Practice

Chapter 5

Performance & learning

Performance is observed, learning inferred Performance can improve without improved

learning Learning can improve without improved

performance• What is learning, really?

Amount of practice

Do we become less dependent on the environment, or more?• Important implications – do you practice

powerlifting in front of a mirror to aid form? (Proteau & Temblay, 1998)

Amount of practice

As we learn, do we rely less on feedback? Proteau’s task (1987, 1992)...

Amount of practice

As we learn, do we rely less on feedback? Proteau’s typical paradigm...

• Task: 90cm movement in 550msec• Condition 1: 200 trials with vision• Condition 2: 2000 trials with vision• Test condition: No vision

Has also used walking (see next slide), force control, and others

Sometimes as little as 20 vs. 200 trials too.

Amount of practice

As we learn, do we rely less on feedback? Typical Results:

The full vision practice condition typically transfers to a no vision condition badly, and this gets worse as full vision practice increases

Amount of practice As we learn, we seem to rely more on the

information that is present and used when we learn• For the powerlifting form example – mirrors not a

good idea (Proteau & Tremblay, 1998)• Also think of learning to type, drive (shifting gear),

play piano (watching fingers) and so on• “learning is specific to the source or sources of

afferent information that are more likely to ensure optimal performance”

Amount of practice More recent findings:

• Weak vs. strong visual cues (still a reaching task) – weak vision transfers as well as no vision to a no vision condition

• Weak vision encourages processing of other sources of information like proprioception

Amount of practice More recent findings:

• Ball interception – touch the interception point of a moving ball with the index finger

• Two conditions: full vision, or ball only

Amount of practice More recent findings:

• Ball interception – touch the interception point of a moving ball with the index finger

• Two conditions: full vision, or ball only

Normal specificity effect when

transferring to practiced trajectories

Effect disappears in new trajectories

Variability of practice

Imagine you’re trying to teach catching• Should you make it as simple as possible, by

choosing only one type of ball, one type of throw, one catching technique…etc…

• Or not?

Variability of practice

Schema Theory (Schmidt, 1975)• More variability means more generalized schema

for learning• Like a regression rule• Your performance of the right movement

depends on the proximity of previous behavior to the desired behavior

Variability of practice

Supported?• Generally, I’d say so, provided key assumptions

are met• Are the participants genuinely novices?• Is sufficient practice given to form a strong enough

prediction rule?• Is prediction of a novel version of the task ultimately

required?• See Schmidt and Shapiro (1982) for a summary

• Does not imply that the governing theory is accepted• Now as for organization of variability...

Contextual interference Practice order (3 tasks – A, B, and C)

Blocked

All A’s

…then all B’s

…then all C’s

All A’s

…then all B’s

…then all C’s

SerialA

CB

RandomWho

knows – it’s

random!

Amount of contextual interference

Low High

Contextual interference Practice order (3 tasks –

A, B, and C)• Stimulus light goes off

• Color signifies which movement pattern to perform

• Pick up tennis ball• Knock down barriers• Replace tennis ball• RT and MT measured

Contextual Interference effect

From the classic study (Shea & Morgan, 1979)

Practice – Low CI is better (time is being measured, so smaller scores are better)

Retention – High CI is better

Contextual Interference Theory

• 2 primary hypotheses• Elaboration

• Compare the sequence of tasks practiced within blocked and random practice – what kinds of comparisons between or among the tasks are promoted by each type of practice?

Contextual Interference Theory

• 2 primary hypotheses• Action plan reconstruction

• Compare the sequence of tasks practiced within blocked and random practice – how long, on average, do you have to wait before the task is repeated in each practice order?

• Brown-Peterson (1958), Peterson-Peterson (1960)

Recall worsens as interval “A” increasesA

A

Recall improves (!) as interval “A” increases

Contextual Interference Some research examples, and some

conclusions...http://www.youtube.com/watch?v=CIG3El76ltg&feature=related

Contextual Interference Smith & Davies (1995)

• Used a Pawlata roll• Compared progressive part learning of a full roll with

either alternate (high CI) or blocked (low CI) practice• All transferred to both a full and a half roll one week

later (score is 5 - average # attempts prior to success)

Contextual Interference Now for something completely different

(...and quite a bit more difficult)

We’ll see that these findings may severely limit the generalization of the CI effect

Contextual Interference Task:

• Notice: overall duration varies across tasks; relative timing does not

Contextual Interference Task:

• With this task, you can vary overall duration without varying rhythm

• see previous slide• Or both• Or vice versa

• E.g. • 300-200-400• 400-300-200• and 200-300-400

Contextual Interference Findings

• Experiment 1:• The more consistent

the practice type, the better people perform in retention and transfer

Contextual Interference Findings

• Experiment 2:• Feedback type has a

radical effect on this outcome

• Hard to see, but depending on fdbk, effect is almost reversed

• Generally, whatever results in stability of RT during practice works (random practice with segment fbdk did this, & so did blocked practice w/ratio fdbk)

Contextual Interference Since then...

• Still celebrated as a general effect• Does not seem to be the case• Shea’s (& colleagues) work clearly important• Findings largely limited to overall timing (simple

adaptations of already known movements)• Smith & Davies (1995, see also Smith, 2002, Smith et al,

2003) may be a result of negative transfer rather than CI• But these things matter too!

• Subsequent work emphasizes the disconnect between simple and complex tasks...

Contextual Interference Complexity as a moderator (for CI & others)

A good review paper for the final

Part vs. Whole practice

Segmentation, fractionation, simplification, component interdependence...• Do the parts fit together naturally, or can they be

easily separated?• Think of a free throw – should you practice the knee

movement and the arm movement separately?• Juggling...from the annals of 257 (Spring 2000) – Knapp

& Dixon (1952) revisited.

Part vs. Whole practiceSections broken down by 3 mastery levels

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

1 2 3 4 5 6 7 8 9 10

Blocks of 40 attempts

Av

era

ge

# c

atc

he

s 11am Beginners

11am Intermediates

11am Masters

12.35pm Beginners

12.35pm Intermediates

12.35pm Masters

11am class: move through practice stages quickly (get to the full juggling phase as soon as possible)

12:35pm class: practice each stage thoroughly (master each stage before moving on)

Similar findings have been published by Knapp & Dixon, 1952.

Part vs. Whole practice In this case, part practice of juggling didn’t

work well Seems that the skill is highly organized, and

as such should not be practiced in parts See also Hautala (1988): scarves not a good

idea.