Psych 2021 ch 5-13

Changes in Body Size and Muscle-Fat Makeup

During the first two years of life: children's bodies change enormously

Infants and toddlers: grow in spurts, not in steady gains

• "Baby fat" peaks at about 9 months

• Muscle tissue increases very slowly during infancy and will not peak until adolescence Intro to Child Development

Two Growth Patterns

cephalocaudal and proximodistal

Cephalocaudal trend

The head develops more rapidly than the lower part of the body; by age 2, the lower portion of the body catches up.

Proximodistal trend

growth proceeds from the center of the body outward

Growth Norms

height and weight averages for children of the same age

Skeletal Age

measure of bone development, best estimate of Childs physical maturity

Neurons

nerve cells that store and transmit information

Synapses

tiny gaps between neurons

Neurotransmitters

chemicals released by neurons that send messages across synapses

Programmed Cell Death

makes space for neurons and synapses

Vital to Survival of Neurons

stimulation

Synaptic Pruning

returns neurons to an uncommitted state to support future development

Gilal Cells

- makeup about half brains volume

- multiply rapidly from fourth month of pregnancy through second year of life

Myelination

coating of neural fibres with myelin

Myelin

insulating fatty sheath

Brain development birth - age 2

increases from 30% of adult weight to 70%

Brain Development Influence

genetically programmed events and child experiences

Measures of Changes in Electrical Activity in Cerebral Cortex

- EEG

- ERPS

- Neuroimaging

- PET

- fMRI

- NIRS

Electroencephalogram (EEG)

used to examine brain-wave patterns for stability and organisation

Event-Related Potentials (ERPs)

used to detect general location of brain-wave activity

Limitations of measures of brain functioning

- PET: required injection of radioactive substance

- PET and fMRI: require subject to remain motionless

- NIRS: only examines functioning of cerebral cortex

Cerebral Cortex

- largest brain structure (20 billion neurons)

- sensitive to environmental influences

- frontal lobes; cortical regions with most extended period of development

Prefrontal Cortex:

- lies in front of areas controlling body movement

- responsible for complex thought

- undergoes rapid growth during preschool and school years, and again in adolescence

Lateralization

Specialisation of the hemispheres

Left Hemisphere

responsible for verbal activities and positive emotion in most ppl

Right Hemisphere

handles spatial abilities and negative emotion

Handedness

most obvious reflection of cerebral lateralisation in humans

Brain Plasticity

depends on the timing of lateralization

Breastfeeding

- ideally suited to infants needs

- provides some protection against respiratory and intestinal infections

- helps increase spacing among siblings

- has become more common in industrialised nations

- no difference in psychological development between breastfed and bottle-fed infants

Reduce Risk of Obesity

- breastfeed for first 6 months

- avoid giving babies unhealthy food

- provide toddlers with opportunities for energetic play

Malnutrition

lack of proper nutrition

Malnutrition Contribution

nearly half of worldwide infant and early childhood deaths and to growth stunting kids under age 5

Marasmus

diet low in all essential nutrients

Kwashiorkor

unbalanced diet very low in protein

Iron-Deficiency Anemia

affects up to half of children younger than age 5 worldwide

Weight Faltering in Infants and Young Children

-weight is substantially below growth norms, and the child is withdrawn and apathetic

-caused by inadequate caloric intake and contributing factors such as disturbed parent- child relationship

-affects nearly 10% of US infants and young children

-can lead to lasting cognitive and emotional difficulties

Classical Conditioning

- made possible by infant reflexes

- requires and unconditioned stimulus (UCS) to consistently produce and unconditioned response (UCR)

Note on Classical Conditioning

- neutral stimulus is presented just before presented just before or at the same time as the UCS

- if learning occurs, neutral stimulus alone, now a conditioned stimulus (CS) will produce a response similar to the reflexive response now a conditioned response (CR)

Operant Conditioning; infants operate on the environment

- stimuli that follow their behaviour change the probability that the behaviour will occur again

- plays a vital role in the formation of social relationships

Reinforcer

stimulus that increases the occurrence of a response

Punishment

removing a desirable stimulus or presenting an unpleasant one to decrease the occurrence of a response

Habituation

gradual reduction in the strength of a response due to repetitive stimulation

Recovery

return to a high level of responsiveness when a new stimulus is introduced

Novelty Preference

- recovery to a new stimulus

- assesses recent memory

Familiarity Preference

- recovery to the familiar stimulus

- assesses remote memory

Statistical Learning

ability to detect fundamental structure of complex flow of information by extracting frequently occurring patterns fairly automatically

Imitation

learning by copying the behaviours of others

- seen even in newborn primates, including chimpanzees

- some investigators believe that newborns imitate much as older children and adults do

Mirror Neurons

specialised cells in motor areas of the cerebral cortex in primates that may underlie in early limitation

The Sequence of Motor Development

- gross-motor development: control over actions that help infants get around in the environment

- fine-motor development: control over smaller movements (grasping)

- babies show large individual differences in rate of motor progress

- motor skills are interrelated

Motor Skills as Dynamic Systems

according to dynamic systems theory of motor development, mastery of motor skills involves acquiring increasingly complex systems of action

Each New Skill is a Joint Product of:

- CNS development

- body's movement capacities

- goals the child has in mind

- child's perceptual and cognitive capacities

- environment supports for the skill

Micro-genetic Studies Follow Development of Babies Skills

- infants reaching "feet first"

- new walkers carrying objects

Cultural Variations in Infant Rearing Affect Motor Development

- delayed sitting and walking in sandbar-reared infants in China

- earlier walking among Kipsigis and West Indians

- delayed gross-motor milestones in Western cultures

Prereaching

newborns poorly coordinate swipes toward objects

Fine-Motor Development 3-4 Months

purposeful, forward arm movements

Fine-Motor Development 5-6 Months

reaching for objects in darkened room

Ulnar Grasp

clumsy motion in which fingers close against the palm

Pincer Grasp

well-coordinated grasp using thumb and index finger

Hearing Perception

active process in which we organise and interpret what we sense

Speech Perception

- infants discrimination of speech sounds activates both auditory and motor areas in the cerebral cortex

- around 5 months infants become sensitive to syllable stress patterns in native language

- at 7-9 months infants divide speech stream into world-like units and detect syllable-stress patterns \

- adults' style of communicating with infants facilities analysis of speech structure

Perceptual Narrowing Effect

perceptual sensitivity that becomes increasingly attuned with age to information most often encountered

Vision

visual development is supported by rapid maturation of the eye and visual centres in the cerebral cortex

At 2 Months (vision)

focusing on objects as well as adults

Around 4 Months (vision)

adultlike colour vision

Emergence of Sensitivity to Depth Cues

- motion at 3-4 weeks

- binocular depth

Vision: Pattern Perception

- newborns prefer patterned over plain stimuli

- with age, infants prefer increasingly complex patterns

- increasing knowledge of objects and actions supports pattern perception

Vision: Around 3 Months

make fine distinctions among features of different faces

Vision: Newborns

- show a preference for face like patterns

- experience with particular faces influences face processing leading to information of group biases

Vision: Developing Children

- early experience promotes perceptual narrowing with respect to gender and racial info in faces

- face identification continues to improve throughout childhood

Object Perception

- size constancy

- shape constancy

- at 5m can track object travelling on a curve and linear speed

- experience boosts older infants attention to objects surface features

- perception of object identity is mastered gradually over the first year

Size Constancy

perception of an objects size as the same, despite changes in the size of its retinal image

Shape Constancy

perception of an objects shape as stable, despite changes in shape projected on retina

Intermodal Perception

perception of intermodal input as an integrated whole

Intermodal Stimulation

simultaneous input from more than one modality or sensory system

Amodal Sensory Properties

information that overlaps two or more sensory systems

Intermodal Perception Information

- light, sound, tactile, odor, and taste info

- develops rapidly in first year

- facilitates both perception of the physical world and social and language processing

Differentiation Theory

- infants actively search for invariant features of the environment in a constantly changing perceptual world

- later, infants notice stable relationships among features of a stimulus

Affordances

action possibilities that a situation offers an organism with certain motor capabilities

Cognitive POV:

the belief that babies impose meaning on what they perceive

Piagets Ideas About Cognitive Change

- schemes

- adaption

- assimilation

- accommodation

- organization

Schemes

organized ways of making sense of experience

Adaptation

building schemes through direct interaction with the environment

Assimilation

using current schemes to interpret external world

Accommodation

creating new schemes and adjusting old ones to better fit the environment

Organization

linking schemes with others to create a strongly interconnected cognitive system

Sensorimotor Stage Info

- Piagets first stage (first 2 years)

- infants and toddlers "think" with their sensorimotor equipment

Piaget's Cognitive Developmental Theory; sensorimotor

1. reflexive schemes (birth-1month)

2. primary circular reactions (1-4months)

3. secondary circular reactions (4-8months)

4. coordination of secondary circular reactions (8-12months)

5. tertiary circular relations (12-18months)

6. mental representation (18months-2 years)

Circular Reactions

Piaget's term for processes by which an infant learns to reproduce desired occurrences originally discovered by chance

Intentional or Goal-Directed Behaviour

coordinating schemes deliberately to solve simple problems

Mental Representations

internal depictions of information that the mind can manipulate

Invisible Displacement

finding a toy moved while out of sight

Deferred Imitation

ability to remember and copy the behavior of models who are not present

Make-Believe Play

acting out everyday and imaginary activities

Violation-of-Expecation method

- asses infants knowledge of physical reality based on their attention to expected vs. unexpected events

Object Permanence

the awareness that things continue to exist even when not perceived

Deferred Imitation

- requires representation of a models past behaviour

- used by toddlers to enrich their range of schemes

Inferred Imitation

- older infants and toddlers infer others' intentions and may imitate actions they try to produce

- cornerstone of social understanding and communication

Displaced Reference

realisation that words can cue mental images of things not physically present

- emerges in first year and strengthens in second

Evaluation of the Sensorimotor Stage

- cognitive attainments do not develop in the neat, stepwise fashion that Piaget predicted

- most researchers now believe infants have some built-in cognitive equipment for making sense of experience

Core Knowledge Perspective

- babies are born with core domains of thought that permit a ready grasp of new info

- infants have inherited foundations of physical, linguistic, psychological, and numerical knowledge

- evidence for the core knowledge perspective is inconsistent