PAM Task 6 Grasping and reaching
Learning goals:
1. Nature and nurture in motor skills
2. Measuring differences in motor skill development
3. Adapted A-not-B task
A dynamic systems approach to development, core assumptions:
- Systems part: Developing humans are composed of multiple heterogeneous parts that
cooperate together to produce coherent and patterned behaviour. This system is self-
organizing, without a central component giving demands. The patterns produced in
such systems depend critically on the organism itself, but also on the constraints of the
environment. All components are intertwined in development and can not be seen as
separate.
- Dynamic part: The patterns that self-organize can themselves be complex, but are
always continuous in time. Processes occurring on different time scales are completely
nested within one another, as well as being coupled to one another. Therefore the
major challenge is to understand how activity on the short time scales (seconds, ms)
becomes transduced to the behavioural changes we are interested in, which happen in
days, weeks, months.
- Stability: when patterns self-organize, they may be variously stable or unstable. In
complex dynamic systems, stable patterns must lose stability in order to change. The
system may be destabilized by a variety of means. Sometimes the coherence of a
pattern is threatened by a new input and sometimes by changes in one of the organic
components as well. Instability allows the components to self-organize in new ways.
The task of learning to reach
Babies first reach and grab objects at 4m, but it is variable. What must infants do to reach and
grab:
1. Motivation, normally provided by vision.
2. Visual capacity to detect and localize the object.
3. Must learn what objects afford reaching and grasping, see what is a reachable space.
4. Must have means to transducer the coordinated of the object in the external space into
a reference suitable to moving their arms which is internally referenced
5. Ability to plan movements, requires recognition what muscle activations and forces
move the limbs into what positions in space
6. Ability to correct movements based on sensory feedback
7. Have control of their muscles to lift the arm and keep it stable while the hand grasps
the object
8. Stabilize their heads and trunks so they do not slump over: anticipatory postural
reactions
9. Ability to remember the action they just performed in relation to their success in
obtaining the goal.
Theories on how infants learn to reach
Piaget: constructionist (putting a skill together from initially independent parts), visually
elicited grasping and reaching evolve gradually from the progressive modification and
moulding of several more elementary schemata, especially the schema for visually interesting
objects, (and feel) of the hand and the reflexes of grasping and sucking. With each repetition,
Learning goals:
1. Nature and nurture in motor skills
2. Measuring differences in motor skill development
3. Adapted A-not-B task
A dynamic systems approach to development, core assumptions:
- Systems part: Developing humans are composed of multiple heterogeneous parts that
cooperate together to produce coherent and patterned behaviour. This system is self-
organizing, without a central component giving demands. The patterns produced in
such systems depend critically on the organism itself, but also on the constraints of the
environment. All components are intertwined in development and can not be seen as
separate.
- Dynamic part: The patterns that self-organize can themselves be complex, but are
always continuous in time. Processes occurring on different time scales are completely
nested within one another, as well as being coupled to one another. Therefore the
major challenge is to understand how activity on the short time scales (seconds, ms)
becomes transduced to the behavioural changes we are interested in, which happen in
days, weeks, months.
- Stability: when patterns self-organize, they may be variously stable or unstable. In
complex dynamic systems, stable patterns must lose stability in order to change. The
system may be destabilized by a variety of means. Sometimes the coherence of a
pattern is threatened by a new input and sometimes by changes in one of the organic
components as well. Instability allows the components to self-organize in new ways.
The task of learning to reach
Babies first reach and grab objects at 4m, but it is variable. What must infants do to reach and
grab:
1. Motivation, normally provided by vision.
2. Visual capacity to detect and localize the object.
3. Must learn what objects afford reaching and grasping, see what is a reachable space.
4. Must have means to transducer the coordinated of the object in the external space into
a reference suitable to moving their arms which is internally referenced
5. Ability to plan movements, requires recognition what muscle activations and forces
move the limbs into what positions in space
6. Ability to correct movements based on sensory feedback
7. Have control of their muscles to lift the arm and keep it stable while the hand grasps
the object
8. Stabilize their heads and trunks so they do not slump over: anticipatory postural
reactions
9. Ability to remember the action they just performed in relation to their success in
obtaining the goal.
Theories on how infants learn to reach
Piaget: constructionist (putting a skill together from initially independent parts), visually
elicited grasping and reaching evolve gradually from the progressive modification and
moulding of several more elementary schemata, especially the schema for visually interesting
objects, (and feel) of the hand and the reflexes of grasping and sucking. With each repetition,
