Midterm 2 Flashcards
Lecture 2.2 Sensory Information 2
Sensation
4 main functions
neural activity triggered by a stimulus activating a sensory receptor 4 main functions: -perception -control of movement -regulation of body function -maintenance of arousal (can happen together or independently) *not all conscious experiences
Perception
multistage process in the central nervous system
-meaning is attached to sensory input
involves integration, selection, organization, and interpretation of information
-sensory stimulus perceived differently between people (culture/environmental differences)
ex. pain of childbirth
optical illusions
identical sensations can yield different perceptions
-not seeing both images at first, thinking to see second
sources of sensory information
afferent sources- sensory pathways/info to CNS
exteroception-sensory info that comes from sources outside the body (what/where)
-vision, audition, olfaction
(not really taste or smell unless specific-chef)
-imperative for skilled performance
-emphasis on the usefulness of the source
sources of sensory info cont’d
feedback (actual)- info produced from various sensory sources as a consequence of movement
-info about movement itself
-what you do with info is up to you
-someone else or own performance
feedforward (desired)- information about the intended action…should be happening
-expectation about the movement consequences before any action begins
-lots of practice and repetition to know desired state
vision
anatomy of the visual system image -retina -optic nervce -lens -pupil -cornea -iris (structures taking light toward the visual cortex)
anatomy of the visual system cont’d (steps)
- light enters through the cornea (outer/superficial)
- light passes through the iris and pupil (attached)
- light hits the lens once it passes through the iris
- light hits the retina at the back of the eye (waves transferred from light to impulses)
- light impulses travel from retina to the optic nerve (CN II)
- Optic nerve carries impulses to the visual cortex
anatomy of the visual system (functions)
cornea- clear outer layer at the front of the eye
iris- controls the amount of light that enters the eye
Pupil-opening in the iris, controls the intensity of light permitted to strike the lens
lens- controls the focus of the light
retina- converts light into neural impulses (light waves to impulses)
optic nerve CN II- carries neural impulses to the brain
visual cortex- region of the brain that receives, integrates and processes visual info
Snellen scale
measure of static *visual acuity -clarity of vision -ability to recognize small details with precision 20/20, 6/6, 20/200 (blindness)- exteroception is important *visual acuity=test distance/letter size -stand 6ft away -cover one eye -letters standardized sizes
visual system (3)
focal vision-conscious identification of objects in the centre of the visual field (focused) 1/2 types vision
ambient vision- orientation of one’s body in the environment, taking in all of the visual field (within periphery/ still identify) 2/2 types vision
optical flow- visual perception of motion, position, timing or direction
-have to take in all visual info in order to perceive info
Visual system (what/where is it?)
visual info processed in different ways what is it? -ventral pathway (front) -object perception Where is it? -dorsal pathways (back) -movement -cerebral akinetopsia (motion blindness-lesion or impairment to the pathways) -vision choppy/no smooth transition -timing (spatial/temporal anticipation) -in physical space
Optical illusions
identical sensations can yield different perceptions
- ventral pathway (object perception) fooled by the illusion- right side is bigger
- dorsal pathway (movement) scales hand appropriately when moving to it- moving hand to face
time to process visual information
experimental approaches:
whiting (1970)
-ball catching task
-varied viewing time prior to attempted catch
-catches still made with 100ms viewing time
-at 400ms (90%)
at 100ms (30%)- not zero/ visual system responds quickly
perception-action coupling
- cycle that fuels itself
- we must perceive in order to move, but all we must move in order to perceive (James Gibson)
- context/task specific
- move to ready self prior to
- coaching in game environment
perception-acton coupling
vision and balance: moving wall experiment
Lee and Aronson 1974
- toddler shift in way walls move, not adults
- young and not fully developed
- visual stim more important than mechanical
- adult loses balance when balancing on object and room moves/eyes closed
visual cliff paradigm: depth perception
- infants reluctant to crawl over “cliff”: due to perceived depth (Gibson & walk 1960)
- perceived depth
- arousal- moms smiling baby would come
- role of nonverbal communication in determining behaviour in uncertain contexts (how are other people reacting)
Tau
Tau (t) optic variable that specifies time until perception
-involved judging of distance between multiple stimuli
-when object will reach us
-how long we have to react/ ready
Tau effect:
-if distance and time between stimuli is constant, the difference is perceived as such
-if distance and time between stimuli is not constant, the interval with a shorter temporal interval will be incorrectly judged as having a shorter spatial interval
-longer spatial intervals = longer perceived temporal intervals; shorter spatial intervals = shorter perceived temporal intervals
-brains assumption of stimulus velocity
Tau cont’d
when the time intervals between stimuli become inconsistent, the shorter time interval saw the corresponding stimulus perceived as being closer
vestibular system
- functions to maintain static and dynamic equilibrium (balance and posture)
- directs the gaze of eyes (vestibule-ocular reflex)
- assists in preserving a constant plane of vision (head position) by modifying muscle tone
