PSYC304 Week 6 Notes

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PSCY304 | LESSON 6: SELECTIVE ADAPTATION Introduction We all live in an environment that offers stimuli to all of our senses, things we taste, smell, see, hear, and touch. In this lesson you will learn about how we focus on some stimuli more than others. Our senses can also change their sensitivity when exposed to extremes by becoming more or less sensitive. We can also fill-in-the-gaps to perceive an object as constant even though the stimuli change. This lesson focuses on the relationship between the information available to our senses and the way the brain processes this information to create a meaningful experience and even change how our receptors react to the stimuli. Topics to be covered include:  Sensory interaction  Selective attention  Sensory adaptation  Perceptual constancy and deception Sensory Interaction Are you aware of just one sense at a time? When you sit down to a delicious meal, you smell enticing aromas, you see the colorful food. You do not have to actively think “I want to smell this.” Our individual senses react to the chemicals released by the steak and to the rays of light reflecting off the food, but we react to how these are processed by the perceptual system and how our brain combines the sensory information with prior experience. If you love to eat grilled steak, your brain converts the chemicals in the air and the rays of light into joyful anticipation that the meal will taste delicious. This automatic processing of the information from multiple senses is called sensory interaction . When you look at the face of a loved one, you are not just sensing a pattern of colors and shapes. Your brain puts those colors and shapes together with prior knowledge and you identify the image as someone you love. Selective Attention Have you ever been at a social event or a restaurant where many people are talking and yet you can focus on your conversation with your friends? You are able to focus on hearing your friends and tune out the other conversations in the room. Selective attention allows us to focus on one stimulus and ignore others (Baron, 2003). However, we are not completely focused on your friends. If yet another friend came in to the restaurant and called your name, you would probably notice even if your back was to the door where they entered. Saylor Academy (2012) calls this the cocktail party phenomenon . While we are using selective attention to listen to our friends, your perceptual systems are still monitoring the environment. This is a valuable survival trait. If

a new sound meant a dangerous predator approaching, your perception system would alert you to the danger. That said, sometimes we do completely tune out the world. How many times have you gone up to a friend using their cell phone and started talking to them without getting a response? Distracted walking accidents are increasing at alarming rates. According to the National Safety Council (n.d.), the number of pedestrian fatalities rose by nine percent from 2015 to 2016 due in part to phone users selectively attending their phones. Sensory Adaptation Your body can change the sensitivity of your senses to persistent stimuli. Sensory adaptation , also called selective adaption , is a change in the response to one type of stimuli due to its persistence (Wallach, Eytan, Marom, & Meir, 2008). For instance, if a teacher uses yellow highlighting to emphasize important information in the notes posted on the course website, you would give those parts extra attention. However, if the teacher highlights an entire document in yellow, the yellow loses its ability to inspire an extra effort. Let’s look at some examples of sensory adaptation (Sahyouni, 2013). 1/5  Ears Have you ever walked into a room such as this nightclub where the music was very loud? After you have been there for a while, it does not seem as loud to you. When exposed to a high intensity sound, muscles of the inner ear contract making the ear less sensitive to sound. When you leave the room and go somewhere quieter, at first you might have trouble hearing your friends when they speak due to this decrease in sensitivity. Unless you did permanent damage to your hearing (which is entirely possible even from one exposure), the inner ear muscles relax making your ears more sensitive to sound. Then you can easily hear your friends talk again. 2/5  Nose You will learn more about your chemical senses in Lesson 7, but you already are familiar with being able to smell odors. If you use perfume, you smell it when you put it on, but later you cannot detect it. You probably know smokers who are not aware that they and their home smells like cigarette smoke. It is not that the odor goes away quickly. When molecules of perfume or cigarette smoke enter the nose, there are neurons that have odor receptors to detect the chemical stimulus. Then the neurons send an electrical signal to the brain that an odor was detected. After just a few breaths, the chemical sense system responds less to the odor. 3/5  Vestibular

