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Sensing and Perceiving”, Chapter 4 from the Book Beginning Psychology (Index.Html) (V This is “Sensing and Perceiving”, chapter 4 from the book Beginning Psychology (index.html) (v. 1.0). This book is licensed under a Creative Commons by-nc-sa 3.0 (http://creativecommons.org/licenses/by-nc-sa/ 3.0/) license. See the license for more details, but that basically means you can share this book as long as you credit the author (but see below), don't make money from it, and do make it available to everyone else under the same terms. This content was accessible as of December 29, 2012, and it was downloaded then by Andy Schmitz (http://lardbucket.org) in an effort to preserve the availability of this book. Normally, the author and publisher would be credited here. However, the publisher has asked for the customary Creative Commons attribution to the original publisher, authors, title, and book URI to be removed. Additionally, per the publisher's request, their name has been removed in some passages. More information is available on this project's attribution page (http://2012books.lardbucket.org/attribution.html?utm_source=header). For more information on the source of this book, or why it is available for free, please see the project's home page (http://2012books.lardbucket.org/). You can browse or download additional books there. i 154 Chapter 4 Sensing and Perceiving Chapter 4 Sensing and Perceiving 155 Chapter 4 Sensing and Perceiving Misperception by Those Trained to Accurately Perceive a Threat On September 6, 2007, the Asia-Pacific Economic Cooperation (APEC) leaders’ summit was being held in downtown Sydney, Australia. World leaders, including the then-current U.S. president, George W. Bush, were attending the summit. Many roads in the area were closed for security reasons, and police presence was high. As a prank, eight members of the Australian television satire The Chaser’s War on Everything assembled a false motorcade made up of two black four-wheel-drive vehicles, a black sedan, two motorcycles, body guards, and chauffeurs (see the video below). Group member Chas Licciardello was in one of the cars disguised as Osama bin Laden. The motorcade drove through Sydney’s central business district and entered the security zone of the meeting. The motorcade was waved on by police, through two checkpoints, until the Chaser group decided it had taken the gag far enough and stopped outside the InterContinental Hotel where former President Bush was staying. Licciardello stepped out onto the street and complained, in character as bin Laden, about not being invited to the APEC Summit. Only at this time did the police belatedly check the identity of the group members, finally arresting them. Chaser APEC Motorcade Stunt (click to see video) Motorcade Stunt performed by the Chaser pranksters in 2007. Afterward, the group testified that it had made little effort to disguise its attempt as anything more than a prank. The group’s only realistic attempt to fool police was its Canadian-flag marked vehicles. Other than that, the group used obviously fake credentials, and its security passes were printed with “JOKE,” “Insecurity,” and “It’s pretty obvious this isn’t a real pass,” all clearly visible to any police officer who might have been troubled to look closely as the motorcade passed. The required APEC 2007 Official Vehicle stickers had the name of the group’s show printed on them, and this text: “This dude likes trees and poetry and certain types of carnivorous plants excite him.” In addition, a few of the “bodyguards” were carrying camcorders, and one of the motorcyclists was dressed in jeans, both details that should have alerted police that something was amiss. The Chaser pranksters later explained the primary reason for the stunt. They wanted to make a statement about the fact that bin Laden, a world leader, had not been invited to an APEC Summit where issues of terror were being discussed. The secondary motive was to test the event’s security. The show’s lawyers approved the stunt, under the assumption that the motorcade would be stopped at the APEC meeting. 156 Chapter 4 Sensing and Perceiving The ability to detect and interpret the events that are occurring around us allows us to respond to these stimuli appropriately (Gibson & Pick, 2000).Gibson, E. J., & Pick, A. D. (2000). An ecological approach to perceptual learning and development. New York, NY: Oxford University Press. In most cases the system is successful, but as you can see from the above example, it is not perfect. In this chapter we will discuss the strengths and limitations of these capacities, focusing on both sensation1—awareness resulting from the stimulation of a sense organ, and perception2—the organization and interpretation of sensations. Sensation and perception work seamlessly together to allow us to experience the world through our eyes, ears, nose, tongue, and skin, but