Lecture 10: Sensory and Motor Development 2 Flashcards
Learning Objectives:
- Tactile Development
- Motor development
- Perception and cognition
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- Describe the principle methods used in infancy research
- Describe the significant changes that take place during the first year of life
- Critically discuss key studies in infancy research
1: Tactile Development
Early touch
Touch is the first sense to develop
- 8 weeks: fetuses respond to the area around the lips being touched
- 10 weeks: reflexive grasp response when palm is touched
- 12 weeks: toes curl when soles of feet touched
First 6 months, newborn infants show an automatic grasp reflex
Touch (particularly skin contact) is an essential part of attachment bonding for infants
Can children recognise objects presented in one modality…
…through using another modality?
Do they know what something looks like just by feeling it…
…and do they know what something feels like just by looking at it?
1: Tactile Development
1: Matching touch to vision
Newborn infants (mean age: 41.8 hours, Apgar score 9 or 10) were given small objects to hold, until habituation
How long do newborns look at each of these?
Infants look longer at the novel object – even though they’ve never seen either object before
1: Tactile Development
2: Matching vision to touch
Newborns were shown one of two objects, until habituation
How long do newborns hold each of these?
Infants don’t hold the novel object for longer than the familiar object
1: Tactile Development
The development of touch
At birth, cross-modal matching is not bi-directional
Infants can identify an object that they’ve previously held by visual means only
Infants cannot detect an object that they’ve previously seen by touch only
2: Motor Development
BIG FAT GRAPH OF STUFF
slide 16 xx
2: Motor Development
Motor Development and Cognition
Motor development has major consequences for cognition
This is notable with the onset of crawling
This can occur from 5 months to 11 months
Acquiring the ability to move unaided brings concurrent improvements in memory (Herbert et al., 2007)
2: Motor Development
Motor development and Memory
9-month-olds were tested on an infant memory task
Half the children were able to crawl at time of testing, and half were not
(Mean ages: 9.13 months and 9.14 months)
Crawling: “the ability to traverse at least one metre using arms and/or knees”
Infants were shown how to play with a novel toy
The toy had a specific novel action associated with it
Could the 9-month-olds remember the action 24 hours later?
Could they remember the action in a novel context, and therefore produce the action with a different toy?
This would be evidence of flexible memory
Findings:
- Both crawling and non-crawling infants could remember the target action
- Only crawling infants were able to retrieve that memory in a new context
This difference between crawlers and non-crawlers can’t be due to age, since the two groups were the same age
The onset of crawling brings with it greater memory flexibility
Crawling likely brings with it new experiences of being in different and changing contexts
These **new experiences, rather than just moving, are likely to affect cognition
2: Motor Development
From crawling to walking
Going from crawling to walking means infants give up being expert crawlers…
…in favour of being poor walkers
The change requires muscle development, different patterns of limb coordination, and balance control
Skilled crawling is a better means of getting about than novice walking
- Crawlers are better able to judge the steepness of slopes, or the depth of a drop
- Walking leads to an increase in falls
So why do novice walkers persist with such an initially unpromising strategy?
Compared to crawling, walking:
- Covers space more quickly
- Gives access to more distant objects
- Allows different interactions with others
- Affords better visual input
However, skilled walking takes months to develop (Hallemans et al., 2006)
3: Perception and Cognition
Definitions
Perception: refers to how we see, or hear, or directly experience the world
Cognition: refers to how we form, use and act upon internal thoughts, states or pictures
- known as “mental representations”
3: Perception and Cognition
Perception vs Cognition
Studying cognition in infants involves understanding the content of their mental representations of the world
Not just what they can see, but what they think about what they can see
Much of what we know has been learned using the “Violation of Expectation” task
3: Perception and Cognition
Violation of Expectation
Children are shown an event repeatedly until they habituate
They are then shown one of two variations of the same event
If they look at one event for longer, it suggests they’re surprised by it
i.e. it has violated their expectation
3: Perception and Cognition
Counting in infants
A classic use of the VoE task was to test what infants understand about number
4- and 5-month-olds were shown an event where objects were moved behind a screen, and the screen was then removed
The event was either possible or impossible
Findings:
- 4- and 5-month-olds looked longer at the impossible event
- They looked longer at events with the structure 1 + 1 = 1, and 2 – 1 = 2…
…than at events with the structure 1 + 1 = 2. and 2 – 1 = 1
- Infants’ expectations seem to be specific to precise numerosity
- They also looked longer at a “1 + 1 = 3” impossible event than at a “1 + 1 = 2” event
This suggests they have a more precise sense of number than just “there should be more than one”
3: Perception and Cognition
Object perception
A fundamental question of early cognition is “When do infants move beyond being limited by what they can currently see?”
When do they begin to mentally represent objects that are not visible or absent?
This ability is known as object permanence: the ability to understand that even if an object can no longer be seen, it still continues to exist (Piaget)
Piaget’s view of development was founded on the idea that children aren’t born with knowledge of the world. Instead, they gradually construct knowledge, and the ability to internally represent the world around them (constructivism)
Piaget observed that prior 9 months, infants made no response to an object after it was hidden - true even for desirable objects that children were motivated to find
By around 9 months, infants are able to search for objects that are out of view - suggests they can act on the basis of thought, rather than just perception. However, their performance is still remarkably not adult-like
3: Perception and Cognition
A-not-B Tast
Object repeatedly placed in box A, then once put in B at the end
Infants at around 9 months persist in reaching to the old location, even though they have seen where the object is
By around 12 months, infants reach correctly to the new location
They are able to flexibly update their memory of the object’s location
