midterm 2 Flashcards
speed accuracy trade off
when trying to perform a skill quickly, we end up making more mistakes
-ex: athletes performing open skills - have to make shots quickly and accurately
fitts’ law
- the second law of motor behaviour
- predicts how much time you requires to move to a target when speed and accuracy matter
- predicts MOVEMENT TIME
what is Fitts’ law’s equation
MT = a + bLog2(2A/W)
which two things do we need to know in order to predict movement time using Fitts’ law?
amplitude moved and target width
which part of Fitts’ law equation represents the index of difficulty? (ID)
Log2(2A/W)
- quantifies how difficult target width and movement amplitude are together
- when writing in the form of Log2, the exponent is the ID
Woodworth’s two component model
- reaching movements include two distinct phases:
1) gets us most of the way to our target (initial ballistic phase) - for bigger targets, can only use ballistic movement because you don’t need as much accuracy
2) last second movement corrections (homing in phase)
how does the speed accuracy trade off relate to open and closed loop control (our model)?
when we move quickly, more mistakes are made in the RESPONSE PROGRAMMING PHASE, need more corrections
-when we want to do something carefully, often take more time to complete the movement
what are 4 things that Fitts’ law tells us?
1) MT increases as the distance increases
2) MT increases as the size of the target decreases
3) MT is constant for a given ID
4) Fitts’ law only applies when we are doing things as quickly and accurately as possible
what are the 2 violations of Fitts’ law?
1) effective target width
2) dependent on the visual context being presented
- when movement amplitude doesn’t necessarily mean increased MT: MT is less when aiming at the last target in a row of targets (choice reaction time task) as opposed to the second last for example
violation of Fitts’ law: effective target width
- when we don’t use the whole target
- calculated as if you had a smaller target
- calculated using variable error
linear speed accuracy trade off describes which law?
- Schmidt’s law
- movement velocity as the independent variable
- measuring effective target width (dependent variable)
- as movement velocity increases, so does effective target width (linear relationship)
more force results in more variability in our movement
which stage of programming is affected by the sources of error in rapid movements?
- NOT response selection
- the problem is in RESPONSE PROGRAMMING (adding parameters)
- fast or forceful movement, open loop process is more variable
- closed loop process to make corrections
at what percentage of force are we most variable in our movements?
- when looking at participant standard deviation
- 70-75% of our max force is where we are most variable, and then it starts to decrease
- at 100% of our force, we are NOT LESS VARIABLE than we are at 5% (for ex)
what are two exceptions to the speed accuracy trade off?
1) extremely rapid and forceful movements
- longer movement times, more time for closed loop control
- move really fast, see a decrease in variability
2) timing accuracy is critical to the action
- with more time, comes more timing error
- ex: counting to 10, you’ll have less error than when counting to 20
which 5 factors play a role in analyzing rapid movement (ex: hitting a base ball)?
1) visual processing
- able to more accurately predict where the ball will be at impact
2) swing initiation timing accuracy
- decision made closer to ball contact - less time for error
3) movement timing accuracy
- MT is more consistent - better chance of hitting the ball
4) movement spatial accuracy
- relates to force variability curve
5) ball impact
- physics - hitting harder will make the ball go further
prehension - def
the action of reaching for and grasping an object that is stationary or moving
how does prehension relate to Fitts’ law?
as we grasp for an object, we initially reach quickly but decelerate once we get closer because we need to be more precise with our movement
how does bimanual coordination relate to Fitts’ law?
when performing bimanual movements, the target that is more difficult will be the rate limiting factor in the movement; the limb with the easier target will not move faster
what stage of programming is affected in bimanual coordination tasks?
response programming
-one motor program is being sent to both limbs even though they are supposed to perform different movements
symmetric bimanual coordination
-preferred pattern of movement
1) anti-phase: alternating movements
2) in-phase: homologous muscle for movements on both sides
how can you measure relative phase in bimanual coordination?
- way of measuring relationship between two limbs
- position of right hand subtracted by position of left hand for example
- if they’re perfectly in phase, there is a difference of 0 degrees
- if they are perfectly anti-phase, difference of 180 deg (walking)
asymmetric bimanual coordination
- can be learned
- ex: skilled drummers
what are two possible explanations of bimanual coordination?
