The Act of Creation (77 page)

p. 513
. Cf. Polànyi, 1958, p. 364:
'Behaviourists teach that in observing an animal we must refrain above
all from trying to imagine what we would do if placed in the animal's
position. I suggest, on the contrary, that nothing at all could be known
about an animal that would be of the slightest interest to physiology, and
still less to psychology, except by following the opposite maxim. . . .

 

 

To
p. 516
. This response is mediated either by
resonance (Helmholz's theory) or, more likely, by the locus of maximum
hydraulic pressure in the 'travelling wave'.

 

 

To
p. 517
. The latter assumes that in visual
perception a spatial 'picture' is projected on to the primary optical
cortex, which reproduces the retinal image. But the excitation-pattern in
the auditory cortex has no 'contours' separating figure and background,
and it would be difficult to imagine 'field currents' created by them.

 

 

To
p. 533
. There are strong arguments against
the segmentation of language according to the letters of the written
alphabet (cf. e.g. Paget 1930; Ladefoged in
Mechanization of Thought
Processes
, 1959).

 

 

To
p. 537
. There exist of course both innate
and acquired preferences for choosing one system of 'coloured filters'
rather than another as a criterion of equipotentiality. Two notes an
octave apart sound more 'similar' to man and rat than two notes close
together. Evidently the nervous system finds it for its own 'intents
and purposes' more convenient to regard two frequencies of the ratio
2p:p as more similar than two frequencies of the ratio p:(p - r).

 

 

To
p. 539
. The protracted controversy about
the existence of progressive, systematic changes in perceptual traces
('levelling' and 'sharpening') was unfortunately restricted to one type of
change only -- the reduction of 'dynamic stress' in the physical trace,
predicted by Gestalt physiology -- see Wulf, quoted by Koffka (1935);
Hebb and Foord (1954). No psychologist would dare to deny that 'memory
plays us false'; but its confidence-tricks are evidently not of the
grossly mechanical type, divorced from the subject's living experience,
which Köhler's theory of cortical field-processes demanded.

 

 

To
p. 540
. 'Negative recognition' could be
called the
unconscious
variety of Woodworth's (1938) 'schema
with correction'.

 

 

 

 

 

XI
MOTOR SKILLS
In the process of becoming an expert typist, the student must go
through the whole range of learning processes variously classified as as
instrumental conditioning, sign-learning, trial and error, rote and place
learning, insight. He is, of course, quite unaware of these categories --
which, in fact, overlap at almost every stage. The essence of the process
is the step-wise integration of relatively simple codes of behaviour into
complex and flexible codes with a hierarchic structure. This conclusion
was actually reached (although expressed in different words) in the
1890s by Bryan and Harter [1] -- then buried and forgotten for nearly
half a century. Woodworth was one of the few experimental psychologists
who kept harking back to the subject. The following is taken from his
summary of Bryan and Harter's
Studies on the Telegraphic Language. The
Acquisition of a Hierarchy of Habits
. [2]

The beginner first learns the alphabet of dots and dashes. Each letter
is a little pattern of finger movements in sending, a little pattern of
clicks in receiving. It is something of an achievement to master these
motor and auditory letter habits. At this stage the learner
spells the words in sending or receiving. With further practice he
becomes familiar with word-patterns and does not spell out the common
words. The transition from the letter habit to the word-habit
stage extends over a long period of practice, and before this stage
is fully reached a still more synthetic form of reaction begins
to appear. "The fair operator is not held so closely to words. He
can take in several words at a mouthful, a phrase or even a short
sentence." In sending he anticipates, as in other motor performances;
but in receiving, he learns to "copy behind", letting two or three words
come from the sounder before he starts to copy. Keeping a few words
behind the sounder allows time for getting the sense of the message.