vestibulo-ocular reflex (VOR)
- directs the gaze when head moves to maintain focus of image on retina
- fairly direct (minimal lag time - 10ms)
- lag time=neurological issues
Audition overview
-exteroceptive
-external, middle and inner ear
organ of courti in the cochlea (sounds waves to electrical impulses)
-internal aspect of cochlea (inner part of inner ear)
-body’s microphone
-mechanoreceptors (hair cells)
-relay nerve impulses via cochlear branch of cranial nerve VIII (bending/being displaced)
characteristics of sound waves
frequency- measure of pitch with units of measure cycles per second (Hz)
amplitude or intensity: a measure of loudness with units of measure in decibels
-40-60 (normal convo)
-120 (startle response)
-140 (pain threshold)
proprioceptive organs
muscle spindles- excitatory in nature and respond to stretch of the muscle
-found within the muscle itself
Golgi tendon organs- inhibitory in nature and respond to excessive force to the muscle
-found in the musculotendinous junction
joint receptors- provide info on joint position
-found in joints and joint capsules
cutaneous receptors
- sensory organs located in most skin areas
- tactile sensation (touch, pressure, stretch, vibration)
- temperature monitoring (heat and cold)
- pain (nociceptors)
- free (widely distributed) and encapsulated (deeper) dendritic endings
- individual receptors may monitor several different kinds of stimuli
reflex pathways
latency- time for response to occur -or delay for reflex to occur synapse- region of contact where a neuron transfers information to another cell -junction between neurons afferent- toward CNS efferent- away from CNS
reflexive modulations
(5 specific topics)
1. monosynaptic
1.monosynaptic reflex
-mono (one)
-synapse (nerve junction)
-short latency (10-50ms) -simple, rapid
-stretch reflex (myotatic)
-rapid compensatory action to stimulus
reflex arc:
1. sensory receptor
2.afferent
3.synapse
4.efferent
5.effector
-latency 10ms
- interneurons
- neurons whose cell bodies and processes remain within the CNS
- no direct contact with peripheral structures
- functions in modification, coordination, integration, facilitation and or inhibition between sensory and motor output
- increases time for reflex to occur
- polysynaptic reflex
(more than one)
- can involve interneurons, other spinal segments, and/or supra-spinal structures
- short latency 50-80ms (more synapses=longer)
- more flexibility/role of instruction (resist or let go)-train or override
ex. pickup something hot with baby underneath
- triggered reaction
- polysynaptic reflex
- longer latency (80-120ms)
- still too short to be voluntary
- large role for instructions (pre-structured to enviro stimuli, not black/white)
- high flexibility
- simple stimulus may generate composite response
- cutaneous receptors that facilitate the crossed extensor reflex
ex. soldier/long distance ( acquire ability to react specific way)
crossed extensor reflex
- excitatory and inhibitory to different muscles
- latency of 120ms+ (200ms)
- voluntary response
- methodology or technology can affect measure (EMG, discrete movements of distal musculature)
- number of alternatives can also affect RT
ex. stepping on Lego
Lecture 2.3 Motor Programs
motor programs: overview
- pre-structured set of neural commands, organized in advance (hand off hot surface)
- capable of producing movement with a minimal role for sensory info
- movement is carried out essentially open-loop until enough time has passed to allow processes to operate
- central representation of action
- organized in advance of movement
- when skilled, a movement seems to take care of itself (not w/ novice performers) -don’t think just do it
- open loop control
open loop control systems
- advance instructions specifying operations, sequencing, and timing;
- once initiated. program is executed without modification;
- no way of detecting errors;
- most effective in stable, predictable environments
ex. formula one racer (navigating multiple barriers)
what might a motor program specify?
5
- particular muscles used for the action
- orders of muscle recruitment (kinetic chains)
- forces of muscle contractions
- timing and sequencing of actions
- duration of each action segment
- lots of info and capacity saved
- exteroception
Deafferentation studies
- Lashley
- Taub and Berman
- studied deafferented patient wit loss of sensory info from lower limbs (gun shot)
- can move and position legs with reasonable accuracy
- did not lose motor signalling, but lost fine motor control - deafferented monkeys (brachial plexus) maintained capability to perform motor skills
- dexterity impaired
- kept ventral roots
- more aggressive with arms, seemed foreign to them
ex. cone of shame- can’t feel from anesthesia-block sensory pathway
Deafferentation studies cont’d
Is movement possible without sensory feedback?
- can movement be produced without feedback (yes)
- evidence suggests that movements can be produced without sensory feedback
- sensory feedback is not necessary, BUT important for finer control and adjustment of movement
- need multiple sources to inform as best as possible
Deafferentation studies cont’d
Reafferentation
-feeling of sensation back
-so movement is still possible without sensation, but is the opposite possible? (reintroducing sensation)
Yes
-bionic limbs/amputees
-take in tact motor nerve and re-innervate it in another muscle belly
reaction time and movement complexity: overview
If a motor program is prepared in advance then do movements of greater complexity take longer to prepare?
Yes…
-RT should increase as movement complexity increases
-increased time required to organize more complex movements
Henry and Rogers
studied simple RT and response complexity
response conditions:
-finger lift
-finger lift and grasp ball
-etc.