1) generalized motor program
- develop 1 or 2 new programs?
- with practice, able to merge more than one program together
2) dynamical systems
- new attractor state ‘emerges’
- in phase and anti phase
- with practice, SD (variability) goes down, becomes a stable pattern
what are two possible explanations that explain the speed accuracy trade off?
1) motor program
- movement longer (reduced speed)
- accuracy decreases (variability increases)
2) dynamical systems
- if variability increase; seek new coordination pattern
- as you move faster, relative joint positions become more variable, you seek a new coordination pattern that takes longer to perform
how do novice vs expert golfers differ in coordination patterns?
novice golfers move their head with their putter (in phase)
-experts move in anti phase (opposite way of the putter)
motor learning - def
a set of processes associated with practice or experience leading to relatively permanent gains in the capability for skilled performance
- beyond just saying that someone got better at something, want to know how they got better
- accuracy: variable error, constant error
- adapt in different situations (consistency)
performance - def
what happens on any individual trial, test, competition, practice, etc.
capability - def
what you are capable of doing but your performance might not reflect this
-qualitative change in capability between beginners, average, and experts
what 3 things affect someone’s ability to perform? (not capacity)
- stress
- environment injury
- fatigue - alertness
what is the difference between capability and performance in beginners?
performance might be higher than capability but not consistent
what is the difference between capability and performance in experts?
it’s more likely that our capability matches our performance because we become more consistent
what is learning not?
- NOT an improvement due to growth/maturation
- NOT improvement due to CV fitness or strength (more about coordination patterns)
learning is relatively permanent
true or false?
true, not due to luck
we can measure motor learning directly
true or false?
false, not with today’s technology
learning: neural perspective
-neuro-plasticity is the process that underpins learning
short term plasticity
- neurotransmitters - forget it more easily, not long term
- if you’re using those pathways, you use more neurotransmitters
long term plasticity
- structural changes to neurons - retained for longer
- when you keep using the pathway
learning: behavioural perspective (our model)
we get better at implementing a response (performing)
-get better at interpreting sensory feedback
what are the 3 changes that happen with learning? what concepts do these relate to?
improvements:
1) better at assessing (perceive) what play is happening
- relates to the concept of stimulus identification and response selection
2) able to execute movement as planned
- motor program
3) better able to make corrections to movement
- quality of feedback
- comparator
learning results from practice or experience
true or false?
true
learning can be observed directly
true or false?
false
learning is inferred from changes in performance
true or false?
true
learning involves processes in the muscles
true or false?
false, not muscle memory
if performance changes than learning has occurred
true or false?
false
learning leads to an acquired capability for skilled performance
true or false?
true
changes due to learning are relatively permanent
true or false?
true
what are the limitations of performance curves?
1) performance curve does not equal learning curve
2) between subject effects are masked
3) within-subject variability are masked
what is the law of practice?
- see early changes in performance as you’re figuring out the task
- improvement tends to level off as you achieve initial basic competency
why is it not always beneficial to lump all the data together when assessing whether someone has ‘learned’?
- by lumping everything together, we can miss sub-groups or patterns in performance that give us more information
- ex: tool passing task; end-state comfort
performance - def
the act of executing a motor skill
1) at a specific time
2) in a specific situation
learning - def
requires a change in the capabilities of the performer
1) cannot be directly observed
2) inferred from performance observation
what can affect a person’s performance on a given attempt?
- alertness
- fatigue
- stress
- arousal
- motivation
- feedback
- etc.
what are the 4 defining features of performance?
1) observable behaviour
2) may or may not be due to practice
3) temporary (related to situation)
4) may be influenced by performance variables
what are the 5 key features of learning?
1) improvement
2) consistency
3) stability
4) persistence
5) adaptability
key features of learning: improvement
performance improves over time
- defining improvement is dependent on the task
- ex: time, accuracy, etc.
key features of learning: consistency
- performance will become more consistent over time
- experts are able to reliably execute their skills at a high performance level
- ex: stanley cup vs super bowl - hockey is best of 7, don’t need to be consistent to win the super bowl
key features of learning: stability
- resistance to perturbations
- may be internal OR external
- external: weather, noise, etc.
