Theories of motor control

Question 1

What are the 3 stages in the information processing model?

Answer 1

1. perceptual stage
2. decision making stage
3. programming stage

Question 2

Explain the perceptual stage of information processing, expand on the 2 primary tasks of this stage.

Answer 2

First stage, where sensory information is detected and identified through sensation and perception. Sensation involves detecting and selecting information for further processing. Perception involves giving sensation a meaning through comparison of sensations to info stored within a memory.

Question 3

Explain the decision-making stage of information processing

Answer 3

Second stage, where decisions are made concerning an appropriate course of action. The more possible choices the more time this stage takes.

Question 4

What is Hick’s Law?

Answer 4

The time it takes for a person to make a decision is relative to the amount of choices. Increase in choices = increase in time

Question 5

Explain the programming stage of information processing

Answer 5

Third stage, where a motor program is prepared and action is initiated

Question 6

What is an open-loop system?

Answer 6

Movement commands are prestructured and executed without a corrective intervention from feedback

Question 7

What are the advantages and disadvantages of an open-loop system?

Answer 7

ADVANTAGES: quick movements (reactive skills), low attentional demand
DISADVANTAGES: not effective for unpractised skills, not effective in changing environments

Question 8

What is a closed-loop system

Answer 8

Feedback is compared to a reference of correctness during the course of action and errors are corrected as necessary

Question 9

What are the advantages and disadvantages of a closed-loop system?

Answer 9

ADVANTAGES: good for unpractised skills, allows for error correction, high precision.
DISADVANTAGES: high attentional demand, the greater time required

Question 10

Explain the Fitt’s Law; speed-accuracy trade-off. How does it relate to open and closed-loop systems?

Answer 10

As speed increases, accuracy decreases = open loop system

As speed decreases, accuracy increases = closed-loop system

Question 11

Within Fitt’s Law, What are the 3 phases of control?

Answer 11

1. movement preparation
2. initial flight phase
3. termination phase

Question 12

Explain how Adam’s closed-loop theory explains the specificity of practice hypothesis

Answer 12

Memory traces are skill-specific. Skills should be practised as they will be performed/used.

Question 13

Explain the novelty problem

Answer 13

motor programs contain specific rules for action meaning no program would exist for a new skill or a new variation of a skill

Question 14

Explain the storage problem

Answer 14

Each motor program is unique, a vast memory capacity would be needed, especially for skill performed in open environments

Question 15

How does Schema theory address the problem of novelty and storage?

Answer 15

A motor program is generalised to represent an entire class of similar actions or skill variations, this generalised motor program can be modified to produce various action outcomes.

Question 16

What are the 3 determinants (invariant features) of a generalised motor program?

Answer 16

1. relative force
2. relative timing
3. muscle sequencing

Question 17

What are the parameters of a generalised motor program?

Answer 17

1. absolute time/duration
2. absolute force
3. muscles used

Question 18

What are the 3 types of constraints?

Answer 18

organismic
environment
task

Question 19

What is an attractor?

Answer 19

A preferred pattern of stability toward which a system tends

Question 20

What is a phase shift?

Answer 20

A spontaneous transition from one phase to another as a result of self-organisation

Question 21

What is emergence?

Answer 21

a new property that transcends the parts from which it is produced

Question 22

What is self-organisation?

Answer 22

when individual components adapt in unique ways, contributing to the emergence of new patterns

Question 23

Explain how the emergence of motor skills is viewed from a dynamical system perspective

Answer 23

• CONSTRAINTS limit movement possibilities
• Diverse components of the movement system self-organise into EMERGENT PATTERNS
• SELF-ORGANISATION directs emergent patterns towards preferred attractor states

Question 24

What is Berstein’s Synergy (coordinative) structure?

Answer 24

Solution to the degrees of freedom problem and the context conditioned variability problem.
The temporary task-specific linking of degrees of freedom. Elements are constrained to act as a single unit. These synergies are able to be assembled and unassembled (soft assemblies).

Question 25

What are 3 levels of Berseints Synergy Structure? Novice, advances, expert.

Answer 25

Novice: freezing the degrees of freedom; limiting movements at limbs and joints
Advanced: Development of synergies
Expert: Attunement to affordances

Question 26

What are the stages within the Programming stage

Answer 26

1. retrieve motor program
2. prepare posture
3. prepare order and timing of contraction
4. orient sensory systems
5. initiate action

Question 27

What is an organismic constraint? Give an example

Answer 27

characteristics of an individual (structural and functional) that act as constraints on movement. e.g. poor flexibility, lack of motivation

Question 28

What is an environmental constraint? Give an example

Answer 28

features of the physical environment that act to constrain movement patterns

Question 29

What is a task constraint? Give an example

Answer 29

constraints on movement imposed by the task performed