Psychology 2021 - Chapter 5

Physical development in finance and toddlerhood

General growth

• first 2 years have faster growth period after birth

• happens in spurts not steadily

• baby fat peaks at 9 months to help regulate temperature

• muscle develops slowly

Growth patterns

parts of the body grow at different rates

• cephalocaudal trend

• proximodistal trend

Cephalocaudal trend

head develops faster than the body

• by age 2, lower body has caught up

Proximodistal trend

grows from the center outwards

• core first then limbs

Growth norms

average height and weight for kids of the same age

Skeletal age

measure of bone development

• best indicator of physical maturity

Neural development

• neurons

• synapses

• neurotransmitters

• glial cells

• myelination

Neurons

nerve cells that store and transmit information

• communicate via synapses using neurotransmitters

Synapses

tiny gaps between neurons

Neurotransmitters

chemicals released by neurons that send messages across synapses

Process of brain growth

• programmed cell death

• stimulation keeps neurons alive

• synaptic pruning

Programmed cell death

orderly process where old, damage, and not needed cells are deleted

• makes space for new cells to grow

Synaptic pruning

removes weak or not needed connections between neurons

• makes things more efficient, faster, and more organized

Glial cells

• provides care and maintenance to neurons

• makes up around half of the brain’s volume

• multiply rapidly from 4th month of pregnancy to second year of life

Myelination

• coating of neutral fibers with myelin, as insulating fatty sheath, around the nerves in your brain

• speeds up transmission of signals

Brain growth

• brain goes from 30% →70% of adult weight by age 2

• influenced by genes and experiences

Types of brain measurement

• electrical activity measures

• neuroimaging techniques

Electrical activity measures

• electroencephalogram - EEG

• event-related potentials - ERPs

Electroencephalogram - EEG

• measures brain-wave patterns for stability and organization of brain activity

• good for tracking general brain development

Event-related potentials - ERPs

• helps identify general locations of activity

• measures brain’s response to specific stimuli

• useful for studying perception, attention, etc

Neuroimaging techniques

• positron emission tomography (PET)

• functional magnetic resonance imaging (fMRI)

• near-infrared spectroscopy (NIRS)

Positron emission tomography (PET)

• imaging test that shows how your brain is working, not just what it looks like

• shows metabolic activity in the brain

• tracks which areas are active

Functional magnetic resonance imaging (fMRI)

• maps brain activity by tracking blood flow changes

• indicates which areas of the brain are being used during certain tasks

Near-infrared spectroscopy (NIRS)

• measures oxygen levels of the blood in brain

• most suitable for infants

Limitations of PET scans

• requires injection of radioactive substance

  • not ideal for infants

• requires child to stay completely still

Limitations of fMRI

• requires child to stay completely still

Limitations of NIRS

• only measures out brain

• cannot assess deeper brain structures

Key structures of the brain

• cerebral cortex

• prefrontal cortex

Cerebral cortex

• largest brain structure

• contains 20 billion neurons

• located in the frontal lobes

• allows you to think, feel, and interact with the world

• has the longest period of development

  • sensitive to environmental influences for a longer period than any other part of the brain

Prefrontal cortex

• located in the frontal areas

• responsible for complex thinking and skills for planning and making decisions rather than just following impulses

• grows rapidly in preschool and school years, and again in adolescences

Lateralization

the two halves of the brain are specialized to do certain tasks

• left hemisphere

  • controls right side of body

  • verbal activities, language, positive emotion

• right hemisphere

  • controls left side of body

  • spatial skills, negative emotion

Brain plasticity

the brain’s ability to change, grow, and reorganize itself throughout our entire life

• early brain is highly adaptable

• early injury can lead to lots of different developmental delays

• effects may not appear until later when higher-order skills should develop

• age and many other factors affect the extent of the brain’s ability to recover

Sleep development

• sleep patterns change quickly between birth and 2 years

  • affected by cultural beliefs and practices and parents’ needs

  • around 1 year infants have a more adult like sleep/wake scheduled

  • disturbed sleep and clinginess in toddlerhood come about as infants become aware of themselves

• sleep supports learning and memory

• consistent routines help

Cultural differences and influences in infants sleep

cultural values influence infant sleeping arrangements

• 90% of world practices cosleeping

• western cultural practice separate sleeping

Cosleeping

parent and baby sleeping together

• highlights an interdependent self

Separate sleeping

parent and baby sleep apart

• highlights an independent self

Influence on physical growth in infancy and

toddlerhood

• heredity

• nutrition

• obesity

• malnutrition

• emotional well-being

Heredity and its influence on physical growth in infancy and

toddlerhood

• contributes considerably to height and weight

• genes affect body weight

• if environment changes from a negative one to a positive, catch up growth occurs

Nutrition and its influence on physical growth in infancy and

toddlerhood

• critical for development in the first 2 years

• breastfeeding

  • ideally suited for infants’ needs

  • protects against illness like respiratory and intestinal infections

  • most common in industrialized nations

Obesity and its influence on physical growth in infancy and

toddlerhood

• rapid infant weight gain leads to a higher risk for obesity later in life

Ways to prevent obesity in infant and toddlerhood

• breastfeeding for the first 6 months

• healthy diet

• active play

Malnutrition and its influence on physical growth in infancy and toddlerhood

• happens a lot in developing countries where there is limited food resources

• contributes to nearly half of the worldwide infant and early childhood deaths and growth stunting of kids under 5

