From Visual to Aural Space: a Change of Paradigm?*

FROM VISUAL TO AURAL SPACE: A CHANGE OF PARADIGM?*

FREDERICO ALBERTO B. MACÊDO

Resumo: neste artigo discuto como a influência de Visualism levou à concepção equivocada segundo a qual o espaço é principalmente um domínio visual. Diferentes abordagens para a percepção mostram evidências de que todos os sentidos estão envolvidos na percepção do espaço. Pesquisas recentes sobre percepção auditiva e localização humana também mostram evidências de que o sistema auditivo tem a capacidade de detectar e processar as infor- mações espaciais em um nível insuspeito por pesquisadores que consideravam a audição como uma sensação com pou- cas informações sobre as relações espaciaia. Na conclusão, sugerem que a mudança de visual para o espaço auditivo pode representar mais do que simplesmente uma mudança de variáveis, mas um sintoma de uma mudança cultural mais profunda, uma consideração mais equilibrada dos sentidos como um todo, refletida na antiga idéia de sensus communis.

Palavras-chave: Percepção auditiva do espaço. Percep- ção. Percepção espacial.

n order to describe space as an aural domain, the first , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. step is to deconstruct, or overcome, the idea that space is primarily a visual domain. The emphasis on the visual estudos I sense exerted a powerful influence on the development of western philosophy. This influence also permeated the stud- 151 ies of perception. As happened with the study of all senses other than the visual, so the auditory system has often been described in its relation with vision, and in many cases research on auditory perception has been conceived of as an attempt to transpose to the aural domain the principles and mechanisms of visual perception. In a sense it may be the natural consequence of the fact that much more is known about visual perception than about any other sensory modality. However, it is important to keep in mind that this emphasis should not mean the reduction of all experience to what can be understood or conceptualised in visual terms. As Ihde points out:

Philosophy and its natural children, the sciences, have often blindly accepted this visualism and taken it for granted. It is not that this tradition has been unproductive: the praise of sight has indeed had a rich and varied history. The rationality of the West owes much to the clarity of this vision. But the simple preference for sight may also become, in its very richness, a source of the relative inattentiveness to the global fullness of experience and, in this case, to the equal richness of listening (IHDE, 2007, p. 8).

According to McLuhan, this visualism is a cultural feature of western civilization, and had its origins in the development of literacy and the collapse of oral traditions in early Greece. In the Middle Ages orality was still important, as literacy was not wide- spread and written language was regarded as just a representation for speech, and the texts were meant to be read aloud. With the development of print, the consequent dissemination of literacy and the increasing development of the sciences, the visualist tendency became dominant in western culture, exerting a powerful influence both on the way reality is perceived and, on the way perception is understood and conceptualized by western man. Before the development of the alphabet and literate cultures, the emphasis in

the aural sense was not the norm among oral cultures: 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v.

For hundreds of thousands of years, mankind lived without a

straight line in nature. Objects in this world resonated with estudos 152 each other. For the caveman, the mountain Greek, the Indian hunter […], the world was multicentered and reverberating. It was gyroscopic. Life was like being inside a sphere, 360 degrees without margins; swimming underwater; or balancing on a bicycle. […] Speech, before the age of Plato, was the glorious depository of memory (MCLUHAN, 2004, p. 68).

Originally, the reflection about perception started in philosophy. Heraclitus and Aristotle discussed the differences and relative value of different sensory modalities. Democritus, Plato, Descartes, Locke and the phenomenologists discussed the role of the senses for the constitution of knowledge (IHDE, 2007, p. 6-13). The early 20th century saw the emergence of the experimental study of perception, constituted by the confluence of contributions from specific fields in physical sciences, such as acoustics, optics and psychology. Behaviourism was the dominant paradigm of the moment, and this influence is evident in the early studies of perception, which tended to focus just on observable behaviour, disregarding high level processes, such as prior knowledge, cognition, expectations and beliefs (Neuhoff: 2004, p. 6). Despite being still important, the experimental approach is no longer the only one. Nowadays, the study of perception is a rich interdisciplin- ary field, which welcomes contributions from different areas of research, including neurology, neurosciences, cognitive sciences and trends in psychology other than behaviourism. According to Valkenburg and Kubly (2004, p. 113), two kinds of rifts separate the community of perceptual researchers, theoretical rifts and modality specific rifts. Two main theoretical approaches can be identified, the constructivists, or experimentalists, which “use simple stimuli and well-controlled artificial environments to explore lower level sensory processes” (VALKENBURG; KUBLY, 2004, p. 113), and the ecologists, which use “real-world stimuli and less controlled environments to explore higher level sensa- tion, cognition and behavior” (VALKENBURG; KUBLY, 2004, p. 113). The modality specific rifts exist because most researchers

