Visual and Auditory Perception.

As indicated earlier, vision was the last of the senses to evolve. However, it is by far the most complex. Seemingly, more data are fed to the nervous system through the eyes at a much greater rate than through the senses of touch or hearing. For example, the information a blind person can gather outdoors is limited to a circle of 20 to 100 feet because a blind person can perceive by way of auditory or olfactory stimuli only what is immediately surrounding him or her. However, with sight a person can see the stars at night. Even very talented blind persons are limited to an average speed of perception of 2 to 3 miles an hour over familiar territory. In contrast, with sight a person has to fly faster than sound before additional visual aids are needed to avoid bumping into things. The amount of information that can be gathered by the eyes in contrast to the ears cannot be calculated precisely. Such a calculation would require not only a translation process but also the knowledge of precisely what to count. A general notion held by most scientists is that the relative complexities of the two systems, visual and auditory, can be obtained by comparison of the size of the nerves connecting the eyes and the ears to the centers of the brain ( ; ).

The optic nerve contains roughly 18 times as many neurons as the cochlear nerve; therefore, one might assume that it transmits at least that much more information. The eyes may act as a defense mechanism because they normally alert us to danger; the eyes may be as much as a thousand times more effective than the ears in gathering information to protect us from harmful stimuli. The area that the unaided ear can effectively cover in the course of daily living is quite limited. The ear is very efficient but only up to a distance of 20 feet. At about 100 feet, one-way vocal communication is possible but at a somewhat slower rate than at a conversational distance. Although two-way conversation is also possible at this distance, it is considerably altered. Beyond this distance the auditory cues begin to break down rapidly. The unaided eye, on the other hand, can gather an extraordinary amount of information within a 100-yard radius and is efficient for human interaction at up to a mile ( ).

The impulses that activate the eyes and the ears differ in speed and quality. For example, at a temperature of 0° C (32° F) at sea level, sound waves can travel 1100 feet per second and be heard in frequencies of 50 to 1500 cycles per second (Hertz). On the other hand, light rays can travel 186,000 miles (300,000 km) per second and thus are visible at a maximal frequency of 500 trillion at yellow-green ( ).

Many complex and remarkable instruments have been invented to extend the eyes and ears. Radio, television, and the Internet have revolutionized the perception of space and shortened distances among people worldwide. During World War II, radio was relied on quite extensively to bring news from the occupied countries to parts of the free world. Perhaps one of the most famous broadcasts of this period was done by Tokyo Rose, whose broadcasts, which were reported to be untrue, influenced many people in the listening audience about the nature and direction of World War II. However, radio lacked the visual stimuli offered later by television, which filled in perception gaps left by radio. Television came of age in the 1960s, when for the first time, brighter, clearer, and bolder pictures were offered to viewers. The addition of color filled another perception gap and enhanced our receptor fields. For the first time in history, from their living rooms, the people of the United States could view their president doing the ordinary, the extraordinary, and the unusual. For example, the people of the United States were informed about the Cuban missile crisis by U.S. President Kennedy on television. They were also able to see this president playing with his children in the Oval Office. In 1963, when President Kennedy was assassinated, little was left to the imagination of the people of the United States, who were mesmerized by complete television coverage from assassination to burial. Because of television, the nation and the world at large experienced grief that is still present today and mourned collectively.