good evidence that as responses become more complex RT increases
muscle activity patterns: overview
measured in EMG
-study electrical activity of muscles during movement production
Wadman 1979
-examined muscle activity patterns during rapid movement
(extend elbow- tricep, agonist, bicep, antagonist)
-don’t want to see them active at the same time
Hypothesis: expect drastic changes in EMG pattern due to block (immovable pole)
-didn’t move but musculature movement identical to original
Wadman 1979
Wadman 1979
-examined muscle activity patterns during rapid movement
(extend elbow- tricep, agonist, bicep, antagonist)
-don’t want to see them active at the same time
Hypothesis: expect drastic changes in EMG pattern due to block (immovable pole)
-didn’t move but musculature movement identical to original
-once motor program initiated-going to matter what
-@120ms things start to deviate - due to reflexive pathways (stretch reflex)
additional example of Wadman
patterns in cycling:
- muscle guarding-become active to protect joint
- narrow every muscle in 30s
- you have it hardwired into muscle
- people initially move only in the way they know
Inhibition of a response
-studied ability to stop/inhibit movement
Slater-Hammel 1960
Slater-Hammel
-study ability to stop movement at different stages of preparation
-movement:
-make rapid movement to a target
-inhibit if stop signal is given
experiment:
-finger on key until 800ms
-experimenters would stop arm at different points to see if finger movement occured
result:
-more time before 800ms pretty good success
-as time decreased the probability of inhibition decreased
Slater-Hammel Interpretations
-if stop sign is given too late in RT interval, movement is still executed
-movement commands are pre-structured or programmed in advance, then executed as unit
-once movement is planned, and internal go signal is given, response is initiated
Input (150ms)-exectutive-effector-output (150-170ms) of total (300ms)
Problems and Solutions:
(lines of evidence for motor programs)
Specificity of motor programs
- is a separate motor program required for each action?
- are motor programs stored in memory?
storage problem
-do we need to store a motor program for each possible movement?
-if so how do we store the countless number of motor programs that we would need?
(need to be able to pull out and perform instantly)
novelty problem
-if we need a new motor program for every action, then, how do we produce new actions that are not represented in a stored motor program?
(no 2 kicks same, no 2 letters same)
motor program solution
generalized motor programs (GMP) - refers to a motor program for a class or family of actions rather than specific actions
- invariant features of a motor program are those that make the pattern appear the same time after time (similarities between skills)
- surface features (parameters) of a motor program are those that allow changes in the performance of a given skill
support for GMP
relative timing
-variations in movement time show similar but compressed pattern (Armstrong 1970)
-relative timing as invariant feature
in experiment: baseball swing
-active muscle not changed
-relative timing invariant
-muscle move in order and timing they activated
-muscle durations remain relatively constant when the movement time of the action changes (upper vs lower panel)
support for GMP
amplitude
-variations in movement amplitude of handwriting showed similar patterns of acceleration (Hollerbach 1978)
-acceleration of pen example:
-besides amplitude little difference
-amplitude of force is parameter of amplitude/invariant feature
-temporal organization remains the same
Overall amplitude of force=surface
Relative timing of muscle force/activity=invariant feature
support for GMP:
effector independence
-variations in limbs/muscles used (Robert 1977)
-temporal structure of movement preserved
experiment:
-writing with different effectors
-same skill will have similarity regardless of effector
-any effector preserves invariant features
additional reflex knowledge
monosynaptic (M1)
polysynaptic (M2)
Triggered reaction
voluntary response (M3)
lecture 2.4
speed accuracy trade off
speed accuracy trade off:
fitts’ law
-if you do the same skill quicker, it will be performed with less accuracy
-can be different in skilled individuals
-consistent in intra-inter individual differences
first noted by Woodworth 1899
(tap to target)
Fitts’ law con’t
-accuracy held constant: all dots within blue lines independent variables: manipulated -amplitude (distance had to move) -width (of target) dependant variable: responding -movement time experiment: what happens if... double width-decrease MT 1/2 width-increase MT double width and closer- decrease MT closer and less wide- similar to first
Fitts’ law: the math behind it
MT=a+b (log2(2A/W))
(log2(2A/W)) = index of difficulty (ID) -quantifying the degree of difficulty
-this is the equation of a line (linear relation). so MT is linearly related to ID
examples: basketball hoop, beer pong
accurate=concentration
ID increases as game goes on with shrinking (beer pong)
Fitts’ law: evidence in everyday tasks
keyboard: qwerty-based on typewriter, people typing too fast to process
Dvorak keyboard- different- using Fitts’ law to make it human friendly
Evidence in everyday tasks: Fitts’ law
pop-up ad:
-utilizing speed-accuracy trade off
-inconvenient to get to hidden ‘x’ at top of the ad
Fitts’ law is a general law of motor behaviour
-consistent across application and populations
-extended to more complex movements (not just tapping tasks)
ex. video game controllers (less time having to move=decreased amplitude)
-button size to make easier to pick
linear speed-accuracy trade off:overview
what happens for rapid, discrete, open loop movements with no time for feedback? Experiment: independent variables: -MT (reinforced with feedback) -A (distance to move) dependant variable: We=effective target width (deviation) We=A/MT -how accurate will they be when moving as fast as possible?
linear speed-accuracy trade off: 2 main effects
- for a given rapid MT, as A increases, We increases (further away=less accurate)
- as MT decreases, We increases
- these effects are largely independent
linear speed-accuracy trade off: general relationships
- variability related to velocity
- We related to A/MT, as A increases We increases, We and MT are inversely related
- not identical to Fitts’ law (logarithmic vs linear)
- both open (very rapid) and closed (slower) control show speed-accuracy trade off
sources of error: very rapid movements
very rapid movements:
strength/power- cannot have movement without power
power=strength x speed
-every connection (synapse) is an analog process, susceptible to transient factors (amount of receptors/NTs)
analog vs. digital
NMS=analog signals
- contains noise (transient factors)
ex. microphone recording a conversation in a stadium
very rapid movements cont’d
each connection can introduce error
because every connection is an analog process, and susceptible to transient factors…
each connection can introduce error
-known as noise
-increased noise=increased error
-this is why it is difficult to produce the exact same movement twice
very rapid movements cont’d:
percentage of maximum force
in general, when we produce more force (up to about 70% max), we introduce more noise (variability) - similar to We
- 70% plateau
- 0-70% linear increase in variability
very rapid movements cont’d:
coordinating muscles
Imagine we need to coordinate the following three muscles to strike a nail with a hammer:
What happens if:
1. muscle 2 is too strong?
