midterm 2 Flashcards
what is optic flow
visual processing in the dorsal stream that allows person to detect motion, positioning and timing
describe how optic flow can determine distance, speed, direction
distance is proportional to the angle in the retina of the object’s image
speed is proportional to the rate of change of the angle in the retina
direction is proportional to the direction the angle changes about the middle
what is tau
time to contact is proportional to retinal image size/ rate of change of retinal size
describe open loop control
closed loop but no feedback or comparison.
what is the motor program
set of prestructured commands at the executive level and defines the skilled action
what are degrees of freedom
components of the control system that can be controlled to produce action
what are open loops used for
rapid discrete movements.
predictable and stable environments
to initiate movements
long strings of learned/rehearsed movements
how does movement complexity change reaction time
for a simple reaction time test
the more complex, limbs or time of action the longer the RT
what is deafferentation
cut afferent nerves from an arm. blocks proprioception
How does deafferentation support motor program theory
monkey’s performance does not change even without proprioception and vision of arm. no feedback possible so must be open loop
What is a central pattern generator
controls genetically defined repetitive actions like walking or chewing
how does CPG support motor program theory
one input results in complex repetitive behaviour
how does limb blocking support motor program theory
EMG data shows that muscle still activates for the movement that now cannot take place because it is blocked
what does the clock stopping experiment prove.
that if the clock is stopped 150ms to the target then there will be a failure to inhibit the participant stopping it themselves
explain postural/anticipatory adjustments and how they are motor programs
muscles fire from the feet up to stabilise the body for a lift.
postural support and the lift are one programmed action. too complex and must be considered a motor program
what is a reflex reversible phenomenon
M2. reflex with different responses based on the context.
what are the problems with motor program theory
storage problem, novelty problem
how does general motor program theory address the problems with motor program theory
,motor program only defines a pattern of movement but parameters of the movement can be adjusted to make different movement variations for different demands.
how does GMP fit into the 3 stage IP model
perception and decision are to select a GMP
action is to adjust the parameters of the GMP
what is an invariant feature.
parts of the movement that are the same for the GMP
how does relative timing work in GMP
the movement pattern in GMP will always have the same relative timing even if the total duration of the GMP is changed
what is fitts’ law
finds a linear relationship between movement time and Index of difficulty. (differing amplitude and target width). Logarithmic relationship without index of difficulty
independent: amplitude and width
dependant: movement time
testing on closed loop system
what is the linear speed-accuracy trade off test
independant: MT, amplitude
dependant: endpoint variability
endpoint variability increases with independent increases in amplitude and independent decreases in MT
how does muscle force influence accuracy of the movement
increases with muscle force until 70% then declines. This is due to the fact that near maximal contractions recruit almost all muscle fibres which decreases variability. Under 70 % then a random number of muscle fibres will be recruited and this increases variability
what is spatial accuracy and how is it different to timing accuracy
spacial accuracy is where the end position of the movement is the most important variable to be accurate
timing accuracy is where the accuracy of the MT is the most important
the faster the MT the better the timing accuracy
the slower the MT the better the spacial accuracy
what is needed to make a scientific conclusion
central tendency (mean)
variability (standard deviation
sample size
normal distribution
what do bimanual skills show about motor programs
only one in use at one time to control both arms. two cannot be used without significant interference. dominate side usually dominates
how does the bimanual obstacle test show that there is a joint motor program
left moves around obstacle like expected but so does right even though there isn’t an obstacle
what do the timing and coordination of bimanual movements say about joint motor programs
moments more stable in the same rhythm. this allows using same joint motor program
anti phase has more error and is less intuitive. increases in error before falling into line with in phase during increasing speed
what evidence is there for multiple motor programs being developed in the brain
in go before you know tests, it was found that multiple motor programs were created and the average between them was used before a stimulus allowed one to be selected to complete the movement.
how is the dress an example of individual differences
the colour perception of the dress changes based on whether the individual perceives the light in the image to be shining directly on the dress or if the dress is shaded
what is an individual difference (3 criteria)
stable across many attempts of the same skill
endures over time
difficult to establish from only a single measurement
why are individual differences important for making predictions
characteristics of a person can help predict the likelihood of success or failure in a situation
ie. insurance
why should individual differences be studied to understand abilities
end performance of a skill is more than just the result of practice. some innate ability present. Looking for individual differences compared to their performance may reveal abilities.
what are the two methods to test individual differences
experimental and differential
what is the experimental approach to individual differences
multiple groups on a single test variable. variations are removed and it is a general method that can produce cause and effect statements.
ex. Jim and John. who had the higher grade last year
what is the differential approach to individual differences
individual performance on multiple tests.
correlation
ex. do students who exercise regularly have higher grades?
plot out on a scatter board and attempt to find correlation data. R score. (magnitude for correlation, sign for direction)
what is the relationship between ability and skill
abilities are the innate capabilities built into a person cannot be changed. skills are what the person does with these capabilities can be modified with practice.
hardware vs software
what is the general motor ability theory
only 1 general motor ability
some people are just good at sports and will always out perform people who are not good at sports in every sport.
perfect correlation in multisport performance
r=1
too general
activities are too varied for this principle to be reasonable
what is the specificity hypothesis for motor abilities
performance is dictated by a unique combinations of abilities and that there are so many different motor abilities.
being good at one thing doesn’t mean you will be more capable in another. no correlation in multisport performance
R=0
too specific. refuted by generally athletic people with physiological, biomechanics advantages
what is the groupings of abilities theory on motor abilities
performance in tasks can share some common abilities among the 50 -100 abilities. imperfect correlation.
what process can be used to identify abilities that are involved in multiple skills
factor analysis
what is superability
a weak general factor common among most movement skills
analogous to IQ for cognitive tasks.
not great but does work.
can future capacity be predicted by current capacity?
difficult. being good as a novice and being good at as an advanced athelte requires two different abilty combinations and often things change with practice. Abilities are also difficult to measure.
what are the problems does motor programs solve
when does voluntary movement start.
how does the increased noise with increased force explain the accuracy speed trade off
more force required for more speed. introduces more noise which reduces end point accuracy
how do degrees of freedom provide a solution for the speed accuracy trade off
increased degrees of freedom allow complex moments to converge on a more stable and efficient movement that can optimise accuracy at different speeds.
ex. efficiency of running vs walking at different speeds.
How do motor programs influence the actions of M2 reflexes
they set the pathway, determining the output of the M2 reflex
how do motor systems deal with an increase in speed and a decrease in accuracy.
switch general motor programs to find a movement better suited to the speed.
how to answer a problem that asked what type of problem a scenario is.
for novelty look for indications that the event is new.
for storage look for indications that the event has happened before and that there is many different variations of this action.
what is motor learning.
processes associated with practice that leads to relativly permanent gains in skilled performance.
specific transfer vs general transfer
learning for specific task usually closed skills (free-throw)
vs
learning for general skills that can be used in different settings (jump shot)
near vs far transfer
near is when skill is similar to training
far is when goal is very different to training
what should a person do during practice
perform the target skill as well as possible
try and find new ways to optimize the skill
what are the fitts stages of learning
1) cognition. focus on applying basic instruction and existing skills to create a new skill.
2) fixation. less about thinking and now about optimizing the movement
3)autonomous. relative expert. gaining ability to self error detect and divert attention while doing task.
Bernstein’s stages
1) reduce degrees of freedom
2)release degrees of freedom
3)exploit passive dynamics (gravity, momentum, elasticity)
what are some limitations of stages of learning
not concrete. can regress and may progress in different directions
which tasks are easier to forget
discrete with cognitive componenets
why warm up
eliminate short term set losses.
