Development of Maniplulative Skills Flashcards
What is prehension?
Grasping of an object with the hands
What do maturationalist think about grasping?
We get better at grasping as the CNS matures
What did Halverson propose about development?
Ten stages of development
Transition from power grip to precision grip
At birth - no grip
2 months - limited contact, grasping with entire hand
3 months - hand adjustment (power grip)
4 months - thumb on object
5 months - change to precision
(limitations of study = only one object used)
What did Hohlstein experiment?
Similar to Halverson but used different objects Power to precision grip Object shape and size influenced grasp 9 months - hand shape matched object Constraints interact in prehension
How are grip movements body scaled?
Grip depended on the relationship between hand size and object
Object affected by size is most important than shape
What is the ratio of hand size to object size?
Consistent for transitioning from using one hand to using two hands
How does vision play a role in grasping tasks?
Children often knock over objects before lifting
Adults make one or two hand decisions before making contact
What did Thelen study about reaching?
Transition form pre-reach to reach (3-4months)
Starts with the ball park reach
Speed of movement is unique to the child
Demonstrated infants learn to reach by doing not the development of the CNS
Memory building rather than cognitive process
What are hand-mouth movements?
3-4 months infants become consistent in moving the hand to the mouth
5 months they open the mouth in anticipation of hands arrival
What happens at 2 months for bimanual reaching and manipulation?
Unilateral arm extension and reaching
What happens at 4.5 months with bimanual reaching and manipulation?
Reach for objects with both arms
When do infants alternate between predominantly unimanual and bimanual reach and what is it due to?
During the first year and it is due to changing constraints
When do they start manipulating with both hands?
8 months
By 12 months they are doing what?
Pulling apart and insertion actions (around when they start to walk)
When do we see complimentary activities?
End of the 2nd year
What are the roles of posture?
Reaching improves when infants can maintain postural control
What did Kauranen and Vanharanta do in regards to manual performance in adulthood?
Manual performance declines after age 50
Movement slowed; coordination scores declined
What did Hughes do in regards to manual performance in adulthood?
Strength declines
More individuals exceeded time threshold
When can be maintained?
Accuracy in well practiced tasks
What is rapid aiming movements? (RAM)
RAM is involved in manipulating complex displays (cockpit of a plane)
- Initiation and acceleration phase
- Deceleration and termination phase
What is the difference in young and older adults in RAM?
Young- symmetrical phases
Older - less force and travel in acceleration phase
-long deceleration
What are fundamental manipulative skills?
When the performer gains possesion or control of an object by reaching to intercept
Catching is the most common
What happens in early catching?
Difficult as developmental skill
If a child catches a ball usually reflect the thrower
Interception is the most difficult aspect
How do young catch?
Position arms and hand rigidly
little force absorbed
Trap the ball against chest
Turn away and close eyes
How do the proficient catch?
Hands give to absorb force Catchers moves (side to side or forward/backward) Fingers pointed -up for high balls -down for low balls
What are the developmental changes to a catchers arms?
1) little response
2) hugging
3) scooping
4) arms “give”
What are the developmental changes to a catchers hands?
1) palms up
2) palms in
3) palms adjust
What are the developmental changes to a catchers body?
1) no adjustment
2) awkward adjustment
3) proper adjustment
How do you assess catching?
For comparison, task and environmental constraints must be consistent
The number of catches in a set of attempts can be scored
The developmental sequence can provide information about the movement process
How is anticipation involved in catching?
Anticipation is involved in many manipulative tasks and interception skills
Studies often involve coincidence anticipation tasks
Anticipating completion of movement, to coincide with arrival of moving objects
Young children are less what are the movement required of them is more complex?
accurate
Less accurate if the interception point is farther away
When are children successful in intercepting?
When the balls are larger
The trajectory is lower and the speed is not too fast
What is the IP perspective of intercepting?
Receive all info and perform calculations of all the data
What does the perception-action perspective say about intercepting?
PAP theory states that all information needed is in the environment. No calculations necessary
Environment specifies movement possibilties
What are the 2 characteristics of person-environment system for catching?
1) Invariant: keeping patterns in the environment constant
2) Expanding optical array
a) optic array expands on the retina when movement is towards
b) optic array constricts when the movement is away
What is McLeod and Dienes theory about intercepting?
Intercept a high trajectory ball by keeping the ratio at 0
Positive ratio ball lands behind
Negative ratio ball lands infront
By staying at 0 catcher knows to move
What is Oudejans theory about intercepting?
Intercept a high trajectory ball by keeping the vertical optical acceleration at 0
Focus on acceleration of ball rather than angle of gaze
Acceleration of ball tells the catcher to move
What is Leneoir’s theory about intercepting?
Intercepting using side ways movements
Catchers are able to intercept balls by keeping the bearing angle between themselves and the ball constant
Math is not important
It is possible to arrive at the catching point without calculations
How do children learn to arrive at the right place?
Learn that the ratio is zero when they stand still and catch a ball.
Eventually they learn to move to keep the ratio at 0
Experience is important in learning
What happens to catching in older adlts?
Little research
Catching might be influenced by factors affecting movements speed or ability to reach
Less accurate and more variable on coincidence - anticipation tasks
Can improve with practice
