KNPE 261

Motor Skill

Task with specific goal, performed voluntarily, requiring body and/or limb movement, needs to be learned

Components of a Motor Skill

• Perceiving relevant environmental features

  • Need to take in info from sensory receptors

  • Defining the goal positions and outcomes

• Deciding what to do and the timing of the action

  • Planning and programming how to achieve that goal

• Producing the muscular activity required to generate the movement goal

  • Sending the commands and adjusting the commands as needed

Discrete vs Serial vs Continuous

• Discrete: Specific motions, defined start and end point (bat-swing, free throw, wrist shot)

• Serial: Set of discrete movements strung together (gymnastics, typing, piano) 

• Continuous: repetitive over a period of time, no defined start or end

Open vs Closed Skills

• Open skills: happen in highly unpredictable environments

  • Success influenced by

    • Perception of external stimuli

    • Adaptability

• Closed skills: happen in more predictable environments

  • Success influenced by

    • Persistence and consistence

    • Planning and programming

Fine vs Gross Motor Skills

• Fine: smaller movements from smaller muscle groups in coordination (writing, sewing)

• Gross: bigger movements from larger muscle groups in coordination (dancing, serving)

What do we consider when measuring motor skills?

• Objectivity: two tools can come up with the same measurement of performance. Dependent on the tool. One measure may be more objective than another.

• Reliability: the same measuring tool, how likely it is that they will produce the same measurement on two separate occasions.

• Validity: how well do our measurements translate to performance if we change the environment

Constant Error (CE)

• Used on a single trial

• The amount and direction of bias away from the target

• Measures accuracy

• Useful for providing feedback about tendencies or bias

• Gives us the magnitude of error

  • How far performance is from target

  • Can be computed in more than one axis

  • Sign gives the direction of the error

• Mean CE is the average error in the response

  • 

Variable Error (VE)

• Computed by first summing the differences between the performance score and the person's own mean

• Reflects the participant's variability or consistency

• Variable error does NOT depend on whether the performer was close to the target

• Variable error is not concerned with the target position

Total Variability

• Measure of "overall error"

• Total variability accounts for of the bias and variability

  • Also known as Root Mean Square Error (RMSE)

• Sum of the squared differences between the achieved position and the goal position

  • Similar to VE with reference to the target position

• Measures consistency around the target values

Absolute Error (AE)

• Absolute deviation between the performers movements and the target

  • Complex mathematical relationship between CE and VE

  • Not as clear as E

• Used a lot in early research

• You use the absolute value for xi-T before dividing it by the number of trials

• You can cancel out bias when summarizing the whole group

• Is just absolute value of CE

Measuring Performance in a Continuous Task

• Can compute the difference between performed trajectory and target trajectory

• RMSE

Biomech vs Motor Control

• Biomechanics and rehabilitation is often concerned with the quality of movement

  • Examining loading, muscle activation patterns, joint reaction forces

  • Purpose: preventing injury, making movements more efficient

• Motor control and learning is often concerned with errors and performance

  • Examining endpoint variables and strategies (kinematics)

Characterizing Movement Features

• Movements can be characterized by looking at kinematics

  • Concerned with motion rather than the forces that created that motion

• Kinematic markers can be used to describe movements

  • Position information (where the limb is in space)

  • Velocity information (rate of change of position)

  • Acceleration (rate of change of velocity)

• Temporal and temporal-kinematic variables are also used to describe movement

  • Reaction Time, Movement Time, Time to/after Kinematic Markers

Why are Kinematics Useful?