2. muscle 3 is too weak?
3. you are in space?
-human body is complex
-even hammering a nail requires coordination and stimulus
-multiple synapses and muscles= increased error produced/ more variable
very rapid movements cont’d:
open loop speed-accuracy trade off
-lots of variables that affect performance:
increased force= increased variability, and that noise in any muscle can affect the resultant force
Exceptions to speed-accuracy trade off:
max force
Example: T-ball game, hit ball as quickly as possible
findings:
-movement time decreased as torque increased
-low number of error with less torque
-movements of 70% or more of max force become less variable
-force production decreases variability after 70%
-high % max force is more accurate- change in the relationship
-if you are performing an action as rapidly as possible more accurate if you perform is at 85%+
Exceptions to speed-accuracy trade off:
spatial and timing accuracy
spatial: accuracy of rapid movements for which the spatial position of the movement’s endpoint is important to task performance
(kicking soccer ball to specific spot)
timing: accuracy of rapid movements for which the accuracy of the movement time is important to task performance
(guitar hero)
Exceptions to speed-accuracy trade off:
movement timing
which trial would have better…
- spatial- 300ms (more timing=better spatial accuracy)
- temporal- 150ms (rapid)- (more time to estimate=less accuracy)
putting it all together
Batting example: Assumptions: average pitch takes 460ms to get to home plate average swing takes 160ms to contact ball Breakdown: decision time (150ms) time to plan swing (150ms) time to swing bat (160ms)
what does an extra 20 seconds get you?
- visual information processing (more time)
- swing timing accuracy (better timing accuracy for initiation and production)
- spatial accuracy (swinging faster? little worse- not as accurate in making contact) or if closer to max force more spatially accurate
- ball Impact (swing at right time but not hit at right place) or more force=harder hit
Lecture 2.5: Speed accuracy trade off: bimanual coordination
Accuracy in coordinated actions
Up util now we have only considered the motor system capable of performing a single motor output..but…we all know we can simultaneously control multiple effectors
-does not consider unique object manipulation
-2 distinct roles for each limb
Bimanual skills- skills requiring control of coordination of the two hands
-magic on surface blows mind
-precision higher when time longer
ex. piano, baking, figure skating
Bimanual coordination:
predictions based on unimanual Fitts’ tasks
- left and right hand both fast (low ID) - large target width and closer together
- left and right hand both slow (high ID) -target width small, far apart
- left slow, right fast (high ID left, low ID right) ACTUALLY
left slow, right slower than expected
-movements of right limb affected by tasks of left limb (attempt by executive to deal with overload demand/ more complex movement)
-suggests the two limbs are coordinated… perhaps by joint motor program/command?
Bimanual Fitts’ tasks cont’d
Pie charts:
-if we have one complex and one simple movement, simple impaired by complex
Obstacles
Kelso et. al 1983
-simple movements (tapping)
one side hurdle, other side no hurdle (vertical displacement still)
-Additional evidence of single or coordinated motor plan:
-can’t have more than one motor program executed at once (movements of right limb affected by tasks limbs of left)
Defining motor program:
movement time and kinematics are determined by joined motor program of each limb, not independently
Gamma V Experiment
Step 1: with your left hand by itself, practice making some capital V’s
-with your right hand by itself practice making some gammas
Step 2: Now combine them
Step 3: Now combine them and switch:
-while making capital V’s with your right hand, make gammas with your left
Gamma V experiment cont’d
End results
End results:
unimanual- form motor plan for each action individually
bimanual- same action on both sides
-very difficult to execute 2 motor programs simultaneously
What do the unimanual results tell us?
-that you can form a motor program for each action independently
What do the bimanual results tell us?
-that two motor programs cannot be run without significant interference. More evidence for a single motor program limit.
because…
response time (MT+RT)
response programming/fake= serial processing (RT limit=executive)
movement time- limited by single motor program at once=effector
Continuous Timing:
See for yourself
- point your left and right index fingers in front of you and wiggle them slowly
- majority wiggled in phase, some anti phase
Continuous timing: in-phase vs anti-phase
research shows that in phase and anti-phase bimanual movements are more stable than out of phase…why?
- have similar timing structure/rhythm (temporal component, easier to perform)
- simplifies the joint motor program
- easier to use the same effectors across different limbs
Continuous timing: in-phase vs anti-phase
Kelso and group
Research also shows that in phase is more stable than anti-phase
faster= lose accuracy
speed increases= change in effectors to increase accuracy (too fast to perform anti-phase-switch)
anti-phase- less accurate increase standard deviation
Continuous timing: in-phase vs anti-phase
Having a preferred (more stable) coordinated movement suggests another way the motor system solves the speed accuracy trade off
When the demands of speed in one coordinated movement (eg anti-phase) produce too much error, we can switch to another coordinated movement (eg in-phase)
Continuous timing: beyond the lab
Where else can we see this principle of switching movement patterns as a result of speed demands?
