Do we control our brains or do our brains control us?
Oliver Sacks, the author and neurologist, describes
how the experiences of blind people provide a fascinating insight into the
nature of consciousness.
In the last letter he wrote,Goethe observed: "The Ancients
said that the animals are taught through their organs; let me add to this,
so are men, but they have the advantage of teaching their organs in return."
He wrote this in 1832, a time when phrenology was at its height, and the
brain was seen as a mosaic of "little organs" subserving everything from
language to drawing ability to shyness. Each individual, it was believed,
was given a fixed measure of this or that faculty, according to the luck
of his birth.
Although we no longer pay attention, as the phrenologists did,
to "bumps" on the head (each of which, supposedly, indicated a brain-mind
organ beneath), neurology a and neuroscience have stayed close to the idea
of brain fixity and localisation - the notion, in particular, that the highest
part of the brain, the cerebral cortex, is effectively programmed from birth:
this part to vision and visual processing, that part to hearing, that to
touch, and so on. This would seem to allow individuals little power of choice,
of self-determination, let alone of adaptation, in the event of a neurological
or perceptual mishap.
But to what extent are we - our experiences, our reactions
- shaped, predetermined, by our brains, and to what extent do we shape our
own brains? Does the mind run the brain or the brain run the mind - or, rather,
to what extent does one run the other? To what extent are we the authors,the
creators,of our own experiences? The effects of profound blindness can cast
an unexpected light on this. To become blind,especially in later life , presents
one with a huge, potentially overwhelming challenge:to find a new way of
living, of ordering one's world, when the old way has been destroyed.
A DOZEN YEARS ago, I was sent an extraordinary book called
Touching the Rock: An Experience of Blindness. The author, John Hull,
was a professor of religious education who had grown up in Australia and
then moved to England. Hull had developed cataracts at the age of 13, and
became blind in his left eye four years later. Vision in his right eye remained
reasonable until he was 35 or so, and then it started to deteriorate. There
followed a decade of steadily failing vision, until, in 1983, at the age
of 48, he became completely blind.
Touching the Rock is the journal he dictated in the
three years that followed. It is full of piercing insights relating to Hull's
life as a blind person, but most striking for me is Hull's description of
how he experienced a gradual attenuation of visual imagery and memory, and
finally a virtual extinction of them (except in dreams) - a state that he
called "deep blindness".
By this, Hull meant not only the loss of visual images and
memories, but a loss of the very idea of seeing, so that even the sense of
objects having "appearances", visible characteristics, vanished. He could
no longer, for example, imagine how the numeral 3 looked unless he traced
it in the air with his hand. He could construct "motor " image of a 3, but
not a visual one. Though at first greatly distressed about the fading
of visual memories and images, Hull came to accept it with remarkable equanimity.
He seemed to regard this loss of visual imagery as a prerequisite for the
full development, the heightening, of his other senses.
Two years after becoming completely blind, Hull had apparently
become so non-visual as to resemble someone who had been blind from birth.
In a profoundly religious way, and in language sometimes reminiscent of that
of St John of the Cross, Hull has entered into this state, surrendered himself
with a sort of acquiescence and joy. And such "deep" blindness he conceives
as "an authentic and autonomous world, a place of its own... Being a whole-body
seer is to be in one of the concentrated human conditions."
Being a "whole-body seer", for Hull, means shifting his attention,
his centre of gravity, to the other senses, and he writes again and again
of how these have assumed a new richness and power. Thus he speaks of how
the sound of rain can now delineate a whole landscape for him, for its sound
on the garden path is different from its sound as it drums on the lawn, or
on the bushes in his garden. "Rain," he writes, "has a way of bringing out
the contours of everything; it throws a coloured blanket over previously
invisible things; instead of a fragmented world, the steadily falling rain
creates continuity of acoustic experience...presents the fullness of an entire
situation all at once."
Hull comes to feel an intensity of being-in-the-world, beyond
anything he knew when he was sighted. Blindness now becomes for him "a dark,
paradoxical gift". This is not just "compensation" he emphasises, but a whole
new mode of human being.
Important studies of adaptation in the brain were begun in
the 1970s by, among others, Helen Neville, a cognitive neuroscientist now
working in Oregon. She showed that in prelingually deaf people (that is,
those who had been born deaf or become deaf before the age of two or so)
the auditory parts of the brain had not degenerated or atrophied. These had
remained active and functional, but with an activity and a function that
were new: they had been transformed, "reallocated"
in Neville's term, for processing visual language. Comparable studies in
those born blind, or early blinded, show that the visual areas of the cortex,
similarly, may be reallocated in function, and used to process sound and
'Even though I am totally blind I consider myself a visual person.I "see" objects. I can see my hands typing the keyboard now'
With the reallocation of the visual cortex to touch and other
senses, these can take on a hyperacuity that perhaps no sighted person can
imagine. Geerat Vermeij, a blind biologist, has been able to delineate many
new species of mollusc based on tiny variations in the shapes and contours
of their shells.
