Chapter 5: Sensation and Perception (5.1, 5.3, 5.6) (EXAM 4)

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Does the trichromatic theory of color vision or the opponent-process theory of color vision helps us understand afterimages?

Opponent-process theory of color vision helps us understand afterimages

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the path of visual information from light entering the eye to where the visual cortex receives it.

-The eye is the major sensory organ involved in vision (Figure 5.10). Light waves are transmitted across the cornea and enter the eye through the pupil. The cornea is the transparent covering over the eye. It serves as a barrier between the inner eye and the outside world, and it is involved in focusing light waves that enter the eye. The pupil is the small opening in the eye through which light passes, and the size of the pupil can change as a function of light levels as well as emotional arousal. When light levels are low, the pupil will become dilated, or expanded, to allow more light to enter the eye. When light levels are high, the pupil will constrict, or become smaller, to reduce the amount of light that enters the eye. The pupil's size is controlled by muscles that are connected to the iris, which is the colored portion of the eye -After passing through the pupil, light crosses the lens, a curved, transparent structure that serves to provide additional focus. The lens is attached to muscles that can change its shape to aid in focusing light that is reflected from near or far objects. In a normal-sighted individual, the lens will focus images perfectly on a small indentation in the back of the eye known as the fovea, which is part of the retina, the light-sensitive lining of the eye. The fovea contains densely packed specialized photoreceptor cells (Figure 5.11). These photoreceptor cells, known as cones, are light-detecting cells. The cones are specialized types of photoreceptors that work best in bright light conditions. Cones are very sensitive to acute detail and provide tremendous spatial resolution. They also are directly involved in our ability to perceive color. While cones are concentrated in the fovea, where images tend to be focused, rods, another type of photoreceptor, are located throughout the remainder of the retina. Rods are specialized photoreceptors that work well in low light conditions, and while they lack the spatial resolution and color function of the cones, they are involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field. -We have all experienced the different sensitivities of rods and cones when making the transition from a brightly lit environment to a dimly lit environment. Imagine going to see a blockbuster movie on a clear summer day. As you walk from the brightly lit lobby into the dark theater, you notice that you immediately have difficulty seeing much of anything. After a few minutes, you begin to adjust to the darkness and can see the interior of the theater. In the bright environment, your vision was dominated primarily by cone activity. As you move to the dark environment, rod activity dominates, but there is a delay in transitioning between the phases. If your rods do not transform light into nerve impulses as easily and efficiently as they should, you will have difficulty seeing in dim light, a condition known as night blindness. Rods and cones are connected (via several interneurons) to retinal ganglion cells. Axons from the retinal ganglion cells converge and exit through the back of the eye to form the optic nerve. The optic nerve carries visual information from the retina to the brain. There is a point in the visual field called the blind spot: Even when light from a small object is focused on the blind spot, we do not see it. We are not consciously aware of our blind spots for two reasons: First, each eye gets a slightly different view of the visual field; therefore, the blind spots do not overlap. Second, our visual system fills in the blind spot so that although we cannot respond to visual information that occurs in that portion of the visual field, we are also not aware that information is missing. The optic nerve from each eye merges just below the brain at a point called the optic chiasm. As Figure 5.12 shows, the optic chiasm is an X-shaped structure that sits just below the cerebral cortex at the front of the brain. At the point of the optic chiasm, information from the right visual field (which comes from both eyes) is sent to the left side of the brain, and information from the left visual field is sent to the right side of the brain. -Once inside the brain, visual information is sent via a number of structures to the occipital lobe at the back of the brain for processing. Visual information might be processed in parallel pathways which can generally be described as the "what pathway" and the "where/how" pathway. The "what pathway" is involved in object recognition and identification, while the "where/how pathway" is involved with location in space and how one might interact with a particular visual stimulus (Milner & Goodale, 2008; Ungerleider & Haxby, 1994). For example, when you see a ball rolling down the street, the "what pathway" identifies what the object is, and the "where/how pathway" identifies its location or movement in space.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are feature detectors role in our "visual experience"? [In class.]

