Singing to the Plants: A Guide to Mestizo Shamanism in the Upper Amazon (49 page)

The symptoms of schizophrenia are thus predictable on the assumption
that the disease involves misidentification of imaginings.'? Indeed, the weakening of these ontological boundaries transcends pathology. The various
modes of perceptual imaginings, such as visual and auditory imagery, share
important features with the corresponding kinds of perception. We normally
use the same descriptive terms for both internal imaginary perceptions and
external real perceptions-sounds are loud or distracting; images are dim or
incomplete. It is not difficult to confuse the two. I have had dreams so realistic and persuasive that it required serious thought to rule out that the events
had actually occurred. I am not alone; people can find it difficult to remember
whether they have actually seen something or simply formed a visual image
of it.i8 Conversely, in a classic experiment, people were asked to visualize a
banana, without knowing that there was in fact a just barely visible image of
a banana on the screen in front of them. It was clear from their descriptions
that what they took to be their internal images were really perceptions of the
external picture.19

It is tempting to hypothesize that source-monitoring judgments-note
that I said judgments, not mistakes-are a key element in ayahuasca hallucinations. It is important to bear in mind, too, that source monitoring can be affected by learning and, presumably, by culture; an experienced shaman may
see spirits, even if vaguely, all the time, because a combination of ayahuasca,
other psychoactive plants, learning, and social expectation may have systematically affected the source-monitoring process.

SPIRITS AS CONSTRUCTIONS

Here is the content of a series of visions-golden sparks, melting purple
blobs, a dancing brown spot, snowflakes, saffron and light blue waves, a corona of light "like a chrysanthemum composed of thousands of radiating petals." Then, as the visions solidified, there appeared a Cuban flag flying over a
bank building, an old lady with a gray umbrella walking through the side of a
truck, a cat rolling across the street in a small striped barrel.

These are not ayahuasca visions. They are what writer James Thurber reported seeing after he became completely blind.20 Neuroscientist Vilayanur
Ramachandran believes that Thurber suffered from a neurological condition called Charles Bonnet syndrome.21 One of Thurber's famous cartoons depicts
a startled-looking woman sitting in a doctor's office looking at the giant rabbit in a suit and bow tie sitting behind the desk. You said a moment ago that everybody you look at seems to be a rabbit, the doctor says. Now just what do you mean by
that, Mrs. Sprague? The cartoon in many ways depicts a typical Charles Bonnet
hallucination-three-dimensional, integrated into perceptual space, persistent, coherent, interactive, present.

Thurber had been blinded in his right eye, accidentally, when he was six
years old; as he grew older, the vision in his left eye began to fade as well, until, by the age of thirty-five, he was completely blind.22 In his 1937 piece The Admiral on the Wheel, Thurber wrote of the spectacular things he saw despite the
serious and growing deterioration of his vision-bridges rising lazily into the
air like balloons; a "noble, silent dog" lying on a ledge above a brownstone
house on lower Fifth Avenue; a "little old admiral in full dress uniform," his
beard blowing in the wind and his hat set at a rakish angle .23

Charles Bonnet Hallucinations

One study of people with Charles Bonnet syndrome reports that hallucinatory
episodes could last from a few seconds to several hours.24 The patients described the content of their hallucinations as people, animals, plants, a large
variety of inanimate objects, and sometimes complete scenes. The content
of hallucinations was often mundane-for example, an unfamiliar person,
a bottle, a hat. The hallucinations could also be funny; one woman saw two
miniature policemen guiding a tiny villain to a tiny prison van. Some people
saw translucent figures floating in the hallway, a dragon, people wearing one
big flower on their heads, a beautiful shining angel, wonderful bunches of
flowers, little circus animals, clowns, and-interestingly-elves. Indeed,
many patients see people-a Canadian Mountie in full military dress; a group
of Elizabethan figures; little girls playing in the yard, wearing white dresses
with pink sashes and pink bows in their hair.25

Most patients described a large variety of hallucinations, differing in each
hallucinatory episode; sometimes the sensation of specific objects returned,
but stereotyped hallucinations, identical in every respect, were uncommon.
Hallucinations contained both familiar and unfamiliar images, and they occurred both in black and white and in color. They could be clearer, equally
clear, or less clear in comparison to reality. Most patients hallucinated only
with their eyes open. Some perceived hallucinated objects as floating in the
air or projected on a wall or ceiling; others reported that the objects fitted well into the surroundings-for example, an unreal person sitting in a real chair.
Patients hallucinating while their eyes were closed perceived hallucinations in
the dark subjective space in front of the eyes.