• 16% of US kids suffer from food insecurity

Types of malnutrition

• marasmus

• kwashiorkor

• iron-deficiency anemia

Marasmus

• lack of all essential nutrients

Kwashiorkor

• unbalanced diet that is very low in protein

Iron-deficiency anemia

• blood disorder where the body lacks sufficient iron to produce enough hemoglobin

• affects up to half of children younger than 5

Emotional well-being and its impact on physical growth in infancy and toddlerhood

• weight faltering

  • very low weight that is below growth norms

  • kid is withdrawn and apathetic

  • linked to not enough caloric intake and bad parent-child relationship

  • can cause many long-term cognitive and emotional difficulties

Classical conditioning

• based on infant reflexes

• learning through association

  • if learning happens, the unconditioned stimulus turns into a conditioned stimulus and will produce a conditioned response

Operant conditioning

• behavior shaped by consequence

• reinforcer

  • give something to increase the occurrence of a behavior

• punishment

  • take something away to decrease the occurrence of a behavior

Habituation

• decreased response to repeated stimulus

• used to measure kids memory

  • novelty preference (recent)

  • familiarity preference (long-term)

Recovery in habituation

the return of a response that had previously diminished due to repeated exposure to a stimulus

Statistical learning

• detects fundamental structures of complex flow of information by extracting frequently occurring patterns automatically

• built in at birth so starts working right away

• is constrained at the start so young learners dont get overwhelmed

Imitation

• learned by copying behavior of others

  • seen in newborn primates (chimpanzees)

• may involve mirror neurons

Motor development in infancy and toddlerhood

• gross motor

• fine motor

Gross motor

movements that help infants get around in the environment

• walking

Fine motor

smaller movements such as reaching

• grasping

Dynamic systems theory

• mastery of motor skills depends on getting increasingly complex system of action

• each new skill is a joint product of

  • central nervous system

  • body movement abilities

  • goals the child has in mind

  • child’s thinking/cognitive capacities

  • environmental support for the skill

• develop through interaction and multiple components

Cultural influence on motor skills

motor milestones vary by child-rearing practices

• delayed sitting and walking in sandbag-reared infants in Chine

• earlier walking among Kipsigis and West Indians

• delayed gross-motor milestones in Western cultures

Reaching and grasping in infancy and toddlerhood

• newborns - prereaching

• 3-4 months - Ulnar grasp

• 4-5 months - transferring objects from hand to hand

• 5-6 months - reach for objects in a dark room

• 9 months - pincer graps

Prereaching

poorly coordinated swipes towards an object

Ulnar grasp

• all fingers closed against palm

• clumsy

Pincer grasp

• thumb + finger to grab something

Perception

• kids use their senses to take in, organize, and interpret information about the world around them

Speech perception

• activates auditory and motor areas in the cerebral cortex

• 5 months - sensitive to syllable stress patterns in native language

• 7-9 months - recognize word-like units and detect syllable-stress patterns

Perceptual narrowing effect

• infants’ brains become specialized to frequently experienced stimuli

• loss the ability to distinguish unfamiliar stimuli

• happens within the first year of life

Vision in infancy and toddlerhood

• improves rapidly

  • 2 months can focus better on objects and adults

  • 4 months have full color vision

  • steady increase in visual acuity until age 4

• depth perception develops gradually

Visual acuity

the clarity or sharpness of vision

• measures how well you can distinguish fine details at a specific distance

Depth perception developing

• 3-4 weeks → motion

• 8 weeks → binocular depth cues

• 3-4 months → pictorial depth cues

Pattern perception

• newborns perfect patterns over plain stimuli

• with age, kids prefer more complex patterns

Face perception

• newborns have a preference for faces early on

• 3 months - make distinctions among features of different faces

• experience shapes face recognition

• early experience prompts perceptual narrowing with respect to gender and racial information in faces

• face identification improves throughout childhood

Perceptual narrowing

process where infants transition from the ability to discriminate between all types of faces to an ability that is limited primarily to the faces they see most often

Object perception

• size constancy

• shape constancy

• 5 months - infants can track objects travelling on a curvilinear course at varying speeds

• develops gradually over the first year

Size constancy

seeing an object as the same size despite changes in the size of its retinal image

Shape constancy

seeing an object as the same shape despite changes in shape projected on retina

Intermodal stimulation

stimulation input from more than one modality or sensory system

Intermodal perception

• ability to integrate and coordinate information from multiple senses as an integrated whole

• combining senses

Amodal sensory properties

• the aspects of an object or event that our brain perceives even when our senses are not directly receiving that information

  • cat walks behind a picket fence, you only see pieces of it between the fence but your brain knows it is one single, continuous cat, not five separate cat parts.

Different theories and their influence on physical development in infancy and toddlerhood

• differentiation theory

• affordances

• cognitive point of view

Differentiation theory

• infants actively search for stable features in the environment in a constantly changing perceptual environment

  • viewing angles, lighting, distance can change

Affordances

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

Cognitive point of view

• the belief that babies impose meaning on what they perceive