Human Perception: Making Sense of the World

Learn how human perception, the process by which the brain interprets and organizes the chaos that bombards our senses, is formed and how it affects our memories.

| January 2015

  • According to neuroscientists, everything we perceive is a construction of the brain, thus, human perception is largely a linguistic and cultural process that assigns meaning to the millions of sensations we encounter daily.
    Photo by Fotolia/kengmerry
  • “Listening, Thinking, Being: Toward an Ethics of Attunement,” by Lisbeth Lipari, aims to make us aware of the value and importance of listening, to alert us to the complexity of listening and to offer a way to think of listening as a mode of communicative action.
    Cover courtesy Penn State University Press

Listening, Thinking, Being (Penn State University Press, 2014), turns everything you knew, or thought you knew about language and communication, listening and speaking, inside out. It’s not about how to be a good listener or the ten barriers to good listening; it’s about how listening brings humans into being. The following excerpt from Chapter 2, “Vibrating Worlds and Listening Bodies,” explains how sensation is organized and filtered during the process of human perception.

We encounter, in each nanosecond of our lives, billions of sensations, some of which we are aware and many, many more of which we are not. The vast majority of these sensations are ignored by our conscious mind, while those that we recognize and name become perceptions—categorized sensations of which we are consciously aware. Consider a conversation between two people in a crowded café. The air is filled with a cacophony of sound that includes the murmuring of voices, the clanking of spoons, the hiss of the various coffee-making machines, the faint strains of Muzak, and the ring of the cash register. Similarly, the air is also thick with the sharp aroma of coffee as well as of cologne and baked goods, and is also perhaps peppered with a sharp waft of perspiration or the faint odors of sour milk and ammonia. At the same time, thousands of colors, shapes, and patterns surround the pair in the short and middle distance—even when each looks steadily at the other’s face, their peripheral vision observes movement, color, size, shape.

Though neither person may be aware of it, the skin and bones of both their bodies receive thousands of simultaneous touches—the smooth warmth of the coffee mug beneath the fingers, the hard wood of the chair on the sit bones, the soft rubber of the mat under their feet, and the cool metal of the table under their wrists. They might even feel a mordant burn in the solar plexus when a tricked-out muscle car passes by outside, subwoofers roaring. And at the same time, there may be a sharp tang of Sumatra dark roast on one’s tongue, balanced by a sweet burst of cranberry and orange from a morning muffin. All of which is not to even mention the thunderstorm of thoughts in both their heads—everything from worries and plans to memories and dreams tumbling around like clothes in a big round laundromat dryer. And all of this is happening together, at the same time, while one friend tells the other about the disturbing dream he had last night.

So in order to listen, one must zero in and pay attention to the speaker and his or her words, and thereby ignore the zillions of other sensations competing for awareness. The better one can do this, consciously, the better one’s focus, concentration, and presence. The American epidemic of ADD (attention deficit disorder) is a disturbance of conscious focus that makes concentration tremendously difficult for some people. And while most of us can choose (to greater or lesser degrees) where we place our attention, our brains are in fact doing this unconsciously all day long. According to neuroscientists, the brain receives vastly more sensory information per second than it can process, so it has to filter things out and organize the remaining sensations into patterns and categories. This filtering and classifying process is what we call perception, and it illustrates the difference between sensation and perception. Since the eighteenth century or so, some Western philosophers, such as Immanuel Kant, Henri Bergson, and William James, have surmised that objects presumably “out there” in the “real world” are not entirely “out there,” and that, in fact, the human mind is partly responsible for constructing our perceptions. Kant’s legendary dictum that without concepts (“thoughts”) our perceptions (“content”) are empty and without perceptions (“intentions”) our thoughts are blind basically means that sensations need to be processed by the mind before they can be considered perceptions. Similarly, William James observed how “[t]he baby, assailed by eyes, ears, nose, skin, and entrails at once, feels it all as one great blooming, buzzing confusion.”