-feature detectors are in the visual cortex -simple cells are detected for bars and lines -complex cells are detected for moving cells -hypercomplex cells are detected for angles and simple shapes

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are the 5 Gestalt principles organization?

1.) Figure-ground 2.) Proximity 3.) Continuity 4.) Similarity 5.) Closure -Wertheimer, and his assistants Wolfgang Köhler and Kurt Koffka, who later became his partners, believed that perception involved more than simply combining sensory stimuli. This belief led to a new movement within the field of psychology known as Gestalt psychology. The word gestalt literally means form or pattern, but its use reflects the idea that the whole is different from the sum of its parts. In other words, the brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways. Gestalt psychologists translated these predictable ways into principles by which we organize sensory information. As a result, Gestalt psychology has been extremely influential in the area of sensation and perception (Rock & Palmer, 1990). -GESTALT LAWS OF ORGANIZATION= "strategies for interpreting the world"

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are the 5 basic structures of the human eye?

1.) Pupil 2.) Iris 3.) Lens 4.) Retina 5.) Fovea

(PERCEPTION QUIZ: 4.13.20) 8.) When bored in class, Denise stares at her finger first with only her right eye, then with only her left eye, to watch her finger seem to dance back and forth. Denise's dancing finger demonstrates: A.) binocular disparity B.) convergence C.) motion parallax D.) relative size

A.) binocular disparity

(PERCEPTION QUIZ: 4.13.20) 5.) You write a reminder post-it and stick it on the door where you see it every day. A month later, you forget your appointment because of the tendency to ignore what is always in your environment. The failure to notice something that is completely visible because of a lack of attention is known as: A.) inattentional blindness. B.) subliminal persuasion C.) sensory adaptation. D.) kinesthesia.

A.) inattentional blindness.

(PERCEPTION QUIZ: 4.13.20) 6.) Cues that help us determine visual distance or depth that require only one eye are known as ______________ cues. A.) monocular B.) subliminal C.) difference D.) habituated

A.) monocular

(PERCEPTION QUIZ: 4.13.20) 2.) People can be affected by stimuli that are presented to them so quickly that they are not able to consciously perceive the stimuli. This phenomenon is known as: A.) subliminal perception B.) sensory accommodation. C.) habituation. D.) sensory adaptation

A.) subliminal perception

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the lens structure of the human eye

After passing through the pupil, light crosses the lens, a curved, transparent structure that serves to provide additional focus. The lens is attached to muscles that can change its shape to aid in focusing light that is reflected from near or far objects. In a normal-sighted individual, the lens will focus images perfectly on a small indentation in the back of the eye known as the fovea, which is part of the retina, the light-sensitive lining of the eye.

(PERCEPTION QUIZ: 4.13.20) 1.) In order to determine your _______, you might slowly turn up the volume on the stereo one decibel at a time until you could just hear it. A.) just noticeable difference B.) absolute threshold C.) difference threshold D.) adaptation level

B.) absolute threshold

(PERCEPTION QUIZ: 4.13.20) 3.) When you first put your clothes on this morning you felt them on your skin, but within minutes you no longer noticed them. This is an example of: A.) habituation. B.) sensory adaptation. C.) perceptual constancy. D.) sensation-seeking.

B.) sensory adaptation.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the two binocular cues of binocular disparity and convergence [In class]. Understand these monocular cues of depth perception: linear perspective, interposition, and relative size. [In class.]

BINOCULAR CUES OF DEPTH PERCEPTION: (involving both eyes, 3-dimensional) 1.) Binocular Disparity -binocular disparity, the slightly different view of the world that each of our eyes receives. To experience this slightly different view, do this simple exercise: extend your arm fully and extend one of your fingers and focus on that finger. Now, close your left eye without moving your head, then open your left eye and close your right eye without moving your head. You will notice that your finger seems to shift as you alternate between the two eyes because of the slightly different view each eye has of your finger. A 3-D movie works on the same principle: the special glasses you wear allow the two slightly different images projected onto the screen to be seen separately by your left and your right eye. As your brain processes these images, you have the illusion that the leaping animal or running person is coming right toward you. -brain compares slightly different retinal images -each eye sees the world a bit different, but they work together to see it as one whole 2.) Convergence -physical turning inward of the eyes -only within arms length -the more the eyes are turned inward, the closer the object is to the eyes "basically the more cross-eyed you are, the closer it is" MONOCULAR CUES OF DEPTH PERCEPTION: (only one eye needed, 2-dimensional) 1.) Linear Perspective -An example of a monocular cue would be what is known as linear perspective. Linear perspective refers to the fact that we perceive depth when we see two parallel lines that seem to converge in an image (Figure 5.15). -converging parallel lines suggest depth 2.) Interposition -overlapping 3.) Relative size -smaller things are farther away