crawl-walk-run (multiple stages-complex)
-as speed increased, kinematics changes (way we move)
-half court shot in basketball- decreased time to produce skill, 1/2 court shot- switching due to movement demand
-video game designers (Tetris), increase speed of bricks= decreased movement time, decrease in accuracy= failure
Continuous timing: beyond the lab cont’d
This suggests that the degrees of freedom available to multi-limb coordinated movements is actually an advantage- can converge on more stable movements patterns… each best suited to a specific speed (or set of conditions)
Continuous timing: speed accuracy/coordination-summary
Fitts’ law: MT slows as ID (proportional to A/W) goes up
Linear speed-accuracy trade off: for very rapid movements, error increases with short MT and larger A
Coordination stability: when one pattern of movements becomes unstable due to speed, a switch can be made to a more stable one
Parallel motor planning:
Affordance competition hypothesis: action specification and action selection are performed by the same neural circuits, distributed among a large set of brain regions
2 monkeys reaching task
record eyes, RT, MT, exact movement of hands
+ is a curser for 500ms
red and blue appear and disappear 500ms (constant positions not colours)
center circle change color
or move the curser to certain color
-overall performance excellent
-it suggests that decisions are determined when a competition between actions is resolved within the sensorimotor system
Parallel motor programming cont’d:
only one Motor program?
More than one motor program encoded in the brain
Dorsal premotor cortex: part of brain where motor programs and planned an executed
-multiple motor programs prepared and stored: 1 active
Parallel motor programming cont’d:
only one motor program?
Chapman, Gallivan Cognition
- right handed
- focus on + sign
- beep, plus replaced by white/ black circles
- finger on button- when lifted reach toward a color
Parallel motor programming cont’d:
only one motor program?
One target
-rapid action
Parallel motor programming cont’d:
only one motor program?
2nd experiment
2 targets with color
respond to shape and color
late trials- when taking visual and motor simultaneously… reliant on combined motor program
Altogether:
-average motor problem until all info available
-not several motor programs but average instead
Parallel motor programming cont’d:
only one motor program? Explanation
- These results suggest that the brain does make more than one motor plan (program) at a time (potential exists, plan for all)
- But since we are usually limited to only one effector (e.g. reaching hand), the competition between plans is resolved either before movement, or is reflected in the movement (without all the info=average program)
- This work doesn’t speak to multi-limb movements which probably do require some shared properties (e.g. shared timing structure)
- effect of practice and learning- how we can play something complex (instrument and manipulation)
Lecture 2.6:
(Stages of) motor learning
Theoretical depictions of stages of learning
Models
Recall models: artificial constructs based on scientific reasoning to better understand complex concepts (can’t see into brain)
Bryan and Harter (1899)
“studies on the telegraphic language: the acquisition of a hierarchy of habits”
-hierarchy of habits in learning morse code (wasn’t just clear linear relation)
-plateaus reached when no improvement is seen (different stages and steps within learning process)
-plateau of performance exist until a higher order habits is formed allowing improvement
experimental plateaus:
1) receive letters and make words
2) sentence structure and communicate without delays
Fitts and Posner (1967)
Cognitive (trial and error): thinking your way through skill
-desired vs actual, isn’t like evolution of abilities, ex. throwing ball with dominant vs non dominant hand
Associative: (homing in): associating relevant components
-closer to desired/ actual, refining movement pattern
Autonomous (free and easy): automaticity (free of cognition-not entirely)
-much learning and practice, not entirely free of cognition, What happens when you think about it? (decrease performance)
ex. playing an instrument American Idol example
Adams 1971
-restricted to linear positioning
Verbal motor: talking your way through the skill (coach)
Motor: less talk, more action
-closed-loop theory of motor learning
-feedback based on corrections for skill learning (intrinsic and extrinsic)- know cause of error
Adams 1971 cont’d
Two elements in this theory:
memory trace: used in the selection and initiation of a movement (response selection, memory/association to stimuli)
Perceptual trace: built up over practice, becomes the reference of correctness
Key feature here is the role of feedback:
-analyze the reference model actions, the result of those actions and the desired goals
-refine the reference model to produce the required actions to achieve the desired goals
Gentile 1972: 2 stages
- Initial stage (beginner)
- latter stage (experienced/practiced)
a. fixation (closed): movement becomes fixated, that is, refines the movements position pattern so consistency is achieved with little conscious effort and minimum energy (we act 1st, enviro 2nd)
b. diversification (open): movement requires diversification, that is, capacity to modify the movement pattern according to the environmental demands
Gentile 1972: 2 stages cont’d
Initial stage
Acquire the movement coordination pattern that allows some degree of success (takes time)
-beginner develops movement that matches the regulatory conditions of the environmental context (pairing performance with environment)
Discriminate between regulatory and non-regulatory conditions:
regulatory: characteristics in environment that directly influence movement required to reach goal
non-regulatory: characteristic that do not influence movement required to reach a goal
Gentile 1972: 2 stages cont’d
latter stage
- performer is able to adopt the movement to any performance situation (minimum movement time)
- performer increases their consistency in achieving their goals (certainty)
- person increases their economy of effort in performing the movement (efficiency)
- *Recall Guthrie’s definition of skilled performance
ex. parkour
Newell 1985: 3 stages
- coordination
- control
- movement
Newell 1985: 3 stages cont’d
- coordination (pattern acquisition)- firing pattern, motor programs built off continual movement
- control (pattern adaptability)- keyboard tapping, changing/improving/increasing efficiency
- Mastering the degrees of freedom problem (Bernstein): How do we control the multiple degrees of freedom of the human biological system?
