chapter 5 Flashcards
coordination
the patterning of head, body, and/or limb motions relative to the patterning of the patterning of environmental objects and events
degrees of freedom
of independent elements or components in a control system and the # of ways each component can vary
degrees of freedom problem
a control problem that occurs in the designing of a complex system that must produce a specific result
the design problem involves determining how to constrain the system’s many degrees of freedom so that it can produce the specific result
open-loop control system
a control system in which all the information needed to initiate and carry out an action as planned is contained in the initial instructions to the effectors
closed-loop control system
a system of control in which, during the course of an action, feedback is compared against a standard or reference to enable an action to be carried out as planned
feedback
info from the sensory system that indicates the status of a movement to the CNS;
in a closed loop control system, feedback is used to make corrections to an ongoing movement
theory
accurately describes a large class of observations
makes definite predictions about results of future observations
motor learning and control theories focus on
explaining human movement behavior
providing explanations about why people perform skills as they do
motor program
a memory representation that stores info needed to perform an action
generalized motor program (GMP)
memory representation of a class of actions that share common invariant characteristics;
provides the basis for controlling a specific action w/in the class of actions
invariant features
a unique set of characteristics that defines GMP and does not vary from one performance of the action to another
-identifying signature of a GMP
parameters
features of the GMP that can be varied from 1 performance of a skill to another;
features of a skill that must be added to the invariant features of a GMP before a person can perform a skill to meet the specific movement demands of a situation
relative time
the proportion, or %, of the total amount of time required by each component of a skill during the performance of that skill
schema
a rule or set of rules that serves to provide the basis for a decision; drives the performance
in Schmidt’s schema theory, an abstract representation of rules governing movement (GMP)
dynamical systems theory
explaining the control of coordinated movement that emphasizes the role of info in the environment and the dynamic properties of the body and limbs;
it is also known as the dynamic pattern theory
non-linear behavior
a behavior that changes in abrupt, nonlinear ways in response to systematic linear increases in the value of a specific variable
(e.g., the change from smooth to turbulent water flow in a tube at a specific increase in water velocity; the change from a walking to a running gait at a specific increase in gait velocity).
stability
a behavioral steady state of a system that represents a preferred behavioral state and incorporates the notion of invariance by noting that a stable system will spontaneously return to a stable state after it is slightly perturbed
attractors
the stable behavioral steady states of systems.
In terms of human coordinated movement, attractors characterize preferred behavioral states, such as the in-phase and anti-phase states for rhythmic bimanual finger movements
order parameters
functionally specific variables that define the overall behavioral of a system;
they enable a coordinated pattern of movement to be reproduced and distinguished from other patterns;
known also as collective variables
control parameters
coordinated mvoement control variables (ex. tempo, speed, force) that freely change according to the action situation
they may change a system’s behavior from 1 coordination pattern to another.
according to the dynamical systems view of motor control when a control parameter is systematically varied, an order parameter may remain stable or change its stable state characteristic at a certain level of change of the control parameter
self-organization
emergence of a specific stable pattern of behavior due to certain conditions characterizing a situation rather than to a specific control mechanism organizing the behavior
ex. in the physical world hurricanes self-organize when certain wind and water temp conditions exist
coordinative structures
functionally specific collections of muscles and joints that are constrained by the nervous system to act cooperatively to produce an action; sometimes referred to as muscle, or motor, synergies.
perception-action coupling
he spatial and tempo- ral coordination of vision and the hands or feet that enables people to perform eye-hand and eye-foot coordination skills; that is, the coordination of the visual perception of the object and the limb move- ment required to achieve the action goal.
affordance
he reciprocal fit between the char- acteristics of a person and the characteristics of the environment that permit a specific action to occur, such as stairs having the physical characteristics to permit stair climbing.
characteristics of an attractor
- identified by order parameters (walking)
- control parameters (speed) influence order parameters
- min. trial-to-trial performance variability
- stability - retains present state despite disturbance
- energy efficient
