Ch. 12 and 13 - questions
1. What function does freezing and freeing degrees of freedom have?
This is something that can occur as people learn movements. It has been suggested that it
occurs because as we learn new movements we tend to deliberately control our actions (that is,
we are in the cognitive stage of learning – see chapter 12 on stages of learning). Because we are
trying to deliberately control our actions, and because we cannot deliberately control multiple
degrees of freedom (muscles, joints) simultaneously, we “freeze out” (lock, stiffen) several of
these muscles or joints until such a time as we have discovered how to allow them to be
controlled without deliberate attention. Hence we freeze degrees of freedom during learning,
and unfreeze them as skills are learned.
2. What are intrinsic dynamics?
Simply, put, these are just your preferred movement tendencies. As you live, you accumulate
movement experiences. As these experiences increase, you will develop preferences for some
styles of movement, and tendencies to avoid others. Over time, these preferences can become
quite strong, and give you a particular style of moving…your intrinsic dynamics.
The important thing to note is that one’s intrinsic dynamics can be a way of explaining positive
transfer effects: if the dynamics of the movement to be learned are similar to your intrinsic
dynamics, then you’d expect to learn the task quite quickly. But if the movement to be learned
is dissimilar to your intrinsic dynamics, you’d expect to take a long time to adapt.
3. Give an example of how experts differ from novices in their use of their senses.
The simplest example is in eye movements. This is common to many sports, but one of the most
well known is in ice hockey (or research into ice hockey) where it’s been found that expert (elite)
ice hockey goalies, when trying to stop a shot, will have reliably different eye movements just
before they start to move than do near-elite goalies. One can imagine that they are testing
(perhaps subconsciously) certain hypotheses about what the shooter might be intending to do,
and searching the visual workspace for clues. This is probably entirely similar to how you started
to use your eyes differently when learning the red box-blue box task. When you realize there is a
pattern to the way the chasing boxes move, you look for it as you perform, so that you can
precisely anticipate when and where to move next.
4. Why is it supposed that early success at movement skills is no guarantee of later success?
This relies on the underlying assumption that learning progresses through different stages (e.g.
cognitive, associative, autonomous, Fitts & Posner, 1968). There is some debate on this topic
these days (see chapter 14 and chapter 15), but you probably remember early stages of learning
being associated with confusion and anxiety, and this fits well with being in the cognitive stage
of learning. So, assuming this is the case, performance during the cognitive stage is suggested to
be dependent on one’s general cognitive abilities, so those with good amounts of these would
perform better, relative to those who possessed less. However, performance during later stages
of the skills relies on perceptual-motor abilities. And having high amounts of cognitive abilities
does not guarantee (is independent of) having high amounts of perceptual-motor abilities. So
being successful early in learning does not guarantee being successful later in learning.
5. Give a pair of skills between which you would expect
a. positive transfer
Throwing a Frisbee and throwing a ball, catching a ball and catching a TV remote.
b. Zero transfer
Catching a ball and frying an egg.
c. Negative transfer
Driving in Britain and driving in the USA (opposite sides of the road). Baseball swing and
golf swing.
6. Why does positive transfer happen?
Similarity of movement parts, or movements, and similarity of movement contexts.
7. Why does negative transfer happen?
A familiar stimulus (baseball bat hitting ball, versus golf club hitting ball) requiring a new
response (golf swing rather than baseball swing).