- recall bimanual coordination (two movements cannot occur at same time without significant interference)
- changes in movement coordination are the result of freeing (activating) and freezing (inhibiting) the DOF
- selective and intentional with movement type
Ericsson (1993)
- expertise
- length of time needed: 10,000 hours
- deliberate practice:
- optimal instruction (beginner-heavily reliant on external feedback)
- intense
- work like practice
- not inherently enjoyable ( high jumpers)
ex. the Dan plan- pro golfer article
Motor learning: overview
- changes in internal processes that determine an individual’s capability for producing a motor action
- improves with practice
- inferred by observing relatively stable levels of motor performance
- learning is not directly observed
- a relatively permanent change in behaviour as a function of practice or experience
motor learning: overview cont’d
- change not as a function of maturation (developmental change) -learning to walk as baby vs post accident
- change result of practice
- change of state: permanent not temporary
- effect of heat on milk vs egg (egg is permanent- learning)
motor learning: measurement of learning
- indirect measures
- process vs product (end goal), process harder to measure
- process goals focus on the quality of movement production
- qualitative assessment
Ericsson (1993)
Associated motor performance characteristics
early—————————later
(qualitative)
stiff——–more relaxed——automatic
Measurement of learning
- product (outcome) goals focus on the end result of an activity
- quantitative assessment (measuring outcome or final product)
Performance Curves
how do we do we depict learning?
- “learning curve” -misnomer
- plot of individual or mean performance against practice trials
- type of task will influence if curve increases or decreases with practice (read axis)
- not directly observing learning, observation and performance infer learning
- more trials=increased performance
Performance Curves
how do we do we depict learning?
- “learning curve” -misnomer
- plot of individual or mean performance against practice trials
- type of task will influence if curve increases or decreases with practice (read axis)
- not directly observing learning, observation and performance infer learning
- more trials=increased performance
Performance Curves cont’d
- a universal principle of practice: rapid improvements at first and slower later (biggest jump first)
- genetic ceiling?
- changes in behaviour (but is it learning?)
Learning vs motor performance
- relatively permanent changes which persist over many days (learning)
- performance can be affected by transient or temporary effects which can vanish wth time or with a change in condition (performance)
- what procedure can tell us if the effects of the following graph are due to learning or to a transient (performance) effect?
transfer designs for learning
- post acquisition time: sufficient time for temporary effects to dissipate
- transfer tests-novel variation of task (some relation)
- retention tests- same task as in acquisition
- this is the basis by which learning is determined
- size of the performance effect can be maintained, reduced, eliminated, reversed
criteria for learning
- what is important? (concepts important)
- performance of the same task? (repeatability)
- performance on new variations of the same task? (generalizability)
Transfer of learning: does non-specific practice lead to learning?
Specificity of practice for learning: best learning experiences are those which closely approximate that of target skill and context (RBC training ground)
Transfer of learning: the gain or loss of a person’s proficiency on one task as a result of previous experience on another task
transfer of learning: does non-specific practice lead to learning?
- is there transfer from acquisition session to relatively permanent behaviour? (anything you learn is better than what you don’t)
- performance in one task contributes to performance in some other task
- transfer can be positive or negative
Transfer of learning: positive transfer
- when practice on one task improves performance on another task
- squat ROM and swimming
Transfer of learning: negative transfer
-when practice on one task degrades performance on another
-McGregor vs. Mayweather
UFC-boxing, baseball-softball
-usually affected by the rules or dynamics of sports
Transfer of learning: Near transfer
- a type of transfer of learning that occurs from one task to another very similar task or situation (generalization)
- mechanic working on new model
- VR/simulators
Transfer of learning: Far transfer
- a type of transfer of learning that occurs from one task to another different task or setting
- speed skating-cycling
- similar underlying principles
3.1: motor learning
Definitions: motor learning
motor learning- is a set of processes associated with practice or experience leading to relatively permanent gains in the capability for skilled performance
ability- is a stable enduring trait that influences skilled behaviour (genetic foundation)
capability- is the reflection of the fact that any single performance may not reflect the skill level that underlies performance
-Usain bolt losing one race at the end of career
-cannot infer learning from single performance
-function of practice
Learning is NOT directly observable
Practice leads to alterations in CNS (stimulus ID, response selection and programming, executive- spinal cord)
CNS alterations are known as brain plasticity (changeable under various conditions)
-not directly observable
Inferred from changes in performance (or infer changes in plasticity)
Examples of changing conceptual model (executive)
stimulus identification:
-increase automaticity (more automatic, cut down response and reaction time)
-together with speed and accuracy in analyzing environmental and movement feedback info
response selection:
-improvements in ways responses are selected (automaticity- seen before)
Response programming:
-improvement in ways responses are parametrized
-coding for muscle and force
-putting code for motor program
Examples of changing conceptual model
motor programs:
-more effective GMPs and effector processes
-improving NMS
-more practice
Feedback:
-more accurate and precise
-gone through so many times, know what to expect
-actual and desired closer
-easier to detect error and analyze internal feedback
Output/actual:
-establish more accurate references of correctness to aid in movement
Mentioned before but keep in mind…..LEARNING
Learning:
- result of practice
- not directly observable
- changes are inferred from certain performance changes
- set of processes in the CNS
- not all changes in performance (transient factors) are due to learning
- produces acquired capability for skilled performance
- changes relatively permanent
Process vs Product
Process goals: focus on the quality of movement production
-qualitative assessment- hard to measure
Process vs Product
Product (outcome): goals focus on the end result of an activity
Quantitative assessment (measuring outcome or final product)
-measures of accuracy, consistency, dispersion (performance curves)