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Why are there two explanations for color vision?

But these two theories—the trichromatic theory of color vision and the opponent-process theory—are not mutually exclusive. Research has shown that they just apply to different levels of the nervous system. For visual processing on the retina, trichromatic theory applies: the cones are responsive to three different wavelengths that represent red, blue, and green. But once the signal moves past the retina on its way to the brain, the cells respond in a way consistent with opponent-process theory (Land, 1959; Kaiser, 1997).

(PERCEPTION QUIZ: 4.13.20) 10.) Which of the following senses does not typically show sensory adaption effects in our everyday lives? A.) hearing B.) touch C.) vision D.) smell

C.) vision

(PERCEPTION QUIZ: 4.13.20) 7.) _________ processing refers to our use of beliefs, experiences, expectations, or other concepts to shape our view of the world. A.) Bottom-up B.) Parallel C.) Subliminal D.) Top-down

D.) Top-down

(PERCEPTION QUIZ: 4.13.20) 9.) The principle of _____________ suggest that we that we organize our perceptions into complete objects rather than as a series of unconnected parts. A.) similarity B.) proximity C.) interposition D.) closure

D.) closure

(PERCEPTION QUIZ: 4.13.20) 4.) If you look at the color green for an extended period of time and then look away, you will see an afterimage of red. Which theory accounts for this phenomenon? A.) binding theory B.) trichromatic theory C.) parallel-processing theory D.) opponent-process theory

D.) opponent-process theory

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are feature detectors?

Feature detectors are neurons that respond to very specific features in the environment

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe bottom-up processing

IN-CLASS: Bottom-Up Processing: -combining small features to build up a complete perception (via feature detectors) -side note: bottom-up processing and top-down processing work together in processing information through perception TEXTBOOK: While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to the fact that perceptions are built from sensory input. On the other hand, how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts. This is called top-down processing. -side note: One way to think of this concept is that sensation is a physical process, whereas perception is psychological. For example, upon walking into a kitchen and smelling the scent of baking cinnamon rolls, the sensation is the scent receptors detecting the odor of cinnamon, but the perception may be "Mmm, this smells like the bread Grandma used to bake when the family gathered for holidays."

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Define sensation

IN-CLASS: Sensation: -first step on experiences -sensation comes from the outside world -(physical process: eye, ear, nose.....) -sensory information (light, sound,etc.) is detected by a sensory receptor -EX: the man who could describe the rose he saw didn't know it was an actual rose thought, but once he smelt the rose he knew it was a rose. This shows that he had an issue with perception, but was fine in sensation TEXTBOOK: Sensation: What does it mean to sense something? Sensory receptors are specialized neurons that respond to specific types of stimuli. When sensory information is detected by a sensory receptor, sensation has occurred. For example, light that enters the eye causes chemical changes in cells that line the back of the eye. These cells relay messages, in the form of action potentials (as you learned when studying biopsychology), to the central nervous system.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the Figure-ground Gestalt principle

IN-CLASS: -tendency to divide visual scenes into figure and background (to find out what is important) TEXTBOOK: One Gestalt principle is the figure-ground relationship. According to this principle, we tend to segment our visual world into figure and ground. Figure is the object or person that is the focus of the visual field, while the ground is the background. As Figure 5.23 shows, our perception can vary tremendously, depending on what is perceived as figure and what is perceived as ground. Presumably, our ability to interpret sensory information depends on what we label as figure and what we label as ground in any particular case, although this assumption has been called into question (Peterson & Gibson, 1994; Vecera & O'Reilly, 1998).

