Virtually every practicing psychologist had encountered
chidren who could not grasp what they were assembling in the object assembly
task (when they were not told in advance what the object was supposed to be). These children
usually progress by trial and error, erratically, grope in the dark, and only
if and when they finish the task, and the object is complete, they say in
surprise: "Oh, that's a dog!" (There is no dog there but I will not
reveal items from the test here ...).
There is no doubt that these children have a disadvantage
compared with children who see and say instantly, before beginning to assemble
the pieces: "This is a dog." Children
who know instantly that it's a dog know where they are going. They can monitor their work and check on their
progress towards the goal, because they know what the goal is. They hold the object in its entirety in their
mind's eye.
Is it possible that
the style of work and perception that a child exhibits in the object assembly
task will appear only in this test? Perhaps this style characterizes the way he
approaches the world, the way he interprets the world? And what are the
implications of such a style?
Andy Clark is professor of logic and metaphysics at
Edinburgh University in Scotland. Clark wrote an article in 2013 that was received with a wave of reactions from researchers and philosophers, and was quoted about 1700 times in the
professional literature. This is a very difficult article to read (for me
anyway). Clark presents a theoretical concept that I understand was first
introduced by Karl Friston in 2005. The theory is called HIERARCHICAL PREDICTIVE PROCESSING
or HPP. The basic idea is familiar from
Kant's philosophy, but it is presented here in new and interesting costume,
which may help to understand what happens to a child who does not see Gestalt
in object assembly.
But
not only object assembly. This theory
offers an explanation of perception as well as other phenomena such as
attention, mental imagery, dreaming, hallucinations and delusions, emotions,
autism, and even reading difficulties. In this post I will focus on some of
these phenomena. I'll also try to walk
on less secure ground for me and offer some links between cognition and psychoanalytic
concepts (in the spirit of the work model presented in the previous post).
When I
look out the window and see countless little green bits swaying in the breeze,
my brain must understand that I see a tree swaying in the wind. How does that
happen? According to HPP theory, the brain does not wait passively until
sensory signals arrive, and then interprets them. The brain constantly produces
predictions about the sources of signals it will receive from the senses. These
predictions are the best guess, the best hypothesis the brain has about the
sources (the objects in the world, in this case: the tree) from which sensory
data are obtained. The brain creates these predictions based on its
expectations and beliefs about how the world is structured, that is, based on
its pool of knowledge.
As
these predictions "descend" to sensory organs they affect the way the
sensory signals are perceived. When there is a good match between the
predictions and what is actually absorbed in the senses, all is well: the
prediction worked. The world is really what we predicted it would be.
When
there is a mismatch between the predictions and what is actually absorbed in
the senses, prediction errors, ie, the differences between what the brain
predicted and what sensory organs have absorbed, "ascend" from the
sensory organs to the brain. Prediction
errors cause slight changes in subsequent predictions to fit them more with
what exists in reality. Because predictions are based on models we have of
reality, that is, on our crystallized knowledge, prediction errors lead to
changes in the models, changes in the crystallized knowledge - that is,
learning. The goal of the brain is to minimize prediction errors as much as
possible. The brain aspires to be in a state where it perfectly predicts the
sources of signals it receives from the senses. There is a perpetual cycle of
predictions and error correction.
This
means that what we perceive is determined by our predictions as much as by the
signals that come to our senses from the objects we perceive. The predictions
that "flow" down are rich in content, while the sensory information
that "flows up" is composed only of prediction errors. The rich
prediction that "flows down" enables us to know what is in the world,
to "grasp" the world before it is actually caught in our senses. If
this theory is true, then the role of sensory contact with the world is only to
verify the best guess of the mind about what is out there, and
when necessary - correct it. According to this approach, our predictions are
the main source of all the contents of our perceptions, even though these
contents are continually tested and constantly corrected by the prediction
errors generated by sensory input.
The
sensory signals always come to us with a certain "noise". For
example, when we listen to a person talking, we do not hear the speech sounds
in a completely clear way. There are background noises, the person
"swallows" some of the sounds and does not separate the words (the speech
sounds flow in a continuous sequence). We are able to understand what is said
because of the predictions that the brain projects toward the sensory signals.
The brain expects to hear certain things (according to the context of the
conversation, according to the knowledge we have about syntax and grammar) and
the expectations help it bridge imperfections in input quality, complete
auditory Gestalt and understand what is said.
Perceptual illusions can also demonstrate HPP theory. Square A in the left chess board
appears to be darker than Square B. But as indicated by the gray lines drawn on
the right chessboard, the two squares are identical in color. We do not see the
color of the squares "objectively".
What we see is our best guess about the color of the squares. We know
that a chess board is made up of dark and light squares, and that between four
dark squares there must be a light square. Our expectations about the structure
of a chessboard affect the way we perceive it.
We see
the green object lying on the chessboard as a cylinder even though it is really
a two-dimensional object. This is because we interpret the "shadow"
painted on the left side of the green object and the circle painted at the top
of it as indicating 3D, and the object being a cylinder. We do not perceive
what is actually drawn but our interpretation of what is drawn. And so it
should be: the role of the visual system is not to be a physical measure of
light, but to help us perceive reality. And the predictions that the brain
produces do indeed help us perceive reality.
Our
ability to generate predictions about objects in reality is at the basis of our
ability to generate mental images and to dream. Predictions are perception without sensory stimulation.
In a normal process of perception, predictions are always compared with sensory
data. We use the same system that generates predictions about what is in the
world to create mental images or dreams that are not contrasted with sensory
data.
