Chapter 1-4 Flashcards
motor control
the study of neural, physical, and behavioral aspects of movement
motor learning
the study of acquiring skilled movement as a result of practice
motor development
the study of the neurological and musculoskeletal processes involved in skill acquisition
What do we mean by “skill”?
-an act or motor task
-i have the skill of _____
-observable characteristics of an individual’s performance
- I am a skilled____
why we study?
teaching/coaching
-there is a proper way (based on science) to structure learning
-providing skill instruction for athletes at all levels
- younger athletes need help learning fundamental skills
- experienced athletes require assistance in refining movements
why we study?
rehabilitation
-need to understand processes to help indivuduals recover normal movement control
fundamental skills from birth
-require minimal maturation and practice (chewing, balancing, crawling, etc.)
- others are achieved only through extensive practice and maturity
motor skill (motor task)
a skill can be classified according to characteristics:
-how is the movement organized?
- single discrete action
- a series of discrete movements strung together in a particular order
- a rhythmic repetition of basically the same action
- brain vs. brawn
- what is the relative importance of motor vs. cognitive elements?
- predictability of the enviroment?
-is it open or closed?
discrete skill
has a defined beginning and an end
usually starts and ends quickly
- ex. kicking a FG, hitting a baseball
serial skill
-several discrete skills
- connected in a sequence to perform movement patterns
-requires a longer time than discrete skill
-progresses from an individual focus to a combined focus
- eventually becomes one single, smooth, rapid, movement
continuous skill
unfolds w/out a recongnizable beginning and ends in an ongoing fashion
-is repetitive
- contiunes for many mintues
brain vs. brawn: motor elements
- a skill that is primarily motor emphasizes the quality of movement. that makes the skill successful
- correct movement patterns are key
- decision making is minimized and motor performance is maximized
cognitive elements
-In a skill that is primarily cognitive, the movement is less important than the actual decision guiding the movement
- Emphasis is placed on what to do (not the actual doing)
- Decision is maximized and motor control is minimized
motor and cognitive elements
- most skills are a combination motor and cognitive elements
important concept
- new skills require a great deal more cognition (thinking) than skills performed by an elite performer
- what happens when a skilled performer thinks too much? they mess
skills and enviromental and predictability (CLOSED SKILL)
performed in an environment that is stable and predictable
skills and enviromental and predictability (OPEN SKILL)
-performed in an environment that is variable and unpredictable
- performer must use perception and decision making to adjust movement
Skills and environmental predictability
Most skills are performed between low (i.e, open) and high (i.e., closed) environmental predictability
performance proficiency perspective
- as skill level progresses, a person is better able to achieve:
- maximum certainty - able to meet performance goals or results with certainity
- high degree of accuracy on demand - minimum energy expenditure
- accomplishes task while expending as little energy as possible- able to perform in the shortest amount of time possible
- maximum certainty - able to meet performance goals or results with certainity
stages of learning/performance
understanding the difference between motor learning and motor performance
motor performance
- always observable
- influenced by motivation
- influenced by attentional focus
- influenced by fatigue, physical conditions
- fluctuates
motor learning
- internal process that determines movement capability
- improves with practice
- often based on observing person’s stability of motor performance
- stable over serveral observations under varied circumstance
3 main stages of performance and learning
-cognitive
-associative
-autonomous
early learning
- cognitive
-understanding the movement pattern
- self talk
- characterized by:
-inaccuracy
- slowness
- inconsistency
- stiff movement
later stage
- associative
- good idea of the movement pattern
- practice enough
- movements can be refined and modified
-characterizied by
- greater accuracy
- greater consistency
- fluidity of movement
later stage
- autonomous
- movements become virtually automatic
- thinking can actually impair performance
processing information and making decisions
- information processing
- understanding the 3 stages of information-processing
processing information and making decisions
- reaction time
understand reaction time and the factors that affect it
processing information and making decisions
- information processing demands
- identify the primary information-processing demands of various tasks
processing information and making decisions
- arousal and attentional demands
understand how arousal/attention influence performanceme
processing information and making decisions
- memory
appreciate how three discrete componenets of human memory affect people’s motor performance
information - processing approach
- a computer anaolgy is often used to explain the concept of information processing
- input > information processing > output
sources of input
- stimulus input
- signal to which the individual responds
- stop light, starter’s gun, etc.