The development of cyberspace technology has added another visual dimension to space. On September 11, 2001, the nation and the world collectively experienced shock as terrorists crashed airplanes into the World Trade Center and the Pentagon. Not only did many view the disasters as they happened on television and on the Internet, but also horrific images and reports of the September 11 terrorist attacks were broadcast for weeks. Technology also allowed the world to see the emotional reactions of others to the disaster and in turn precipitated responses of condolence. Immediately, e-mail messages offering sympathy to grieving Americans poured in from friends around the world. Cyberspace technology united the world in grief as memorials on each continent were displayed on the Internet. The visual impressions provided by technology enabled persons who did not directly experience the disaster to be profoundly disturbed by it ( ). In 2005, the nation experienced a similar phenomenon with the devastation of Hurricane Katrina that became a part of the lived experience of persons who had access to television or the Internet ( ). The Internet and multimedia technologies provided a range of quasi-public spaces that encouraged debate and active citizenship to assess the reaction of the government and the nation to this event ( ). More recently, natural disasters such as the massive earthquake in Haiti in 2010, which killed approximately 250,000 people, and the earthquake and tsunami in Japan in 2011 that killed thousands and caused a nuclear disaster have all been widely covered not only on television but through other social networks such as Twitter, Facebook, and YouTube.

In summary, visual space has an entirely different character from that of auditory space. The overriding quality that differentiates visual space from auditory space is that visual information tends to be less ambiguous and more focused than auditory information. Therefore, visual information is less subject to external manipulation than is auditory information. One major exception to this rule is the blind person who has learned to understand selectively the higher audio frequencies, which can assist him or her in locating objects within a familiar or unfamiliar room. For example, a blind person may know where the door is in a room by the relationship of the sound that comes from that direction.

Even today it is not known what effects the incongruities between auditory and visual space have on individuals. Some data indicate that auditory space is a factor in performance. J. W. Black, a phonetician, demonstrated that the size and reverberation (vibrations of external sounds) of a room can affect an individual’s reading rate. In a classic study, found that people read more slowly in larger rooms, where the reverberation time, or circulation of sound, is slower than that in smaller rooms. interviewed subjects in regard to the slowing of reverberation time in a larger room. Among the inter­viewees was a gifted English architect who improved the performance of a malfunctioning committee by simply blending the auditory and visual worlds of the conference chamber where the committee met. The complaint the architect had received was that the chairman was inadequate and was about to be replaced. However, the architect had reason to believe that the difficulties this committee encountered were caused by more in the environment than just the chairman. In this situation the meeting room was next to a busy street, and traffic noises were intensified by reverberations from the hard walls and rugless floors inside the building and particularly in the meeting room. The architect was able to adjust the room by adding an acoustic ceiling, carpet, and soundproof walls. Once interferences were reduced, the chairman was able to conduct the meeting without undue strain, and complaints about the chairman ceased.

People who are brought up in different cultures learn unknowingly to screen out various bits of information and to sort information into relevant or irrelevant categories; once set, these perceptual patterns remain stable throughout life. For example, Japanese individuals tend to give meaning to spaces that a Westerner may classify as empty ( ). Japanese readers expect to be presented with the parts first and then the whole rather than getting the “big picture” and then a breakdown of material into its component parts ( ; ). In addition, Japanese people screen visually in a variety of ways and are more perceptive to visual stimuli. Japanese people are therefore perfectly content with paper walls as acoustic screens. A Westerner who finds himself in a Japanese inn where a party is going on next door may be in for a new sensory experience since only paper-thin walls separate each room. In contrast, German and Dutch people depend on double doors and thick walls to screen out sound and may have difficulty if they must rely on their own powers of concentration to do so. If two rooms are the same size and one screens out sound and the other does not, a sensitive German or Dutch person who is trying to concentrate will feel less intruded on in the former and thus less crowded ( ). Cultural patterning of space can also be seen in the arrangements of urban space in different cultures. For example, U.S. cities are usually laid out along a grid with the axis north–south and east–west. In Paris, main streets are laid out radiating from centers with no grid system ( ). The layout of French cities is only one aspect of the theme of centralization that characterizes French culture. In French offices, the most important person has the desk in the middle of the office.

Yet another aspect of cultural patterning of space is function of space. For example, space in India is sometimes related to concepts of superiority and inferiority. In Indian cities, villages, and even homes, spaces may be designated as inferior or polluted. Spaces in India are divided so that high and low castes, secular and sacred activities, and male and female can be kept segregated ( ).

Olfactory Perception.

