The founder of Gestalt therapy, Fritz PERLS, stated that if perception is organized
according to Gestalt principles, perhaps the guides to behavior could be shown to
be organized in a similar fashion. Gestalt deals with Images and I will here present
evidence that indeed behavior is guided by "Images of Achievement" which
are to a considerable extent similar in their brain topography to perceptual images.
There is one major difference, however: perceptual images deal, for the most part
with the here and now; images of achievement are future oriented.
Future orientation is, of course, the essence of the use of imaging in therapy.
PERLS' use of imaging in dreams is a case in point. When he has a subject interpret
his dream of a bicycle as indicating a wish to become a big wheel that is going
somewhere, PERLS is using the image to provide a guide to the future.
Take another example, my favorite. When PERLS interprets responsibility to mean
"response-ability" this changes a vague command to passively assume an
attitude to a challenge to develop skills in coping with what needs to be accomplished.
The saying that freedom entails responsibility" takes on a new depth of meaning:
freedom entails choices (given by the available degrees of freedom) and response-ability
demands the development of skills to choose optimally.
What then are these "Images of Achievement" that guide actions?
How are they formed and what is the brain process that allows them to become effective?
To answer these questions I must first indicate that the term "behavior"
has come to have two meanings: ordinarily ethologists speak of behavior as "movement"
which describes a sequence of muscle contractions. By contrast, experimental psychologists
use the term to denote the environmental consequences of muscle contractions. Thus
SKINNER pointed out that for him "behavior" is the inked record created
by the performances of his subjects, records he can take home in the evening to
study. Experimental psychologists do not care whether such a record was made by
a pigeon, a rat, cat, monkey or human. Nor is the psychologist concerned as to whether
that record is made by a beak, a paw, the right or left arm, or the nod of a head.
TOLMAN called this aspect of behavior "action", a tradition which I have
followed.
Images of Achievement guide actions. This means that in some way or other there
must be composed -- in the brain cortex or elsewhere -- a 'representation' of the
environmental consequences of movements. Since there are a variety of movements,
patterns of muscle contractions, that can produce the same environmental consequence,
how is such a 'representation' constructed and formed? This is the issue of motor
equivalence that so troubled LASHLEY which he enunciated in his essay on 'The problem
of serial order in behavior.' It is a problem that we recognized but did not solve
in 'Plans and the Structure of Behavior'.
Progress toward a solution has been made, however, in the four decades since we
composed that volume. Rather than develop the story of the research involved historically,
I want here to indicate its results. Take the thermostat as a model. Many thermostats
have a small wheel by which a set point can be adjusted. The set point, say 20 deg.
Celsius governs the pattern of the output (the turnings on and turnings off) of
a furnace or air conditioner. In the language of non-linear dynamics (e.g. so-called
chaos theory), the setpoint acts as an attractor guiding the behavior of the system.
In another sense the set point "represents" the pattern of activity of
the heating and cooling apparatus. But the representation is not a memory of prior
patterns but an image of what the system needs to accomplish; in short an image
of achievement.
In the case of the thermostat this image of achievement is a simple one: to maintain
the room temperature at 20 deg. Celsius. But what about an image of achievement
such as that required to accomplish writing? Writing on a desk top requires a different
set of muscle contractions from that required to write the same message on a blackboard.
To accomplish an image independent of this variety of muscle contractions but true
to the more or less invariant characteristic of their environmental consequence,
we need to substitute a formula, a computable attractor, for the set point.
The key to what such a formula might look like came from the experiments performed
by BERNSTEIN and amplified by JOHANNSEN. BERNSTEIN dressed people in black leotards
and had them perform simple tasks such as running or hammering nails against a black
background. The leotard had been decorated with white dots over each joint. Bernstein
took cinematographic films of these activities. On his films he therefore had a
record of the movements of the dots which described a series of waveforms. When
he analyzed the records according to a Fourier procedure he was able to accurately
predict the next movement in the sequence!
I reasoned that if BERNSTEIN could do this so could his brain and, not to be outdone,
if BERNSTEINs brain could do this so could mine and yours. What we needed was direct
proof that cells in the motor cortex were responsive to wave forms. So Amad SHARAFAT,
an engineering student and I devised an apparatus which moved a cats paw up and
down at different frequencies. We recorded from motor cortical cells and found many
that were tuned to the frequencies with which the paw was moved.
Such frequency tuned cells in the primary visual cortex are considered to play a
role in visual imaging. My colleagues and I have shown that similar tuning occurs
in the somatosensory cortex and, of course, such tuning in the auditory system has
been known for decades. The processing of signals in the dendrites of such cells
can be likened to the processing that results in the images produced in tomography
(PET, CAT, and MRI) and in holography.
What the data suggest is that there exists in the cortex, a multidimensional holographic-like
process serving as an attractor or set point toward which muscular contractions
operate to achieve a specified environmental result. The specification has to be
based on prior experience (of the species or the individual) and stored in holographic-like
form. Activation of the store involves patterns of muscular contractions (guided
by basal ganglia, cerebellar, brain stem and spinal cord) whose sequential operations
need only to satisfy the 'target' encoded in the image of achievement much as the
patterns of sequential operations of heating and cooling must meet the setpoint
of the thermostat. Q.E.D.
GTA Home page Deutsch |
GTA
Home page Italiano |
GTA
Home page Français