- environmental input
- variety of signals
- perceived through the senses; sight, audition, touch, kinesthesis
- selective choice of one over others
- as you become more advanced in a skill, you learn which signals to attend
stimuli
- skilled athelets learn to “block out” irrelevant stimuli
three stages of information processing
- stimulus identification
- response selection
- response programming
stimulus identification (stage 1)
- in this stage, we use our senses to determine what’s happening
- we direct our attention to a source of input
response selection (stage 2)
- once we’ve attended to stimulus, we have to decide what to do about it
- the response to be selected will depend on several factors: what responses are available? which one(s) is/are appropriate?
response programming (stage 3)
- organizing for movement
- selecting the appropriate “motor program”
- note : does not include the actual movement
- selecting the appropriate “motor program”
reaction time
- the amount of time that passes from the presentation of a stimulus until the beginning of a person’s response, when the movement is initiated
- reaction time encompasses the 3 stages
factors that influence reaction time
- number of possible stimuli
- number of possible choices (SR options)
- practice
- response compatibility
(1) number of possible stimuli
- simple reaction time
- shortest reaction time
- one stimulus and one response
- shortest reaction time
(2) number of possible choices
- choice reaction time
- the interval of time between the presentation of:
- one several stimuli and
- the beginning of one several responses
- the interval of time between the presentation of:
(2) number of possible choices
hick’s law
- stable relationship between number of stimulus-response (SR) options and choice reaction time
- as the number of SR options increases, choice reaction time increases in a linear fashion
(3) effect of practice on reaction time
- greater practice time results in shorter reaction times
- Practice can also keep RT from increasing, even when SR alternatives increase
- Learning what to expect reduces SR options, thereby improving RT
- Also, if the same stimulus always leads to the same response, choice RT becomes quicker
- Practice can also keep RT from increasing, even when SR alternatives increase
(4) response compatibility
- “naturalness” of response to stimulus decreases reaction time
- the stages of information processing take time
- even if it is on the order of milliseconds - how do we control with processing delays?
how do we deal with processing delays?
- anticipation
- organizing a response before actually initating it…makes it faster
- decreases choice RT
- by “loading” response selection/programming BEFORE the stimulus
- organizing a response before actually initating it…makes it faster
types of anticipation
- spatial
- temporal
spatial
- the ability to anticipate performance movement
- i.e., WHERE something/someone is going to be next
temporal
- the ability to predict the time course of an event
- i.e., WHEN something is going to happen
improving anticipation
-practice~skilled
- anticipate better
- predict more accurately
- use different cues effectively
- quicker choice reaction time
benefits of anticipation
anticipation creates obvious advantages, but requires:
- knowledge (you must understand the situation)
things affecting anticipation
- regularity
-… irregular behavior can counter anticipation
- e.g., very the snap count in FB (make sure your own teammates can anticipate temporally and spatially, but your oppnents can’t)
cost of anticipation
- delays the speed of responding
- if the events change unexpectedly
- “costs” more if incorrect movement is started
- most common error
- inhibiting an action take time ( 40 ms to stop a simple action) … then prepare again for the new action
- if the events change unexpectedly
Anticipation Recap
- Types of anticipation
○ Spatial or event anticipation
○ Temporal anticipation- Factors influencing reaction time and decision making
○ Number of stimulus-response alternatives
○ Practice
○ Stimulus-response compatibility - Advantages and disadvantages
○ If correct, response is faster
If incorrect, response is slower, in error, or both
- Factors influencing reaction time and decision making
information processing under pressure
deciscion making and performance : arousal/anxiety
arousal = general nervous system activity
- degrees of arousal
- low arousal = sleeplike state
- high arousal = high degree of alertness, agitation, etc.