Could it be that the infant's evolving cognitive ability
to create a mental image of his mother or caretaker (a mental image of the
mother as a whole or partial object, a mental image of the mother's look,
voice, touch, etc.) helps him to survive the moments when the mother is not
with him? We know that there are individual differences in the ability to
create mental images. How do babies with poor mental imagery endure in these
difficult moments?
Our
predictions not only affect what we perceive but also our actions in the world.
When we want to pick up a cup of coffee, for example, we imagine or predict the
state of the future goal (our hand holding the cup of coffee) and generate
motor commands that will help us realize the prediction. Of course, we also
predict the touch of the cup,
the smell of the coffee and its taste. As predictions
flow down, prediction errors flow up and set the next predictions flowing
downwards.
Hallucinations and delusions
We
have seen so far that what we perceive is always a subtle combination of
"top-down" knowledge-based predictions and "bottom-up"
prediction errors. Normal perception is
always a balance between sensory signals coming from the world and our
expectations for these signals.
Could
it be that precisely here - at the point
of connection between expectations / predictions and sensory signals, between
the internal and external realities, between the subjective and the objective -
is the potential space that Winnicott speaks of?
Our
perception of the world is a kind of "controlled hallucination," a
fantasy that fits reality. The predictions of the brain are restrained by
sensory information from the world. We have partners to this controlled
hallucination: different people who look at the same object (for example, the
image of the cylinder on the chessboard) usually agree about what they see.
When we agree about our hallucinations we call them reality.
But sometimes
there is an imbalance between the prediction errors that flow up and the
predictions that flow down. When the scale is tipped too much toward the
predictions (the brain over- weights predictions and under- weights prediction
errors), we may be under the impression that we perceive certain objects that
are not actually there, and then we experience a hallucination. Alternatively, hallucinations
and delusions may also arise when something
goes wrong at the level of sensory data, which causes us to generate false
prediction errors. False prediction
errors (ie. incorrect corrections of our predictions) cause unjustified changes
in our internal model of the world (delusions).
From
this erroneous model, we generate false predictions that flow down and affect
the way we interpret sensory data. Thus more erroneous prediction errors are
created that reinforce the wrong internal model and thus a cycle of misperception
and misinterpretation of the world is created.
I
suggested earlier that one can think of the point of balance, the delicate
connection between the inner world (the predictions that flow down) and the
external world (the prediction errors that flow up) as the potential space. If
this is the case, we may think of tilting the scales toward the predictions
(attributing excessive weight to predictions and not enough weight to
prediction errors) as a collapse of the potential space
to the fantasy pole. Ogden argues that in trauma or great anxiety, we may
experience fantasy as reality. A frightening thought is experienced as a
frightening reality, a crocodile doll a child plays with as a real crocodile
about to devour the child. The child loses the ability to play.
Perhaps in moments of collapse into the pole of fantasy, perhaps when
the brain attributes too much weight to predictions and too little weight to prediction
errors, a child will tell TAT stories that are not well linked to the stimuli
in the picture. Perhaps such a child will give a very unusual interpretation to
the stimuli in the picture. Perhaps such a child will see the objects in the
picture as objects in the real world and respond to them as such.
Object assembly
I
suspect that difficulties of children who do not see the whole object when
working on an item in object assembly may result from tilting the scales to the
sensory signals (the brain over- weights prediction errors and under- weights
predictions). When predictions are underweighted, they can't guide perception
and can't form expectations for the whole object. Perception
is guided primarily by sensory signals. Thus, the ability to integrate what is
perceived and to interpret it is greatly weakened. The ability to create
categorization is weakened, and each piece of stimulus is perceived as a
separate object.
In the
spirit of Winnicott and Ogden's theories, one may think of tilting the scales
toward the sensory signals (attributing excessive weight to the senses and under-weight to the
predictions) as a collapse of the potential space to the reality pole. This situation can
also occur, according to Ogden, following trauma and when people feel anxious. A person may cling to reality defensively, as
a defense against fantasy. In this state
a person can not play or imagine.
Perhaps
in moments of collapse into reality, when the brain attributes too much weight
to the senses and too little weight to predictions, a child will not be able to
tell a story in the TAT test, and instead describe in detail the objects he
sees in the drawings. In this way he clings to reality and leaves no room for
fantasy.
I am
reminded of a short story by Jorge Luis Borges, "Funes, the memorious" , that my
friend Garciella Neumann introduced me to. In this fictional story, Borges
tells the story of Ireneo Funes, a 19-year-old boy who was hit in
the head after falling from a horse. Borges writes:
"On falling from the horse, he lost
consciousness; when he recovered it, the present was almost intolerable; it was
so rich and bright. A little later he
realized that he was crippled. This fact scarcely interested him. He reasoned
(or felt) that immobility was a minimum price to pay. And now, his perception
and his memory were infallible. In
effect, Funes not only remembered every leaf on every tree of every wood, but
even every one of the times he had perceived or imagined it.
…He was, let us not forget, almost
incapable of general, platonic ideas. It was not only difficult for him to
understand that the generic term dog embraced so many unlike specimens of
differing sizes and different forms; he was disturbed by the fact that a dog at
three-fourteen (seen in profile) should have the same name as the dog at three fifteen
(seen from the front).
…He was the solitary and lucid spectator
of a multiform world which was instantaneously and almost intolerably exact.
…Without effort, he had learned English,
French, Portuguese, Latin. I suspect, nevertheless, that he was not very
capable of thought. To think is to forget a difference, to generalize, to
abstract. In the overly replete world of Funes there were nothing but details,
almost contiguous details".
Ogden, T.
H. (1993). The matrix of the mind: Object relations and the
psychoanalytic dialogue. Jason Aronson
