Motor development Quiz 1

Arnold Gesell

First to use cinematography/video to document babies’ behavior (recorded 12,000 children

Cultural “infant guru” for his time

Motor development as morphology approach

Defined by change in form of behavior, development of motor skills morph as these skills advance

Neural maturation is driving force that causes movements to change

Mechanisms underlying motor development are genetically driven and only receive slight assistance from the environment

Gesell Development Schedules

o   Document age-related changes in behavior (particular focus on first year)

o   Look for preformation of later behaviors

o   Battery organized according to assumption; more mature behaviors presaged in early forms

o   Concept (and test items) appear in many current assessments

Contributions of Myrtle McGraw

Interest in process of growth, not just identification and descriptions of stages, also mechanisms causing these changes.

Interest in understanding brain-behavior relationships in infancy

Reasons for dormant years of motor development

o   Extensive catalogues of motor milestones, descriptions of behavior, but had little theories

Rise of learning theorists and experimental psychology

o   Question of how people move not seen to be interesting

Direct perception

Directly perceive structured information in environment that enables us to act functionally within it (not reconstructed by brain)

Causes of rebirth of motor development

Dynamic systems theory and self organization

Advances in neuroscience - neural networks, brain plasticity, role of experience

Advances in technology to the present day

Domains of Development

Physical (body), neural (brain), perception, motor, cognition, social-cognition, language, emotion, attachment, morality, gender, social

Environmental context of a child

Good theories…..

·      Guide research

·      Explain facts: facts across the board, not just for one instance

·      Are testable: Experiments, way to measure the data

·      Predict: What will happen next? Even in a slightly different version?

·      Are useful

Good observations……

·      Inform theories

·      Lead to new facts; confirm or deny facts

·      Lead to interesting and productive tests

·      Are insightful

Reliability

measuring what you intend to measure; consistency of a phenomena

Inter-rater reliability

you and another researcher have similar results

Experimenter bias

researcher subconsciously influence the results through their actions

Subject bias

Subjects wants to present themselves in a certain way in their actions/while answering questions

Sex/Race/ethnicity bias

Oversampling or undersampling a certain population

Socioeconomic status (SES) bias

Availability of participants, certain participants might not be able to help with study based on jobs/other commitments

Cultural bias

Western cultural perspective in the US

WEIRD people

Western, Educated, Industrialized, Rich, Democratic make up most children and parents in research

No control in….

naturalistic and structured observations

Can control in…..

Experiments

Correlation can’t infer causation because…..

3rd variable problem that wasn’t considered

Higher than 0.6 correlation

good chance of relation

0\.2 to 0.6 correlation

moderate correlation

Less than 0.2 correlation

not related correlation

1

perfect correlation

Pros of naturalistic observation

Ecologically valid; can generalize

Cons of naturalistic observation

No control; no causality

Pros of Self-Report

Quick and easy

Cons of Self-Report

Full of biases

Pros of Correlational study

Can see realtions

Cons of Correlational study

No causality

Pros of Experimental study

Lots of control; causal mechanisms

Cons of experimental study

Ecologically invalid

Case study

Involves 1-3 kids

Cross sectional

1 observation made per participant

Longitudinal

2 or more observations made per participant

Pros of case study

Unique opportunities

Cons of case study

Hard to generalize

Pros of cross-sectional design

Quick and easy

Cons of cross-sectional design

Can’t see development

Pros of longitudinal design

Can see developmental changes

Cons of longitudinal design

Expensive, requires repeated testing

Cohort Effects

Generational changes in samples due to large-scale historical events (9/11, COVID, etc.)

Age Error

Cannot use age as an IV or grouping variable in experiments, can use as predictor in correlational studies

Getting older only as a passage of time

Age and getting older does not equal development, rather age-related changes

Sampling Interval Error

Concluding that development is stage-like or continuous based on too-large sampling intervals, sampling intervals that are “convenient” might not truly capture developmental trajectory

Need non-invasive techniques to fetal sensitivity and responsivity

Heart rate and movement, ultrasound and cerebral blood flow

Development of Touch

50 days

Development of sense of balance

100 days

Development of hearing

150 days

Development of seeing

180 days

Fetal olfactory learning experiment

½ mothers ate licorice, ½ did not, Infants then exposed to licorice odor vs control odor, measure head turns and facial expressions, infants whose mother ate licorice, and exposed to smell had highest reaction

Implications of Fetal olfactory learning experiment

Fetuses detect and remember odor information from pregnant mother’s diet

Maternal diet during pregnancy can influence infant behavior

Prenatal flavor preference experiment

Measure exposure to smell and taste influence preferences after weaning

Babies of pregnant who either drank carrot juice during last trimester, 1st months of breastfeeding, or not at all, measured how much carrot cereal infants ate, negative facial expressions. Infants in prenatal carrot juice and breastfed carrot juice liked carrots in solid food.