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. work with a single sensory modality, with its own theories and terminology, which may not apply to other sensory modalities. In the last twenty years a number of researchers started to recognise estudos the need to integrate the findings of different approaches, which is noticeable in studies of intersensory perception (STEIN; MER- 153 EDITH, 1993), crossmodal attention (DRIVER; SPENCE, 1998) and ecological psychoacoustics (NEUHOFF, 2004). However, there is still a long way to go, if one thinks of a largely accepted and comprehensive theory which incorporates all sensory modalities. Spatial perception is a case of crossmodal perception, which involves the use of different sensory modalities. In order to understand properly the phenomenon, it is impossible to adhere to a single approach. Instead, it is important to have an open attitude, which incorporates the contributions of different approaches. In this paper, firstly, I introduce some basic concepts related to the study of perception and spatial perception, integrating information from constructivist and ecological approaches, mentioning, also, studies on multisensory integration, crossmodal attention and spatial cognition. Secondly, I discuss the possibility of conceiving space as an aural domain, including the concepts of acoustic space and aural architecture and, also, studies in human echolocation. Finally, I conclude discussing some of the broad implications of the consideration of space as an aural domain.

PERCEPTION AND SPACE PERCEPTION

Perception can be understood as the study of “the complete immediate relation of the organism to its surrounds” (BARTLEY, 1980, p. 11). This relationship involves both passive reception of information and active responses to the environment. These two aspects are evident in Gibson’s distinction between perception and behaviour. “Every animal”, he says, “is, in some degree at least, a perceiver and a behaver. [...] It is a perceiver of the environment and a behaver in the environment” (GIBSON, 1986, p. 8). Spatial perception involves both aspects of perception, the passive, related to the reception of information from the environment, and the active, related to locomotion and spatial navigation.

The Theory of Affordances , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. Gibson proposes the concept of affordance to describe the relationship between the organism and the environment. Because

each species has different sense organs and perceptual systems, estudos 154 they do not perceive the world in the same way. The theory of affordances describes the world as it appears for the species under consideration. In his own words:

The affordances of the environment are what it offers to the animal, what it provides or furnishes, either for good or ill. The verb to afford is found in the dictionary, but the noun affordance is not. I have made it up. I mean by it something that refers to both the environment and the animal in a way that no existing term does. It implies the complementarity of the animal and the environment (GIBSON, 1986, p. 127).

The affordances are always measured in relation to the animal, and are not conceived in absolute terms, as are the units of classical physics. A horizontal terrestrial surface, for instance, affords support for a terrestrial animal, but for an aquatic animal, the support is afforded by the water surrounding its body. The most important point in the theory of affordances is that the information about the environment must be detected by the perceptual systems of the organism under consideration.

Perceptual Systems

Gibson (1966) also proposes the concept of perceptual system to replace the traditional concept of sense and a new typology to classify them. According to the traditional view advocated by Aristotle, there are five senses, each one corresponding to a sense organ: sight for the eye; hearing for the ear; touch for the skin; taste for the tongue and smell for the nose. This classification poses problems for the researcher, among them the exclusion of important kinds of perceptual experience, especially the proprio- ceptive, and the fact that the sense of touch does not have a single organ. According to Gibson, there are five perceptual systems, which have some correspondences, but which are not the same as Aristotle’s five senses. , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. Each perceptual system is specialized in sensing and interpret- ing different kinds of information provided by the physical energies estudos of the environment, having a particular role in the perception of the external world and in the performance of specific tasks and 155 behaviours. The basic orienting system [1] uses the apparatus of the inner ear, especially the vestibular system, to receive information provided by gravitational forces to orient the body in relation to the pull of gravity. The haptic system [2] has no sense organ, but receptors in different tissues of the organism, which receive information related to the mechanical aspects of the environment, including direct contact and temperature, being essential for spatial orientation and locomotion. The taste-smell system [3] incorporates the senses of taste and smell in one single system. The auditory system [4] and visual system [5] correspond to the traditional senses of audition and vision (GIBSON, 1966, p. 49). The perceptual systems are interconnected, and work together to create a map of the external world. Each organism needs to extract from the environment the information which is essential for its survival and orientation. This information may come from a single perceptual system or from any combination of them. The perception of space relies on information provided by different perceptual systems, or, in other words, is a case of crossmodal, or multimodal perception.