The vestibular system is often called the sixth sense. Along with proprioception (perception of our body’s position) and kinesthesia (our perception of how our body moves through space), it allows us to know if we are standing up or lying down, even if blindfolded (Lumen, n.d.). According to Saylor Academy (2012), in an experiment subjects wore virtual reality goggles that skewed their view, showing their reversed so that everything was upside down or tilted at an angle. The subject’s brain adjusted and soon the subject perceived the view as right-side-up even though the goggles showed them the room upside down. Balance is a rather complex ability that comes from a combination of what we see, what we touch (proprioception), input from our muscles and joints, and the vestibular system. The vestibular system gives us a sense of motion, equilibrium and spatial orientation using input from the vestibular apparatus, part of the inner ear (Vestibular Disorders Association, n.d.). 4/5  Sight You are probably already familiar with visual sensory adaptation. If you wake up in a dark room and open your eyes, your pupils dilate so that more light can reach the retina. Not only that, but your rods and cones also become more sensitive to light. If you then go outside on a sunny day, your pupils contract to decrease the amount of light that reaches the retina. 5/5  Touch Have you ever jumped into a pool or lake and thought the water was far too cold? However, after just a moment you no longer feel so cold because your brain stops paying attention to the temperature of the water. Selective Adaptation Why does our body change its sensitivity to a continued stimulus? Scientists believe the ability to ignore unchanging stimuli allows our brains to focus on new important changes in our environment that might require our attention. Sensory adaptation does not happen in response to every stimulus. Consider this man walking down a path. If he stops and stares at a tree, the image does not fade away due to sensory adaptation. Why not? Do you remember from Lesson 4 how our eyes are constantly moving to look at different parts of an image in tiny movements called saccades? According to Saylor Academy (2012), these eye movements result in the light rays coming to our retina are ever-changing and our brain considers these changing images to be new information. You can take this selective attention test by watching the video: Selective Attention Test . Perceptual Constancy One of the important functions of our perceptual system is to recognize an experience even when the stimuli are different. You can recognize your coffee cup if you see it from above, from the

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side, from the bottom, or from other angles. “The ability to perceive a stimulus as constant despite changes in sensation is known as perceptual constancy (Saylor Academy, 2012, ch. 4.5). You also have perceptual constancy with the relative difference of colors. If you have black coffee in a white cup in your kitchen and then walk into a dimly lit room, both the coffee and the cup will seem dimmer, but the cup will continue to be perceived as brighter than the coffee. However, our perceptions can be deceived. How and why they are deceived gives us insight into how our perceptual system interprets information provided by our senses. Perceptual Deception 1/7  Which is brighter, square A or square B? Watch this video to see if were correct at: Lightness Constancy Test . If the video does not convince you, cover up most of the image with your hands so that you only see squares A and B so as to compare them. In general with the images in this slideshow, the height/width ratio of your computer screen may distort some of the illusions and make them ineffective. 2/7

 When you look at the top three lines, which shaft is the longest? It turns out that your brain is deceived. When you look at the bottom three lines, it shows that all the shafts have the same length. This is known as the Müller-Lyer illusion (Saylor Academy, 2013). This deception is thought to be related to our brains perceiving the arrows as three-dimensional views of a box. The upper arrow is perceived to be an outside edge of the box. The middle arrow is perceived to be an inside edge of the box. The brain assumes the outside edge to be closer than the inside edge. Our experience with how an object looks smaller when it is farther away leads us to believe that the inside edge (the middle arrow) is the longer arrow. 3/7 

We perceive the moon to be as much as 50 percent larger when it is near the horizon than when it is overhead. You can watch an explanation at: Moon Illusion . Illusions like these show that our perceptions can misinterpret visual clues, highlighting the role of expectations in perception. Psychologists have used their understanding of perception found that as planes land, the pilot see the lights on the ground as larger (and closer) than they really are, similar to the moon illusion effect (Kraft, 1978). Kraft’s work inspired airlines to require co-pilots to tell the pilot the altitude frequently during the landing process, which may have decreased the number of landing incidents. 4/7  The Poggendorff illusion is a distortion illusion. The task is to identify whether the red or blue line connects with the line on the other side of the rectangle on the left. It uses misalignment to deceive our perception. The line on the left of appears to recede into the distance, making us interpret that as being higher in the vertical plane and thus we perceive the blue line as connecting to the black line. The rectangle on the right shows what is actually happening, where it is the red line that connects with the black line. You can see a demonstration of the Poggendorf at: Poggendorf Illusion . 5/7 