During the second half of the twentieth century, neuroscientists and cognitive scientists began to identify the actual physical processes that transform sensations into perceptions. According to this new scientific paradigm, everything we perceive, including “external reality,” “is a construction of the brain. Our senses are confronted by a chaotic, constantly changing world that has no labels, and the brain must make sense of that chaos. It is the brain’s correlations of sensory information that create the knowledge we have about our surroundings, such as the sounds of words and music, the images we see in paintings and photographs, the colors we perceive.” Thus, perception is a process of distilling sensations into culturally distinct patterns—what transforms that blooming buzz into more or less organized perceptions is largely a linguistic and cultural process that describes, names, and gives meaning to those zillions of sensations. The neuroscientist Israel Rosenfield describes how “there are no colors in nature, only electromagnetic radiation of varying wavelengths (the visible spectrum is between 390 and 750 nanometers). If we were aware of our ‘real’ visual worlds we would see constantly changing images of dirty gray, making it difficult for us to recognize forms . . . colors themselves are not in our surroundings.”

While color recognition may be a universal human perception, the kinds and numbers of categories named for color in a given language can differ greatly from culture to culture. A few cultures have no semantic category for color, and of those that do, the number of basic colors can range from eleven (as in English), to a two-color system (containing black and white or warm and cool) and combinations in between. Consider: I just this moment glance out the window and am caught by a bloom of red and dying leaves, the wind animating the branches of the giant maple in my neighbor’s yard. Then a flash of yellow as a neighbor’s child pedals by on her bike on the sidewalk in the rain. This brief experience is not a transcription of visual sensory input, but is instead a kind of linguistic tableau filled with culturally imbued words, meanings, and categories—it is as much a description of me (my nationality, age, race, gender, social class, etc.) and my language and culture as it is of the scene itself.

Thus, perception is not always conscious and intentional; in fact, it is far more often also unconscious and habitual, and this often creates problems. It’s one thing when we jump back and recoil at the sight of a big snake, only to realize it’s an old, tattered piece of rope. It’s quite another when we unconsciously (or consciously) make presumptions about a person’s ability on the basis of the color of their skin, the tones of their accent or dialect, or the style and quality of their clothing. All too often, we habitually and automatically respond to sensory information in ways that we may not be consciously aware of. For example, the sounds of human footsteps carry a vast amount of social information that people pick up on and respond to, often unconsciously. Even while unaware, people can infer the mood, gender, social status, and even personality traits of the walking person by only listening to their footsteps. As it turns out, even our footfalls, like traffic, music, and color, are culturally shaped.

So what perceptions get named, as well as how they get named, is ultimately a social and political matter. In the United States, unless the speakers are artists or designers, the use of certain color words such as “mauve” and “chartreuse” tends to be associated with female gender and gay male sexuality. Similarly, the choice of words used to describe skin color carries significant political weight with meanings that differ depending upon who the speaker is. For example, while African American speakers describing someone’s skin color as “mocha,” “dusky,” or “yellow” may be quite acceptable ordinary practice, these descriptions are likely to signify differently when uttered by a white speaker. But the political and social dimensions of skin color play even more powerfully in large-scale social formations, such as the U.S. Census. For example, the first U.S. Census of 1790 sorted people according to white males sixteen and up, free white males under sixteen, free white females, other free persons, and slaves. But the gender only of free white persons was noted—the gender of “other” people, whether free or enslaved, was not categorized, named, or counted. One hundred years later, the 1890 census separated gender from skin color and asked each person in the house- hold to identify their “Race” as “White,” “Black,” “Mulatto,” “Quadroon,” “Octoroon,” “Chinese,” “Japanese,” or “Indian.” Here we have people sorted and labeled by color, proportion of ancestor color, ethnicity, and nationality. Notice, however, that neither European ethnicities nor nationalities are named or counted.

Forty years later, in 1930, the question had changed to “Color or Race” and the categories included white, black, Mexican, American Indian, Chinese, Japanese, Filipino, Hindu, and Korean. Here we find categories of color that are not sorted by ancestry, along with the continued categorization of only non-European ethnicities, nationalities, and, now, religion. By the year 2000, the census asked people to self-identify their “Race” in an open-ended question, and to indicate whether they were Spanish, Hispanic, or Latino—a combination of national, ethnic, and linguistic categories. As we can see from this brief historical account, for over 220 years the U.S. Census has categorized, named and counted people by various and continually changing “racial” and “color” labels. The bare fact of this naming, in addition to the fact that these words and categories have changed over time, indicates just how much racial categories are social and political signifiers that attach meaning to skin color and ethnicity in ways that correspond to politics, power, and the social order.