anxiety = personal interpretation of a situation
- i.e., if we perceive a situation is threatening arousal levels are elevated (even if the situation isn’t actually threatening)
arousal affects performance, and anxiety affects arousal, so…
anxiety is important to study
inverted-U principle
- low levels of arousal = poor performance
- moderate levels of arousal = good performance
- high levels of arousal = poor performance
- bottom line: in general, moderate levels of arousal are optimal
- but, for every task, there is a “best” level of arousal which one should have in order to perform it well
3 factors to consider (inverted-u principle)
(1) person
- high trait anxiety = generally higher level of arousal (in most situations)
- more situations likely to be perceived as more serious/threatening
- zone of optimal functioning
- range of arousal level associated with an individual’s maximum performance
3 factors to consider (inverted-u principle)
(2) nature of the task
- the more fine muscular control in a task, the lower the level of arousal needed to perform it well
information processing under high arousal
- focus narrows ( perceptual narrowing) to most pertinent info
- aka, tunnel vision
- advantages
- avoid attending to irrelevant stimuli
- heightened focus on one or two things
- disadvantages
- less attention to other stimuli which may become important or critical during the skill
- less ability to handle unexpected stimuli
- advantages
- aka, tunnel vision
3 factors to consider (inverted-u principle)
(3) the situation
- if we perceive that there is a problem.. then there is a problem
- flight-or-flight response regardless of whether the situation is actually threatening
information processing under high arousal
- under extreme arousal
- attention shifts
- may start attending to internal processes
- ” paralysis by analysis”
- RT slows
- attention shifts
cue utilization hypothesis
- helps to explain:
- why performance could be poor in situations of low arousal and high arousal
cue utilization hypothesis
- low arousal - attentional focus is wide
- if you’re too relaxed in a situation
- no discrimination between useful and useless cues
- high arousal - attentional focus narrows
- performance improves, up to a point
- but you’re too anxious or arousal is too high in a given situation
Cue Utilization and Arousal
Main point:
An optimal level of arousal is one that produces an attentional focus narrow enough to exclude irrelevant cues and wide enough to gather the most important cues
attention: limitations in information processing
attention is a limited mental resource
- rule of thumb: it is only possible to concentrate on (attend to) one thing at a time
- e.g., our opponent, our movement strategy, how we feel right now
limited attention
where does the hang-up occur?
- at some stages of information processing, things can happen together (parallel processing)
- at other stages, they must happen sequentially
examing parallel processing
- stroop test >to stroop effect
- when names and colors are in agreement = faster time reaction time (RT)
- when names and colors are different =slower RT
- conclusion: color and name are processed together; but if the color and name are not in agreement, then a “hang up” occurs if participant is required to identify the color
-Must be that the response selection stage is affected
stimulus identification:
information processing in parallel
- sensation can be parallel
- e.g., we can see, hear several different things at the same time
- parallel processing - when two or more stimuli enter the system and are processed together without interference
parallel processing auditory example
- cherry’s (1953) dichotic
- different streams of information directed to each ear
- subject;s “heard” both stream, but could only recall information to which they attended
- “cocktail party effect” -we’re able to engage in conversation in a crowded noisy room despite background interference
- what happens when someone calls your name? what does that mean?
- different streams of information directed to each ear
information processing delays
- if we can process sensory information (stimuli) in parallel…
- then information processing delays must occur at later stages
- response selection/programming
- then information processing delays must occur at later stages
- coin lab example
- stimulus ID relatively the same
- visual > coins on paper
- auditory > “ready, set, go?”
- delay had to occur in later stage
- stimulus ID relatively the same
response selection: input filter
-in a response to a stimulus
- we typically can only do one thing effectively at a time
- only after extensive practice…
- … can we “select” multiple responses in which to engage
- actions move from controlled to automatic processing
-When tasks compete with each other: response selection
-Controlled processing- deliberate and requires consciousness; slow, serial, attention demanding, and more prominent during the early stages of learning
- It’s hard to do two things at a time
- Automatic processing- quick, parallel; not attention demanding; prominent during later stages of learning, and takes lots or practice
if we can only do one thing at a time…
-for example:
- A volleyball serve involves simultaneous motions with left and right arms and legs
- For a beginner, controlled processing leads to difficulty in executing simultaneous tasks
- With practice, a server creates production units, in which multiple tasks are combined as one
production units and output chunking
- how do we complete multi-faceted tasks even though we can only engage in one thing effectively at a time?
- production units
- parts of a response which are lumped tg and treated as if they are one unit
- these units can be seen as “chunks” of motion - output chunking
- automaticity places chunks tg as if they are continuous
- parts of a response which are lumped tg and treated as if they are one unit
- production units
bottom line
- how do we develop “automatic” processing?
- PRACTICE
- repetitiveness of practice facilitates creation of production units
- PRACTICE
- the more practiced a person becomes…
- the more automatic the response selection/programming becomes
- how do we contend with an opponent’s automaticity?
- double-stimulation paradigm (aka, the FAKE)
Response programming: serial movement organization (chunking and automaticity)
- the fake
- double-stimulation paradigm
- start one movement and change very quickly to a different one
- opponent gets caught off guard by setting up for the counter to the first movement
- start one movement and change very quickly to a different one
- double-stimulation paradigm
the fake
- what’s the point?