Faced with such evidence, neurologists began to concede that
there might be a certain flexibility or plasticity in the brain, at least
in the early years of life. But when this critical period was over, it was
assumed, the brain became inflexible, and no further changes of a radical
type could occur. The experiences that Hull so carefully recounts give the
lie to this. It is clear that his perceptions, his brain, did finally change,
in a fundamental way. Indeed, Alvaro Pascual-Leone and his colleagues in
Boston have recently shown that, even in adult sighted volunteers, as little
as five days of being blindfolded produces marked shifts to non-visual forms
of behaviour and cognition, and they have demonstrated the physiological
changes in the brain that go along with this.
The brain, clearly, is capable of changing even in adulthood,
and I assumed that Hull's experience was typical of acquired blindness -
the response, sooner or later, of everyone who becomes blind, even in adult
Had I been wrong, or at least one-sided, in accepting Hull's
experience as a typical response to blindness? Had I been guilty of emphasising
the mode of response too strongly, oblivious to the possibilities of radically
In this, it seemed, he had been extremely successful, developing
a remarkable power of generating, holding, and manipulating his mind, so
much so that he had been able to construct an imagined visual world
that seemed almost as real and intense to him as the perceptual one he had
lost - and, indeed, sometimes more real, more intense, a sort of controlled
dream or hallucination. This imagery, moreover, enabled him to do things
that might have seemed scarcely possible for a blind man.
"I replaced the entire roof guttering of my multi-gabled home
single-handed," he wrote, "and solely on the strength of the accurate and
well-focused manipulation of my now totally pliable and responsive mental
space." (Torey later expanded on this episode, mentioning the great alarm
of his neighbours at seeing a blind man, alone, on the roof of his house
- and, even more terrifying to them, at night, in pitch darkness).
In his new memoir, Out of Darkness, he explores how his
life has been affected by blindness. Torey's father was the head of a large
film studio in Hungary before the war and would often give his son scripts
to read. "This," Torey writes, "gave me the opportunity to visualise stories,
plots and characters, to work my imagination - a skill that was to become
a lifeline and source of strength in the years ahead."
He emphasised to me the importance of a most critical choice
at this juncture: "I immediately resolved to find out how far a partially
sense-deprived brain could go to rebuild a life." Put this way, it sounds
abstract, like an experiment. But in his book one senses the tremendous feelings
underlying his resolution - the horror of "the empty darkness", "the grey
fog that was engulfing me -and the passionate desire to hold on to light
and sight, to maintain, if only in memory and imagination, a living visual
John Hull, who did not use his potential for imagery in a deliberate
way, lost it in two or three years, and became unable to remember which way
round a 3 went; Torey, on the other hand, soon became able to multiply
four-figure numbers by each other, as on a blackboard, visualising the whole
operation in his mind.
He became able "to imagine,to visualise for example, the inside
of a differential gearbox in action - as if from inside it's casing. I was
able to watch the cogs bite, lock and revolve, distributing the spin as required.
I began to play around with this internal view in connection with mechanical
and technical problems visualising how subcomponents relate in the atom,
or the living cell." This powerful imagery was crucial, Torey thought, in
enabling him to arrive at a solution of the brain-mind problem by visualising
the brain "as a perpetual juggling act of interacting routines."
Living in the world of the blind
SOON AFTER READING Torey's manuscript, I received proofs of
yet another memoir by a blind person: Sabriye Tenberken's My Path Leads
to Tibet. Tenberken has travelled, often alone, throughout Tibet, where
for centuries blind people have been treated as less than human and denied
education, work or any role in the community. Almost single handedly, Tenberken
transformed the prospects of blind people over the past half-dozen years,
devising a form of Tibetan Braille, establishing schools for the blind, and
integrating the graduates of these schools into their communities.
Tenberken herself impaired vision almost from birth, but was
able to make out faces and landscapes until she was 12.As a child in Germany,
she had a particular predilection for colours, and loved painting, and when
she was no longer able to decipher shapes and forms she could still use colours
to identify objects. Tenberken has, indeed an intense synaesthesia.
"As far back as I can remember," she writes, "numbers and words
have instantly triggered colours in me ... number four, for example [is]
gold. Five is light green.Nine is vermillion... Days of week, as well as
months, have their colours, too." Her synaesthesia has persisted and been
intensified, it seems,by her blindness.