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the Proximity Gestalt principle

IN-CLASS: -things close to each other are related (see slide #30 of part 2: perception, there are 8 lines in total, but technically 4 groupings) TEXTBOOK: -Another Gestalt principle for organizing sensory stimuli into meaningful perception is proximity. This principle asserts that things that are close to one another tend to be grouped together, as Figure 5.24 illustrates. -How we read something provides another illustration of the proximity concept. For example, we read this sentence like this, notl iket hiso rt hat. We group the letters of a given word together because there are no spaces between the letters, and we perceive words because there are spaces between each word. Here are some more examples: Cany oum akes enseo ft hiss entence? What doth es e wor dsmea n?

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Compare an absolute threshold to a difference threshold

IN-CLASS: ABSOLUTE THRESHOLD is the minimum amount of stimulation needed to detect a stimulus 50% of the time , while DIFFERENCE THRESHOLD is the smallest physical difference between 2 different stimulus that is detectable 50% of the time (basically how different do 2 sounds need to be for you to be able to tell they are 2 different sounds) TEXTBOOK: Absolute thresholds are generally measured under incredibly controlled conditions in situations that are optimal for sensitivity. Sometimes, we are more interested in how much difference in stimuli is required to detect a difference between them. This is known as the just noticeable difference (jnd) or difference threshold. Unlike the absolute threshold, the difference threshold changes depending on the stimulus intensity. As an example, imagine yourself in a very dark movie theater. If an audience member were to receive a text message on her cell phone which caused her screen to light up, chances are that many people would notice the change in illumination in the theater. However, if the same thing happened in a brightly lit arena during a basketball game, very few people would notice. The cell phone brightness does not change, but its ability to be detected as a change in illumination varies dramatically between the two contexts.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What is an absolute threshold?

IN-CLASS: Absolute Threshold: -minimum amount of stimulation needed to detect a stimulus 50% of the time -EX: how bright a light needs to be, to be able to see it -EX: how loud a sound needs to be to be able to hear it -EX: SENSE: Hearing STIMULUS: Light waves RECEPTORS: Pressure-sensitive hair cells in ear's cochlea ABSOLUTE THRESHOLD: The tick of a watch at 20 feet -everyone is different, and can also depend on the situation you're in (beeping hearing test from slide #9) TEXTBOOK: The sensitivity of a given sensory system to the relevant stimuli can be expressed as an absolute threshold. Absolute threshold refers to the minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time. Another way to think about this is by asking how dim can a light be or how soft can a sound be and still be detected half of the time. The sensitivity of our sensory receptors can be quite amazing. It has been estimated that on a clear night, the most sensitive sensory cells in the back of the eye can detect a candle flame 30 miles away (Okawa & Sampath, 2007). Under quiet conditions, the hair cells (the receptor cells of the inner ear) can detect the tick of a clock 20 feet away (Galanter, 1962).

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the retina structure of the human eye

In a normal-sighted individual, the lens will focus images perfectly on a small indentation in the back of the eye known as the fovea, which is part of the retina, the light-sensitive lining of the eye.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Define perception

IN-CLASS: Perception: -second step in experiences (first one being sensation) -brain gets information from senses, and then uses information from brain to interpret what the senses captured -(psychological process: brain) -sensory information is interpreted and consciously experienced TEXTBOOK: Perception: While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are selective attention [In class] and inattentional blindness, and how do they affect our perceptions?