Perception of Space

Space is a central and essential part of human experience, as all that can be experienced by human beings happens in a specific location, at a specific time. Dufrenne (1973) conceives time as the origin of subjectivity, and space as the source of objectivity. “Just as time is the form of inner sense and thus lies at the source of subjectivity”, he says, “space is at the origin of externality” (DU- FRENNE, 1973, p. 243). In this sense, all perceptual systems are involved in the perception of space, as they can be conceived of as the primary mechanisms through which the individual relates to the external world. Within the studies of perception, space perception (italics for emphasis?), or perception of space, has a more restricted meaning. The former has been defined by Bartley

as follows: 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v.

Space is a domain within which the individual is situated and

within which he or she moves about. It is a domain within estudos 156 which there are other humans and other animals and inani- mate objects [...]. So, among other things, the individual must be able to perceive the location, size, shapes, and motion of objects. This is space perception (BARTLEY, 1980, p. 268).

Gibson (1966, p. 59) defines perception of space as:

a basic type of perception on which other perceptions depend, that is, the detection of the stable permanent framework of the environment. This is sometimes called the perception of “space”, but that term implies something abstract and intellectual, whereas what is means meant is something concrete and primitive – a dim, underlying, and ceaseless awareness of what is permanent in the world.

The perception of space involves the use of information provided by different perceptual systems. According to Gibson, the primary orientation for all terrestrial, aquatic and flying animals, is the orientation towards gravity, provided by the basic orienting system. An organ, in its simplest forms called a statocyst, detects information about the direction “down”, temporary accelerations and the permanent acceleration of gravity. For human beings and other mammals, this information is provided by the vestibular system, essential for locomotion and posture (GIBSON, 1966, p. 60-1). The haptic system is responsible for the detection of the second kind of spatial affordance of the environment: the sensibility of the body to its immediate surroundings. The haptic system is related to two kinds of perceptual information: kinesthesis, or perception of body movement, and skin pressure, being defined by Gibson as follows:

The sensibility of the individual to the world adjacent to his body by the use of his body will be here called the haptic system. [...]. The haptic system [...] is an apparatus by which the individual gets information about both the , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. environment and his body. He feels an object relative to the body and the body relative to an object. It is the perceptual estudos system by which animals and men are literally in touch with the environment (GIBSON, 1966, p. 97). 157 The receptive cells and units which compose the haptic system are called mechanoreceptors and are primarily affected by mechanical energy, being distributed throughout the whole body: in and below the skin; in joints and ligaments which connect the movable bones of the body; in muscles and tendons; wrapped around blood vessels and in the inner ear (GIBSON, 1966, p. 108). Particularly important for spatial orientation is the sensitivity of the joints. The appendages of the skin – hairs, nails, fur, claws, hooves, horns, feathers – are also connected to nerve fibres in their roots and are essential parts of the apparatus used by the body to perceive its surroundings. Together, these receptors afford information which can be classified in different categories or sub-systems: cutaneous touch, haptic touch, dynamic touching, touch-temperature, touch- pain and oriented touch (GIBSON, 1966, p. 134). The extremities of the body, hands and feet, can also be used as sense organs. The fact that most humans are not aware of the importance of the information provided by the haptic system does not minimize its importance for spatial orientation and perception, as Gibson points out:

the haptic apparatus [...] is so obviously involved in the con- trol of performance that we are introspectively not aware of its capacity to yield perception; we allow the visual system to dominate our consciousness. Nevertheless the perceptions of the blind, and of blindfolded subjects, can sometimes rival those of seeing persons and this fact shows how much information is obtained by it (GIBSON, 1966, p. 134).

VISUAL PERCEPTION OF SPACE

The visual affordances of the environment are important for spatial perception and navigation for different species, especially those which are active during the day. Perhaps because of the dominant visualism characteristic of western culture, and also because, being primates, human beings rely heavily on visual information

for spatial orientation, perception of space has been sometimes 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. conceptualized primarily as a visual domain, as Bartley does:

The first thing to note regarding vision is the fact that in- estudos 158 formation from almost a hemisphere of the space domain is given to the visual sense organ at any one instant [...]. Not only is a focal pattern represented but also a huge segment of total space, a segment so big that it constitutes a working framework in and for itself. [...] space is made meaningful (functional) in terms of vision and what can be imagined (conceptualized) visually. Space experientially is primarily visual space (BARTLEY, 1980, p. 269).

