psych 318 exam 2 - motor development

lecture 11

motor development

motor development involves increasing

agency

prospectivity

behavioral flexibility

means-end understanding

agency

sense of control

prospectivity

looking ahead

behavioral flexibility

adapting to circumstances

means end understanding

understanding links between actions and goals

motor development is a dynamic systems theory meaning

it is dependent on interplay of many factors

it affects other aspects of development (cognitive, social, communication)

postural control

sensorimotor behavior that maintains balance by counteracting gravitational forces and anticipating postural challenges induced by external demands and perturbations

average and range age for holding head steady when upright

2.5 months

1-5 months

average and range age for turns from side to side

2.5 months

3 weeks - 5 months

average and range age for turns from back to side

2.5 mo

2 - 7 months

average and range age for sits with slight support

3.7 months

2 - 6 months

average and range age for sits alone briefly

5.2 months

4-8 months

reaching and grasping at birth

pre-reaching movement

clumsy motions in direction of target object

show same amount of reaches with or without object until 10 weeks, reaching hits a low point at 7 weeks

why does reaching hit a low point at 7 weeks

van hofsten suggests looking inhibits reaching

coordination of vision and reaching a new skill

reaching and grasping 3-4 mo

looks at and swipes at object

retains object placed in hand

reaching and grasping 4-5 mo

contacts toy placed on table

reaching and grasping 5 mo

sits with support and grasps object

contact then form hand

reaching and grasping 6-7 mo

bangs, shakes, rattles, explores, transfers object from hand to hand

preform hand in anticipation of dowel orientation

reaching and grasping 9 months

open hand while reaching begin to close in anticipation of contacting object

reaching involves increase in which motor characteristic

increasing prospectivity (anticipatory)

reaching lays a groundwork for

perceptual and cognitive advances

(inter-sensory integration, tool use, means-end understanding)

reaching and grasping 8 mo

scissors grasp with raisin

finger grasp with block

10 mo reaching and grasping

may begin using spoon

11-12 mo reaching and grasping

pincer grasp

feed self cheerios

2 years reaching and grasping

handedness fully estabilshed

Needham Barrett and Peterman artificially enhanced reaching ability

3 mo olds some enrichment with velcro mitten some no enrichment

enrichment group showed more exploration, swatting, and swatting with looking

locomotion - birth

stepping reflex

locomotion - 5 mo

crawling motions

locomotion - 8 mo

crawling

locomotion - 10 mo

cruising - while standing holds onto furniture and moves

locomotion - 12-15mo

stands alone

walks alone

locomotion - 18 mo

runs and gallops

variability in locomotion

highly variable

variability in crawling

5-11 mo

variability in pulls to stand

5-12 mo

variability in stands alone

9-16 mo

variability in walks alone

9-17 mo

variability in walks up stairs with help

12-23 mo

changes that occur with increased walking experience

increased step length

less variable step length

less lateral movement

less flat-footed

more symmetrical steps

better balance

better able to adjust to surfaces

arnold gesell thoughts on environment and develoment

environment does not generate the progression of development

effects of infant sleep position on motor development

prone (face down) sleepers more quickly develop

• pull to stand

• crawl

• creep

• tripod sit

• roll prone to supine

not affected by sleep position

• rolls back to front

• sitting

• transferring objects

• walking

crawling is considered a

developmental organizer

what changes occur around crawling (8-9 mo)

perceptual development - depth perception, fear of heights

communication - social referencing, nonverbal communication

memory - less context sensitive memory

attachment style - stranger anxiety, separation anxiety

evolutionary perspective on crawling

as baby is self mobile becomes separated from mom but still vulnerable so

• motivated to reconnect with mom

• monitoring her emotions

• communicating with her from distance

crawling depth perception experiment

infants with low crawling experience will cross visual cliff

infants with m ore crawling experience will not cross visual cliff

age independent but experience dependent

crawling experience drives fear of heights

changes of posture on depth judgments

infants accuratley judged reach in sitting but not crawling posture

• each new posture involves re-learning what is safe and possible