Chapter
28 Contents
Chapter 30
The obviously extensive researches of Ludwig Koch, psychologist at Die technische Hochschule, Braunschweig, Germany, reported in Jan-Feb. 1936 (see Sources), seem to be virtually unknown outside of Germany. His goal was to discover the most efficient way to teach the Morse code to prospective radiotelegraph operators to meet the International requirements for commercial radio operators. These requirements were:
TESTS TO
DETERMINE WHAT COMPETENT OPERATORS ARE DOING
He ran three
series of tests to determine how the code is comprehended and for this
purpose used four competent, actively-practicing radio telegraphers.
Three of these operators had learned the code solely by sound, while the
fourth was self-taught from printed code charts.
SENDING
TESTS
For the first
test each operator was to send by regular handkey the series of ten letters
b c v q f l h y z x at various speeds while monitoring his sending
with a pair of headphones to satisfy himself as to its quality. Out
of his sight and hearing a recording system made an accurate timed graphical
record of his sending, so that the actual timing of signal and space durations
could be examined in detail. He was instructed to send, using standard
International Morse timing, at each of six different speeds ranging from
about 20 to 80 characters per minute. Standard International Morse
timing, as described in Chapter 12, was then used
to compare their sending at all speeds.
Below about 10 wpm the only operator who closely conformed to standard timing was the one who had visually learned the code. The three others deviated considerably from "standard" timing. At 5 wpm these deviations were appreciable:
At successively higher speeds this situation changed slowly and somewhat irregularly until by about 10 wpm character rate all four operators were forming fairly accurate patterns of sound (nearly to the International Standard), except that the letters themselves were somewhat faster and the spaces between letters were somewhat longer than standard. By about 12 wpm all sending had become quite consistent with the standard. (Only the well-known individual peculiarities of sending by hand were obvious. At 10 wpm and above these deviations were always very small.)
The three operators
who had learned by sound obviously showed no real sense of sound patterning
(Gestalt) at these very low speeds: no sense of unity, but rather just
a series of separate elements strung together. Only by about
10 wpm were the code characters now felt to be entities of sound in themselves,
patterns which were clear-cut in each operator's mind, no longer
shattered elements, disjointed parts.
RECEIVING
TESTS
Test number
One: - Each operator was to copy the 30 German Morse characters sent by
a machine in perfect "standard" timing at each of four different
speeds over the same speed range as before.
At about 5 wpm these experienced operators hardly recognized a single character correctly! At 7 wpm only 40% to 60% of the letters were correctly identified. At 10 wpm all operators were getting about 95% correct. By 12 wpm all of them correctly identified every character.
Test number
Two: - Here the length of the spaces between the letters was doubled.
This time the operators recognized almost all letters correctly at all
speeds. That is interesting.
From these
tests it was concluded that experienced operators recognize a code character
by its overall acoustic pattern (Gestalt), and that this pattern stands
out clearly only when sent at a minimum character speed of about 50 characters
per minute. At lower speeds it is heard simply as a disjointed series
of signals. -- Koch concluded that these operators
could recognize the too-slowly sent letters only when letter spacing was
doubled, because this increased interval gave them time to integrate the
sound and mentally speed it up to where they could recognize it. (A beginner
would not have the skill to do this.)
The operator
who had learned from a printed code chart apparently formed better proportioned
characters at very low speeds because his visual mental picture was so
strong. However, the price paid for this was that it limited his maximum
speed of copying: he could barely meet the minimum requirements - a marginal
operator. (See below.)
ANALYSIS
AND CRITICISM OF PREVIOUS TEACHING METHODS
The "Analytic"
Method introduces the student to the code using some sort of systematic
arrangement, or chart, where the code characters are arranged by number
and type of related elements, etc., in a visual form. The student
is required to memorize this as a mental picture before going any further.
After that, the characters are sent to him in standard timing, at first
very, very slowly . This means they are sent with long drawn out
dits, dahs and spaces. The speed is then very gradually increased
in tiny steps.
The faults with this system are:
Unfortunately, visual mental pictures are usually very much stronger and easier to recall than auditory sound patterns. Thus the student tends to convert the signal pattern he hears into the corresponding visual representation, break it into its component parts, and then finally into the letter. This complex action tends at least partially destroys the wholeness of the acoustic impression.