• Kinematics can give a researcher/ teacher/ coach detailed information about current performance and improvements in actions

• Can provide detailed and understandable feedback to participants

• Neuronal firing patterns reflect direction and speed of upcoming actions

Kinematics in the Brain

• Neuronal firing patterns in motor related areas in the brain predict the kinematics of movements

  • Posterior parietal cortex

  • Motor cortex

• Speed of upcoming movements corresponds nicely with the firing of neurons in the pre motor cortex

• Most neurons represent direction of movement but also velocity

• Speed and direction are represented by areas associated with movement production in the brain

Reaction Time

• Reaction time (RT) was traditionally used as a proxy for cognitive function

• RT is a measure of the time from the arrival of a stimulus to the beginning of the response

• response Stimulus is unanticipated

Breakdown of Reaction Time

• Trial starts with a warning (wait for the gun fire)

• Stimulus presented (gun fires)

• Premotor RT - no muscle activity

• Motor RT - Upon the stimuli being presented, when there is muscle activity but no overt movement

• RT - time between premotor and motor RT

Movement Time

• Movement time is the time interval from the initiation of the response to the completion of the movement

  • Precision of units depends on the skill

Response Time

• Response Time = RT + MT

• Different processes may be studied using RT and MT

  • Processes to initiate a movement

  • Processes to complete a movement

  • Different processes may underlie correcting a movement as well

Correlation

• Correlations measures both the direction and strength of a relationship

  • Correlation coefficient (R)

    • Number indicates —> Strength of relationship

    • Sign indicates —> Direction of the relationship

  • R² measures the shared variance (can convert to a percentage by multiplying by 100)

• Important to keep in mind that correlations can be spurious

• Correlation does not always mean causation

Regression

• Regression allows to predict one variable from another

• Simple regression fit a linear model to data that we have collected

Attention and Motor Performance

• An indirect way of measuring capability in a motor task is to measure performance on a dual cognitive task

  • Attention is a limited capacity resource

  • The less attention a task takes, the more the performer has mastered it

Dual Cognitive Tasks

• It is harder to do a dual cognitive task

  • Doing a skill while doing a cognitive task on top, is a good measure of how good someone is at performing the actual skill

  • Limiations to this

    • Few underlying changes

Human Information Processing

• Black box approach

  • Input --> Processing -- > Output

• Motor behaviour takes a chronometric approach

  • Measure the timing of this input to output and infer the amount of processing that takes place

• Many different information processing activities take place during the RT period

  • It is critical to have a well designed experiment to use RT as a measure of processing

  • We can infer that as RT becomes quicker, processing increases and vice versa

Simple Reaction Time Tasks

• A task that involves reacting to one stimulus

• Fastest reaction times

• Gives a measure of processing time

  • Correlated with age

  • Affected by fatigue, attention, sensory modality of the cue

The Stages of Information Processing

Parallel vs Serial Processing

• Parallel processing

  • Overlapping processes

• Serial processing

  • Processing in sequential steps

• With regard to human information processing

  • Some steps can occur in parallel under certain conditions

  • Some steps must occur in sequence in certain conditions

Stimulus identification

• First the individual must perceive the stimulus

• Involves stimulus detection and then identification

• The stimulus must be sensed and processed

  • Processed until it contacts memory

    • Some memorized aspect of its relevance is aroused

• There are many variables that can affect the stimulus identification stage

Sensation and Perception

• Sensation involves the activation of sensory receptors

  • Sensory receptors have a minimum amount of stimulation required to detect a stimulus

  • Can be affected by attention at both the behavioural and neural level

• Perception involves interpreting those sensations

  • Involves the combination and integration of numerous sources of information to form a percept

• We move from sensation to perception

Stimulus Detection is affected by….

Stimulus clarity, stimulus intensity, predicability

Response Selection

• After the stimulus is detected, the actor must now decide what response to initiate

  • Move or not to move

  • Move high or move low

  • Block or cover

• Experimentally, we can explain the relationship between the reaction time and the number of possible stimulus-response alternatives

  • Choice-RT: A reaction time task wherein the participant is presented with more than one possible stimulus and the required response is dependent on that stimulus

Hicks Law

• The time it takes to make a response is related to the number of stimulus response alternatives

• Hick's Law was based on an experiment by Hick and Hyman

  • Presented an increasing number of stimulus-response pairs and measured RT

• Choice RT increases nearly a constant amount (~150 ms) when S-R alternatives are doubled

  • Log-linear relationship

    • The relationship between the choice RT and the logarithm of the number of SR alternatives should be linear

Bits of Information

• Log₂(N) = a bit of information

• The amount of information required to reduce uncertainty by half

• Least amount of binary decisions

• Bit = Binary Digit

Interpreting Hick’s Law

• What is the y-intercept (a) experimentally?