IN-CLASS: SELECTIVE ATTENTION: -focus awareness on specific features of the environment -EX: "cocktail party" , you can focus on one person, even though there are 100 people around you INATTENTIONAL BLINDNESS: -failure to notice something that is completely visible because of a lack of attention -EX: focusing on people passing the basketball in white shirts, made it so that you didn't notice the curtain changing color, or the player from the black shirt team leaving, or the monkey that walked through (video from slide #5 of Part 2 of chapter 5) TEXTBOOK: SELECTIVE ATTENTION: There is another factor that affects sensation and perception: attention. Attention plays a significant role in determining what is sensed versus what is perceived. Imagine you are at a party full of music, chatter, and laughter. You get involved in an interesting conversation with a friend, and you tune out all the background noise. If someone interrupted you to ask what song had just finished playing, you would probably be unable to answer that question. INATTENTIONAL BLINDNESS: One of the most interesting demonstrations of how important attention is in determining our perception of the environment occurred in a famous study conducted by Daniel Simons and Christopher Chabris (1999). In this study, participants watched a video of people dressed in black and white passing basketballs. Participants were asked to count the number of times the team in white passed the ball. During the video, a person dressed in a black gorilla costume walks among the two teams. You would think that someone would notice the gorilla, right? Nearly half of the people who watched the video didn't notice the gorilla at all, despite the fact that he was clearly visible for nine seconds. Because participants were so focused on the number of times the white team was passing the ball, they completely tuned out other visual information. Failure to notice something that is completely visible because of a lack of attention is called inattentional blindness.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Define sensory adaptation and explain why it is helpful.

IN-CLASS: Sensory Adaptation: -sensory system becomes less responsive to unchanging stimuli -focus on "new" environmental changes (this is how it's helpful) -EX: when you first walk into a room, you will notice the clock ticking, but as time goes by you won't even know it is ticking -EX: you'll feel a sock when you first put it on, but after a few minutes you won't even realize it's on -regards all senses, besides vision because even though we don't realize it, our eyes are currently moving and doesn't sit still to be able to do this. Can happen in very controlled labs, but not in every day life TEXTBOOK: Although our perceptions are built from sensations, not all sensations result in perception. In fact, we often don't perceive stimuli that remain relatively constant over prolonged periods of time. This is known as sensory adaptation. Imagine entering a classroom with an old analog clock. Upon first entering the room, you can hear the ticking of the clock; as you begin to engage in conversation with classmates or listen to your professor greet the class, you are no longer aware of the ticking. The clock is still ticking, and that information is still affecting sensory receptors of the auditory system. The fact that you no longer perceive the sound demonstrates sensory adaptation and shows that while closely associated, sensation and perception are different.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe top-down processing

IN-CLASS: Top-Down Processing: -use of pre-existing knowledge to organize features into something meaningful -starting with intelligence, and then breaking it down into smaller pieces TEXTBOOK: While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to the fact that perceptions are built from sensory input. On the other hand, how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts. This is called top-down processing.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the Similarity Gestalt principle

IN-CLASS: group by similar patterns , see slide #30 from ch.5 part 2: perception TEXTBOOK: We might also use the principle of similarity to group things in our visual fields. According to this principle, things that are alike tend to be grouped together (Figure 5.25). For example, when watching a football game, we tend to group individuals based on the colors of their uniforms. When watching an offensive drive, we can get a sense of the two teams simply by grouping along this dimension.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the Closure Gestalt principle

IN-CLASS: see slide #30 from ch.5 part 2: perception, we see it as a triangle, but it technically isn't one TEXTBOOK: The principle of closure states that we organize our perceptions into complete objects rather than as a series of parts (Figure 5.27).

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What does research say about subliminal persuasion? [In class.]

IN-CLASS: subliminal persuasion is persuasion through subliminal stimuli through the method of using subliminal perception EX: gin advertisement having the ice cubes spelling out "sex" so people will unconsciously want to but it, and lion kings movie cover looking like a women half naked turned around so people will want to watch the movie -research shows that subliminal effects are weak and short-lived if they even work, and not very powerful and there is no real research saying this works.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the Continuity Gestalt principle

IN-CLASS: see slide #30 from ch.5 part 2: perception TEXTBOOK: The law of continuity suggests that we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines (Figure 5.26).

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the fovea structure of the human eye

In a normal-sighted individual, the lens will focus images perfectly on a small indentation in the back of the eye known as the fovea, which is part of the retina, the light-sensitive lining of the eye.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are perceptual constancies, and why are they important? [In class.]

