Essays: David Naylor on Practicing (part 2)

Part II: The "It Never Works When You Watch" Effect.
by David Naylor
"I did it ten times in a row at home. Honest!"

   Has this ever happened to you?  You've been working on a really
impressive trick at home.  After lonely weeks of ardent, dedicated,
agonizing practise you finally have it mastered.  Now it's time to
dazzle your juggling buddies.  You say, "Hey, watch this!"  Then,
with all eyes watching, you fail miserably.  Oh sure, you get it
after the third or fourth try, but by then no one's looking.

   Why does this happen?  How come "it never works when you watch"?
Was it that you didn't practise enough?  Probably not; after all,
you did do the trick ten times in a row.  According to motor
learning research, your problem is not lack of practise, but
something called "conditions of practise".  This has to do with
such things as your practise environment and how you distribute
your practise time among different tricks.  You may find it
surprising that, " .. the amount of practise is not the critical
variable influencing motor skill acquisition"[1].  Many other
factors interact with practise to affect learning and performance.

  Recently, there have been some exciting findings on making the most
of your practise time. Researchers have looked at whether it's best
to concentrate on a single trick ("blocked" practise) or to work on
several tricks in each session ("mixed" practise). Here it's
important to remember the difference between learning and
performance.  Experimental results show that "blocked" practise
improves performance in the actual practise session, but "mixed"
practise improves long term skill retention.  On top of that, a
skill learned through "mixed" practise is more easily transferred
to another context, such as a performance situation.

   Why is "mixed" practise better than "blocked" practise?  It's
thought that practising several tricks in a single session improves
learning because of the mental "interference" of one trick with
another.  Each time you switch tricks, you have to partially
rethink how to do the next trick.  This brief mental rehearsal
enhances learning.  On the other hand, you don't go through this
process if you are practising the same trick for the whole session.
For this reason it's best to practise in a "mixed" fashion to
optimize learning and performance reliability.  In fact, Magill [1]
gives the practical suggestion that high levels of "interference"
could be achieved by trying all variations of a specific trick in
each session.

   Perhaps the main cause of the dreaded "it never works when you
watch" effect, is your practise environment.  Do you always
practise alone?  Do you always practise in the same place?  Do you
always practise at the same time?  Well, don't!  Motor learning
experts will tell you that your surroundings, and even subtle
factors such as your clothing, should be varied in order to develop
performance reliability.  This means you should try to juggle your
practise space as well as your props.  Also, if you want to become
solid at a trick in a performance situation, you need to practise
the trick in front of spectators.  Certainly this is one of the
benefits of attending a juggling club meeting instead of practising

  While reading these articles, you may have wondered why this
information isn't common knowledge.  Why didn't your phys. ed.
teacher tell you this stuff in high school?  Well, the main reason
may be that the field of study is very young.  Although the
earliest research into motor learning can be traced back to the
1850's, it was not until 1971 that a comprehensive testable theory
of motor learning was developed [2].  In fact, most of the research
findings I've presented are post-1971.  Much is still unknown.  For
example, another "condition of practise" which could affect
learning is the length of your practise session.  As yet, there's
not much solid information on this, but research is continuing.
Someday we might even understand why it works best of all, no
matter who's watching, when you hold your mouth just right!


1. Magill, R.A.,"Motor Learning: Concepts and Applications", Third
Addition, WCB Publishers, Dubuque, Iowa, 1989.

2. Adams, J.A. "A closed-loop theory of motor learning".  Journal
of Motor Behaviour, Vol. 3, pp. 111-149, 1971.

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