Some cultures place more importance on olfactory perceptions than do others. For example, Americans are culturally underdeveloped in the use of their olfactory apparatuses ( ). contended that the deprivations of the olfactory stimulus are a result of the extensive use of deodorants and the suppression of odors in public places, which has resulted in a land of olfactory blandness and sameness that is difficult to duplicate anywhere else in the world.

People in the United States are continuously bombarded with commercials for room deodorizers, antiperspirants, mouthwashes, carpet deodorizers, and so on. All of these factors result in bland, undifferentiated spaces and deprive many people in the United States of the richness and variety of life. For example, if one is cooking with garlic, a room deodorizer may be used during the cooking process, causing the garlic smell to be eliminated. It is this type of behavior on the part of people of the United States that obscures memories. It is believed that smells evoke much deeper memories than either vision or sound; when the sound or the sight of what has happened has passed, the memory of the smell lingers on. Even today many U.S. citizens equate certain holidays, such as Christmas, with certain smells. For example, because Christmas is traditionally equated with the smell of baked goods, holly, pine, and fruit, today many people in the United States try to reproduce these smells at Christmas. An individual who has an artificial Christmas tree may buy a pine-scented spray to create the effects of a fresh tree. Another old-fashioned scent for many U.S. citizens is country potpourri, which has now been simulated in aerosol cans for easy dispensing. A new car odor can be simulated by a car spray that smells like new leather. Soap may be purchased to re-create a desired feeling; for example, the soap Mother used at home may create a feeling of hominess. Smells may also create a negative reaction; for example, an individual who washes with lye soap may be thought to have body odor because the smell is unusually strong and medicinal. A medicinal smell is perceived by most individuals in the United States to be appropriate for a hospital room but not elsewhere.

Odor is perhaps one of the most basic methods of communication. It is primarily chemical in nature and is therefore referred to in a chemical sense. The olfactory sense has diverse functions and not only differentiates individuals but also makes it possible to identify the emotional state of others. Even an infant can learn to identify his or her parents through the sense of smell. Although the young infant has not learned to see and discriminate patterns well, the infant can distinguish identity through the olfactory sense.

In a hospital setting an employee who has an unpleasant odor creates a real management dilemma. The supervisor may counsel and even reprimand the employee for poor hygiene. Employees who have the smell of alcohol may be sent home. It is important that the nurse appreciate that odors may be caused by pathological conditions, as in certain diabetic states, or the result of certain mouthwashes or soaps. If a client has an unpleasant odor, the nurse should first assess whether some pathological condition is present, such as an inflammatory process. In a psychiatric hospital, a client’s odor could be associated with a condition such as schizophrenia, and although there is some thought that such an odor may be pathological, it is more likely to be related to a lack of motivation for self-care skills.

Skin Membranes.

Human beings receive a tremendous amount of information from the distance receptors, which include the eyes, ears, and nose. Because of the vast amount of information that is received from the distance receptors, few people think of the skin as a major sense organ. However, if we humans lacked the ability to perceive heat and cold, we would soon perish. Without the ability to perceive heat and cold and to react appropriately to these stimuli, we would freeze in the winter and become overheated in the summer. The skin, as a major sense organ, is so grossly overlooked that even some of its subtle sensing and communicating qualities go unnoticed. Nerves called proprioceptors keep us informed as to exactly what is happening as we work our muscles. These nerves provide the feedback that enables us to move our bodies smoothly; thus, they occupy a key position in kinesthetic space perception. The body also has another set of nerves called exteroceptors, which are located in the skin and convey the sensations of heat, cold, touch, and pain to the central nervous system. In light of the fact that two different systems of nerves are used in the perception of space, kinesthetic space is considered qualitatively different from thermal space. However, nurses must remember that these two systems work together and are mutually reinforcing most of the time.