PERCEPTUAL CONSTANCIES: -despite changes in what the eye senses, we perceive stable images -is a critical tool, we would not be able to survive as a society without these 3 types: 1.) Shape Constancy -EX: see slide #32 from part 2 of ch. 5) 2.) Size Constancy -EX: Sensation: Professor is walking away (thought: he's shrinking) Perception: Professor is walking away (thought: he's not getting smaller, he's just walking away) 3.) Brightness Constancy EX: Sensation: light gets brighter in room where there is a piece of paper (thought: the piece of paper just got brighter in color!) Perception: light gets brighter in room where there is a piece of paper (thought: the room just got brighter, not the actual piece of paper)

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are the rods distinct purposes and where are the rods generally located on the retina?

TEXTBOOK: -While cones are concentrated in the fovea, where images tend to be focused, rods, another type of photoreceptor, are located throughout the remainder of the retina. -Rods are specialized photoreceptors that work well in low light conditions, and while they lack the spatial resolution and color function of the cones, they are involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field. -in peripheral retina (sides of retina, not the center) -IN-CLASS: Rods: -120 million rods per eye -in peripheral retina (not in the center) -no color, not able to detect color -low light, allows us to see in the dark. Takes 30 minutes to fully adjust, and after it adjusts it's 100,000 times more sensitive to light

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What are the cones distinct purposes and where are the cones generally located on the retina?

TEXTBOOK: Cones: The fovea contains densely packed specialized photoreceptor cells (Figure 5.11). These photoreceptor cells, known as cones, are light-detecting cells. The cones are specialized types of photoreceptors that work best in bright light conditions. Cones are very sensitive to acute detail and provide tremendous spatial resolution. They also are directly involved in our ability to perceive color. IN-CLASS: Cones: -6 million cones per eye -near center of retina (fovea) -fine detail and color vision -when looking straight forward you are using cones -cones=color

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What does research say about the power of subliminal perception?

TEXTBOOK: It is also possible for us to get messages that are presented below the threshold for conscious awareness—these are called subliminal messages. A stimulus reaches a physiological threshold when it is strong enough to excite sensory receptors and send nerve impulses to the brain: This is an absolute threshold. A message below that threshold is said to be subliminal: We receive it, but we are not consciously aware of it. Over the years there has been a great deal of speculation about the use of subliminal messages in advertising, rock music, and self-help audio programs. Research evidence shows that in laboratory settings, people can process and respond to information outside of awareness. But this does not mean that we obey these messages like zombies; in fact, hidden messages have little effect on behavior outside the laboratory (Kunst-Wilson & Zajonc, 1980; Rensink, 2004; Nelson, 2008; Radel, Sarrazin, Legrain, & Gobancé, 2009; Loersch, Durso, & Petty, 2013). IN-CLASS: -subliminal effect are weak and short-lived -doesn't influence real-world choices

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What does subliminal mean?

TEXTBOOK: It is also possible for us to get messages that are presented below the threshold for conscious awareness—these are called subliminal messages. A stimulus reaches a physiological threshold when it is strong enough to excite sensory receptors and send nerve impulses to the brain: This is an absolute threshold. A message below that threshold is said to be subliminal: We receive it, but we are not consciously aware of it. Over the years there has been a great deal of speculation about the use of subliminal messages in advertising, rock music, and self-help audio programs. Research evidence shows that in laboratory settings, people can process and respond to information outside of awareness. But this does not mean that we obey these messages like zombies; in fact, hidden messages have little effect on behavior outside the laboratory (Kunst-Wilson & Zajonc, 1980; Rensink, 2004; Nelson, 2008; Radel, Sarrazin, Legrain, & Gobancé, 2009; Loersch, Durso, & Petty, 2013). IN-CLASS: SUBLIMINAL PERCEPTION: -perception without conscious awareness -(below absolute threshold) -basically getting something into someones head without them being aware of it SUBLIMINAL PERSUASION: -persuasion through subliminal stimuli (through subliminal perception)

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Explain the trichromatic theory of color vision, where in our visual system does this process take place?

