability to use binocular (two-eyed) cues to depth by about 3 to 4 months of age

Hearing, Touch, and Pain

• Prenatally at 7 months, infants can hear sounds such as mother's voice and music

• Immediately after birth, infants cannot hear soft sounds or pitch as well as adults do

• Newborns respond to touch and feel pain

Smell and Taste

• Newborns can differentiate among odors

• Sensitivity to taste might be present even before birth

• At only 2 hours of age, babies made different facial expressions when they tasted sweet, sour, and bitter solutions

Language Development

• Language a form of communication-whether spoken, written, or signed- that is based on a system of symbols

• All human languages have some common characteristics 

• Rules describe the way the language works

• Infinite generativity- the ability to produce an endless number of meaningful sentences using a finite set of words and rules

Key Milestones in Language Development

• Babies' sounds and gestures go through this sequence during the first year

• Crying: can signal distress, but there are different types of cries that signal different things

• Cooing: about 1 to 2 months, gurgling sounds that are made in the back of the throat and usually express pleasure during interaction with the caregive

•  Babbling: In the middle of the first year, babies babble -- strings of  consonant-vowel combinations, such as "ba, ba, ba, ba"

• Gestures: Infants start using gestures, such as showing and pointing, at about 8 to 12 months of age

Recognizing Language Sounds

• Phonemes the basic sound units of a language

•  First words occur between 10 to 15 months (average is 13 months)

Two-Word Utterances

• Occurs by the time children are 18 to 24 months of age

• Telegraphic speech is the use of short, precise words without grammatical markers such as articles, auxiliary verbs, and other connectives

Biological Influences

• The ability to use language requires vocal apparatus as well as nervous system capabilities

• Brain regions predisposed for language

•  Broca's area an area in the left frontal lobe of the brain involved in producing words

• Wernicke's area- a region of the brain's left hemisphere involved in language comprehension

• Aphasia a loss or impairment of language processing as a result of damage to brain

• Language Acquisition Device (LAD) -- Humans are biologically prewired to learn language at a certain time and in a certain way and to detect the various features and rules of language

Environmental Influences

• Behaviorists opposed Chomsky's LAD hypothesis

• Stated that language was nothing more than chains of responses acquired through reinforcement

• The behavioral view is no longer considered a viable explanation of how children acquire language

• Language is not learned in a social vacuum

• Most children learn at a very early age

• Vocabulary development is linked to the family's socioeconomic status and the type of talk that parents direct to the child

• Child-directed speech is language spoken in a higher pitch than normal, using simple words and sentences

• Other strategies include recasting, expanding, labeling 

Piaget's Theory of Cognitive Development

• Piaget thought we build mental structures that help us to adapt to the world

• Adaptation involves adjusting to new environmental demands

Processes of Development

• Developing brain creates schemes, which are actions or mental representations that organize knowledge

• Assimilation children use their existing schemes to deal with new information or experiences

• Accommodation -- children adjust their schemes to take new information and experiences into account

• • Equilibrium and Disequilibrium

• • Cognitive conflict -- disequilibrium

• the child is constantly faced with inconsistencies and counterexamples to existing schemes

• An internal search for equilibrium creates motivation for change

• the child assimilates and accommodates, develops new schemes, and organizes and reorganizes old and new schemes

• Cognition is qualitatively different in one stage compared with another

Sensorimotor Stage

• Infants construct an understanding of the world by coordinating sensory experiences (such as seeing and hearing) with physical actions

• Lasts from birth to 2 years

• At the end of this stage, 2-year-olds can produce complex sensorimotor patterns and use primitive symbols

• Object Permanence

• Object permanence understanding that objects continue to exist even when they cannot be seen, heard, or touched

• One of the infant's most important accomplishments

• Watch an infant's reaction when an interesting object disappears. If the infant searches for the object, it is inferred that the baby knows it continues to exist

Evaluating and Modifying Piaget's Sensorimotor Stage

• The infant's cognitive world is not as neatly packaged as Piaget portrayed it

• Some of Piaget's explanations for the cause of change are debated

Piaget's view of sensorimotor development needs to be modified

• Some researchers conclude that infants' perceptual abilities are highly developed very early in development

Learning, Remembering, and Conceptualizing

• Infants can learn through operant conditioning

• Attention is the focusing of mental resources on select information and improves cognitive processing on many tasks

•  Joint attention involves individuals focusing on the same object or event and involves:

• The ability to track another's behavior

• One person directing another's attention

• Reciprocal interaction