Motor Development Flashcards
What are the major milestones of Infant Motor Development
Birth to 5 months
- stepping reflex
- mini push-ups during tummy time
- bounce when held upright
6 to 10 months
- sit up
- crawl up
- stand with support
- cruise
9 to 15 months
- pull to a stand
- stand unsupported
- take first steps
16 to 18 months
- dance
- climb stairs with help
- walk backward
2 years
- run
- kick a ball
- jump from low step
Motor Development:
- what’s it previously believed to be an element of?
- what approach do most researchers now take?
- Previously believed to be an element of neurological maturity
- Most researchers now take a dynamic systems approach
Dynamic Systems Theory emphasises multiple causes, outline these
– increases in strength and weight
– neural mechanisms
– posture control
– balance
– perceptual skills
– motivation
Dynamic Systems Theory:
What are the meanings of dynamic and system?
Dynamic: change over time
System: many elements interacting
What does the Dynamic Systems Theory explain?
DST explains how behaviour changes over time
Milestones and Dynamic Systems Theory:
- is it when or how development occurs?
- what do most children arrive at?
- how do children arrive at milestones?
- what does this process depend on?
- Not “when” but “how” development occurs
- Most children arrive at milestones
(”attractors”) e.g.,crawling, standing, and walking, although by way of different routes. - same idea of magnets - Children may arrive at milestones via
different routes - The process depends more upon
experimentation, curiosity, and learning than
was previously thought
Motor Development is an Ongoing Process
Study looking at when they can stand alone without holding anything for 3 seconds.
- Motor skills do not suddenly “turn on”
- How often you measure also leads to different data. In both cases, if you measure every day, you will think they will stand independently at different times to one another.
Motor skills: fine vs gross
Fine (smaller muscles):
* Grasping (hand)
* Object manipulation
* Drawing
Gross (large muscles):
* Sitting
* Reaching (arm)
* Crawling
* Walking
* Running
Stepping Reflex
- Coordinated behaviour resembling walking
- Alternating leg movements
- “Disappears” around 2 months of age
Why does the stepping reflex disappear?
- Rapid weight gain causes legs to get
heavier faster than they get stronger - DST Demonstration: Make babies
behave like other babies: - Older babies in water
- Younger babies with ankle weights
Stepping reflex:
How do we know it’s not neurological maturity?
We also know it’s not neurological maturity because they can do the same behaviour when laying down (distributed gravitational pull).
Sitting independently:
- what does sitting independently aid?
- What does sitting independently have a cascading effect on?
- what does sitting independently create new opportunities for?
- new opportunities for ______ ?
- Sitting independently aids reaching
- Sitting independently has a cascading effect on infant perception
- Sitting creates new opportunities for exploring
- New opportunities for exploring shape visual
perception
Figure/Ground Assignment
- what does it allow us to identify?
- helps us to understand…
- what do adults use to determine figure/ ground
- why do infants need figure/ ground segregation?
- Figure/ground assignment allows us to identify objects (figures) from the background.
- It helps us understand depth and plan reaching.
- Adults use symmetry, convexity (curvature), lower region to determine figure/ground.
- Infants need figure/ground segregation to guide attention, eye movements and learning.
What were the two categories of the Figure/ Ground Assignment
Consistent and inconsistent
Figure/Ground Assignment: What were the two cues to figure?
Motion and symmetry
Figure/ Ground Assignment:
1. What was the same and difference in the screens?
2. Explain the consistent condition
3. Explain the inconsistent condition
- Both screens had motion (both in front
or both behind): difference is symmetry. - Consistent F/G cues: symmetrical
moves in front or asymmetrical moves
behind - Inconsistent F/G cues: asymmetrical
moves in front and symmetrical moves
behind
Figure/ Ground Assignment: results
Sitting had a higher performance in the consistent condition that non sitters. (0.58 vs 0.45)
- A significant preference indicates sitting infants perceive symmetry as a cue to figure/ground assignment.
- Sitting may be related to perceiving depth.
There was also a difference between how long they looked at the consistent and inconsistent item.
Reaching & Grasping
- Stretching out one or both hands toward
something to touch or grasp it (Rohr et al., 2021). - Initial reaches are swiping movements
- Reaching becomes stable after independent
sitting - With increased experience, more signs of
anticipation in grasping - Their approach is influenced by what they intend to do with the object and its size and material.
What is soft assembling?