This series of actions is encouraged by the long pauses between characters, giving adequate time for thinking, speculation and the cumbersome translation processes. With increasing speeds the pause time becomes too short to go through all this, and so the student gets stuck below or around 10 wpm, just as with the analytic method.
So this method tends to suffer about the same faults as the analytical method. Both generally lead directly to that troublesome plateau at around 10 wpm, where the distinct change in perception from bits and pieces to coherent unity of each signal occurs.
Analyzing these methods, two classes of errors can be seen:
TESTS TO ESTABLISH A BETTER TEACHING METHOD
CHARACTER
SPEED FOR INITIAL LEARNING ?
The obvious
goal was to meet the International requirements. The question is how best
to get there. Would it be better to begin from the first using a
100 character rate per minute, or some lesser speed? This experiment
was tried. For the average student it was found that the demands
on his concentration were significantly greater at 100 letters per minute
than at 12 letters per minute, especially as more and more new characters
were introduced. (Above average students did well, however, at the
higher initial speed.) But, of course, if one learns initially at
some lower speed, speed is going to have to be increased to meet the requirements.
Various tests showed that about 12 wpm was an optimal speed for most people to begin learning. It is far enough above the 10 wpm plateau to avoid it. Further tests showed that once the student had mastered all the code characters at 12 wpm, it was relatively easy for him to advance to 70 letters per minute, and by continuing to practice using the same principles, to advance fairly rapidly, step by step, to the required speeds. Thus a 12 wpm beginning speed seemed well justified.
CAN THE
RHYTHM PATTERNS BE ENHANCED ?
Koch observed
that in the early stages of learning, the beginner has to concentrate intensely
to catch the letter rhythm-patterns. Is there anything which could
be done make this easier for him?
He observed that some teachers were speaking, or even almost singing, the sound patterns of code characters using the syllables "dit" and "dah", whose vowel qualities and lengths make sound patterns stand out somewhat like little melodies. This helps accentuate the differences between sound patterns and simultaneously promotes an immediate sense of meaningful unity of the acoustic patterns.
Could the use of two different pitches, one for dits and the other for dahs, make it easier for the new student to recognize the wholeness of the rhythmic pattern ("melody") of a code character, and make it easier to learn? Could it help reduce the stress caused by the intensity of his concentration in the early learning stages, while he is being introduced to the rhythms and trying to get accustomed to them? It looked worth a try.
He conducted
two classes simultaneously to evaluate the merits of
the two-tone approach. After the first lesson, at each stage
the two-tone group
averaged two lesson periods ahead of the monotone
group. (For the two-tone class the pitches were gradually
merged into one by about mid-course.) Results:- the
two-tone class
in 24 sessions reached what took the monotone class
28 lessons to achieve. Total teaching time was 12 (two-tone)
to 14 (monotone) hours. (With both groups there were
the usual, occasional
short plateaus, each lasting generally no more
than one lesson period.) Conclusion:
- this is a worthwhile improvement to help the beginner.
WHAT LETTERS
SHOULD BE TAUGHT FIRST ?
1) Distinguishing
Between Similar-Sounding Patterns.
What characters
should first be presented to the student? Although
tests had shown that students can, in their first lesson,
readily learn to distinguish similar patterns such as the
series e-i-s-h, the degree of concentration required had a
negative effect
on them. Experience
has shown that many sound patterns, as speeds rise, can
be mistaken for similar sounding patterns, especially in
regard to the
number of dits which become pretty short at higher speeds:
e.g., S and H, or U and V. The dah characters do not
run this risk
so much: e.g., W and J. In addition some beginners
do experience temporary confusion between mirror image characters,
such as B and V, D and U. Thus
it seems best to begin with sound patterns which are distinctly
and obviously different. In this way the student can
learn more gradually
to discriminate between smaller differences.
2) Letters
that Tend to be Troublesome
Koch says
these (for German students) are generally x y p q.
(Z is very frequent
in German.) If these are introduced during the
first third of the program, there is more opportunity to
give them adequate
practice, and this generally results in shortening
the total program.
WHEN TO
INTRODUCE A NEW CHARACTER
His tests
showed that it is safe to introduce a new character into
the list only after the student knows thoroughly all the
characters he
has already studied. He set his working standard at
a minimum of 90%: that is, not to introduce a new character
until the students
were getting at least 90% correct copy at any stage.