One patient described the experience this way: "The world was filled with
hallucinations, both visual and auditory. I couldn't distinguish what was real
from what was fake. Doctors and nurses standing next to my bed were surrounded by football players and Hawaiian dancers."" This same patient, during a discussion with Ramachandran, reported seeing a monkey-"extremely
vivid and real"-sitting in the doctor's lap.27 Visual and auditory hallucinations can be coordinated; one woman patient not only saw children in her left
visual field but could also hear their laughter .21

A study using multiple-correspondence analysis and hierarchical cluster
analysis reports a set of features characteristic of Charles Bonnet hallucinations.29 The hallucinations occur when the patient is alert and with eyelids
open; a sharply focused image suddenly appears, without any apparent trigger or voluntary control; the hallucinations are always outside the body and
can last from a few seconds to most of the day.3° The same study reports such
hallucinations in conjunction with grief reactions. In fact, such auditory and
visual hallucinations are a commonly documented part of the grief reaction,
with as many as 70 percent of recently bereaved people experiencing either
illusions or hallucinations of the deceased.3' Ramachandran reports the case
of a woman with Charles Bonnet syndrome who saw her recently deceased
husband three times a week.32

In another study, factor analysis of structured interviews and questionnaires partitioned visual experiences into three clusters-visual perseveration and delayed palinopsia or recurring visual hallucinations; hallucinations
of grotesque, disembodied, and distorted faces with prominent eyes and
teeth; and hallucinations of extended landscape scenes and small figures in
costumes with hats.33 Another study reports a hallucination of an "elf in the
woodshed."34

Gap Filling

Gap filling is the brain's way of dealing with gaps in the visual image. Migraine sufferers experience blind spots in the visual field, called scotomas,
when a blood vessel goes into a spasm. Such a scotoma will blank out corresponding perceptual areas-a clock on the wall, for example. But the person does not see a blank or void where the clock used to be but, instead, a
normal wall, with the region corresponding to the missing clock covered with the same color of paint or pattern of wallpaper as the rest of the wall.35 More
recent work has shown that such gap filling occurs even across large central
scotomas caused by physical retinal damage;36 it appears that gap-filled figures even generate afterimages .'

In a series of extraordinarily clever experiments, Ramachandran has explored the capacity of the visual process to fill in such perceptual gaps.38 It is
clear that such gap filling is capable of generating even complex perceptions.
In one striking case, Ramachandran put up the numerals i, 2, and 3 above a
patient's scotoma and 7, 8, and g below. The patient saw a continuous column of numbers, with no gap in the middle. When asked to read the numbers
aloud, the patient said, "Um, one, two, three, um, seven, eight, nine. Hey,
that's very strange. I can see the numbers in the middle, but I can't read them.
They look like numbers, but I don't know what they are." When asked if the
numbers looked blurred, he replied, "No, they don't look blurred. They kind
of look strange. I can't tell what they are-like hieroglyphics or something. "39

It is probably worth noting that this report is consistent with the reports of
lucid dreamers who attempt to read while dreaming. Such attempts are consistently difficult and usually unsuccessful; one test for determining whether
one is dreaming is to try to read something. One dreamer reports, "When I
have read several words in this way, partly forwards and partly backwards,
something remarkable happens. Some of them have changed their shape;
they no longer consist of the usual letters, but form figures which bear a distinct resemblance to hieroglyphics. And now I can see nothing but these symbols, each of which signifies a word or syllable, the ordinary letters having
completely disappeared."4° Similar experiences are found in hypnogogic imagery-for example, images of a printed book, in which, at most, a halfa line
can be read, usually nonsense.41 It is plausible to hypothesize that these letters
and hieroglyphics are being generated by processes similar to those used to
fill in the column of numbers over the blind spot caused by the scotoma.