Let us call these three stages of habit-formation the 'letter',
'word', and 'context' levels. The letter habit is acquired by 'serial
learning'. But no chain-response theory can account even for this
first step in acquiring the skill -- for the simple reason that the
homogeneous dots and the homogeneous dashes of the Morse sequence
offer no distinguishable characteristics for the forming of specific
S.-R. connections. The letter 'u' is transmitted by dot-dot-dash; the
letter 'w' by dot-dash-dash. In terms of S.-R. theory, the finger-movement
made in sending the first dot is the initial part-response which
triggers the chain, its kinaesthetic sensation acting as a stimulus
which calls out the next response. But the correct response to the
same
stimulus will be
either
dot or dash; nothing in the
nature of the stimulus itself indicates what the next response should
be; the response is determined at this and each following step not
by the preceding stimulus but by the total pattern. The habit cannot
be represented by a linear series: . -- -- > -- -- -- > . -- .
it can only be represented as a two-tired hierarchic structure:

The related skill of touch-typing was studied by Book [3], who wired his
machines to time every move made by the experimental subjects. In this
case the letter habit is acquired by 'place-learning' -- the keyboard
is hidden from the student by a screen, and he is required to form a
'map' of its layout in his head. This map, one supposes, is structured
by a simple co-ordinate-system: the fixed resting position of the ten
fingers on the third row of the keyboard; the result is a kind of simple
'maze' with variable target positions. But when, after a certain amount
of hit and miss, the letter habit had been mastered:

further practice gave results unexpected by the learner. He found
himself anticipating the sequence of finger movements in a short,
familiar word. Habits were developing for groups of letters such
as prefixes, suffixes, and short words. . . . 'A word simply means
a group of movements which I attend to as a whole. I seem to get
beforehand a sort of feel of the whole group'. . . . The single
letters were no longer thought of and each word became an automatic
sequence. . . . Familiar phrases were similarly organized, the thought
of the phrase calling out the whole series of connected movements. [4]