- internal: stress, fatigue, etc.
- better able to cope when you’ve learned something well
key features of learning: persistence
- improved performance lasts over longer and longer periods of time
- relatively permanent improvement
key features of learning: adaptability
- aka generalizability
- related to stability
- performer can adapt to a variety of contexts and maintain skill improvement
- ex: walking; children adapting to different contexts
what are two ways to test “permanence” of a skill?
1) retention test
2) transfer test
retention test
- need person to come back at a later time
- test in the SAME condition that you practiced in to see if improvement in performance persists over time
transfer test
- to see whether you can perform in a slightly DIFFERENT situation
- ex: transfer to non-dominant limb
positive transfer
practice in one skill gives you a benefit for another skill
-ex: roller blades to skates
negative transfer
because you practiced the one skill, it’ll initially interfere with another skill
-ex: badminton to tennis
a group with ____ transfer will perform better than the group who had no practice; a group with ____ transfer will perform worse than the group who had no practice
positive, negative
specific transfer
- ex: free throw
- practicing at a certain distance and angle and transferring that exact skill to a game
- practice and performance conditions are IDENTICAL
generalized transfer
- near (closer to specific situation) or far (relatively)
- at a novice stage, can have far transfer that transfers over but near transfer is better
- ex: free throw vs jump shot
- jump shot now always performed at same position or angle
- can practice jump shot and the skill remains the same, parameters change (near transfer)
- far transfer ex: fundamental motor skills in children (ex: jumping)
what is practice?
- never new and never old
- practice does not equal repetition
- goal: solve the problem
- practice: solving the problem
when is the only good time to use an aid to improve performance?
the aid is only good if it helps the learner SOLVE THE PROBLEM rather than just doing the work
we have practice specificity for which 3 things?
1) sensory/perceptual characteristics
2) performance context characteristics
- encoding specificity (home field advantage)
3) cognitive processing characteristics
practice specificity for sensory/perceptual characteristics
- motor skill learning is specific to the sources of sensory/perceptual information - Luc Proteau
- initially scientists predicted that the need for vision decreased with practice, but it’s not true (amount of practice with vision increase the need for vision during retention and transfer test)
- difficult to use the same motor plan when you take something out (vision)
the more you practice a skill with feedback, the more you need it
how does this statement fit into ‘our model’?
-processing affected in feedback loop
practice specificity for performance context characteristics
- intentional remembering versus incidental learning: encoding specificity
- learners will learn more about the context than they are intentionally or explicitly trying to remember
- incidental cues or information does benefit later performance
THIS INFORMATION IS NOT CRUCIAL FOR PERFORMANCE
practice specificity of cognitive processing characteristics
- transfer appropriate processing theory
- want the cognitive processing you go through during practice to be appropriate to the transfer environment
- cognitive processing becomes part of the memory representation of the skill
- perform best when you’ve practiced the specific cognitive processes required during test situation
what are the 3 models of stages of learning?
1) Fitts and Posner Three stage model
2) Gentile’s two-stage model
3) Bernstein’s 3 stages
what are the 3 stages that make up Fitts and posner’s three stage model?
what learner is focused on:
1) cognitive stage
2) associative stage
3) autonomous stage
Fitts and Posner’s three stage model: cognitive stage
- listening to instructions
- figuring out the goal of your movement
- what do you need to do; when; how
how if performance during stage 1 of the Fitts and Posner’s three stage model? (cognitive stage)
- beginner
- highly variable (standard deviation used to measure error)
- big errors
- large number of errors
- do not know how to correct errors
- reliant on instructions to point in right direction
- don’t have the GMP yet
Fitts and Posner’s three stage model: associative stage
- intermediate
- learner begins to see relationships between the environment and movements that are required
- start to associate what’s going on around them and what they need to to do be successful
- has developed a fundamental understanding
- working towards refining motor skill
- have the basic GMP, adjusting parameters
how is performance during stage 2 of Fitts and Posner’s three stage model? (associative stage)
- fewer errors
- smaller errors
- variability begins to decrease as you move through stage 2
- can detect some errors
- more efficient
- learning what environmental cues to use
- typically spend a lot of time in this stage
Fitts and Posner’s three stage model: autonomous stage
- requires considerable practice
- skill becomes automatic
- does not require conscious attention
- more room to pay attention to other things
how is performance during stage three of Fitts and Posner’s three stage model? (autonomic stage)
- can easily perform another task
- aka dual task performance (multitasking)
- performance is highly consistent
- aka low variability
- can detect errors and easily make the adjustments
- well developed GMP
- good at adjusting parameters
- identifying errors and corrections
what factors will influence if and how quickly someone progresses through the three stages of learning?