Most of the attention of perceptual researchers has been given to the study of vision and its mechanisms, both in the constructivist and the ecological approaches. The study of the visual mechanisms involved in spatial perception is a complex subject and will not be approached in this paper. Basically, the individual uses the information provided by the light reflected from external objects and captured by the retina to create a map of the external world which enables him or her to locate and navigate in the environment. Particularly important for the description of space perception, is the study of the way that the two eyes work together and the mechanisms involved in monocular and binocular vision. The importance of the visual system for spatial perception should not be ignored, but it should not lead to the equivocal view that it is the only perceptual system involved in spatial perception, and to the mistaken idea that other perceptual systems are not capable of providing accurate spatial information. Bartley, for instance, states that “the auditory mechanism does not include the facilities that would enable it to take a role in intiating the perception of space as a domain” (BARTLEY, 1980, p. 298), which seems to contradict recent research in aural perception and human echolocation. He also expresses arguable views about the limited capabilities of the auditory system to interpret spatial information and the capabilities of nonsighted people to experience externality:

The main thing that a person without vision can do is move his

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. or her head or whole body so as to manipulate intensity and phase relations of acoustic waves, a gross affair compared to the achievements possible with vision. [...] We would assume estudos that the congenitally blind are not able to get away from the body as a reference. In fact it would seem that the burden of 159 proof would rest on those who assume that the congenitally blind do experience externality (BARTLEY, 1980, p. 298-9).

Recent experimental research in multisensory integration, crossmodal attention and spatial cognition shows that perception of space is not based primarily on the visual system, but that it is the result of complex interactions between different sensory systems. Recent research in echolocation also shows that nonsighted individuals not only have a clear and distinguished perception of externality, but that they are able to navigate external space and perform tasks in ways which may seem impossible for sighted individuals who rely strongly on the visual sense for their perception of space.

Multisensory Integration, Crossmodal Attention, Cognitive Spatial Maps

The views expressed here about the role of the different senses in the perception of externality reflect the views of the ecological approach to perception, which have been criticized by the constructivists for not having enough scientific rigour to support their views (NEUHOFF, 2004, p. 3). However, recent experimental research tends to confirm the views advocated by the ecological approach regarding the use of multiple sensory systems in the perception of space. Stein and Meredith (1993), in a work which integrates the contributions of psychology, neuroscience, biology, neurology, neurosurgery and psychiatry, examine the neural basis of the integration of information provided by different sensory systems. Their aim is to understand how the different sensory modalities work together to perceive and interact with the environment. Among other topics, they discuss how one sensory modality can influence and modify the information coming from other sensory modalities, and how different modalities interact together in experiences which involve multisensory data. Evidence suggests

that specific neural structures are responsible for the integration 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. of multisensory information, as they point out:

Although some modality specific stimulus characteristics estudos 160 may be largely preserved as the brain sorts out the inputs from many different cues, others are certainly altered. For the world is not perceived as a series of independent sensory experiences in which the integrity of each modality’s “snapshot” view is preserved intact in its own location in the brain; rather, there is an interweaving of different sensory impressions through which sensory components are subtly altered by, and integrated with, one another. The product of these integrative processes is perception (STEIN; MEREDITH, 1993, p. x-ix).

Driver and Spence (1998) mention different experimental studies which test the relative role of inputs originating from different sensory modalities and their influence and interaction on spatial attention. Despite using the experimental methodology and controlled laboratory situations, their studies aim to understand how different modalities interact with one another, and how the mechanisms of spatial attention operate in daily life. Each sensory modality codes spatial information in different ways. The receptors of each modality can move freely relative to each other and to external objects, which makes the internal representation of external space an impossible task for a single modality. The evidence provided by these studies confirms Gibson’s hypothesis according to which perceived space is a multimodal experience, the result of complex interactions between different sensory modalities:

It has become abundantly clear that the ‘space of common sense’ is indeed constructed, by computations that involve considerable integration between our different senses [...]. The various senses can each sample different regions of space (e.g. we can hear sounds from the invisible region behind our head), and they do so in different coordinates [...]. Our perception of the location of external events depends on integration of information from all the different senses (DRIVER; SPENCE, 1998, p. 254). , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. Blesser and Salter (2007) also mention a number of studies, especially in cognitive psychology and neuroscience, which show estudos evidence that the internal representation of external space is the result of multimodal integration, and that specific neurological 161 substrates combine multimodal information to create spatial cognitive maps. These studies suggest that different factors, such as cognition, perception, lifestyle, biology and personal history, influence the internal representation of space. Cognitive maps of space are personalized, subjective and distorted, and integrate, in different combinations, information from all sensory modalities:

A cognitive map of a space is a combination of the rules of geometry as well as knowledge about the physical world [...]. Although, normally, each of us can fuse any combination of aural, visual, tactile, and olfactory inputs into a cognitive map, it is only a single mental map because there is only one single external reality. [...] different senses provide access to different aspects of a single space. Vision is better for sensing an object’s distance; hearing is better for sensing the volume of an enclosed space; and touch is better for sensing surface texture. [...] We combine sensory cues and then interpret them using our memory of previous experiences to create a compelling internal sense of an external world (BLESSER; SALTER, 2007, p. 46-7).

AURAL PERCEPTION OF SPACE

The environment affords plenty of spatial information to the auditory system. Hearing is the perceptual effect of sound waves reaching the auditory system of a listener. To be transmitted from one place to another, sound vibrations need a medium – solid, liquid or gas, as sound does not travel in a vacuum. The medium in which human beings live is the air, which affords respiration, odour perception, visual perception, unimpeded locomotion, and, essential for the auditory system, “the perception of vibratory events by means of sound fields” (GIBSON, 1986, p. 131). The sources of sound in the environment can be placed at different locations relative to the listener, and have different features in terms of pitch, intensity, harmonic composition and duration. Additionally, the , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. motion of the sources changes some of the features of the sound. On their way to the listener, sound waves are affected in different

ways by the environment. These changes offer spatial information estudos 162 for orientation in the environment: reflections and diffractions of an emitted sound wave off the walls, floor, ceiling, and contents of a typical room enrich the sound field considerably. There is information about the size of the room in the timing of the reflections, information about the wall coverings and contents in the pattern of reverberation, and information about the distance between source and listener in the ratio of direct to reflected sound. If long distances are involved [...], the high-frequency content of the effective stimulus is reduced by atmospheric absorption. There is ample evidence that all of these effects are detectable by a normal-hearing listener (WIGHTMAN; JENISON, 1995, p. 369-70).

Since the early 1970s, different authors started to reflect about upon the possibility of conceiving of space as an aural domain, in order to understand how space can be perceived by senses other than the visual. The concepts of acoustic space and aural architecture, and the studies of human echolocation show how space can, indeed be conceived as an aural domain.

Acoustic Space

McLuhan and Carpenter originally proposed the concept of acoustic space as an attempt to describe some of the important properties of the auditory dimension, in comparison with visual space. Acoustic space, according to them, is defined as:

a sphere without fixed boundaries, space made by the thing itself, not space containing the thing. It is not pictorial space, boxed in, but dynamic, always in flux, creating its own dimensions moment by moment. It has no fixed boundaries; it is indifferent to background. The eye focuses, pinpoints, abstracts, locating each object in physical space, against a background; the ear, however, favors sound from any direc-

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. tion. [...]. If we lie down, it makes no difference, whereas in visual space the entire spectacle is altered. We can shut out the visual field by simply closing our eyes, but we are estudos always triggered to respond to sound (MCLUHAN; CAR- PENTER, p. 67). 163 The concept enhances some important properties of the auditory field, such as its surroundability, its dynamic aspect, the lack of defined boundaries, and the ability of the auditory system to detect the direction of sounds coming from all directions. The properties of the auditory field contrast with the properties of the visual field, which is front-oriented, static and has clearly defined boundaries. The omnidirectional orientation is one of the important features of the auditory field, being evident in the following report of a blind person who acquired sight:

a student trained in phenomenology who had been blind, but who, through treatment, gained limited sight [...] noted that one quite detectable difference in her spatial organization was a gradual displacement of a previously more omnidirectional orientation and spatial awareness to a much more focussed forward orientation. [...] the relative omnidirectionality of awareness and orientation is ‘closer’ to the space-sense of sound than that of vision (IHDE, 2007, p. 65).