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The Necker cube illustrated here is a line drawing that does not give us visual clues as to which side is which. You can choose to see it with either the upper right or lower left side as the side facing you. When you watch the video, The Necker Cube , where do you think the triangle is? Inside the cube? Outside? This is an example of an ambiguous stimulus that our brain tries to interpret using our past experiences of what a cube looks like. 6/7  Which yellow line is wider, or are they same width? The Ponzo illusion fools our perception by using depth cues to suggest distance in the figure. When an object is far away, we know that it will look smaller to us. Since the upper yellow triangle appears to be farther away, our brains use that knowledge to believe that the upper yellow line must be larger than it appears in the drawing. The more an illusion can tap into our prior experience and expectations, the more deceptive it is. 7/7  Which is longer, the vertical or the horizontal line in the drawing? Research has shown that our perception of the size of each segment is influenced by the presence of the other segment. Both lines are the same length, but we tend to underestimate the length of the horizontal line because it is bisected by the other line. Perceptual Expectations While you might think that listening to a voice only involves hearing, the McGurk effect is “an error in perception that occurs when we misperceive sounds because the auto and visual parts of

the speech are mismatched” (Saylor Academy, 2012). When you watch this video, you hear “pa” when you watch the face on the left and “ta” when you watch the face on the right: McGurk Effect: How the Brain Plays Tricks . Your brain combines what you see with what you hear to have a different result with the two pictures. If you close your eyes and only listen, which sound do you hear? The comments below the video will tell you which word is being said. If you are told that something will taste bad, you are more likely to experience a bad taste than someone who is told it will taste good (Nitschke et al., 2006). If you are introduced to an adult and child, you are more likely to think they look alike if you are told they are a parent and child. This is known as talis pater, talis filius . Bressan and Dal Martello described studies where 100 women and 100 men were asked to estimate to what degree an adult and child in a photograph resembled each other. Some were given no additional information, some were given accurate information on whether the pair were a parent and child, and some were given inaccurate information on whether the pair were a parent and child. Being told that the pair were a parent and child was the most significant predictor in the subjects perceiving a resemblance between the adult and the child, even when they were told a lie. Bressan and Dal Martello surmised that finding a family resemblance arose from a desire to please the parents. Stern and Karraker (1989) report that subjects are more likely to consider a baby larger if told the baby is a boy. The subjects viewed girls as smaller, with more delicate features, less attentive, and softer than they did boys. Being told that a child was from a low socioeconomic family caused subjects to perceive children differently than when told that a child came from a high socioeconomic family (Darley & Gross, 1983). The subjects watched a videotape of a child taking an academic achievement test. Some subjects saw a video set in an urban, low-income area. Other saw the video set in a middle-class suburb. The subjects who viewed the child in a lower socioeconomic setting viewed the child as less intelligent than the subjects who saw the child in a middle-class setting. The authors propose that this result is due to the observer expecting the child from a higher class background to be more intelligence. The observers’ expectations channel their perceptions to fit what they expect to find. Sports fans often think that a referee is unfair. Jones, Paull, and Erskine (2002) found that when referees viewed videotaped portions of a soccer game, they were more likely to call a penalty if told that the players had a prior history of aggressiveness than when they were given no additional information. The study assigned 38 soccer referees to an experimental and control group. They all watched the same 50 videos clipped from soccer games between a blue team and another team. The experimental group was told that the blue team had an aggressive history and often committed fouls. The control group was given no information about the prior history of the teams. The experimental and control groups assigned a similar number of fouls to the 50 clips, but the experimental group assigned a statistically significant greater number of fowls to the blue team. This supports the idea that our expectations affect our perceptions. Our motivations and desires affect our senses. Suppose you live in a city close to where you work and can walk from home to work. You hurry down the street after breakfast so you will arrive at work on time. On the sidewalk is a cart where people can buy a doughnut. You most