  • The reaction time when the number of stimulus responses (N) is equal to zero, simple reaction time

• What is the slope (b) experimentally?

  • Amount of time added when you increase bits by one

Go/ No-go tasks

Reacting to 1 stimulus, and not reacting to another

Choice RT Tasks

• Selecting the appropriate response for a given stimulus

• Slowest reaction times

Donder’s Subtractive Method

Other Factors Affecting Response Selection

• Although the number of S-R alternatives affects response selection, features of the S-R relationship could also have an impact

• One prominent example is the stimulus-response compatibility

  • The mapping of the response to the action

Simon Effect

• Irrelevant spatial features have effects on reaction time (Simon, 1969)

  • Participants responded to auditory cues played in either the left ear or the right ear

• Compared responses of spatially compatible trials versus incompatible trials

• Has been replicated with numerous types of trials

The Joint Simon Effect

• Previous research has also suggested that we can co-represent actions

  • When two people perform the simon task, they perform similar to when performing a two-choice task.

Response Programming

• The transformation / translation of the action concept into the muscular actions that will achieve the goal

  • Sensorimotor transformations

  • Events occurring in response programming could be related to memory

  • Involves the preparation of relevant motor structures

• The final set of processes that allow the individual to communicate with the environment

• Programming of more complex movements

  requires more time

• More complex S-R relationships take longer to program

Movement Complexities

• Accuracy requirement - the size of the goal

  • Speed-accuracy tradeoffs (Fitt's Law)

• Movement components - how many individual movements

  • The number of "parts" of a movement can increase the initial programming time

    • The time to say the first word increased with the number of words

  • Time between components is important

    • With a long pause in between movement components RTs did not increase

• Movement duration - how much time from the beginning to the end

  • This might be the major variable - how can we test this?

Programming a Trajectory

• Proponents of sensory-coding theories of motor behaviour argue that we plan a point-to-point visual trajectory

• Neural activation patterns in motor areas represent spatial goals in a visual reference frame

  • Criticisms to this

Motor programming theory

• Motor programs: a prestructured set of movement commands that defines the essential details of a skilled action, with minimal (or no) involvement of sensory feedback

  • Muscles to use

  • Sequence of muscle activations

  • Force, timing and duration of muscle contractions

• During response programming - the motor program to achieve the action is specified

Criticism of Motor Programs

• Storage problem: Imagine if every movement was a distinct motor program - it would require much more space to store them all

• Degrees of freedom problem: There are too many degrees of freedom to control (to many moving parts)

Dynamical Systems Theory

• Stereotypes similarities of movement patterns are not represented in motor programs but emerge naturally due to complex mechanics

• Solves the DoF problem, and explains expertise and freezing the right DoFs so we seek a minimal solution

• Biomechanics and rehabilitation people like this theory a lot

Anticipation

• In information processing - anticipation means the removal / reduction of the response selection stage

• There are different types of anticipation

  • Temporal Anticipation - when anticipation

  • Spatial Anticipation - what/where anticipation

• Precuing any variables leads to a decrease in RT and response selection and an increase in programming

How can we study anticipation

• Anticipation can be studied by examining the startle response

• A startling tone has been shown to trigger a prepared movement at short latency

• Startle is thought to act as a subcortical trigger for prepared movements

  • Startle is thought to release the correct response

  • Greatest response to startle was when there was only one stimulus and one response

• To elicit greater anticipation only have one stimulus and one response

Senses

• The 5 senses:

  • Vision, touch, smell, taste, hearing

• Other important senses:

  • Sense of balance (equilibrioception) - argued that it is part of proprioception

  • Sense of body position (proprioception)

    • Often paired with tactile (touch senses)

  • Sense of temperature (thermoception)

  • Pain sense (nociception)

Sensory Information and Motor Control

• Sensory information is used for both movement planning (feedforward) and movement control (feedback)

• The use of sensory feedback to modify motor commands is referred to as closed-loop control

  • System receives instructions (input)

  • The goal is defined (reference mechanism)

  • Executive level relays instructions to achieve the goal

  • Effector level enacts the instructions that are relayed

    • Produces an output

• Sensors in the environment produce feedback

  • Feedback is compared to the goal

Visual System - Receptors

• Visual sensation begins at the eye
  Light from an object in the visual field is refracted and focused onto the retina

• Photoreceptors: light sensitive cells line the back of the retina

  • Two main types of photoreceptors:

    • Rods (motion / detection)

      • More rods are in the periphery of the fovea

    • Cones (fine detail)

      • Centred around fovea

Visual System - Central Processes

• Visual information travels through the optic nerve, and various subcortical structures to the lateral geniculate nucleus (LGN)

  • From the LGN in the thalamus, visual information is relayed to the primary visual cortex (V1)

• Primary visual cortex is where visual features such as stimulus direction, stimulus speed, and object

Visual Streams

• From the V1, visual information can travel to one of two visual streams

• Dorsal stream where visual information travels to the parietal areas

  • Known as the vision for action stream

  • Inputs from the full visual field

• Ventral stream where visual information travels to the temporal lobe

  • Known as the vision for perception stream

  • Inputs from the LGN mainly from central vision

• Evidence for the two streams comes from perception-action dissociation

Evidence for the Dorsal and Ventral Streams

• Perception scales to illusions, however grip aperture does not

  • Grip aperture is a measure of the distance between index and thumb when performing reaching movements

Gunslinger Effect Experiment Findings

• Most of the time, the person who draws their gun second wins. The reactor wins, not the initiator.

• Replicated the gunslinger effect showing shorter time to peak acceleration for reacted movements

• Target influenced distance travelled to peak deceleration - indicating an influence later in the movement trajectory

• Results suggest that the ventral stream may be used more for limb target control and the dorsal stream used may be used more for planning

• Contrasts with results that suggests ventral stream may be used for planning

Vision’s effect on balance

• Vision does have an effect on balance

  • Visual system indicates where your head and eyes are in space

• Optic Flow: when we move our head, the angle the light rays hit the retina changes

  • The environment flows past us as our head and body move

    • This gives us crucial information about our position and the position of objects

• Moving room experiments have found that children lose balance if the walls of the room shift

Vision & Predicting Impact

• The rate of change of the size of an object on the retina can indicate whether the object is coming toward you or going away from you

  • From this information we can estimate the time to contact (Tau)

    • Retinal image (A) increases as ball comes closer

• Time to contact is directly proportional to the:

  • Size of the image (A) divided by the rate of change of the image (Ả) multiplied by a constant

    • This is true regardless of distance, size, or velocity

Proprioception

• Sensory information about the position of the body in space

  • Also known as kinesthesis or kinesthesia

• Proprioception includes

  • Vestibular system

  • Sensory organs in the muscles and joints

  • Cutaneous receptors

Vestibular system

• The vestibular system is located in the inner ear

  • Otolith organs provide information about the orientation of the head with respect to gravity

    • Utricle and Saccule

      • Sense linear accelerations

• Semicircular canals are three fluid-filled half-circles

  • These structures are in a position sense directions (aligned to the horizontal, sagittal, and frontal planes)

    • Can sense rotations

  • Thick fluid in the canals displace hair cells (mechanoreceptors)