Schafer (1991) criticizes the metaphor of a sphere, because it is not precise from the point of view of psychoacoustics, in the sense that it does not take into account the asymmetry of the head and the distortions produced by the environment on the sound waves. He points out also that, the space created by some kinds of sounds, such as church bells, define spatial boundaries with important political and social implications (SCHAFER, 1991, p. 19-20). A more comprehensive definition of acoustic space, rooted in acoustic ecology, which takes into consideration Schafer’s criticism, has been proposed by Truax. This later formulation of the concept of acoustic space includes the spatial information which may be present in any sound, and also the notion that the sound created by a propagating source creates its own space. This definition is applicable both to real-world situations and to aural environments created artificially with the use of loudspeakers. , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. According to Truax, acoustic space is:

The perceived area encompassed by a soundscape, either an estudos 164 actual environment, or an imagined one such as produced with a tape recording and several loudspeakers. Every sound brings with it information about the space in which it occurs (for environmental sound) or is thought to occur (as with syn- thesized sound). With environmental sound, loudness and the quality of reverberation mainly determine the kind of space that is perceived, enclosed or open, large or small [...]. The sense of speeding motion is usually perceived by the pres- ence of a Doppler effect. [...] Acoustic space may also refer to the profile of a sound or sound signal over its surrounding environment. The acoustic space of any sound is that area over which it may be heard before it drops below the level of ambient noise (TRUAX, 2001, no page number, CD-Rom).

Aural Architecture

Closely related to the concept of acoustic space is the concept of aural architecture. According to Blesser and Salter (2007), aural architecture integrates knowledge from two different groups of disciplines, acoustic sciences – architecture, acoustics and engineering – and social sciences – sociology, anthropology and psychology – in order to understand the many ways in which the acoustic aspects of architecture affect human beings. It differs from acoustic architecture in the sense that aural architecture focuses on the listener’s experience of space, while acoustic architecture focuses on the physical properties of the sound. Aural architecture is an emerging discipline, and not necessarily, at least not yet, a professional modality. The acoustic properties of architecture are defined both by the designers of the space and by those who use the space, and the aural architect is not necessarily a person, being more “a social system rather than a simple application of physical science to spatial design” (BLESSER; SALTER, 2007, p. 24). As they point out:

We can sometimes identify the aural architect of a space, but far

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. more frequently, aural architecture is the incidental consequence of unrelated sociocultural forces. [...] The aural architecture of many modern spaces is created by architects, space planners, estudos and interior designers? with little appreciation for the aural impact of their choices (BLESSER; SALTER, 2007, p. 5). 165 Human Echolocation

The effects of the environment on sound may be barely noticeable by most sighted individuals, who rely heavily on visual information for spatial perception and navigation. However, nonsighted individuals may demonstrate an incredible ability to navigate and locate themselves in the environment, which shows that the role of the visual sense for spatial perception, however important, may not be essential for spatial perception, or, perhaps, that other forms of organization of the perceptual systems regarding spatial perception are also possible. Despite having a relatively marginal status within the studies or perception, the study of human echolocation is a fascinating subject, which can offer some insights into the possibilities of the auditory system to extract spatial information from the environment. In the animal world echolocation is usually understood as the ability of animals, such as porpoises and bats, to navigate using the reflected waves of self-produced sounds. However, the concept has been used in a broader sense when referring to human echolocation:

In the strict sense of the term, echolocation is determining the location of objects in the environment on the basis of how they reflect sounds produced by the listener. However, some researchers have used the term to include the use of ambient reflected sound that is not produced by the listener (NEUHOFF, 2004, p. 103).

The idea that audition could be a spatial sense was regarded with suspicion by traditionalists and early researchers of human echolocation had to face the resistance of mainstream research. Eventually, in the 1940s, Dallenbach and colleagues showed that echolocation was unequivocally the key to successful navigation for nonsighted individuals around obstacles (NEUHOFF, 2004, p. 104). Since then, the study of human echolocation has been

regarded as a more respectful subject and received increasingly 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. more attention among different researchers of perception. A number of studies appeared, describing incredible abilities of blind

