motor learning 2

speed-accuracy trade-off

a characteristic of motor skill performance in which the speed at which a skill is performed is influenced by movement accuracy demands

what is the tradeoff

increasing speed yields decreasing accuracy and vice versa, increased speed causes decreased accuracy 

examples of motor skills that require both speed and accuracy

• penalty kick in soccer

• pitching fast ball

• speed typing

what spacial dimensions of two variables do we need to know to predict movement time for speed accuracy skills

movement distance and target size

what is the equation for movement time 

MT=a+b log2(2D/W)

a and b= constants 

d=distance from the starting point to the target 

W= target width or size 

what does log2(2D/W) indicate

provides an idea of difficulty bc of the lawful relationship btw target size and mt

what increases as index difficulty increases

movement time

what non-laboratory skills does fitts’ law apply to

• throwing darts

• reaching or grasping containers of different sizes 

• moving a cursor on a computer screen 

• playing a piano 

how many motors control process involved in performance of speed-accuracy skills 

two 

motor control process involved in speed-accuracy skills

open and closed loop control

open-loop control

initial movement’s speed, direction, and accuracy are under CNS control without feedback; moves limb into vicinity of the target

closed-loop control

visual feedback about limb’s relative position to the target is used to guide the “homing in” phase of the limb to ensure its accurate landing on the target

phases of speed accuracy skills 

1. movement preparation phase 

2. initial flight phase 

3. termination phase 

movement preparation phase

person uses visual information to determine the regulatory conditions that characterize the environmental context in which the action will occur

initial flight phase

vision acquires limb displacement and velocity information and squires time to contact info that will be used later as movement nears the target to make movement modifications

termination phase 

beings just before and ends when target is hit 

prehension

general term to describe actions involving reaching for and grasping objects

three components of prehension 

1. transport 

2. grasp

3. object manipulation 

relationship btwn transport and grasp components

initial views proposed that they were relatively independent, recent evidence shows that they are temporally coupled and interact synergistically

role of vision in prehension

• assists planning of prehension actions by providing info about regulatory conditions of the environmental context

• transport of hand to object: visual feedback related to movement characteristics will be used by CNS to modify movements

• grasp of object: supplements tactile and proprioceptive feedback to ensure the intended use is achieved

does prehension demonstrate fitts law

yes, shows speed-accuracy tradeoff chatters as predicted by fitts’ law

how does handwriting control demonstrate chacterisitcs of coordinative structure

bc of its motor equivalence capability

motor equivalence in handwriting 

a person can adapt to various demands of the writing context and adjust size, force, directions and muscle involvement to accommodate those demands 

what is important in handwriting and why

vision bc it is important for overall spatial arrangement of words and accuracy of words/patterns

bimanual coordination

motor skills requiring simultaneous use of two arms

two intrinsic coordination characteristics

symmetric bimanual coordination, asymmetric bimanul coordination

examples of symmetric bimanual coordination 

rowing, wheelchair 

example of asymmetric bimanual coordination

playing guitar, tennis

3 phases of catching a moving object

1. initial positing of arm and hand toward the oncoming object

2. shaping of hand to catch the object

3. grasping the object with your fingers

when is constant visual contact needed for catching a moving object 

initial flight phase and just prior to hand contact 

between initial flight phase and just before hadn't contact, what is sufficient

brief, intermittent visual snapshots

what does the visual system use to determine if a person will collide with a moving object

looming

tau 

provides visual basis for timing a catch 

is vision of the hands necessary to catch a moving object?

for inexperienced catchers yes

why Is vision important 

enable us to avoid contact or contact objects 

how does vision tell the body to avoid contact with objects 

it provides the motor-system with advance information about the body to determine how to avoid contact; person orients his or her body accordingly 

what’s involved in control of locomotion

central pattern generators(CPGs) in spinal cord

what Is gait

walking

locomotion

a functional network, generating the rhythm and shaping the pattern of motor neuron activity ; provides rhythm for walking and running gait patterns 

what influence gait 

proprioceptive feedback from muscle spindles and Golgi-tendo organs

what is this the practical benefit of analyzing rhythmic structure of gait patterns

allows for assessment of coordination problems of trunk and legs (ex. parkinson'‘s disease)

what does locomotion do with the head

maintains head stability

gait transitions

important in locomotion due to how people spontaneously change form walking to running gait at critical speed

most popular hypothesis for why spontaneous gait transitions happen

minimize metabolic energy use, no single cause for gait transitions has been determined

action preparation 

occurs btwn action intention and initiation of movement, getting ready to prepare 

what does action preparation require

time

reaction time(RT)

an index of preparation required to produce an action, sometimes called response-delay interval

what does rt indicate

tells us that preparing to perform voluntary movement takes time and does not occur instantaneously; certain action require more time to prepare

what influence preparation

number of response choices, predictability of correct response choice, probability of precue correctness, stimulus-response (S-R) compatibility

how does the choices or alternatives affect preparation 

increased choices leads to increased RT, amount of time required to prepare movement increases 