• The vestibular system is important for balance and orientation

Vestibular-Vision Interactions

• When we move our heads - our eyes stay stable due to vestibular-ocular reflexes

  • When our head moves in one direction - our eyes slowly move in the other direction

• Alternating slow and fast movements are called nystagmus

  • Will stop if the head keeps rotating

Dizzy Training

• Use of spotting may help with overcoming dizzy feeling

  • Focus on a stable visual stimulus (keeping the head still)

• Turning the head after the body has undergone motion - reduces the time the head is spinning

• Training with spotting may shift sensory feedback use to more visual sources

  • May not improve dance performance in novices

Muscle and Joint Receptors: Muscle Spindles

• Muscle Spindles: provides information about muscle stretch

  • Located in the fleshy part of the muscle body

  • Oriented in line with the muscle fibre

    • When the muscle is stretched, the spindle is stretched

• Comprised of intrafusal muscle fibers

  • Innervated by a la afferent fiber

    • Firing rate is related to length and rate in change in length

• Spindle also connects to alpha motor neurons of the muscle

  • Basis of the stretch

Golgi Tendon Organs

• Golgi tendon organs (GTOs) are located at the muscle tendon junction

  • Highly sensitive to active muscle tension

    • Can respond to forces caused by less than 0.1 g

• Each GTO is attached in series to small groups of muscle fibres (<25)

  • Only a few motor units represented by the innervated muscle fibres

• Hypothesized to contribute less to overall position sense than muscle spindles

Joint Receptors

• Joint receptors are embedded in the joint capsule

  • Primarily located in the areas of the capsule that are stretched the most

• Research into the activation of joint receptors have revealed that neural signals are strongest at the end ranges of the joint movement

• Less involved in position sense than muscle spindles

How Important is Proprioception

• Proprioception plays a role in rapid-feedback based responses

  • Stretch reflex based responses to perturbations

    • Critical to both optimal movement control

• Some models of motor control state that proprioception is used to plan distances and vision to plan direction

• Other models of motor control suggest proprioception may be the key feedback based mechanism

  • Both the speed of processing and reflex circuitry make it possible.

Open Loop

• Open loop control is similar in initial design to closed loop control

  • There is an executive level and an effector level

    • The executive sends the motor program to the effectors, and the effector carries out the instructions without modification based on feedback

  • Open loop processes are not necessarily less complex than closed loop processes

    • A response is open loop when the response unfolds without feedback

    • A system is open loop if the system doesn't take feedback into account

Feed-Forward Control

• Although humans are capable of open-loop control, modern theories of movement control suggest we use sensory information for feedforward control

  • Feedforward control involves a signal that readies the system for the motor command

    • Readies the system for some input

• The concept of feedforward control emerged from the study of eye movements (saccades)

Efference Copy

• A copy of the motor command that was sent to muscles is delivered to sensory regions in the brain

  • E.g. if you reach to tickle your own foot, an efference copy of the reaching movement is sent to your brain, preparing you to be tickled

    • This is why you can’t tickle yourself, because you are expecting it

• The efference copy allows for the prediction of the action outcome and the sensory consequences of the action

  • Tells the sensory system what was 'ordered' by the motor system, readying the sensory system for feedback

  • Uses the predicted and actual sensory feedback to compute an error

Error Detection and Efference

• We can use active versus passive tasks

• Participants are generally better at error estimate when they have efferent information

  • Proprioception may play more of a role than previously thought

• People perform better when they prepare their own movement as opposed to being guided

Forward Models and Motor Control

• Forward models are used to establish predictions about the desired state

  • Produce predictions about the movements intended outcome and desired feedback

• Establishes a reference of correctness for which to compare to based on sensory information

  • Forward models are used continuously throughout the movement to update the reference of correctness

Outstanding Problems - Motor Programming

• Storage problem - there is not enough room to store separate motor programs for each movement

• Degrees of freedom problem - the system has two many independent states to control at the same time

• Novelty problem - how do we learn new actions

Computational Solution to Outstanding problems

• To solve these problems, it was hypothesized that motor programs must be generalized

• The motor program must resemble a function

The Generalized Motor Program

• Invariant or algorithmic features of the GMP

  • Relative timing - the timing of muscle activations relative to others

  • Relative force - the force of muscle activations relative to others

  • Sequence of events - the sequence of events

• These components are in the function - they are not changed by the user

• Think of motor input as a song on a turntable. You can make adjustments to volume, the speed and which speaker the song comes out of but the song plays nonetheless. Movement patterns are the same.

