Motor Development Flashcards
What are the two types of movement?
- Reflexes
- Voluntary movements
Voluntary movements
Purposeful.
Initiated entirely within the central nervous system.
Performance improves with practice
Reflexes
These are fixed, automatic, triggered in response to a specific sensory.
Patellar Reflex
The sudden move of the leg when a light tap hits the knee.
Reflexes in Newborns
- Rooting reflex
- Grasp reflex
- stepping reflex
- Moro reflex
Rooting reflex
When brushed on the cheek, babies will move their mouth towards it.
Grasp reflex
Babies grab on anything on their hand
Stepping reflex
Babies make the motion of walking when they are lowered on a surface
Moro reflex
Arms move to the side when they are not supported.
Many of the reflexes that the newborns have will disappear in the first few months of life, why?
What are the two theories of Motor Development?
- Maturational Theory
- Dynamic Systems Theory
Maturational Theory
This theory says that motor development depends entirely on the development of the cortex. As the cortex develops, it begins to override these early reflexes.
What supports the maturation theory?
- Practice has little effect on the age at which children begin walking
- Experiment by Gesell and Thompson (1929)
- This experiment was made with twins in which ne of them got daily practice and the other didn’t
- No difference in skills between the practice baby and their sibling after 52 weeks.
- Dennis and Dennis (1940)
- Hopi people carry their babies swaddled (have less mobility)
- Reduced motor experience didn’t affect onset of walking.
NOTICE extreme deprivation may result in motor delays but they can be reversed
What challenges the maturity theory?
Some research suggests that experience does affect motor development:
- Restrictive parenting may delay the onset of walking
- Back to Sleep campaign
- Esther Thelan research
Motor development timeline
- 2-3 weeks can lift chin
- 5-10 weeks can lift chin and take their head off the floor
- 3 months can hold-steady, roll over
- 6-7 months sit up
- 8 months no more stepping reflex
- 8-10 months crawl
- 9 months cruising
- 12-14 months walking
What does it mean when we have a U-shaped Developmental Trajectories?
This indicated that a child is figuring out a new way of doing something.
Why does stepping stop?
Notice that when the baby is laying on their back, they still make this motion. This is because it is easier to do it! This stops when the baby becomes heavier!
NOTICE This is inconsistent with maturation theory
Stepping reflex stops with weight: Study 1
Thelen, Fisher and Ridley-Johnson (1984)
- Tested on 2, 4 and 6 weeks old!
- The babies were powered on a surfaced and the number of steps they made was counted and arousal levels
- They also got detailed measured of their bodies
Results: (slide 20, w2e2)
- number of steps decreases with age and arousal level predicted number of steps
- Infants gained weight rapidly between 2 and 4
- correlation between weight increase and stepping decrease
Stepping reflex stops with weight: Study 2
Thelen, Fisher and Johnson (1984)
- 12 4-weeks-old
- Their legs were strapped to some small weight
- They were made to step with and without weights
Results: (slide 22 w2e2)
- More steps without the weight
- No arousal difference
Stepping reflex stops with weight: Study 3
Same principle as the two others but with babies in the water.
Babies stepped more in the water (as it is lighter)
Dynamic Systems Theory
Development of complex behaviour must be understood in terms of the interactions between all of the components involved in executing that action.
Movement:
- Physical properties of the body
- Perception
- Navigating an environment
- What is the context for and the goal of the movement
Voluntary Movements
Newborns can’t move much, they can move their head if it is held properly.
Variability in Motor Milestones
- The order of motor development is not universal. Some infants skip stages and often they are engaged in multiple skills at the same time.
- Infants are continuously discovering new ways to get around but they don’t immediately stop the old ways
What babies learn at one locomotor stage may not transfer to another. Give examples that support this.
The Visual Cliff
This was made to test if the infants would see the cliff ad go over it. In this experiment, the table had a glass that made it seem like there was a cliff.
Results:
7-8 months old: 33% of new crawlers avoided the cliff where 65% of experienced crawlers avoided the cliff.
Karen Adolph
An experiment where babies were faced with a gap. If they were crawling and were experienced crawlers, they would avoid the gap when it was too big but if they were walking (not experienced walkers) they would attempt to continue. This also happened when sitting and crawling situations.
(w2e3 slide 14 to 24)
What does it mean to have successful locomotion?
This means that they can adapt to novel situations.
- Need to be able to develop adaptive solutions
- Even when babies are walking comfortably there will be circumstances in which they can’t do it
- Need experience in a posture to be able to do this.
Learning to Walk
On a study by Adolph et al. 2012, they measured the distance, the number of steps and the number of falls for babies that were learning to walk.
They noticed that as the walking ages increased, the distance and number of steps increased and the number of falls dicreased.
How do caregivers help children with motor action?
- Caregivers give motivation and security.
- calling the baby to you while the other parent helps them
- They also give motor experience
- They provide information such as warnings
Social Reference in Motor Development
- Infants often look at adults to guide their behaviour.
- Social referencing: Look at the emotions of adults to determine their own actions.
- Based on the caregiver’s expression babies would avoid or approach novel tasks, objects and people.
- In a study by Tamis-Lemonda et al. (2008)
- babies were put in different situations with different slopes.
- Most often, if the slope was feasible, the babies would not consider the caregiver’s emotions
- If the slope was clearly difficult they would avoid it
- If it was not clear, babies would tend to listen more to the caregiver.
True or False
Locomotion affects other domains
Yes, this is due to the fact that the baby’s perception changes. They are also able to interact more with their environment. For example, what they see while crawling is different than what they see when walking. They are also able to grab things when they are walking instead of crawling.
Walking allows babies to interact more with adults and to point to objects. This helps them improve their social interactions and language.
(Slides W2E4 4,5,6)