Measurement accuracy: Constant error: -Mean -Mode -Median Measurement of (in)consistency: -Variable error Measurement of dispersion: -Standard deviation
Measurement of accuracy: constant error
Constant error: is the deviation with respect to amount and direction from target value
-average error/ accuracy
CE= sum (Xi-Criterion)/n
Measurement of accuracy: constant error
formative assessment: -previous slide summative assessment: -post acquisition -retention stage Time- to infer learning Formative-------time-------summative
Measurement of accuracy: issues
Constant error utilizes the MEAN: -sum of average scores divided by total number of scores (average) -sensitive to extreme scores- outliers *best measure of accuracy: cluster- mean multiple wide scores- median
Other measures of central tendency: Median: -rank scores from highest to lowest and take middle score (odd numbers) -less sensitive to extreme scores Mode: -score with the highest frequency -also less sensitive to extremes
Measurement of (In)consistency
Variable error: is the spread of scores with respect to the constant error of movement
- formative and summative
- decrease with practice
VE (SD) =Variable Error = Σ (xi - CE)2
n
Measurement of dispersion: Standard deviation
Standard deviation: is the spread of scores
-in a perfect normal distribution (bell shaped), mean/ median/ mode are all equal
Performance curves
dependant= Y
independent= X
-pay attention to direction
Performance curves: limitations
Remember: these are performance curves, not learning curves
- ploys of average performance over practice trials (average leave out meaningful info, hard to plot ALL)
- do not necessarily indicate progress about relatively permanent capability for performance
Differential Approach:
Inter-individual effects are masked (effects bw individuals):
-assumes everyone improves at the same rate
Intra-individual variability is masked:
-only considers average performance
-transient factors masked
Retention-transfer designs for learning
-remove transient factors with time
Retention-transfer designs for learning
- practical design for coaching/teaching
- consistent time intervals
Temporary/permanent effects of practice
Performance vs learning
Motor performance does not equal motor learning
Importance for instructors/coaches
- we strive to know the practice conditions that maximize the development of these relatively permanent changes (learning), so these conditions can be used in various practical settings to enhance learning
- need to know practice conditions for replication
- pay attention to your own feedback and instruction (dynamic)
Importance for instructors/coaches
- some effects can be positive and increase performance levels (motivation)
- some effects can be negative and degrade performance levels (fatigue, incorrect motivation)
- be aware of the power*
- awareness of things like overtraining
Practice effects on learner
- Relatively permanent effects that persist across many days, even years.
- Temporary effects that vanish with time or a change in conditions. (dog at dog park vs home, if practice in 1 environment hard to replicate)
- Simultaneous temporary and relatively permanent effects that can influence performance markedly. (some interaction and overlap between the two, practice in different environments)
Criteria for learning
What is important?
-what do you pay attention to? -particular movement?
-changes with more practice
feedback from coach
Performance on same task (repeatability)
-closed loop?
Performance on new variations of same task (generalizability)
-open skills-maximize ways to solve problems
-diversification- ex. switching foot in soccer
Evaluative phase outcomes- Gentile 1972
-categorize responses and how to proceed with practice
Yes (product), Yes (process)- got the idea, may need to refine to enhance or if becomes more complicated
Yes (product), No (process)- how you define correct process ex. Steph Curry, Degrasse
No (product), Yes (process)- keep refining and nit picking details
No (product), No (process)- anything you do better than everything you don’t
Recap
- Motor learning is stable and enduring and can occur at any part of our conceptual model.
- Assessing motor learning is not as simple as previously outlined.
- As coaches/instructors, you strive to know the optimal conditions for learning.
- If movement does/does not result in correct movement, we can troubleshoot to know why.
Lecture 3.2 Skill Acquisition
Beginner to expert
Beginner guitar player needs to consciously consider several problems:
-Which fingers on which frets
-avoiding certain strings
-what finger positions make up which cords
-Temporal considerations
Expert guitar players do all of this, not only well, but with very little thought.
ex. rap vs stammer
Beginner to expert
Beginner driver has to concentrate on several movement patterns & stimuli. (parent beside you)
Experienced drivers do so seemingly automatic. But what if:
-You spend a year off of driving? -retention design
-You drive a different car for the first time? -transfer
-You drive in England for the first time? -transfer
It would be incredibly inefficient if we had to go through the entire acquisition process every time we drove under different conditions
Principles of practice
Most important aspect of skill acquisition is practice
-motor learning and performance
Repetition
Performing as close to the identical action over and over again. -little variability
Repetition ≠ Practice
Practice should allow performer to explore the best possible movement options to find best solutions. -determine initial success and refine as we go
-novice- inefficient no matter how they do it (Bernstein)
Repetition
“…practice…does not consist simply in repeating the solution of a motor problem time after time, but rather in the process of solving this problem again and again by techniques which we changed and perfected from repetition…” - Bernstein, 1967
What is a potential problem if a person were to only rely on repetition as a form of practice?
- is it ideal or ok (simple) -repeatability
- different from repetition (complex/multi-limb)
Specificity
What you learn is very close to identical to what you practice. -want to be as specific as possible
So if you want your team to do well on a dark rainy night with loud crowd noise, you have to practice on a dark rainy night with loud crowd noise?
-training for specific environment and context very hard to achieve/ create
Specificity
- What you learn is very close to identical to what you practice.
- Benefits of practice will sometimes only extend to the exact context you’re practicing (closed skills?)
- Changes in environment, or sensory feedback, can reduce (eliminate) any performance gains due to practice. (open skills)
So transfer is challenging - specificity is the dominant characteristic of learning
-overly specific detract from learning and facilitating performance
Specificity
- What you learn is very close to identical to what you practice.
ex. Wembley arena 90,000 fans (how do you replicate?) - During practice, the goal should be a mixture of:
1) Performing the target skill as well as possible.