Speed Accuracy Tradeoffs

• When examining voluntary, goal-directed movements, there appears to be a relationship between speed and accuracy

  • Fast movements are less accurate

  • Accurate movements are slower

• Dsecribed by Fitts’ Law

Fitts’ Law

• Increased ID = Increased MT

• Linear relaationship

Speed-Accuracy Open-loop movements

• For open loop (no visual feedback) the effective target width can be determined by the amplitude (distance) and movement time

• Schmidt’s Law

Breakinf Fitts’ Law - Glazbrook

• Participants performed movements to a target location

  • The target was either first, middle, or last in an array

• Measured movement variability across the trajectory as an indicator of planning versus online movement control

  • Differences in variability earlier would indicate planning

  • Differences in variability later would indicate control

• Differences emerged later in the trajectory, meaning the violation could be based on more efficient movement corrections

• We don't actually plan for the worse case scenario - we adapt efficiently!

Impulse-Variability and Speed Accuracy Tradeoffs

• Impulse-Variability Theory

  • The variability in the duration of a group of contractions is related to the mean duration

  • The variability in force produced increases as a function of the force produced

  • Impulse-Variability theory can explain speed accuracy tradeoffs and violations that occur with more forceful movements

Motor Learning

Aset of processes associated with practice or experience that leads to a relatively permanent change in the capability for movement

Motor Learning is Set of Processes

• A process is a set of events or occurrences that lead to a product or state of change

  • In motor learning we are interested in the processes associated with retrieving a motor program from memory

  • In pharmacokinetics they are interested in the processes associated with drug delivery

• These processes are largely assumed

  • We think some events must have occurred for their to be learning as a result of practice

    • The nature of these processes are what learning theorists try to understand

Learning is Associated with Practice or Experience

• Practice: the purposeful repetition of a skill or behaviour

  • Practice makes permanent

• Experience: the fact or state of having been affected by or gained knowledge through direct observation or participation

Motor Learning is Relatively Permanent

• Relatively permanent: change of state is not readily reversible

  • Any change that is readily reversible is not attributable to learning

• When you have learned something, you are a different person

  • There has been some underlying change that is stable

• Learning should have some lasting effect

Learning Produces a Capability for Skilled Movement

• The product of learning: the ability to move skillfully in a particular situation

  • The goal of motor learning is the strengthen the quality of the internal state such that the capability of the skill will be altered (hopefully improved) in future attempts

• Capability for movement

  • Stresses the role of the internal states that leads to the skilled behaviour

    • Motivation, physiological states, fatigue

  • Numerous factors

Learning is not Directly Observable

• Learning involves highly complex phenomena

  • Many processes and many possible explanations

  • Multi-system interactions

• Motor learning is not directly observable

  • We often have to infer these changes based on behaviour

    • We measure and test the stability of learned behaviours

Neural Basis of Learning - Theories

• Donald Hebbs

  • Hebbian processes: Neurons that fire together, wire together

• Neural Networks (Geoffrey Hinton)

  • Most neurons receive inputs from other neurons

    • These inputs are weighted

  • Neurons can adapt their weights

• Activation in networks can be observed by looking at

  • Outputs: electrical activity

  • Energy consumption - bloodflow

Measuring the Neural Basis of Learning with FMRI

• Functional connectivity analysis

  • Measures changes in blood flow between different brain regions

  • Correlate the time-series between different regions of interest (ROls)