This provided a good measure for comparison, and at the same
time let the student evaluate his own progress. It
is indeed interesting that the test classes showed that students
learned new characters almost in exact proportion to the
number of lesson periods (total hours). The experiments
also showed that
three to four new characters were about optimum for
any one lesson period.
SHOULD PRACTICE
BE BY GROUPS OF LETTERS ?
The question
he asked is this: should the student practice one group
of characters until he knows them well, then work on a second
group separately in the same way, and after that combine
the groups?
He began this teaching test with characters composed of dahs only: t m o ch (German single character ch). After enough practice (a couple of class sessions) to "master" this group of letters, he began teaching the dit group e i s h by itself in the same way. Next he combined these two groups together, and found that somehow during the intensive study of the second group, the students had forgotten the first group almost completely, and their confidence was badly shaken. He had to begin all over again teaching these eight letters together until they were mastered together.
After this, when these eight letters had been practiced to the point where they were correctly and consistently identified, two new groups were studied separately in the same way as the first two groups. First the group d b g, then after that the group u v w. Next, when these two new groups were mixed together, it was found that the d b g group had been forgotten. But worse, after these two groups had been re-learned together (d b g u v w) to the point of correct identification, and then combined with the first 8 letters, alas, the (combined) first two groups of 8 letters had been virtually forgotten!
It appears
that the student's intense concentration upon a new group
of characters by itself causes that group to override and
replace what had
been previously "learned". He sensibly concluded
that teaching by groups is wrong-headed. Therefore,
the most efficient
way is to introduce one new letter at a time and
then immediately integrate it into the group of letters already
learned, until finally the whole alphabet is complete. In
this way all the previously learned characters are under
constant review
and repeated frequently without lapses.
TROUBLESOME
CHARACTERS
Experience
has shown that quite a few students have some trouble identifying
one or more individual characters, tending to miss or
confuse them. They show up as little plateaus on his record
of advancement.
What letters these are varies greatly from student
to student. The five-column copying forms described
below serve to
help identify which these troublesome ones are -- needing
more practice.
HOW LONG
SHOULD LESSONS BE AND HOW DISTRIBUTED IN TIME ?
He cited B.
Jost's researches which found that people learn more quickly
and retain it longer for a given total learning time, when
the lesson periods are shorter and widely separated in time.
E.g., for a total of 24 lesson periods (which always include
reviews):- to schedule four lesson periods a day for six
days is four times
more effective than to schedule eight lesson periods
a day for 3 days, and that to schedule two lesson periods
a day for 12 days is eight times more effective. That
is, spread out
the lessons in time.
What is the
ideal length of a lesson period? -- Koch found by testing
that to have a long morning lesson, and then after corresponding
length of rest period to continue in the afternoon,
demanded too much intense concentration. The students
got tired too quickly and the repetition practice was not
as effective as it should be. By trial he determined that a
half-hour lesson
period was about optimum. (Even a 45 minute period
began to show diminishing returns.) He finally recommended
two half-hour periods, one in morning and one in the afternoon
as optimum.
Several courses
using various of these principles were conducted.
However, at the time of this report, he had not had classes
where he could combine all the optimum test conditions. The
students savable were people who were interested, but not
primarily, at
least, for professional purposes. Furthermore, they
were employed at full-time work during the day, and were
often tired by
class time, which had to be scheduled in the evenings.
Also, he could schedule only two or three half-hour lesson
periods per week. Hardly ideal.
In spite of
this progress was good, and no difficulties were encountered.
Three to five characters were presented and learned
in the first half-hour period. He aimed for many repetitions
during each lesson, never less than ten repetitions of
each character during a given lesson period, even after the
entire alphabet
had been introduced. Each successive period began
with a lively review of what had been learned up to that
point.
NEW PHILOSOPHY FOR TEACHING
DESIGNING
AN EFFICIENT TEACHING PROGRAM
1) The first
exercise is to teach the student to hear and begin to become accustomed
to hearing the
different overall rhythms of sound and silence:-
a)
Character rhythm: Character - space - character - space ...
b)
Group rhythm: Letter-group - space - Letter-group - space ...
From the very
first, to get the student accustomed to overall rhythms,
he is supplied with "copying" sheets having several sets
of five-column groups of little squares like graph paper,
as shown below.