TEXTBOOK: Normal-sighted individuals have three different types of cones that mediate color vision. Each of these cone types is maximally sensitive to a slightly different wavelength of light. According to the trichromatic theory of color vision, shown in Figure 5.13, all colors in the spectrum can be produced by combining red, green, and blue. The three types of cones are each receptive to one of the colors. IN-CLASS: Trichromatic Theory: -color is produced by the activation of 3 types of cones in the retina (red, green, blue cones) -in the back of the retina, stimulated by other colors -overall stimulation produces our sense of color -trichromatic theory CAN NOT explain afterimages, which are complementary color "ghost images"

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) What is depth perception?

TEXTBOOK: Our ability to perceive spatial relationships in three-dimensional (3-D) space is known as depth perception. With depth perception, we can describe things as being in front, behind, above, below, or to the side of other things.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the pupil structure of the human eye

TEXTBOOK: The pupil is the small opening in the eye through which light passes, and the size of the pupil can change as a function of light levels as well as emotional arousal. When light levels are low, the pupil will become dilated, or expanded, to allow more light to enter the eye. When light levels are high, the pupil will constrict, or become smaller, to reduce the amount of light that enters the eye. The pupil's size is controlled by muscles that are connected to the iris, which is the colored portion of the eye.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the iris structure of the human eye

TEXTBOOK: The pupil's size is controlled by muscles that are connected to the iris, which is the colored portion of the eye.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Explain the opponent-process theory of color vision , where in our visual system does this process take place?

TEXTBOOK: The trichromatic theory of color vision is not the only theory—another major theory of color vision is known as the opponent-process theory. According to this theory, color is coded in opponent pairs: black- white, yellow-blue, and green-red. The basic idea is that some cells of the visual system are excited by one of the opponent colors and inhibited by the other. So, a cell that was excited by wavelengths associated with green would be inhibited by wavelengths associated with red, and vice versa. One of the implications of opponent processing is that we do not experience greenish-reds or yellowish-blues as colors. Another implication is that this leads to the experience of negative afterimages. An afterimage describes the continuation of a visual sensation after removal of the stimulus. For example, when you stare briefly at the sun and then look away from it, you may still perceive a spot of light although the stimulus (the sun) has been removed. When color is involved in the stimulus, the color pairings identified in the opponent-process theory lead to a negative afterimage. You can test this concept using the flag in Figure 5.14. IN-CLASS: Opponent Process Theory: -color is produced from 3 separate Paris of ganglion cells 1.) red-green 2.) blue-yellow 3.) black-white -after one cell stops firing, the "paired cell" fires briefly, resulting in different colored "afterimage". Basically is a "rebound effect" from being held down.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) Describe the roles of rods and cones in the process of dark adaptation. Why is there a blind spot?

TEXTBOOK: We have all experienced the different sensitivities of rods and cones when making the transition from a brightly lit environment to a dimly lit environment. Imagine going to see a blockbuster movie on a clear summer day. As you walk from the brightly lit lobby into the dark theater, you notice that you immediately have difficulty seeing much of anything. After a few minutes, you begin to adjust to the darkness and can see the interior of the theater. In the bright environment, your vision was dominated primarily by cone activity. As you move to the dark environment, rod activity dominates, but there is a delay in transitioning between the phases. If your rods do not transform light into nerve impulses as easily and efficiently as they should, you will have difficulty seeing in dim light, a condition known as night blindness. Rods and cones are connected (via several interneurons) to retinal ganglion cells. Axons from the retinal ganglion cells converge and exit through the back of the eye to form the optic nerve. The optic nerve carries visual information from the retina to the brain. There is a point in the visual field called the blind spot: Even when light from a small object is focused on the blind spot, we do not see it. We are not consciously aware of our blind spots for two reasons: First, each eye gets a slightly different view of the visual field; therefore, the blind spots do not overlap. Second, our visual system fills in the blind spot so that although we cannot respond to visual information that occurs in that portion of the visual field, we are also not aware that information is missing.

(FROM EXAM #4 REVIEW , THIS IS FROM CLASSES SWITCHING TO ONLINE 3.16.20) How do bottom-up processing and top-down processing work together to provide us with perceptual experiences?

TEXTBOOK: While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to the fact that perceptions are built from sensory input. On the other hand, how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts. This is called top-down processing.