also to combine what we are currently learning from the environment with what we already know about it to make judgments and to choose appropriate behaviors. The study of sensation and perception is exceedingly important for our everyday lives because the knowledge generated by psychologists is used in so many ways to help so many people. Psychologists work closely with mechanical and electrical engineers, with experts in defense and military contractors, and with clinical, health, and sports psychologists to help them apply this knowledge to their everyday practices. The research is used to help us understand and better prepare people to cope with such diverse events as driving cars, flying planes, creating robots, and managing pain (Fajen & Warren, 2003).Fajen, B. R., & Warren, W. H. (2003). Behavioral dynamics of steering, obstacle avoidance, and route selection. Journal of Experimental Psychology: Human Perception and Performance, 29(2), 343–362. 1. Awareness resulting from the stimulation of a sense organ. 2. The organization and interpretation of sensations. 157 Chapter 4 Sensing and Perceiving Figure 4.1 Mechanical engineers, industrial psychologists, sports psychologists, and video game designers use knowledge about sensation and perception to create and improve everyday objects and behaviors. © Thinkstock We will begin the chapter with a focus on the six senses of seeing, hearing, smelling, touching, tasting, and monitoring the body’s positions (proprioception). We will see that sensation is sometimes relatively direct, in the sense that the wide variety of stimuli around us inform and guide our behaviors quickly and accurately, but nevertheless is always the result of at least some interpretation. We do not directly experience stimuli, but rather we experience those stimuli as they are created by our senses. Each sense accomplishes the basic process of transduction3—the conversion of stimuli detected by receptor cells to electrical impulses that are then transported to the brain—in different, but related, ways. 3. The conversion of stimuli After we have reviewed the basic processes of sensation, we will turn to the topic of detected by receptor cells to perception, focusing on how the brain’s processing of sensory experience can not electrical impulses that are only help us make quick and accurate judgments, but also mislead us into making then transported to the brain. 158 Chapter 4 Sensing and Perceiving perceptual and judgmental errors, such as those that allowed the Chaser group to breach security at the APEC meeting. 159 Chapter 4 Sensing and Perceiving 4.1 We Experience Our World Through Sensation LEARNING OBJECTIVES 1. Review and summarize the capacities and limitations of human sensation. 2. Explain the difference between sensation and perception and describe how psychologists measure sensory and difference thresholds. Sensory Thresholds: What Can We Experience? Humans possess powerful sensory capacities that allow us to sense the kaleidoscope of sights, sounds, smells, and tastes that surround us. Our eyes detect light energy and our ears pick up sound waves. Our skin senses touch, pressure, hot, and cold. Our tongues react to the molecules of the foods we eat, and our noses detect scents in the air. The human perceptual system is wired for accuracy, and people are exceedingly good at making use of the wide variety of information available to them (Stoffregen & Bardy, 2001).Stoffregen, T. A., & Bardy, B. G. (2001). On specification and the senses. Behavioral and Brain Sciences, 24(2), 195–261. In many ways our senses are quite remarkable. The human eye can detect the equivalent of a single candle flame burning 30 miles away and can distinguish among more than 300,000 different colors. The human ear can detect sounds as low as 20 hertz (vibrations per second) and as high as 20,000 hertz, and it can hear the tick of a clock about 20 feet away in a quiet room. We can taste a teaspoon of sugar dissolved in 2 gallons of water, and we are able to smell one drop of perfume diffused in a three-room apartment. We can feel the wing of a bee on our cheek dropped from 1 centimeter above (Galanter, 1962).Galanter, E. (1962). Contemporary Psychophysics. In R. Brown, E. Galanter, E. H. Hess, & G. Mandler (Eds.), New directions in psychology. New York, NY: Holt, Rinehart and Winston. 160 Chapter 4 Sensing and Perceiving Link To get an idea of the range of sounds that the human ear can sense, try testing your hearing here: http://test-my-hearing.com Although there is much that we do sense, there is even more that we do not. Dogs, bats, whales, and some Figure 4.2 rodents all have much better hearing than we do, and many animals have a far richer sense of smell. Birds are able to see the ultraviolet light that we cannot (see Figure 4.3 "Ultraviolet Light and Bird Vision") and can also sense the pull of the earth’s magnetic field.
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