They will also be used for all subsequent regular
copying practice.
__ __ __ __ __
__ __ __ __ __ __ __ __ __ __
|__|__|__|__|__| |__|__|__|__|__|
|__|__|__|__|__|
|__|__|__|__|__| |__|__|__|__|__|
|__|__|__|__|__|
|__|__|__|__|__| |__|__|__|__|__|
|__|__|__|__|__|
|__|__|__|__|__| |__|__|__|__|__|
|__|__|__|__|__|
Five letter random groups are then to be sent. At first these will all be unknown letters. As he hears each acoustic pattern of a letter in a five-letter group, he is to place a dot in the square which corresponds to the position of that sound pattern within its group.
Thus he works
along across the five-space line, becoming used to hearing
each letter-rhythm pattern and then writing a dot for it
in the appropriate
square. (At this stage he only recognizes the
sound patterns as entities, nothing more.) He continues to
work line by line
down the column as each new group is heard. In
this way he begins the practice of focusing:
a) on the
coherent acoustic
forms and
b) on the
associated rhythm, letter
by letter,
of the writing hand, and
c) on recognizing
the pause after
each group.
A relatively short initial session (10 minutes or so) of this will begin to accustom him to these overall and detail patterns of sound as entities.
2) The second
exercise is to start him on the way
a) to recognize the differences in rhythm-pattern between two
quite different-sounding
letters, and
b) become familiar
with the sound patterns of each character,
and to become accustomed to them. (All sending to be
machine precise.)
A) This begins by introducing the two first characters just as sound patterns - without identifying what letters they are. They are to be sent separately and at random until the student definitely recognizes and distinguishes their individual patterns (pattern one and pattern two, or whatever). At this time they are not yet to be identified with their printed letters: they are simply recognized as different patterns of sound.
B) Only after he has become accustomed to distinguishing the first two letter patterns from each other, and to the rhythm groups as they are, and writing dots in the little squares, is he to be told the names of these first two characters. He should from then on have no difficulty in writing their letters down in the little squares whenever and as he hears them.
This is to train him during these early stages and later on that he is to recognize and react to the presence of each and every acoustic pattern, either by identifying it or by a dot in the square, and of the larger groupings of letters identified by the longer space.
Is is obvious that, especially in the learning stages, there are going to be acoustic patterns passing by which he may or will not be able to recognize immediately and automatically. He must get accustomed to giving such signals no thought at all (except to put down a dot), so that he can give his undistracted attention to the next incoming sound pattern.
Otherwise, during the all-too-short pause after each signal which he does not immediately identify and before the next one is heard, he is going to try to think about what signal it was. But while he is thinking about it the next signal arrives, tending to upset him and cause him to lose the flow of the rhythm. This interruption must from the very first be stopped. His teacher must insist that whenever the student does not immediately and automatically recognize a sound pattern, just to put a dot in the corresponding square, then immediately let it go, and continue on with the rhythm. This action must become habitual, and this technique has been devised to develop it from the very first.
Now as he identifies the acoustic patterns he will write their corresponding letters in the little squares. If the teacher chooses to mix into the 5-letter groups code characters which the student has not been taught, there should be dots to correspond with them.
After one or two short (about 10 min.) practice periods this way, the relationships between the acoustic impression and the letters they represent should have become so closely knit together that there is an immediate transition from the acoustic sound pattern to the letter (or a dot). Only when this point is reached is a third letter to be added to the first two.
3) Only one
new letter at a time is to be introduced and added to
those already known. The criterion for adding a new letter
is: when
at least 90% of the letters already well known are correctly
identified. Each new letter is added to the group of
recognized sound
patterns in the same way as the first two were:
first by simple
recognition of the pattern without knowing what letter
it is, and in contrast with the previously known ones, and
only when he readily recognizes it its individual sound pattern
is he to be told what letter it is.
As an example
of the introduction of characters and the five-letter
groups used, if the sequence of letters taught were h
- f - a - g - etc.: for the initial two-character lesson,
groups were like:
l) hfhhf
fhfhfh ....
2) Next character:
aahfh
fahfh ...
3) Next: ggbaf
ghfah ...
4) Next:
ccgaf gcafh
..., etc. (In this example he did not begin with the
more frequently
"troublesome" letters.)