2) Explore other ways of performing the target skill to see if any are better than what you know.
Youth-coaches need to balance
Pro- coaches 0’d in one what you have= stuck with it
-not looking to change just immediate results
Learning vs. Performance
-Suggest breaking practice into practice and test sessions, and alternating between the two
During practice:
Avoid repeating what they did earlier, explore different ways of performing
-perform way we want them to
During test:
Perform the target skill as effectively as possible
Applied
Example: Why driving range practice might not be successful.
Repetitions:
Focus is only on repeating the movement of the swing, and very little attention on shot selection and preparation.
-wide variety of clubs
-repeating same shot does not improve any other part
What is a better practice alternative?
Applied
Example: Why driving range practice might not be successful.
Practice design:
Emphasis is usually on improving performance during practice (e.g. hit longer or more accurately on the range).
-very little freedom of movement- hard to find optimal movement pattern
Applied
Example: Why driving range practice might not be successful.
Specificity:
Restricting practice to idealized case of flat surface, raised ball, no obstacles to ball flight, sheltered environment etc.
Applied
Example: Why driving range practice might not be successful.
Learning and performance:
Golfers anticipate that a good driving range performance will translate to a good score on a round of golf. This can lead to frustration.
Dan plan- repeated- did not work out as planned
Benefits of practice: Perceptual skills
-meaning and memory
When you practice a specific skill, you are also enhancing the perceptual processing regarding the specific features of that skill.
Perceptual skills
Perceptual Skills:
- Perceptual skills (ie. chess) - Chase & Simon
- reconstruct what you saw
meaningful- stop game 1/2 through
random- pieces everywhere
3 groups/ levels (novice- no tactics, intermediate-better understanding, master)
Perceptual skills cont’d
Graphs in notes:
Meaningful:
M-improved fastest
A-started 1/2 as good as master
B- most trials, improved slower, started 1/4 as good as master
- ALL groups perceptual skills improved with practice
Random:
M- still improved but at lower rate than other 2- what makes sense
A- improved at one of fastest rate, same
B- improved at one of fastest rate and most- no association with randomness
Perceptual skills
Perceptual Skills
Conclusion:
With practice, you can acquire domain specific advantages in perceptual processing
ex. blindfolded Rubik’s cube- same movement patterns every time
ex. chess without watching
Attention capacity
- finite resource
- Reduced capacity demands
- When you practice a complex skill, you reduce the amount of attention required for that skill (or each component of the skill).
Attention capacity
-reduced capacity demands pie chart
Attention capacity example
ex. skating and stick handling
1) skating with puck harder than without
2) people of poorer skill are affected more by stick handling
adding puck= demanding, decreasing task performance
3) skating and stick-handling get better with age
-not product of development
-better with years of practice
Conclusion:
-the decrement in skating performance during stick-handling is reduced as skill improves (McDavid)
Decreased effector competition
- Practice can reduce the interference experienced by two limbs performing bimanual tasks.
- Given our discussion of bimanual control, what might practice do to the motor program(s) controlling the complex movement?
- bimanual fitts- one impacts the other
- more practice=decreased competition/ move with independence
ex. piano move hands independently
Motor programs
With practice, one motor program can control increasingly complex set of movements.
Ed Sheeran- 1 man with guitar
-feet and legs moving looping pedals
-reduced attentional capacity- motor programs
Motor programs: gear shift analogy
-attentional demanding early practice: keep stalling middle practice: more flow between motions late practice: 1 fluid motion -automatic -7 singular movements
improved error detection
- Practice improves ability to detect and analyze errors in performance on your own (eg. without coaching/guidance)
- ex CPR
- This can ultimately make a learner self sufficient
- *Can be dangerous though
- seizure at hockey game
- CPR- what’s good and bad
- instructor not there when you need it, can be dangerous on only guidance and automatic
Stages of learning: Fiits
Fitts’ Stages emphasizes both the perceptual and motor components of motor learning
Stage 1 - Cognitive
Largely verbal;
Focus on goal identification;
Performance evaluation;
What to do and when/how to do it;
Think about what to focus on in the environment and what movements are critical
-dont have movement pattern- cannot gather without practice
Stage 1- cognitive: applied
- Use instructions, film clips, demonstrations and discussions to guide learners. -integral part of learning process
- Refer to already learned skills to develop new skill. -transfer
- Gains are rapid and large,
- It is expected that performance may be uncertain since this is the building block for future development.
Stage 2- fixation
- Associative/Motor (more motor)
- Shift away from “thinking” (cognitive) to finding optimal movement parameters.
- How might open loop controlled movements change during this stage? -faster
- How might closed loop controlled movements change during this stage? -controlled
Stage 2- fixation: applied
- Performance shows steady improvements. -branch off in own direction
- Some variability is expected as performers search for best movements / parameters.
- Environmental cues are learned, improving anticipation and movement quality.
- Self monitoring of errors develops. -instructor role starts to diminish
Stage 3- Autonomous
- After considerable practice performer attains expert performance.
- Anticipation is high, perceptual processing is fast.
- Motor programs are long and control complex movements. -takes time and effort
- Fewer programs means more resources are available for attention.
Stage 3- Autonomous: Applied
- Additional attentional resources allows performer to perform higher order cognitions
- Self error-detection is further refined.
- Learning progresses, though, slowly.
ex. speech slide
-differential sounds made in oral cavity to get faster
speed-accuracy- less tongue movement