likely will be unimpressed by the cart and only consider it to be restricting your passage down the busy sidewalk. However, you are too busy to eat lunch and work late. Now if you pass the same cart offering fresh doughnuts on your way home, you might perceive those same doughnuts might command your full attention. When we are hungry, food-related words can attract our attention more than we are not hungry (Mogg, Bradley, Hyare, & Lee, 1998). Perceptual Organization: Recognizing Faces When we view a scene, our perceptual system creates a unified experience of what our senses detect. Psychologists disagree over “whether we initially perceive ‘parts’ in order to see the whole, or whether perception of one part of the world critically depends on other parts” (Internet Psychology Lab, 2003). Our brains have to take the information available and process this. What criteria is used by our brain to decide which stimuli to pay attention to and how to process the signals sent by the senses to the brain. How do we recognize the face of a friend? Are there particular features we look for? The shape of an eye? The color of a cheek? Researches in the field of criminal justice have long studied how people can recognize faces, such as when a witness to a crime is used to identify the perpetrator. You can watch a video about this field at: Face Recognition . Open file: Transcript In the study described in the video, subjects were shown pairs of faces and asked to identify a face they had seen before. When a face is shown upside down, the subjects were not as good at recognizing the faces (Yin, 1969; Farah, Tanaka, & Drain, 1995). Farah, Tanaka and Drain suggest that the difficulty in recognizing upside-down faces results from the brain’s utilization of “holistic shape representations” to recognize faces (1995, p. 628). The holistic approach says that we recognize a face as a whole and not as a sum of its features. We are very accustomed to what a face should look like. You can see a striking example of how our expectation of a nose sticking out from a face can deceive our senses. No matter how the mask turns, we always perceive the nose as sticking out: The Rotating Mask Illusion . There are people who claim to recognize every face they have ever seen. A National Public Radio (NPR) show (Klar et al., 2017) featured Matt Doerschlag who says “If I spend 30 seconds looking at somebody, I will remember their face for years and years and years.” However, his wife Julie has a hard time remembering people she just met. You can test your ability to recognize a face at: Are You Any Good at Recognizing Familiar Faces? Here, Test Yourself. According to Dahl (2016), the ability to recognize faces seems to exist on a spectrum, with the two percent of the population who are super-recognizers on one end, and prosopagnosia – that is, the other two percent who are unable to recognize faces (including their own) – at the other. For non-face objects, we rely more on a second mechanisms that utilize a different part of the brain, where we decompose an object into its parts. We recognize the house of a family member from key components – maybe they have a sculpture of a unicorn in the yard and a purple door. We focus more on parts than the perception of the house as a whole.

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Conclusion In this lesson we examined how our senses can interact to create a perceptual impression. We saw how we can tune out some senses to focus on part of what we sense using selective attention. When we are exposed to a continuing stimulus, we become less sensitive due to sensory adaptation. Sensory adaptation also allows us to be more sensitive to stimuli if the intensity of the stimulus decreases. We also studied perceptual constancy. We considered perceptual expectations and how we can our perceptions can be deceived. Perceptual organization is an important issue in the field of perception. We compared the holistic and decomposing mechanisms. Sources Baron, I.S. (2003). Neuropsychological evaluation of the child . New York: Oxford University Press. Bressan, P., & Dal Martello, M. F. (2002, May 1). Talis pater, talis filius : Perceived resemblance and the belief in genetic relatedness. Psychological Science, 13 (3), 213-218. Dahl, M. (2016, June 2). Are you any good at recognizing familiar faces? Here, test yourself. Retrieved from https://www.thecut.com/2016/06/are-you-a-super-recognizer.html Darley, J. M., & Gross, P. H. (1983). A hypothesis-confirming bias in labelling effects. Journal of Personality and Social Psychology, 44 (1), 20-33. Retrieved from http://bear.warrington.ufl.edu/brenner/mar7588/Papers/darley-gross-jpsp1983.pdf Farah, M. J., Tanaka, J. W., & Drain, H. M. (1995, June). What causes the face inversion effect? Journal of Experimental Psychology: Human Perception and Performance, 21 (3): 628-634. Internet Pscyhology Lab. (2003). Visual perception. Retrieved from http://www.ipsych.com/vis/level_2_vis.html Jones, M. V., Paull, G. C., & Erskine, J. (2002, December). The impact of a team’s aggressive reputation on the decisions of association football referees. Journal of Sports Science, 20 (12), 991-1000. Klahr, R., Vedantam, S., Cohen, R., Boyle, T., Schmidt, J., Perkins, L., & Shah, P. (2017, July 4). Some people are great at recognizing faces. Others, not so much. National Public Radio . Retrieved from https://www.npr.org/2017/07/04/535408034/some-people-are-great-at- recognizing-faces-others-not-so-much Kraft, C. L. (1978). A psychophysical contribution to air safety: Simulator studies of visual illusions in night visual approaches. In H. L. Pick, H. W. Leibowitz, J. E. Singer, A. Steinschneider, & H. W. Stevenson (Eds.). Psychology: From research to practice . New York: Plenum Press.