It has been only in modern scientific times that some remarkable thermal characteristics of the skin have been discovered. The capacity of the skin for emitting and detecting radiant or infrared heat is extraordinarily high. One might assume that is so because it was important to survival in the past and most certainly had a significant function in early human beings. Although the discovery of the thermal characteristics of the skin has been only within recent times, the nurse should not overlook the importance of the skin as an immediate receptor.

Humans are well equipped to send and receive messages concerning emotional states based on changes in skin temperature. Skin temperature can give very important clues to the emotional state of the individual. A common indicator of embarrassment or anger in fair-skinned individuals is blushing. However, dark-skinned people also blush. Therefore, blushing cannot be perceived as simply a matter of change in skin coloration. The nurse must carefully observe dark-skinned persons when looking for changes in emotional state, such as embarrassment or anger, by noting a swelling of regions of the forehead. The additional blood to these areas will raise the temperature, and these areas will appear flushed. Therefore, even if there is no significant change in color to these areas in dark-skinned individuals, these areas will feel warm to the touch.

Many novel instruments have been developed to study heat emission. These instruments should make it possible to study the thermal details of interpersonal communication, an area not previously accessible to direct observation. Thermographic devices (infrared-detection devices and cameras) that were originally developed for satellites and homing missiles have been used for recording subvisual phenomena. Photographs taken in the dark using the radiant heat of the human body have shown that an inflamed area of the body actually emits more heat than the surrounding areas. Diagnosis of cancer is also possible with thermographic devices that measure blocked circulation of blood. Thermographic devices have been useful in health care delivery because skin color does not affect the amount of heat delivered; dark skin does not emit more or less heat than light skin. Thus, the observable phenomenon in all individuals regarding heat emission is the blood supply in a given area of the body.

Increased heat on the surface is detected in three ways:

• 1.
  

  Thermal detectors in the skin, particularly if two individuals are close enough to each other.

  
  
• 2.
  

  Intensified olfactory interactions, which are augmented when skin temperature rises. Perfumes and lotions may be smelled at a greater distance when the body temperature is increased.

  
  
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  Visual examination, which can give clues to an increase or decrease in body temperature. For example, an individual who is pale may have a decrease in body temperature, whereas a person who appears flushed may have an increase in body temperature.

Body-heat regulation lies deep in the brain and is controlled by the hypothalamus. Culture affects attitudes in regard to the perception of skin temperature changes. Human beings exert little or no conscious control over the heat system of the body. Many cultural groups tend to stress phenomena that can be controlled and deny those that cannot. In other words, because some individuals by virtue of their cultural heritage have been taught to ignore certain uncontrollable stimuli, they experience body heat as a highly personal stimulus. Body heat is therefore linked to intimacy as well as to the experiences of childhood. An adult who as a child was used to close personal contact with parents and other loved ones may have a pleasant association when in a crowded environment where heat and warmth are radiated. On the other hand, an adult who was subjected to discomfort in close relationships or who was not exposed to closeness as a child may experience a great deal of difficulty and anxiety when in a close environment, such as an overcrowded bus.

A person born in a heavily populated country where closeness was necessitated by overcrowding may experience conscious discomfort in moving to another locality where closeness is not the norm. On the other hand, persons born in thinly populated countries may have a conscious feeling of overcrowding in a country where closeness is the norm. For example, a tourist from the United States visiting a country such as Jamaica or China or a city such as Hong Kong, all of which are extremely overpopulated, may quickly react to the experience of closeness and associate the country or this particular city with unpleasantness. This experience is not limited to different cultures but may also be noted when a rural person visits an urban setting, such as a person from rural Mississippi visiting New York City.

The English language is full of expressions that relate to skin sensation and body temperature changes. For example, it is not uncommon in the United States to hear individuals say that another person made them hot under the collar, gave them a cold stare, involved them in a heated argument, or warmed them up. These expressions may be more than just a figure of speech; they may be a way of recognizing the changes in body temperature that occur both personally and in other people. Thus, these common experiences have been incorporated into language in the United States.