persons to detect the features of external space using primarily estudos 166 aural information, such as the ability to ride a bicycle avoiding obstacles (NEUHOFF, 2004, p. 105); the abilities to perceive small differences in size and identify geometric shapes of nearby objects (BLESSER; SALTER, 2007, p. 44) and the ability to distinguish different textures of cloth, such as velvet and denim, and bare surfaces, such as wood, glass and metal (HANDEL, 1993, p. 110). Human echolocation is not fully understood yet, but some important aspects of the phenomenon are already known. The skill is not conscious; even those who have it highly developed cannot describe in detail how it works. The exclusive use of echolocation is unusual, and most blind people tend to use it as a supplement to their tactile sense of space, developed with the use of the cane. The literature about the possibility of teaching echolocation is ambivalent, and the assumption that it can be taught is still contro- versial. The degree of success in teaching it is relatively small, and because tactile navigation is far easier to teach than echolocation most schools for blind people gave up teaching it. Echolocation seems to be “more a commitment to learn than a teachable skill” (BLESSER; SALTER, 2007, p. 39). Strong motivation, auditory skills greater than the average, extended opportunity to practice, and the courage and determination to live a “normal” life, despite the visual disability are positive factors in learning echolocation. Echolocation can be understood as a? Modality of ear training, in which listeners develop a high sensitivity for aural cues which, despite being afforded by the environment, may not be perceived by sighted individuals, who rely heavily on their visual sense for purposes of spatial orientation and navigation. An urban street, for instance, is a highly complex sound environment, composed of multiple objects, surfaces and sound sources, some stationary, some mobile. Together with the direct sound produced by the sources, different effects happen simultaneously, coming from different directions: reflections, acoustic shadows, echoes, changes in timbre and colouration, and Doppler Effect. The echolocator must develop a different collection of independent abilities, such as hearing and identifying subtle changes in spectral content, acoustic shadows, reverberation and tonal colouration. These abilities are not directly , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. connected, and individual listeners can be good at some of them but mediocre at others. The process also involves the use of “a estudos cognitive strategy to convert binaural cues into spatial images” (BLESSER; SALTER, 2007, p. 40). 167 Research has shown that some skills seem to be highly developed in effective echolocators, among them the ability to sense small changes in amplitude and frequency of continuous sounds. High sensitivity to small changes in intensity and frequency can give information about distance, as Handel points out:

As you approach an object, the amplitude thus increases more and more rapidly. Frequency provides information when a noise signal is reflected from a flat surface. [...] One consequence is a sense of pitch as one approaches a surface; the apparent pitch of the noise gradually increases until about 1 m (40 in) from the surface, and then the pitch increases much more rapidly [...]. For both intensity and frequency, it is the rate of change that gives information about approach. As you close on the object, the increase in loudness and pitch quickens (HANDEL, 1993, p. 110).

Research has shown also that successful echolocators often make use of a wide range of self-produced sounds, such as whistles, vocalizations and finger-snaps, and, that, with the help of head movements, develop the ability to locate objects by listening to the reflections of these sounds. Despite the better performance by nonsighted individuals, studies show that, with practice, sighted individuals may develop accuracy in echolocation (HANDEL, 1993, p. 110). Neuhoff mentions also that “motion cues produced by the movement of the echolocator improve localization estimates” (NEUHOFF, 2004, p. 105). He mentions also that the use of echolocation among sighted individuals may be more common than one might suppose (NEUHOFF, 2004, p. 106). These results are consistent with the ecological views about perception, according to which the auditory system is conceived as a whole, in which the development of sensory skills is closely related to the needs of the organism to adapt to the surrounding environment.

CONCLUSIONS 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v.

Through the criticism of the idea that space is primarily a visual

domain, I tried to show how information provided by perceptual estudos 168 systems other than the visual is essential for the perception of space. I tried to show, also, how space can be conceived of as an aural domain, instead of as a visual one. This is not intended as a new form of reductionism centred in the aural sense instead of the visual. I intended to show how malleable human perception can be, and how, under certain circumstances, as in the case of nonsighted individuals, it is possible to conceive of space as a domain which excludes the contribution of the visual sense. Ihde discusses what the change to the auditory dimension may represent in a context in which the visualism is taken for granted:

A turn to the auditory dimension is thus potentially more than a simple changing of variables. It begins as a deliberate decentering of a dominant tradition in order to discover what may be missing as a result of the traditional double reduction of vision as the main variable and metaphor. This deliberate change of emphasis from the visual to the auditory dimension at first symbolizes a hope to find material for a recovery of the richness of primary experience that is now forgotten or covered over in the too tightly interpreted visualist traditions (IHDE, 2007, p. 13).

McLuhan says that the influence of visualism in western culture has been so strong, that it moulded the modes of thought and the way reality is conceived and perceived. He believes that the linear conceptualization is one of the results of the influence of visualism on western rationality. “If you think of every human sense as creating its own space”, he says, “then the eye creates a space where there can be only one thing at a time” (MCLUHAN, 2004, p. 69). This emphasis on the visual sense may lead to a state of hypnosis, in which the information coming from other senses may be disregarded or simply, kept in a state of dormancy. McLuhan evokes the old notion of sensus communis as a state of balance between the senses and the ideal of health:

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. The term sensus communis in Cicero’s time meant that all the senses, such as seeing, hearing, tasting, smelling, and touch, were translated equally into each other. It was the estudos Latin definition of a man in a healthy natural state, when physical and psychic energy were constant and distributed 169 in a balanced way to all sense areas. […] In any cultural arrangement, trouble always occurs when only one sense is subjected to a barrage of energy and receives more stimulus than all the others. For modern western man that would be the visual state (MCLUHAN, 2004, p. 69).