Hick’s Law

RT increases logarithmically as the number of stimulus-response choices increase, decreased choices-decreased RT(respond faster)

how does predictability influence preparation 

the more predictable a choice is, the lower the RT(respond faster) 

precue

giving advanced info about motor skill

cost-benefit trade off

cost(in terms of slower RT) and benefit(in terms of faster RT) that occur as a result of biasing the preparation of an action in favor of one of the several possible actions

stimulus-response compatibility (S-R)

• physical relationship btwn stimulus and response choices

• the more compatible, the faster the RT b/c less to think about

stroop effect 

• phenomenon that occurs when a person must verbally respond to the ink color of a word that names a color, rt for saying the word is faster when both the same color 

• involved with compatibility 

foreperiod length regularity

time interval btwn a warning signal and the go signal or stimulus; if period of time is constant, rt will be shorter

if it varies than rt will be longer, attributed to anticipation

movement complexity

rt increases as complexity/parts of an action increases

movement accuracy

as accuracy demands for movement increase, amount of preparation required and rt increases

what does repetition of a movement do

lowers rt for next trial(faster), less to think about

Psychological refractory period

PRP, delay of response to second stimulus, slower response time, increases RT, takes longer to react ti 2nd signal b/c still responding to 1st

what does alertness of a performer do to rt

improves rt, decreases rt (react faster) 

what should someone be provided for alertness 

warning signal 

vigilance

long tern maintenance of alertness

how does vigilance affect rt

increases rt bc it ultimately decreases alertness bc person can get tired of being alert for long 

what should people be focused on for faster rt

focus on signal and allow movement to happen form there

where were increases reflected when changes in RT happened due to increased complexity

premotor component( perceptual and cognitive components when preparing for action)

anticipatory postural adjustments 

APAs, organizing movements needed for postural support to complete an action; when preparing for an action 

limb performance characteristics

ways limbs are preparing for movement,

• movement direction

• movement trajectory

• prepare in advance

object control characteristics

force control

end-state comfort control

grasps an object based on what your final destination is with it/ what you wan to do with it

force control 

preparing to lift a box based on how heavy you think it is

examples of preparing a sequence of movements

• playing the piano

• typing on keyboard

• speaking

what is an example of rhythmicity preparation

pre-performance rituals

attention

refers to several characteristics associated with perceptual, cognitive and motor activities that establish limits to our performance of motor skills; relates to consciousness or awareness; we have attention limits when multitasking

Bottleneck theory/ filter theory

person has difficulty doing multiple task at one time because of the inability to serially process multiple stimuli; problem: does not apply to all performance situations

central resource capacity theories of attention

propose one central source of attentional resources for which all activities requiring attention compete, can do multiple task as long as the fit into central resource bubble/ attention capacity  

Kahneman’s attention theory

example of central resource theory, Views attention as cognitive effort, which relates to the mental resources needed to carry out specific activities; central pool: flexible capacity/varies

in Kahneman’s attention theory, the amount of attention capacity available for specific
performance situation is determined by

performers arousal level

how do tasks differ 

in the amount of attention they demand 

3 rules in Kahnmen’s theory that helps allocate attention when multitasking

.1. Allocate attention to ensure completion of at least one task- shift focus on 1 task
2. Enduring dispositions: Involuntary attention to at least two types
of characteristics of events
• Event is novel for the situation in which it occurs
• Meaningfulness of the event to us personally
3. Momentary intentions
• Allocate attention according to the performer’s specific
intentions

exmaple of a novel situation 

making noise during a free throw, attention pulled elsewhere 

ex of a meaningful event

someone call your name when your talking to someone else

multiple resource theory 

alternative to central resource theory, proposes: we have several resources for attention but each has a limited capacity; so multiple bubbles allow us to do better with attention as opposed to task coming from just 1 bubble 

dual task procedure for assessing attention demands

Determines attention demands and characteristics of the simultaneous performance of two different task

what is the primary task known as in dual procedure

task of interest

what is the secondary task known as

the basis to make inferences about the attention demands of the primary task

attentional focus

The directing of attention to specific aspects of our performance or performance environment

width of focus

focus can be narrow or broad

direction of focus 

focus can be internal or external 

attention switching

changing attentional focus

Focus attention

proposes that focus should be in intended outcome, actions are more defective when planned based on their intended outcome rather than movements themselves

automaticity

Performance of a skill (or its parts) with little/no demand on attention capacity

visual selective attention

Visual search locates relevant information in the environment that will enable a person to
determine how to prepare and perform a skill in a specific situation, can focus on multiple things

what helps us with motor skills and allows us to see whats going on outside of central vision 

peripheral vision 

what is tracked in eye movement recording 

central vision, not peripheral vision 

what 3 aspects of action control process does visual search pick up information from

1. action selection

2. constraining the selected action

3. timing of action initiation

quiet eye 

Refers to the amount of time devoted to the final fixation just before movement initiation, longer for elite performers 

visual search success is based on what

specific performance situations, often acquired without specific training or conscious awareness