1) how much they’ve practiced
- conditions
2) skill difficulty
3) individual characteristics
- transfer from other skills
what are the two stages in Gentile’s two stage model of learning?
1) initial stage of learning
2) later stages of learning
Gentile’s two stage model of learning: initial stage
2 goals:
1) acquire the movement coordination patterns
2) learn to discriminate between regulatory and non-regulatory conditions
what in the environment is relevant? (vs non relevant)
-a lot of attention is needed because you haven’t learned how to be efficient with your attention
what are strategies for the initial stage in Gentile’s two stage model?
- trial and error
- successful and unsuccessful - learn to figure out what works
- problem solving approach
goal:
-develop basic coordination pattern
Gentile’s two stage model of learning: later stages
- goal is to develop 3 movement characteristics:
1) adaptability - different environments
2) consistency - reliable performance
3) economy of effort - efficient
- related to attention and in terms of physical efficiency
what are the 3 stages in Bernstein’s 3 stage model of learning?
- dynamical systems perspective
1) reduced degrees of freedom
2) release degrees of freedom
3) exploit passive dynamics
Bernstein’s 3 stages of learning: reduce degrees of freedom
- freezing degrees of freedom
- as a beginner, often simplify movement to one joint
- limit amount of joints you have to pay attention to
- manifests as a co-contraction
- contract both agonist and antagonist in order to stabilize the joint
- requires additional energy and reduces efficiency
Bernstein’s 3 stages of learning: release degrees of freedom
- release degrees of freedom once you have the basic coordination pattern
- bring in other joints progressively
Bernstein’s 3 stages of learning: exploit passive dynamics
- improved energy conservation for same force production
- ex: when performing a task with preferred hand, you can do so with less force
- schmidt’s force variability (law) relationship
- doing something with a smaller force = increased accuracy
- efficient AND effective movement
what are three limitations of the models of learning discussed in class?
1) never meant to be separate categories (beginner, intermediate, expert); meant to be a continuum
2) automaticity may not always be possible
3) some skills lead to more freezing, not less
- ex: gymnasts - better they get, the more stable they are
what is skill retention like for discrete tasks?
- after long delays, law of practice comes back and it’s like you’re re-learning the skill again
- re-learn it a lot faster this time however (did not completely forget it)
- has to do with cognitive demands that come with discrete tasks (heavily open loop, lots of planning ahead of time)
what is skill retention like for continuous tasks?
- can retain a continuous skill even after two years of not practicing
- with a continuous tasks, each trial = multiple practice trials
- more reps than one discrete task where you have one trial each time
what are the 4 benefits that come with practicing a skill?
improvements in:
1) perceptual skills
2) attention/managing attention
3) motor programs
4) error detection
not simply patterns of muscle activity
benefits of practice: perceptual skills
- pick up key information sooner
- specific to knowledge of activity or skill
benefits of practice: attention
1) reduced capacity of demands
- ex: skating and stick handling as a novice vs expert
2) reduced effector competition
- merge 2 motor programs into 1
- trying to do different things with our limbs (ex: drummer)
benefits of practice: motor program
- learning sequences of movements
- repeated sequences become merged
- motor program becomes more refined
- can develop a new motor program that involves moving multiple limbs at the same time
benefits of practice: error detection
- important to develop
- can be conscious or non-conscious
- detect errors using sensory feedback you have available in the specific situation
benefits of practice and it’s relation to our conceptual model
- a skill is never new or old
- you will always have some sort of coordination pattern or motor program that you can use to approximate performance
our model:
- error detection and correction
- need practice using feedback and practice with comparator (nervous system)
- correct movement while it’s happening (online) or in next trial (offline)