- to force competing sources of input at the response selection/programming level
- since only one “action” can be executed at a time…
- the original action must be executed or aborted before the second action begins
double - stimulation paradigm: psychological refractory period
- Interstimulus interval (ISI):
- Time period between two closely paired stimuli
- E.g., time between fake punch and the real job - Psychological refractory period (PRP)
- Processing delay that occurs in response to a fake
- Result: second response 2x longer to make than the first response
- NOTE:
- If ISI is too short-
- Two stimuli probably are perceived to be the same event
- Fake is unsuccessful
- Two stimuli probably are perceived to be the same event
- If ISI is too long-
- Opponent has too much time to reset
-Fake is unsuccessful
- If ISI is too short-
the fake in sports: capitalizing on PRP
- fake uses the PRP to lure a player into responding to a false first movement instead of the “real” second one
- how to fake well: first (fake) movement must look realistic: second (real) movement must follow in 60-100 ms
why does the fake work?
- once a response is selected
- we execute it in form of chunking
- the fake works…
- because a selected response initiates the output automatically
- the action (output) either cannot be stopped once started, or requires effortful processing (and time) to stop
recap
- Our movement control system can only produce “bursts” (or “chunks”) of activity
- We do this because of information processing limitations
- We can only do one thing at a time
- Because of this, the brain takes the carious components of a task and created production units
- …which can be executed as the “one thing”
- With lots of practice…
- Production units can be executed as a string of chunks which leads to fluidity of motion
- We do this because of information processing limitations
further understanding output chunking
- evidence for chunking is seen when trying to do multiple tasks at the same time that involve…
- different rhythms (or timing structures)
- movements that have the same fundamental timing structure can be…
- paired as one
- extremely difficult to execute simultaneous movements with different rhythms
understanding output chunking: the hands
- the “rub your stomach and pat your head” routine…
- when switching back and forth between tasks that have different rhythms, the hands eventually start doing the same thing
- why?
one interpretation : output chunking
- the body likely only outputs one motor program at a time
- each motor program (chunk) has its own timing
- therefore, only one timing system can be running at any given time (i.e., can’t do the stomach rub/head pat at the same time because they require different timing programs)
- i.e., one rhythm dominates at any one time
- therefore, only one timing system can be running at any given time (i.e., can’t do the stomach rub/head pat at the same time because they require different timing programs)
- each motor program (chunk) has its own timing
information processing and memory
three memory systems
- short-term sensory store
- short-term memory
- long-term memory
short-term sensory store (ambient vision)
- held according to sensory modality (auditory, visual, kinesthetic in the muscles and joints)
- very short duration
- very little processing
short term memory: TEMPORARY WORKSPACE
(focal vision)
- “good stuff” gets moved up to short-term memory (conscious recall: what we attend to)
- we only care about some things…the rest gets discarded
- only relevant material sticks
- therefore it changes all the time, according to what we are doing (focusing on)
- skilled athletes only let in the relevant information needed at the time (e.g., ball speed, height, location for a pass receiver)
- STM limited in capcity - rule of 7 (+- 2); lasts ~ 20 sec without effortful recall
- therefore it changes all the time, according to what we are doing (focusing on)
long - term memory
- considered the storage space for experiences over a lifetime
- characterized as having:
- unlimited capacity
- unlimited duration - information reaches LTM through effortful processing of information in STM, which transfers it to LTM
sensory input
visual
- ball tracking, defender awarness, field awareness, background crowd
sensory input
auditory
- crowd noise
sensory input
kinesthesis/propriocpetion
- awareness of body/limb postioning, grasping ball, body orientation
sources of sensory
successful performance depends on how effectively individuals detect, perceive, and use relevant sensory info
exteroceptive information
- from the environment
- outside of the body
- highly visual
- most important sensor for external events
- humans are visually dominant
- most important sensor for external events
- audition (hearing)
- secondary to vision
information from within: 6th sense
- sense of body movement
- $ proprioception
- $ provides information about the state of the body through specialized receptors (proprioceptors)
- $ kinesthesis - conscious awareness of the body
- sensory information coming from proprioceptors…- provides “sense” of joint positions and muscle movements
- $ proprioception
where does this info come from?
- specialized sensory structures : page 2, slide 7 of chapter 3
vestibular apparatus
- located in inner ear > information about balance, posture, and orientation page 2 slide 8 of chapter 3
muscle spindles : intrafusal fibers
- located in skeletal muscle > send information about muscle LENGTH to CNS
- feed info to CNS regarding muscle LENGTH and rate of stretch
- stimulates reflexive contraction
- feed info to CNS regarding muscle LENGTH and rate of stretch
golgi tendon organs
- located between muscle and tendon: provides info on muscle FORCES
- stimulates reflexive muscular relaxtion
cutaneous receptors
- located in the skin > detect pressure, temperature, etc.
closed loop control
- involves the use of feedback and error detection and correction processes to maintain the desired goal
- used to control slow and deliberate movements
not good for explaining rapid movements
- does not account for discrete tasks
- best used to describe slow/continuous activity
: components
(1) comparator - error detection
(2) executive - “brain”; determines actions to take to reach goal
(3) effector - carries out decisions
(4) feedback - provides information on current state
- best used to describe slow/continuous activity
hypothalamus: the body’s thermostat
- page 3 , slide 18
closed loop conceptual model
how does it fit within the conceptual model of motor control?