Lots of components coming together in the moment
“Soft Assembly” of Reaching
- Locate the goal
- Control arm extension
- Stable base
“Soft Assembly” of Reaching:
Variable timing
Need all components to “assemble” into a successful reach.
Sticky Mittens:
Design
- “Sticky mittens” have velcro that help children who are not yet reaching make contact with objects.
- Parents were asked to give infants sticky mitten time for 10min/day for 2 weeks
Sticky Mittens:
Results
- After only one week infants’ in the training group grasps and reached significantly more often than their peers (Libertus & Needham, 2010)
- Kids with sticky mittens were grasping significantly more
- Effect persists for 12 months (Libertus, Joh and Needham, 2016)
- But see Williams, Corbetta & Guam (2015) – non sticky mittens had higher performance
A, Not B
Explain this task
- Piaget created the “A-not-B” task to test 8-10 month old infants’ representations
- “A-not-B” task
– Hide toy at A, infant finds (repeat ~6x)
– Hide toy at B, infant searches A, not B
They still reach for A due to the motor response - Piaget reasoned infants do not have object permanence until ~10 months
DST Account of A-not-B
- what is behaviour the product of?
- what is A not B error the result of?
- Behaviour is the product of past history, just previous past and present (“nested timescales”)
- A-not-B error is the result of previous attention to A and practice reaching to A
DST Account of A-not-B
Motor memory (previous reaches to A)
Draws attention (hiding, just a moment ago)
Perceptual input (see now)
Decision (where to react)
DST Account of A-not-B
- what does DST explanation include?
- errors persist if…
- what happens if you change posture between trials?
DST explanation includes attractors, motor memory, and preservation
Errors persist if:
– There is no reaching on A
– There are no objects (just wave lids)
– Unmarked locations (sandbox) in 2-4yrs
– There are long delays – even in adults
If you change posture between trials errors are reduced (less reliant on motor memory)
(Self-) Locomotion
1. When do infants become capable of self-locomotion?
2. when do toddlers begin walking independently?
- around 8 months
- around 13-14 months, using a toddling gait
Do you need to crawl to have a fear of heights?
Yes
Motor Skills are ….
Context dependent
- Adolph (1997) tracked infants in a weekly longitudinal study from early crawling to proficient walking
- Knowledge does not transfer from crawling
to walking - 67% of children plunged down ALL slopes,
but did become more cautious with
experience - Knowledge is context dependent
The Importance of Falling
- what does falling help you understand?
- study? Han & Adolph (2020, Wiley)
- Falling (errors in balance and motor
control) may help us understand the
role of errors in early development. - In one playroom there were lots of places to climb and the other had none.
- 138 toddlers (13-19mo) were
observed in a laboratory playroom - Toddlers fell 563 times
The Importance of Falling:
Results (Han & Adolph (2020, Wiley)
- Falling did not alter subsequent behaviour
- After a fall, infants returned to play in 1.84s on average
- Impact was mitigated by small body size, and infants’ quick reactive behaviours (e.g., bracing with hands)
- Infants rarely fussed (4% of falls)
- Caregivers were rarely concerned (8%)
- Walking experience did not predict
fussing, caregiver concern or recovery
Han & Adolph (2020) - Frequent, low-impact errors encourage further practice
Road Crossing
1. Which age group have higher rates of pedestrian injuries?
2. Where do most children pedestrian injuries happen?
3. Which age group are slower and enter roads with much smaller gaps in traffic?
- Children 5-14 years
- At mid-blocks- shortened path to school often requires crossing mid-block
- 6-10 year children
What did footage from a virtual reality study where kids practiced a street show?
Children cross after one car because they think the gap is big enough but a car followed closely behind.
Crossing Roads with Friends
- Pairs of friends crossed a virtual road 30 times (half on left/right)
- A stream of traffic came from the left at ~40kmh (25mph)
- Traffic included random 2s-5s gaps
O’Neal et al., (2019) - No instructions to cross together or alone
- They could wait to cross as long as they wanted to
Crossing Roads with Friends:
Results
Summary: Peers pose a risk to safety
- Adolescents took riskier gaps with a friend than alone
- To compensate for short gaps, they entered and crossed faster
- When solo, first crossers were more risky
(and 12yo first crossers riskier than adults)
Motor Experience Is Related to Language
- Emergence of sitting correlates with vocabulary at 10 months and 14 months
- Emergence of walking correlates with both receptive and productive vocabulary
- Children who walk make more bids for communication than same-age children who crawl
- 6-12-year-olds remember new vocabulary better if they exercise after learning the new words