Lumen. (n.d.) The vestibular sense, proprioception and kinesthesia. Retrieved from https://courses.lumenlearning.com/wmopen-psychology/chapter/reading-the-vestibular-sense/ Mogg, K., Bradley, B. P., Hyare, H., & Lee, S. (1998, February). Selective attention to food related stimuli in hunger. Behavior Research and Therapy, 36 (2), 227-237. Retrieved from http://linkinghub.elsevier.com/retrieve/pii/S0005-7967(97)00062-4 National Safety Council. (n.d.). Take steps to avoid injury when walking. Retrieved from http://www.nsc.org/learn/safety-knowledge/Pages/news-and-resources-pedestrian-safety.aspx Nitschke, J. B., Dixon, G. D., Sarinopoulos, I., Short, S. J., Cohen, J. D., Smith, E. E.,… Davidson, R. J. (2006, February 5). Altering expectancy dampens neural response to aversive taste in primary taste cortex. Nature Neuroscience, 9 , 435-442. Sahyouni, R. (2013, November 30). Sensory adaptation. Khan Academy . Retrieved from https://www.youtube.com/embed/8shz0KfqkMo Saylor Academy. (2012). Introduction to psychology. Retrieved from https://saylordotorg.github.io/text_introduction-to-psychology/ Stern, M., & Karraker, K. H. (1989, May). Sex stereotyping of infants: A review of gender labelling studies. Sex Roles, 20 (9-10), 501-522. Vestibular Disorders Association. (n.d.) The human balance system. Retrieved from http://vestibular.org/understanding-vestibular-disorder/human-balance-system Walker, E. (2014, October 27). Proprioception: Your sixth sense. Helix . Retrieved from https://helix.northwestern.edu/article/proprioception-your-sixth-sense Wallach, A., Eytan, D., Marom, S., & Meir, R. (2008, February 15). Selective adaptation in networks of heterogeneous populations: Model, simulation, and experiment. PLoS Computational Biology, 4 (2), e29. Retrieved from http://journals.plos.org/ploscompbiol/article? id=10.1371/journal.pcbi.0040029 Yin, R. K. (1969). Looking at upside-down faces. Journal of Experimental Psychology, 81 (1), 141-145. Image Citations "Symbols of the 5 senses: nose, hand, ear, tongue, and eye" by By Allan-Hermann Pool - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=38142426. "A grilled steak with grilled vegetables" by https://pixabay.com/en/beef-chef-cherry-closeup- colorful-1239187/.

"A group of people in a park all focused on their phones " by https://pixabay.com/en/pokemon- pokemon-go-phone-game-1553977/. "A rock band performing " by https://pixabay.com/en/concert-music-rock--n--roll-819149/. "A man walking down a path" by https://pixabay.com/en/leisure-wildlife-photography-1551705/. "A coffee cup as seen from above" by https://www.pexels.com/photo/beverage-caffeine-coffee- cup-236838/. "A checkerboard with a cylinder casting a shadow across it" by https://en.wikipedia.org/wiki/Color_constancy#/media/File:Grey_square_optical_illusion.PNG . "Two sets of lines that are of equal length, but they are perceived differently because of different configurations of arrows drawn at the end of the lines." by https://en.wikipedia.org/wiki/M %C3%BCller-Lyer_illusion#/media/File:M%C3%BCller-Lyer_illusion.svg . "The moon " by https://pixabay.com/en/moon-the-fullness-of-sky-mystery-1859616/. "Two identical grey rectangles with red and blue diagonal lines crossing each. On the left the lines appear to go behind the rectangle. On the right one line goes over the rectangle and the other one terminates half way across the rectangle" by https://en.wikipedia.org/wiki/Poggendorff_illusion#/media/File:Poggendorff_illusion.svg . "A Necker cube, a simple line drawing of a cube" by https://en.wikipedia.org/wiki/Necker_cube#/media/File:Necker_cube.svg . "A Ponzo illusion, with a drawing that looks like railroad tracks receding into the distance with two yellow lines drawn horizontally on the tracks." by https://en.wikipedia.org/wiki/Ponzo_illusion#/media/File:Ponzo_illusion.gif. "A horizontal line bisected by a vertical line of equal length" by https://en.wikipedia.org/wiki/Vertical%E2%80%93horizontal_illusion#/media/File:Vertical %E2%80%93horizontal_illusion.png.

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