Characteristics of Development

Qualitative Changes: crawling to walking

Rapid Changes: crawling to walking <90 Days

Simultaneous changes: enhanced mobility and new child-caregiver relations

behavioral and physical changes merge to form a coherent pattern: walking accompanied by pointing, ability to follow another's gaze, first words

Critical Period

objectivity: not distorted by preconceptions

reliability: test-retest and inter-rater consistency

validity: actually reflects what is being studies

replicability: similar findings by other researchers 

9th week (with first hardening of the bones) until birth

At 15 weeks, fetus is capable of all movements we see in newborns

Vision - responds to light (heart rate changes and increased movement) at 26 weeks

Sound - responds at 5-6 months, can discriminate outside sounds, but hears mother's voice best (i.e., greatest changes in heart rate)

Sensing motion - sense of balance at 5 months 

Mothers read Cat in the hat 2x a day for last 1 1/2 months of pregnancy

method: changes in rate of sucking turned on or off a tape recorder of mother reading (half read that story, the other half another story)

finding: infants modified their rates of sucking in the direction that produced the familiar story

Examine physiological responses to environmental stimuli, like changes in brain electrical activity or heart rate

capitalize on what they baby can do: looking (how long, what do they prefer), sucking (how fast)

baby talk

newborns prefer human voices and baby talk or motherese

can help infants acquire speech - repetition, slower pace, shorter syllables, exaggerated pitch, simplified sentence structure

As early as two months babies can discriminate between the smallest sound categories: Phonemes - in their native language

Infants are born able to discriminate between phonemes from every language in the world

By 10-12 months this narrows to just the phonemic categories in native language(s)

Immature cones - poor sensitivity to contrast and color until 2-

3 months, catch only 2% of light striking fovea

Babies are nearsighted

Can see objects about 1 foot away

Within 2-3 months, infants can see boundaries between objects, recognize 3D nature of things

Demonstrated that babies less than 2 days old can distinguish among visual forms

Looked longer at more complex patterned forms

Top-heavy elements - newborns prefer to look at faces as long as there are more visual elements in the top half

Motion - babies only 9 minutes old will turn their heads to look at a picture of a face if it is moving (like real faces do)

In <12 hours, infants can recognize their mother's face vs. a stranger

Using motion

- habituate babies to rod moving behind a block

- show the possibilities: one rod or two rods

- infants looked longer at two rods

- like adults they thought there was only one rod

3-12 months

- As a result of this overproduction of synapses infants are prepared to establish neural connections for virtually any kind of experience 

- brain develops regardless of experience, stimulation, or activity

New synapses are generated in response to new experiences 

- Increased rates of learning in standard laboratory tasks, such as learning a maze

- increased amounts of acetylcholineserase - a brain enzyme that enhances learning

- increased overall weight of the cerebral cortex - part of the brain that integrates sensory information

- larger neuronal cell bodies and glial cells

- more synaptic connections

Babies have specific, involuntary responses to particular types of stimulation

Some babies are born with, others they acquire, others disappear and return as part of a more complex behavior

Babinski - bottom of baby's foot is stroked, toes fan out and then curl

Crawling - when baby is place on his stomach and pressure is applied to soles of his feet, his arms and legs move rythmically

Moro - if 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

- Early smiles are probably reflexive

- Between 3-8 weeks after birth, infants smile in response to external stimuli

- around 10-12 weeks, babies begin social smiling (directed at people)

- Coordination of smiles between infants and caregivers reflects recognition and sharing of an emotional state known as primary intersubjectivity

ability to move around by self

most infants can crawl at 8-9 months 

Visual Cliff: The Fear of Heights

- Plexiglass and patterned fabric creates illusion

- Infants become afraid as they learn to locomote 

Temperament refers to individual differences in ways of responding to the environment that seem to be consistent across situations and stable over time

- includes activity level, intensity of reactions, ease of becoming distressed, response to novelty, and sociability

- believe to be present at birth

- some environmental component

- mostly genes

- in monkeys, a particular allele is associated with a reactive temperament and another allele is associated with a calmer temperament 

Three Categories of Temperament

Thomas and Chess

- Easy: playful, regular biological functions, and adapt readily to new circumstances

- Difficult: irritable, irregular biological functions, withdraw or respond intensely and negative to new circumstances

- Slow-to-warm-up: low activity, mild responses, require more time to adapt 

Reactivity: the characteristic level of arousal, or activeness

Affect: the dominant emotional tone, gloomy or cheerful

Self-regulation: control over what one attends to and reacts to 

- Temperament seems to remain stable across first 8 years of life

- Easy babies become happy, unruffled, content children

- After that, we aren't sure 

- Babies sleep about 16 hours a day during their first week

- this goes down over time...only 14 hours a day at 4 months