  • Examine the strength of those relationships

• Some studies have shown the functional connectivity can predict

  motor learning (McGregor and Gribble)

Learning and Adaptation

• Adaptation: the iterative process of adjusting one's movement to new demands

• Motor Adaptation: the trial to trial modification based on error
  feedback

  • Movement retains identity (e.g., walking) but one of the parameters are changed

  • Change occurs with repetition or practice and is gradual over minutes

  • The person must de-adapt after the behaviour

    • They show an aftereffect

Forcefield Adaptation Paradigm

• Error before adaptation            

• Forcefield removed - smaller period of error before de-adaptation

Measuring Acquisition

• In a typical learning experiment:

  • Participant is exposed to a task (acquisition)

  • Performance on the task is plotted as a function of trials

    • Can examine consistency

Performance (not learning) curves

Factors Affecting Performance

• Between participants variability

  • Performance curves usually represent grouped data

    • Individual differences get "washed out"

• Within-person variability

  • Performance of the individual person varies trial to trial

    • Average curve may not do a good job of catching individual variations

• Ceiling Effects: limits at the top scale

• Floor Effects: limits at the bottom of the scale

Ceiling and Floor Effects

• Gymnastics: easier to improve your score at mid-level

  • 6.0 - 6.5 vs 9.0 - 9.5

• Reducing a score in golf is easier when strokes are high

  • 145 - 140 vs 75 - 70

• Changes in performance levels becomes insensitive to changes in learning

Retention and Transfer Tests

• Retention tests: testing participant on the same task after a time interval

  • 24 hours retention interval is often used (for both retention and transfer)

  • Longer retention interval, the more transient effects are reduced

• Transfer tests: involve new variations of the practiced task

  • Can involve the tasks with a twist (new speed or conditions)

  • Can involve a task that has not been practiced before

•  Things that make you worse in practice make you learn better in the end

Learning and Performance Variables

• Changes in acquisition are not relatively permanent

• Performance variables: influence performance in transient ways

  • The effect of the variable disappears when conditions are altered

• Learning variables: influences performance in relatively permanent
  ways

  • The effect of the variable stays when conditions are altered

Overlearning

• The process of having a person or continue to practice after they have reached a performance ceiling

• To assess the effect of overlearning we can calculate what’s called a
  “savings score”

Other ways of Assessing Learning

• Performance on a secondary task

  • Gives us an idea of how much attention is needed to perform a task

    • A well-learned task requires “less” attention

• Measuring indices of effort

  • Physiological markers

  • Psychological markers

• Measuring response latency

  • Speed of correct response or movement performance

• Generalizability of learning

  • Varying the parameters of the task (linked to GMP)

Optimizing Practice Conditions - Performance

• How should practice be distributed

  • Massed practice - practicing with very little rest in between trials

  • Distributed practice - practicing with longer rest periods in between
    trials

• Research on practice distributions are usually conducted
  using continuous tasks

  • Pursuit-tracking task

• General conclusion

  • Short rest periods degrade practice relative to longer rest periods

Distributed Practice and Learning

• Fatigue could play a role in tasks such as the pursuit-rotor task

• Can affect task performance, but does fatigue also affect learning?

• Bourne and Archer (1956)

  • 0 s rest group performed worse in transfer

• Ammons (1950)

  • Only small differences remained after the last transfer trials

  • However, the differences in performance re-emerged on the 24-hour transfer trial

Distribution over a Larger Timescale

• Baddeley and Longman (1978) looked at typing skills in postal workers

  • Compared different distributions and looked at long-term retention

  • Found that more distributed practice led to better retention when practice hours were held constant

  • After 9 months the group that practiced the most showed worse performance. All groups had the same practice. The group with more distributed practice learned more.

Distributed Versus Massed Practice Application

• This practice distribution literature has huge implications for many
  fields

  • Sports

  • Rehabilitation

  • Medical education