Introduction: The Ganzfeld
Take a ping-pong ball. Cut it in half. Place the halves over your eyes and voilà, you are looking at a Ganzfeld. The Ganzfeld is a key concept in the work of German Gestalt psychologist Wolfgang Metzger and was discussed by James J. Gibson in The Ecological Approach to Visual Perception (Gibson 1986). Metzger first devised this phenomenon by adjusting the lighting that fell on a white wall. By lowering the light, he could make the wall fade from view so that all observers could see was an indistinct glow (Metzger 1930). Metzger claimed that what subjects saw in such cases was “space”: the third dimension that was left over after the two-dimensional wall had disappeared. Gibson, however, claimed that what they saw was nothing.
Gibson described some experiments of his own with the Ganzfeld. He constructed a set of goggles for his subjects to wear that would produce a completely homogenous field of illumination (using the aforementioned ping-pong balls). The subjects could see light, but nothing else: no shadows, no gradations of brightness – just luminosity. The only apparition available to the viewer under such tightly controlled conditions is a completely featureless and, indeed, invisible, landscape. Gibson claimed that this uniform distribution of light offered a glimpse of what he considered one of the essential components of the environment: the “medium.” According to Gibson, the medium is ordinarily inaccessible to perception. Its role in his ecological model is to serve as the ether that allows the visual signals emanating from material objects in our surroundings to reach our organs of perception. Gibson inferred that, given its featurelessness, the Ganzfeld could neither be determined as two-dimensional nor three-dimensional. In fact, he claimed, one could not really say whether it was dimensional at all. In order to appear, space – considered phenomenologically as an experience of depth – requires that something be perceived.
Gibson maintains that what prevents the appearance of dimensionality under such conditions is the lack of texture. Texture, he explains, appears to a seeing organism as patterns of variation in the intensity of light that reaches the eye – variations in the otherwise constant and consistent reverberation of light in all directions as it bounces back and forth among surfaces in the landscape. This patterning he terms “the ambient optic array,” and it is what makes the visual perception of surfaces possible. Furthermore, he says that what the eyes are able to detect are not objects, but rather illuminated surfaces. Thus, the existence of textured surfaces and their varying levels of reflection are necessary for visual perception. But texture is not yet sufficient. There is another condition necessary to produce vision: movement. “A surface,” Gibson writes, “is seen when the array has structure, that is, differences in different directions” (1986: 151). Only an organism capable of locomotion, therefore, is capable of vision. Without the capacity for assuming different perspectives, seeing cannot take place. When faced with a Ganzfeld, there are no differences in different directions, and therefore surfaces cannot be seen. Hence Gibson’s verdict that Metzger’s subjects saw nothing and, further, that “depth was not present in the experience but missing from it” (1986: 151). Textured surfaces, then, are not only what an organism is actually able to see; according to Gibson, they are also what furnish the organism’s environment with depth.
There is a sonic analog here, a contrast between a uniform field of sound and one that is somehow textured, a space in which an organism’s movement would result in differences in the sounds perceived. The creation of depth through texture is central to Gibson’s approach to vision and is also relevant to a discussion of depth as it is perceived through listening. In listening, too, the different sound patterns that emerge through movement are what provide space with depth. Depth is a key concept in the phenomenological investigation of embodied perception. Philosopher Scott Marratto describes depth as a unique dimension of space, one in which the objects we perceive reveal themselves to us as either near or far, rather than set alongside one another in a two-dimensional tableau. As a result, things in our environment “appear as somehow enveloped within one world,” an appearance that gives rise to a sense of voluminosity (Marratto 2012: 28). The significance of this definition of depth is that it entails the perspective of a body with motor abilities for which things can appear as being near or far. Because depth is revealed through motion, it is a phenomenon of change and difference not bound to binocular vision. Similarly, audible depth does not rely solely on distant echoes, relative volume, or ITDs and ILDs (that is, Interaural Time Differences and Interaural Level Differences, consequences of binaural hearing that help us determine the direction of sound sources). In the electroacoustic music of Éliane Radigue, the pulsing eddies of sound that appear in distinct locations throughout the performance venue emerge from the physical engagement of the listener and are not the result of stereo imaging techniques. The full force of her music can only be appreciated through the embodied response of a listener in motion.
Our ears can locate sounds in relation to one another through a variety of mechanisms. Some of these are astonishingly subtle, such as the ability to detect phase differences between signals reaching the left and right ears. But there are also sounds that can frustrate the ears’ efforts to discern their point of origin. They may seem to surround a listener and suffuse their environment so completely as to render other perspectives unattainable and other sounds dislocated. And when such sounds without origins also seem to lack texture, that is, when movements of head or body fail to reveal differences in sound, we have a situation where we may well feel ourselves immersed in that sound. We can think of this immersion as a sonic Ganzfeld. We detect sound, but it is so uniformly dispersed through the medium that it lacks direction and takes on an all-encompassing quality, as in Metzger’s experiment with the dimly illuminated wall. But we would not say that we heard nothing, in the way that Gibson claims Metzger’s subjects saw nothing. We still hear the sounds that we are immersed in as having their own character. For example, unlike the illuminated fog that Gibson equates with a Ganzfeld, we can hear the chaotic vibrations of a crash cymbal as a cymbal, even when its long decay pervades our space in a manner that gives no clue to the location or direction of the sound source. Of course, our ability to identify the sound does not mean that a cymbal crash is not a Ganzfeld. It is not hard to imagine, say, a Ganzfeld of blue light – a Ganzfeld that we perceive as something other than simply nothing. But the cymbal crash has a quality the visual Ganzfeld does not: it changes through time. The sound evolves as it continues, and one may, for instance, occasionally notice higher partials that become more salient than lower ones, or vice versa. The attack, sustain, and decay phases of its sonic envelope are neither consistent nor linear. Radigue’s music provides a subtle yet distinct contrast to this distance-obscuring type of immersion. Instead of a dense suffusion of sound, Radigue’s music has a wavering presence that provides the space itself with an audible texture.