But the social and political dimensions of language are of course not limited to what we name, because what we name also has a bearing on what we observe. Consider the question of eyewitness testimony, which often plays a key role in police investigation and court testimony. Eyewitnesses are considered, by and large, to be a highly credible form of evidence, especially when confirmed by seemingly objective tests like a police lineup. People observe something firsthand, and what they honestly report seeing is presumed to be what “is.” But researchers have demonstrated that a variety of factors—such as police procedural errors, faulty memories, and racial bias—make eyewitness testimony far less certain than television police dramas would have you believe. For example, even tiny details in the way police construct and administer a lineup have been shown to influence how witnesses respond to suspect identification. Witnesses often want to help police catch criminals and are therefore highly susceptible to conscious and unconscious cues from police. “Lineup administrator behavior that biases a witness towards a positive identification decision obviously can have devastating consequences if the outcome is the misidentification of an innocent suspect.” Moreover, witness recall is likely to be inaccurate to begin with. Numerous studies demonstrate that witnesses have a tendency to identify innocent bystanders rather than assailants as the criminal. Perhaps even more disturbing, the research shows that witnesses are far less accurate in identifying people of a different race from their own. The numerous exonerations of convicted felons made possible by the recent introduction of DNA evidence that contradicts eyewitness testimony is a case in point.

The issue of what is called “change blindness” is another example of how our perceptions are freighted with social judgment combined with our environment. In the 1970s, psychologists began to study the relationship between attention and perception. In one famous study, they asked people to watch a videotaped basketball game and press a button every time they saw the ball passed. About thirty seconds into the tape, a woman in the video walks through the middle of the basketball court carrying an open umbrella. When the observers were questioned about the tape about a minute later, only six of the twenty-eight observers noticed the woman with the umbrella. Subsequent studies over the next several decades have confirmed these findings, most recently with a person wearing a gorilla suit who rambles through the middle of a game. Apparently some of the observers not only didn’t notice the gorilla, but further, had to be shown the videotape again to convince them that it was actually there. These studies “show that attention plays a critical role in perception and in representation. Without attention, we often do not see unanticipated events, and even with attention, we cannot encode and retain all the details of what we see.”

Thus, selective looking, like selective hearing, is not just dime store psychobabble, but an inevitable part of our perceptual processes. Most challenging, however, is the way that witnesses will reinforce their own faulty memories over time, and the more they report their observations, the more convinced they are of the accuracy of their reports. “Once witnesses state facts in a particular way or identify a particular person as the perpetrator, they are unwilling or even unable—due to the reconstruction of their memory—to reconsider their initial understanding.” Similarly, witnesses can be cued to “remember” events that did not occur. In the 1970s, psychologist Elizabeth Loftus (who later came to develop the controversial “false memory syndrome”) created a laboratory experiment to study eyewitness testimony of automobile accidents. Participants viewed a film of a car accident and then were asked to fill out a form first describing the accident in their own words and then answering several specific questions. Half of the subjects filled out a form containing a question that described the accident with the word “smash,” and the other half filled out a form different only in having the word “hit” rather than “smash.”

Loftus and her colleague discovered that participants who answered the questionnaire with the word “smash” tended to give a higher estimate of the cars’ speed than did those who answered the questionnaire with the word “hit.” When, one week later, the participants were asked to recall features of the accident, those who had previously answered the questionnaire with the word “smash” were more likely to report seeing broken glass, when in fact there was no image or sound of broken glass in the film. What this means is that the word “smash” not only influenced the estimates of speed, but actually influenced people’s memory of the original event. And this leads to the question of what memory is—is it like a film recording, or is it, like perception itself, a complex gestalt influenced by linguistic and cultural formations? What and where is memory, anyway? As it turns out, it lives much more in our bodies than we might imagine.

Reprinted with permission from Listening, Thinking, Being: Toward an Ethics of Attunement, by Lisbeth Lipari, and published by Penn State Press, 2014.

8/13/2016 6:33:32 PM

What? mention of the fundamental survival need to differentiate between hot and cold, black and white, wet and dry, large and small, fast and slow, etc.--AND the need (urge?) to QUANTIFY and MEASURE and COMPARE and COMMUNICATE about these differences AND the urge, eventually, to develop measurement UNITS and utilize NUMBERS, AND then to analyze the data with some kind of LOGIC, sll of which gives us, for better or worse, modern SCIENCE . . . ? On the basis of this excerpt, I would say that this book seeks to substitute masses of data for true insight--social "science" at its worst. Will I choose to read more? No way.

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