Aantekeningen online hoorcolleges
Lecture 2: prenatal and motor development
What is development?
Specific type of change
- Qualitative: it is not more of something or over time. Things qualitatively change over
time
- Sequential: some developments preceed others, need to preceed them
- Cumulative: one developmental stage can build upon other developmental changes
- Directional: it has a certain goal. This can be progressive but also regressive
- Multifactorial: there is not one factor that determines the development
- Individual: developmental pathways are unique for everyone
WEIRD science
Western, educated, industrialized, rich and democratic
These are the features of the people on which most science is based on. 95% of the
participants are characteristic of 12% of the world population. And the WEIRD population
isn’t even representative for the Western population.
The knowledge is not worthless but it is good to keep in mind that it is not characteristic for
the whole world population
Why focus on motor development?
- Behavior is movement
o Provides a window into the mind. If we wouldn’t watch motor development
we wouldn’t be able to investigate what people think etc.
o Eye movements
o Manipulation of objects
o Performance tasks
o Facial expressions
- Motor behavior/development is not isolated
o Intricately related to other domains
Motor system:
- Driving hand movement
- Movement of eyes, head and arm
- Controlling posture and balance
o So she has to control a lot of muscles in her body
Perceptual system:
- Perceiving target
- Guiding movement
, - Vision, touch, proprioception (the information you get from your own body)
Cognitive system:
- Action plan
- Anticipating affordances (the opportunities giving by the environment giving the
possibilities of your body to do certain things)
- Adjusting strategy
- Attention control
Physical state:
- Muscle strength
- Brain/CNS capabilities
- Body proportions (children grow in spurts, not evenly and that does something with
the body proportions)
Environment:
- Gravity
- Characteristics of the support surface
- Characteristics of the object
- Distractions etc.
Motor behavior is embodied, just like cognition is embodied. We are one complete
integrated system where you had the mind and body duality, but now everyone thinks it is
integrated. You can’t have one without the other.
Gibsons: first to talk about affordances; what a child learns during development is how they
can act in the environment, giving what the environment offers and what their body offers
Affordances
James: the affordances of the environment is what is offers the animal, what it provides or
furnishes, either for good or for ill. The verb to afford is found in the dictionary, but the noun
affordances is not. I have made it up
- Eleanor Gibson: during development, children learn/explore what they can do given
the opportunities and constraints imposed by the environment, and by their own
bodies, in a continuous action- perception loop.
Exploration and affordances
0-4 months (lying)
- Explore things that are within reach
- Learn relations between vision, sound and events
Around 5 months (sitting)
- Reach and manipulate objects
- Learn about physical properties of objects
Around 9 months (move by themselves)
- Locomotion
- Learn about bigger world, spatial relations
,Motor development is really dependent on what you can do with your body in the
environment
Meiosis: the most important thing is that the two cells in the telephase 2 are genetically
different and only contain half the complement of genetic material.
Mitosis: normal cell devision. Each with a full complement of genetic material.
The basis for genetic variation
- Genetic basis for individual differences
- Helps us understand the interactions between nature and nurture (monozygotic and
dyzygotic twins)
Four developmental processes
Zygote: the virtualized cell
1. Mitosis: oridinary cell division. Two identical cells after the devision
2. Cell migration: all the cells that are created need to go somewhere. Partly pushed
and some actually migrate. Braincells migrate from the point of origine through the
brain to a new location. They drag themselves their way if it is close and it is far away
the gliacells form long threads from which the cells can drag themselves to their
destination.
3. Cell differentiation: at first when the virtualized zygote, it starts to divide and you get
this little lump of cells which is called the mortula. In this lump, every cell can become
anything. Because of the cell division, the entire lump doesn’t get bigger. Pressure
builds up and that pressure is probably on of the main triggers fort he first type of
cell division. Blastocysts: become part of the fetal part of the placenta. Inner cell
, mass cells: pluripotent; they cannot become anything anymore because they can not
become blastocyst cells anymore, but they can become any tissue within the human
body. What kind of tissue they become, depends on the neurochemical signals they
receive during development. Once they are formed, they dont change anymore.
4. Apoptosis: programmed cell death.
These four developmental processes are far from the full story
If you think of a child in the womb of a mother, some people might think it is a nice, quiet,
peacefull place in the womb but it is not all that. There is a lot of stimulation from the
outside
- 10 weeks: sense of pressure (muscles, joints, skin)
- 13 weeks: detection of movements, if the mother moves around, the fetus feels this
in the womb
- 20 weeks: detection of light even before they open their eyes
- 21 weeks: detection of sound
- 26-28 weeks: detection of smell and taste
- Children start to respond on this
Fetal movement
8-9 weeks: startle like movements
10 weeks: variety of limb movements
10-11 weeks: head movements, breathing movements
11-12 weeks: yawn, sucks, swallow amnionic fluid