- executive
- contains stages of information processing
- stimulus identification, response selection, response programming
- remember: response selection and programming take time > relatively slow
- stimulus identification, response selection, response programming
- contains stages of information processing
- effector
- motor program + nerves/muscles
closed loop: feedforward and error detection
- comparator
- needs something to compare…
- ideal state vs. actual state
- dictates the error
- feedback - information regarding the actual state: occurs as a result of the movement
- intrinsic, movement-related feedback comes primarily from proprioceptors
- needs something to compare…
feedforward
ideal or desired state, as dictated by the executive
- comparing feedforward to the feedback allows for error direction
- this is why you can’t tickle yourself
discrete, fast actions: closed-loop?
- since closed-loop systems are relatively slow, how do we conduct quick actions effectively?
- reflexive modulations
- closed-loop proprioceptive control
- pre-packaged motor programs (ch 4)
- open-loop control
- reflexive modulations
compensations for muscle movements: reflexive modulations
- reflexes can automatically adjust muscle force in response to sudden demands
- e.g., knee-jerk reflex
M-responses - relatively low-level, fast modulations
-
m1 response
30-50 ms
m2 response
50-80 ms
triggered reactions
80-120 ms latencies
RT response
120-180 ms
reflexive modulations
- M2 response - polysynaptic
- 50 - 80 ms
- funcational stretch reflex
- “knee jerk” reflex
- higher EMG activity than M1 reflex
- connections to cerebellum and motor cortex
- characteristics
- unaffected by increasing number of S-R alternatives
- can be “tuned” beforehand - strong response or weak response
reflexive modulations
- triggered reaction
- 80 - 120 ms
- affects muscles related to, but not necessarily directly involved in, the movement
- cutaneous receptors
- wineglass effect
- series of small adjustments made in order not to spill wine on the floor
- still too fast to be voluntary
- series of coordinated movements
reflexive modulations recap
- Time dictates degree of flexibility
- The shorter the latency, the more rigid
- E.g., M1 - 30-50 ms > no flexibility; M3 - 120-180 ms > high flexibility- The more flexibility is desired, more information needs to be processed and more time is required
- Reflex responses in the conceptual model:
- Operates at the level of the effector
- Loops within loops
- Link between muscles and spinal cord is very fast, but very “dumb”
- Operates at the level of the effector
- role of movement time
- how do reflex responses affect movements?
ex.
- MT (movement time) = elapsed time from beginning of movement to end
- boxing jab - 40 ms … no time for M2 response or involvement of the comparator… therefore, can’t modify the punch once it has been started
- baseball swing - 100 ms … M1 responses is fast enough to influence the swing … M2 response doesn’t have time to get the muscles … information from the comparator cannont get the executive in time
- tennis serve - 300 ms … enough time for outer loop information to get back to the muscles, therefore the movement can be controlled by a closed-loop system
visual dominance and visual capture
- visual dominance
- attention to focal vision because it is the dominant system
- visual capture
- too much focus on focal vision because it is the dominant system
- sometimes too much attention to focal vision is a mistake
- why might visual dominance/capture be bad?
- because of time requirements to process focal information
- too much focus on focal vision because it is the dominant system
visual systems
- focal (aka, ventral stream)
- identifies objects, in center of visual field
- retina > primary visual cortex > inferotemporal cortex
- conscious
- whatever you direct your attention to, primarily in the center of the visual field
- contributes to perception of objects
- answers the question “what is it?”
- whatever you direct your attention to, primarily in the center of the visual field
- affected by light
- diminished by dim lighting
- identifies objects, in center of visual field
focal vision and movement control
- conscious vision … we see, decide what to do and then decide how to do it
- for relatively slow events, this critical
- however…
- focal vision is slow (200 ms) so it can’t be used in some movements (e.g., response to a baseball pitch)
ambient vision
- ambient vision (aka, dorsal stream)
- detects orientation of body in environment; specialized for movement control
- peripheral and central (whole visual field)
- retina > primary visual cortex > posterior parietal cortex
- non- conscious
- not affected by dim lighting
- Useful for movement since it helps us to place ourselves in the environment without thinking about how we do it…
- Works in the background, therefore its contribution is not appreciated
- detects orientation of body in environment; specialized for movement control