Despite the strength of visualism in western culture, McLuhan believes that we are living in (or through) times of cultural change, in which features of orality are being rescued and incorporated into contemporary modes of thought. Perhaps the recognition of the spa- tiality of the aural sense, reflected in the concepts of acoustic space and aural architecture, and also in the studies of human echolocation, are nothing but a symptom of larger cultural change. The shaman in oral cultures could be the blind man, as was the prophet of Thebes, Tiresias. Justice, in western culture, is represented as a blindfolded woman. Perhaps this may indicate that the ability to listen, or to use the senses other than the visual to perceive, conceptualise and assess reality, may offer an alternative way to perceive the world in terms other than the visual, or, perhaps, to access another world which can only be perceived once we close our eyes.

FROM VISUAL TO AURAL SPACE: A CHANGE OF PARADIGM?

Abstract: in this paper I discuss how the influence of visualism led to the equivocal conception according to which space is primarily a visual domain. Different approaches to perception show evidence that all senses are involved in the perception of space. Recent research on aural perception and human echolocation also shows evidence that the auditory system has the ability to detect and process spatial information in a level unsuspected by early researchers, who regarded audition as a poor spatial sense. In the conclusion I suggest that the change from visual to aural space may represent more than simply a change of variables, but a symptom of a deeper

cultural change, a more balanced consideration of the senses as a 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. whole, reflected in the ancient idea of sensus communis.

Keywords: Aural perception of space. Perception. Spatial estudos 170 perception. References

BARTLEY, S. Howard. Introduction to Perception. New York: Harper and Row, 1980. BLESSER, Barry and SALTER, Linda-Ruth. Spaces Speak, Are You Listening? Experiencing Aural Architecture. Cambridge, Massachusetts, London, England: The MIT Press, 2007. DRIVER, Jon; SPENCE, Charles. Attention and the crossmodal construction of space. In. Trends in Cognitive Sciences, v. 2, n. 7, july 1998. GIBSON, James J. The Ecological Approach to Visual Perception. Hillsdale, New Jersey, London: Lawrence Erlbaum Associates, 1986. GIBSON, James J. The Senses Considered as Perceptual Systems. Boston: Houghton Mifflin Company, 1966. IHDE, Don. Listening and Voice: Phenomenologies of Sound. Albany: State University of New York Press, 2007. McLUHAN, Marshall. Visual and Acoustic Space. In. Audio Culture: readings in Modern Music. COX, Cristoph and WARNER, Daniel (eds.). London: Continuum International Publishing Group, 2004. MACLUHAN, Marshall; CARPENTER, Edmund. Acoustic Space. In: MACLU- HAN, Marshall; CARPENTER, Edmund (Eds.). Explorations in Communication: An Anthology. London: Johnatan Cape, 1970. NEUHOFF, John G. Ecological Psychoacoustics: Introduction and History. In: NEUHOFF (Ed.). Ecological Psychoacoustics. London, San Diego: Elsevier, 2004. STEIN, Barry E.; MEREDITH, M. Alex. The Merging of the Senses. Cambridge, Massachusetts, London, England: The MIT Press, 1993. TRUAX, Barry. Handbook for Acoustic Ecology. Second Edition:1999 (CDRom Version). Originally published by the World Soundscape Project, Simon Fraser University, and ARC Publications, 1978 VALKENBURG, David Van; KUBOVY, Michael. From Gibson’s Fire to Ge- stalts: A Bridge-Building Theory of Perceptual Objecthood. In: NEUHOFF (Ed.). Ecological Psychoacoustics. London, San Diego: Elsevier, 2004.

, Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. * This paper represents partial results of his research, in which he examines the meaning of space in music and how space can be incorporated as an aspect of musical composition. estudos 171 Recebido em: 14.01.2011. Aprovado em: 24.01.2011.

FREDERICO A. B. MACEDO Licentiate in Art Education with focus on Music (UFG), with a Masters Degree in Contemporary Music, with focus on composition (UFG). He is currently working on his PhD in composition at Lancaster University, U.K.. E-mail: [email protected] , Goiânia, v. 38, n. 01/03, p. 151-172, jan./mar. 2011. 38, n. 01/03, p. 151-172, jan./mar. , Goiânia, v. estudos 172