Implication of prenatal flavor preference experiment

Flavors consumed by pregnant women → fetus or newborn

Transmitted flavor influences postnatal responses to flavor in solid foods

Early flavor experiences may provide foundation for cultural and ethnic differences in cuisine

Habituation

decrease in response to repeated stimuli

Infant’s ability to learn syllables

Repeatedly “Ba-bi” and measured heart rate, tested with “Bi-ba”, infants heart rate decreased as “Ba-bi” repeated, increased at dishabituation of “bi-ba”.

Fetuses can also….

Recognize mom’s voice

Differentiate male and female voices

Can differentiate tones (by 32 weeks gestation)

Reflexes

Involuntary

Not under cortical control

Hard-wired, not learned

Steps disappearing

Skinny babies with weights don’t step, chubby babies in water step

Reasoning for steps disappearing

Upright steps never really “disappear”, matters on size of baby, muscle/fat ratio, age and exercise

Cephalocaudal

development occuring downward from head to feet

Proximodistal

outward from torso to hands and feet

Difficulty with resisting gravity

Newborns’ heads and torsos are larger than their arms and legs (head is twice the size of their body), hard to hold up with weak neck flexors

Newborn control of position

Not much control happening

2-3 weeks control of position

little control of neck, start to lift head slightly

5-10 weeks control of position

need “prop”, push arms out to lift head up

3 months control of position

neck is strong enough to lift head more easily, controlling position

Balance in infants

Weight shift at 5 months, shifting body from side to side by pushing off their arms, goal of reaching for a toy

Why do infants need to prepare to sit independently?

o   Young infants’ neck, torso, and hip muscles are weak and uncoordinated

o   Hamstrings are loose

o   If no external support, will fall over with chest flat on outstretched legs

Infant’s process of gaining control of sitting posture

Control one vertebra at a time.

o   First the head

o   Then the back

o   Finally, the hips

Sitting requires muscular control over entire trunk

Infant torso at 5 months

“tripod sitting”: can lift back but is quite arched, “self-supported sitting”, 2 hands in front to support sitting position

Infant torso at 6 months

“ring position”: hands are free, use legs as a “ring” to increase base of support

How to maintain balance?

o   Detecting perceptual information

o   Integrating that information with appropriate motor responses

Appearance of Stationary postures

Appearance of stationary but body is continually in motion to defy gravity, sways backward and forward, from side to side within permissible sway region

How is posture defined?

Size of available muscle torque (infants’ strength to resist gravity) and size of destabilizing torque (size of gravitational and inertial forces pulling body over)

To keep balance…..

sway in one direction must be followed by compensatory sway response in the other direction

Why do new sitters fall?

Body moves outside sway region without sufficient strength and coordination to pull back into position. They “freeze” in position because they can’t recalibrate sways to changing perimeter of sway region. Can’t turn head or torso or extend arm because these decrease size of sway region and require updating in size of compensatory responses

The Moving Room experiments

Forward movement = optic flow resulting from backward sway →compensatory movement forward

Backward = optic flow resulting from forward sway → compensatory movement backward

New learning opportunities with new positions

·      Different vantage point on the world

·      New body position (sitting vs supine)

o   Hands are free to move and coordinate with visual information

o   Chest and ribcage can expand

Soska and Adolph results

o   Self-sitters: (object play w/looking) > (object play w/o looking)

o   Non-sitters: (object play w/looking) = (object play w/o looking)

Process of skills

New motor skills → attention shift → new perceptual skills

Infants pairing visual and social events with object manipulation (Eppler Study)

Pairing visual to social event, all picked up, had difficulty adjusting picking up with regards to object manipulation 

What allows for production of longer utterances in a single breath?

In sitting posture, rib cage is freed, and respiration is deeper

What enhances production of consonant-vowel (CV) segments? 

Jaw is pulled down by gravity and tongue falls to a more forward position in the oral cavity

Holistic face processing

Processing a face as a whole (rather than a set of features)

What disrupts holistic processing?

Inverting the face

At 3-4 months (face processing)…..

infants process upright and inverted faces holistically

At 6 months (face processing)…..

no holistic processing in either orientation

At 7-8 months (face processing)…..

holistic processing of upright faces only (adult pattern)

Non-sitters ability

unable to sit upright even when propped on arms for more than 2 seconds

Near-sitters ability

can sit upright or in tripod position for 2-10 seconds

New sitters ability

can sit upright without hand support for more than 10 seconds and parents report they had been doing so for no more than 4 weeks

Expert sitters ability

can sit for more than 10 seconds and able to do so for more than 4 weeks

Calculated switch preference scores with face processing and sitting ability (Cashon study)

Only Non-sitters and Expert Sitters had preference scores greater than 0.50 (evidence of holistic processing)

Sitting perturbs continuing advancement in reaching because…..

o   Reaching is established, sitting is new

o   Poor sitting > falling, so arms will be used for support not reaching

o   Sitting requires planning, and planning for two skills at once is difficult

Universals in children’s development

Same basic manual, postural, and locomotor skills despite highly variable experiences

Resources affecting baths (US vs Mali)

Less water and soap in Mali, baths have to be more efficient