Yet even phrases ending with a full stop did not prove to be the highest
units. The records showed 'no pauses between phrases' but an even flow;
and here, too, 'the eyes [on the text to be copied] were well ahead of
the hands' -- to enable the typist to take in the meaning.
As a third example let us consider learning to play the piano (though I
could find no textbook references to this not altogether unusual human
occupation). The 'letter habit' here becomes a 'note habit' -- hitting the
intended black or white key; for 'word' read 'bar' or 'musical phrase';
and so on to more complex integrated patterns. In this case, however,
even the lowest unit of the skill -- hitting the right key -- displays
considerable flexibility. There is no longer, as on the typewriter,
a rigid attribution of each key to one finger; on the piano keyboard
almost any finger can be used, according to circumstances, to hit any key;
several keys may be hit and held at the same time; and a hard or soft
touch makes all the difference to musical quality. (Needless to say,
even the typist's motion-patterns must be adaptable to small portables
and large office machines, and the starting position of the finger varies
according to the preceding stroke. Flexibility is a matter of degrees;
a completely fixed response is, like the reflex arc, an abstraction.)
The skill of hitting the correct piano-key is not acquired by establishing
point-to-point correspondences, but primarily by practising the various
scales; these superimpose, as it were, structured motions on to the
keyboard, sub-structured into triads, septims, etc. At an advanced stage,
when improvization has become possible, the left hand will learn to
accompany the right, which acts as a 'pace-maker' -- a glorified form of
the magnet effect in the gold-fish (p. 438); but the left can also act in
relative independence, according to the commands of the score. At this
level we have approximately the following state of affairs: the visual
input consists in two groups of parallel rows (staves) of coded signals,
of which the upper series must be referred to the right, the lower to
the left hand. In the course of this procedure both rows of signals
must be de-coded and re-coded. The symbols on the two rows are usually
in different parallel codes ('violin clef' for the right, 'bass clef'
for the left). Moreover, there are 'key signatures' -- sharp and flat
signs -- at the beginning of a section, which modify the 'face value'
of the notes; there are symbols which indicate the timing and duration of
notes; and overall instructions regarding loudness, tempo and mood. All
these part-dependent, part-independent de- and re-coding operations for
both hands must proceed simultaneously, in the psychological present,
and more or less automatically.
On an ever higher level, the concert pianist develops a repertory of
oeuvres that he can 'trigger off' as units and play by heart -- though
some of these units may be an hour long. Once again we must assume
that this is done by a combination of several interlocking hierarchies,
each articulated into sub-wholes and the sub-wholes thereof.
Then there is improvisation. It need not be creative; the bar-pianist who,
half asleep, syncopates Chopin and trails off into some variation of his
own, is not a composer; but he has gained additional flexibility -- more
degrees of freedom -- in the practice of his skill. And finally there is
the creative act: the composer who weaves his threads into new patterns,
and the interpreter who sheds new light on existing patterns.
The learning process is, somewhat paradoxically, easiest to visualize
as a reversal of the hierarchic sequence of operations which will
characterize performance when learning is completed. When the typist
copies a document, the sequence of operations is initiated on the semantic
level, then branches down into successive lower levels with increasingly
specific 'fixed action-patterns' -- 'word-habits' and 'letter-habits
'; terminating in the 'consummatory act' of the finger muscles. The
impulses arborize downwards and outwards, whereas learning proceeds in
the reverse direction: the tips of the twigs of the future tree are the
first to come into existence; the twigs then grow together centripetally
into branches, the branches merge into the trunk. It strikes one as a
very artificial procedure; but the type of mechanical learning we have
discussed, where the discrete base-units must be stamped in bit by bit,
is indeed an artificial procedure. The difference between this method
of learning through trial and error and learning 'by insight' becomes
glaringly obvious if you compare what happens during an elementary
violin lesson and an equally elementary singing lesson. The choir boy
can rely on his innate, multiple auditory-vocal feedbacks -- operating
through the air, through his bones, and through proprioceptive sensations
from his vocal tract -- to control his voice. But there exist no innate
feedbacks between the violin student's cochlea and finger-muscles, to
control their motions. No amount of theoretical insight into the working
of the instrument can replace this handicap; it can only be overcome by
supplementing insight with trial and error. In other words, human beings
are biologically less 'ripe' for learning the violin than for learning
to sing. If evolution were to produce a super-cricket or cicada sapiens,
the opposite may be true.
To put it in a different way: the built-in feedbacks of the auditory-vocal
apparatus provide a
direct insight
into the rightness or
wrongness (singing out of tune) of the response; they permit an
immediate 'perception of relations' -- which is Thorpe's definition of
insight. But once more, this insight is far from absolute: when it comes
to professional singing, a heart-breaking amount of drill is required. The
pupil is often taught the proper techniques of breathing with his hand
on the teacher's stomach -- because his insight into, and control of,
his own physiological functions is limited. Verbal instructions are of
little help, and are sometimes a hindrance, in the acquisition of muscle
skills; to become clever with one's hands, or one's feet in dancing,
requires a kind of muscle training which defies classification as either
insightful or trial-and-error learning.
I have repeatedly mentioned the mysteries of riding a bicycle: nobody
quite knows how it is done, and any competent physicist would be inclinded
to deny a priori that it can be done. However, as a two-legged primate,
man has an innate 'ripeness' for the acquisition of all kinds of postural
and balancing skills such as skating, rock-climbing, or walking the
tight-rope; accordingly, the hierarchy of learning processes in the case
of the cyclist starts on a higher level of already integrated sub-skills,
than in the examples previously discussed. Broadly speaking, the pupil
must turn the handle-bar in the direction he is falling, which will
make him tend to fall in the opposite direction, and so forth, until he
gradually 'gets the feel' of the amount of correction required. This is
certainly trial-and-error learning in the sense that errors are punished
by a fall; but the trials are by no means random, and the errors are
all in the right direction -- they merely over- or under-shoot she
mark. The code which is formed by successive adjusments of the neural
'servo-mechanism' is presumably of the analogue-computer type -- and
the same applies probably to dancing, skating, or tennis-playing.
But once the skill has been mastered and formed into a habit, its
integrated pattern is represented as a unit on the next-higher level in
the hierarchy, and can be triggered off by a single (verbal or nonverbal)
command. To take a more complicated example: the soccer-player must
acquire a variety of basic routines of taking command of the ball --
'stopping' it with foot, thigh, chest, or head; volleying it in flight
without stopping; kicking it with the instep, the inner or outer side-wall
of the boot; dribbling, passing, and shooting at the goal, etc. When
these elementary, yet very complex, techniques have been mastered,
each of them will become a self-contained sub-skill in his repertory,
and he will be able to decide, in a split second, which of them to employ
according to the layout of the field. The decision whether to shoot or
pass is based on discrete yes-no alternatives of the digital type; but
the execution of the actual move -- shooting, passing, etc. -- seems
to require an analogue-computer type of code. A further step down the
'analogue' process of flexing the leg-muscles for a pass of appropriate
length is again converted into the digital on-off processes in individual
motor units; while on the top level a fluid strategy is converted into
discrete tactical decisions.