Such gap filling is in fact part of our everyday perceptions. Our retinal images are distorted, tiny, and upside down; most of the retina is nearly color
blind and has severely limited powers of discrimination; the eye is in nearly
constant motion;42 yet we see a world that is relatively stable, detailed, and
consistent. We are constantly filling in perceptual gaps-in a dog behind a
wire fence, say, or one object partially obscured by another. It is clear, says
Ramachandran, that the mind "abhors a vacuum and will apparently supply
whatever information is required to complete the scene."43 Philosopher Alva
Noe puts it this way: "We experience the presence of that which we perceive to
be out of view. 1144

Gap Filling and Ayahuasca

According to Ramachandran, the hallucinations of Charles Bonnet syndrome
are an exaggerated version of such common imaginative and perceptual processes-precisely the same processes that account for gap filling in patients
with scotomas.45 Perception, under this theory, is the end result of interplay
between current percepts and previously constructed and stored visual images from the past. This is a dynamic process. The higher visual centers receive a set of percepts, come up with best-match stored images, and project
these back to the visual cortex, which uses them as perceptual gap fillers. In
this way, the initial impoverished image is progressively refined; the resulting
perception-a cat, a person, a Confederate flag-is the result of successive iterations of the matching and gap-filling process. As Ramachandran suggests,
perhaps we are hallucinating all the time.46

There are several points of interest in this theorizing. First, it meshes closely with my own experiences of ayahuasca's gap-filling ability, described in the
previous chapter. In addition, no one has attributed any psychopathology to
any person with Charles Bonnet syndrome; the hallucinations apparently occur through normally operating visual mechanisms. Certainly there has been
no discussion of any defect in source monitoring; apparently the hallucinations, acting through ordinary visual processes, are so compelling that they
override culturally mediated source-monitoring judgments.

How does this happen? Normally, when we imagine, say, a rose, we do not
hallucinate a rose. Ramachandran suggests that this is because we normally have real input coming in from the retina and optic nerve, even when the
eyes are closed; there is always spontaneous activity in the retina. But where
there is macular degeneration, or a scotoma, this visual input is completely
missing, and internally generated images can assume vividness and clarity
and have the irrevocable quality of real stimulus-evoked sensory experience.
In other words, imagination produces weak images because there is competing real visual input; but when that competing input is absent, then, as Ramachandran says, we start confusing internal images with external reality.47 In
other words, partial blindness can affect source monitoring.

If that is the case, there is a continuum from the hallucinations of Charles
Bonnet syndrome to ordinary, everyday perceptions-from the monkey on the
neurologist's lap to the monkey in the enclosure at the zoo. What differentiates one from the other is, precisely, source monitoring-learned, fallible, alterable, culturally determined.

AYAHUASCA AND VISIONARY EXPERIENCES

Imaginal Beings

In December 1913, Carl Jung first experienced what he was later to call active
imagination. However, he did not talk about these experiences until twelve
years later, when, in May and June 1925, he spoke for the first time of his inner
development at two sessions of a series of weekly seminars he was giving in
Zurich.48 The contents of these lectures were not published until 1989;49 but
a partial account was given in 1962 by Aniela Jaffe in Memories, Dreams, Reflections, a purported autobiography of Jung that she largely wrote.5°

In 1913, according to this account, Jung, profoundly distressed by his
break with Freud, began to experiment with different ways to enter into his
own imaginings. As James Hillman describes it, "When there was nothing
else to hold to, Jung turned to the personified images of interior vision. He
entered into an interior drama, took himself into an imaginative fiction and
then, perhaps, began his healing-even if it has been called his breakdown."S'