Theories of motor control Flashcards
What are the 3 stages in the information processing model?
- perceptual stage
- decision making stage
- programming stage
Explain the perceptual stage of information processing, expand on the 2 primary tasks of this stage.
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.
Explain the decision-making stage of information processing
Second stage, where decisions are made concerning an appropriate course of action. The more possible choices the more time this stage takes.
What is Hick’s Law?
The time it takes for a person to make a decision is relative to the amount of choices. Increase in choices = increase in time
Explain the programming stage of information processing
Third stage, where a motor program is prepared and action is initiated
What is an open-loop system?
Movement commands are prestructured and executed without a corrective intervention from feedback
What are the advantages and disadvantages of an open-loop system?
ADVANTAGES: quick movements (reactive skills), low attentional demand
DISADVANTAGES: not effective for unpractised skills, not effective in changing environments
What is a closed-loop system
Feedback is compared to a reference of correctness during the course of action and errors are corrected as necessary
What are the advantages and disadvantages of a closed-loop system?
ADVANTAGES: good for unpractised skills, allows for error correction, high precision.
DISADVANTAGES: high attentional demand, the greater time required
Explain the Fitt’s Law; speed-accuracy trade-off. How does it relate to open and closed-loop systems?
As speed increases, accuracy decreases = open loop system
As speed decreases, accuracy increases = closed-loop system
Within Fitt’s Law, What are the 3 phases of control?
- movement preparation
- initial flight phase
- termination phase
Explain how Adam’s closed-loop theory explains the specificity of practice hypothesis
Memory traces are skill-specific. Skills should be practised as they will be performed/used.
Explain the novelty problem
motor programs contain specific rules for action meaning no program would exist for a new skill or a new variation of a skill
Explain the storage problem
Each motor program is unique, a vast memory capacity would be needed, especially for skill performed in open environments
How does Schema theory address the problem of novelty and storage?
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.
What are the 3 determinants (invariant features) of a generalised motor program?
- relative force
- relative timing
- muscle sequencing
What are the parameters of a generalised motor program?
- absolute time/duration
- absolute force
- muscles used
What are the 3 types of constraints?
organismic
environment
task
What is an attractor?
A preferred pattern of stability toward which a system tends
What is a phase shift?
A spontaneous transition from one phase to another as a result of self-organisation
What is emergence?
a new property that transcends the parts from which it is produced
What is self-organisation?
when individual components adapt in unique ways, contributing to the emergence of new patterns
Explain how the emergence of motor skills is viewed from a dynamical system perspective
- CONSTRAINTS limit movement possibilities
- Diverse components of the movement system self-organise into EMERGENT PATTERNS
- SELF-ORGANISATION directs emergent patterns towards preferred attractor states
What is Berstein’s Synergy (coordinative) structure?
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).
What are 3 levels of Berseints Synergy Structure? Novice, advances, expert.
Novice: freezing the degrees of freedom; limiting movements at limbs and joints
Advanced: Development of synergies
Expert: Attunement to affordances
What are the stages within the Programming stage
- retrieve motor program
- prepare posture
- prepare order and timing of contraction
- orient sensory systems
- initiate action
What is an organismic constraint? Give an example
characteristics of an individual (structural and functional) that act as constraints on movement. e.g. poor flexibility, lack of motivation
What is an environmental constraint? Give an example
features of the physical environment that act to constrain movement patterns
What is a task constraint? Give an example
constraints on movement imposed by the task performed