These disparities do not faze her in the least - she is happy
to have so vivid a visual imagination. Hers is essentially an
artistic imagination, which can be impressionistic,
romantic: whereas Torey's imagination is that of an engineer, and has to
be factual, accurate down to the last detail.
If we are sighted, we build our own images, using our eyes,
our visual information, so instantly and seamlessly that it seems to us we
are experiencing "reality" itself. One may need to see people who are
colour-blind, or motion-blind, who have lost certain cerebral visual
capacities from cerebral injury,to realise the enormous synthesis, the dozens
of subsystems involved in the subjectively simple act of seeing. But can
a visual image be built using nonvisual information - information conveyed
by the other senses, by memory, or by verbal description?
There has been much recent work on the neural bases of visual
imagery, and it is now generally accepted that visual imagery activates the
cortex in a similar way, and with almost the same intensity, as visual perception
itself. And yet studies on the effects of blindness on the human cortex have
shown that functional changes may start to occur in a few days, and can become
profound as the days stretch into months or years.
Torey, who is well aware of all this research, attributes Hull's
loss of visual imagery and memory to the fact that he did not struggle to
maintain it, to heighten and systematise and use it, as Torey himself did.
Perhaps Torey was able to stave off an otherwise inevitable loss of neuronal
function in the visual cortex; but perhaps, again, such neural degeneration
is quite variable, irrespective of whether or not there is conscious
But what if their differences reflect an underlying predisposition
independent of blindness? What of visual imagery in the sighted? I first
became conscious that there could be huge variations in visual imagery and
visual memory when I was 14 or so. My mother was a surgeon and comparative
anatomist, and I had brought her a lizard's skeleton from school. She gazed
at this intently for a minute, turning it round in her hands, then put it
down and without looking at it again did a number of drawings of it, rotating
it mentally by 30 degrees each time, so that she produced a series, the last
drawing exactly the same as the first.I could not imagine how she had done
this, and when she said that she could "see" the skeleton in her mind
just as clearly and vividly as if she were looking
at it, and that she simply rotated the image through a twelfth of a circle
each time, I felt bewildered, and very stupid. I could hardly see anything
with my mind's eye at most,
evanescent images over which I had no control.
I was, however, to get a vivid idea of what mental imagery
could be like when, during the 1960s,I had a period of experimenting with
large doses of
These can produce striking perceptual changes, inducing dramatic enhancements
of visual imagery and memory. For a period of two weeks or so, I found that
I could do the most accurate anatomical drawings. I could mentally project
the image onto the paper before me and trace its outlines with a pencil.
But when the amphetamine-induced state faded, after a couple of weeks, I
could no longer visualise, no longer project images, no longer draw nor have
I been able to do so in the decades since.
A few months ago, at a medical conference in Boston, I spoke
of Torey's and Hull's experiences of blindness. Alter my talk,a man came
up to me and asked how well, in my estimation, sighted people could function
if they had no visual imagery. He went on to say that he had no visual imagery
whatever, at least none that he could deliberately evoke, and that no one
else in his family had any either.
So is Torey's greatly developed visual imagery not as indispensable
as he takes it to be? Might he have done everything he did, from carpentry,
to roof repair to making a model of the mind, without any conscious imagery
Simple visual imagery may suffice for the design of a screw,
an engine or a surgical operation, and it may be relatively easy to model
these essentially reproductive forms of imagery or to simulate them by
constructing video games or virtual realities of various sorts. Such powers
may be invaluable, but there is something passive and mechanical and impersonal
about them which makes them utterly different from the higher and more intimate
powers of the imagination, where there is a continual struggle for concepts
and form and meaning, calling upon all the powers of the self. Imagination
dissolves and transforms, unifies and creates, while drawing upon the "lower"
powers of memory and association. It is by such imagination, such "vision",
that we create or construct our individual worlds.
At this level, one can no longer say of one's mental landscapes
what is visual, what is auditory, what is image, what is language, what is
intellectual, what is emotional - they are all fused together and imbued
with our own individual perspectives and values. Such a unified vision shines
out from Hull's memoir no less than from Torey's, despite the fact that one
has become "nonvisual" and the other "hypervisual". What seems at first to
so decisive a difference between the two men is finally, a radical one, so
far as personal development and sensibility go. Even though the paths they
have followed might seem irreconcilable both men have "used" blindness to
release their own creative capacities and emotional selves, and both have
achieves a rich and full realisation of their own individual worlds.
© Oliver Sacks. This is an extract from an article
first published in The New Yorker, For more details, visit