Sensation and Perception Lecture 3 PDF

SENSATION AND PERCEPTION 14.10.2024 INTRODUCTION TO PSYCHOLOGY ▪ https://www.youtube.com/watch?v=vo4pMVb0R6M ▪ https://www.youtube.com/watch?v=hFV71QPvX2I SENSATION AND PERCEPTION ▪ https://www.youtube.com/watch?v=unWnZvXJH2o ▪ https://www.youtube.com/watch?v=fxZWtc0mYpQ ▪ https://www.youtube.com/...

SENSATION AND PERCEPTION 14.10.2024 INTRODUCTION TO PSYCHOLOGY ▪ https://www.youtube.com/watch?v=vo4pMVb0R6M ▪ https://www.youtube.com/watch?v=hFV71QPvX2I SENSATION AND PERCEPTION ▪ https://www.youtube.com/watch?v=unWnZvXJH2o ▪ https://www.youtube.com/watch?v=fxZWtc0mYpQ ▪ https://www.youtube.com/watch?v=n46umYA_4dM  The process by which sensory systems (eyes, ears, and other sensory organs) and the nervous system receive stimuli from our environment. SENSATION Bottom-up processing: Information processing that analyzes the raw stimuli entering through the many sensory systems.  The process of organizing and interpreting sensory information PERCEPTION Top Down Processing SENSATION AND PERCEPTION ▪ Sensation allows you to know that an object is a red sphere; that it has a cool, hard surface; and that it fits comfortably in your hand. ▪ The object has a pleasant aroma when you smell it and a satisfying crunch when you bite into it. When chewed, it produces a taste both sweet and tart. ▪ Analysis of this bottom-up stream of data leads to the perception that you’re eating an apple. THRESHOLDS ▪ A threshold is an edge, a boundary. ▪ One of the thresholds that interests psychologists is the absolute threshold, the minimum amount of stimulation needed to detect a particular stimulus. ▪ For example, the dimmest visible star in the sky would be right at the absolute threshold for vision because it is just barely bright enough for you to see. ▪ Likewise, the least amount of basil you can taste in the spaghetti sauce would be at the absolute threshold for taste. ▪ Humans have absolute thresholds that are low enough to detect most significant events that occur in our environment. THRESHOLDS ▪ Difference threshold (just noticeable difference, or jnd) ▪ The minimum amount of difference needed to detect that two stimuli are not the same. ▪ The difference threshold represents an edge, too—this time, the minimum difference to detect that two stimuli are not the same. ▪ How much does the volume have to increase before you can tell that the music playing from your stereo has become louder? ▪ How much do the laces on your hiking boots need to be loosened so that they feel slightly less tight? ▪ How much does the room have to cool down before you realize there’s a problem with the heating system? ▪ These are examples of the difference threshold—the smallest detectable change in a stimulus. SENSORY ADAPTATION ▪ Our adaptive nature means we filter out the nonchanging aspects of our environments, a process known as sensory adaptation. ▪ When stimulation is constant and unchanging, you eventually fail to respond because you usually don’t need to. ▪ One example of sensory adaptation occurs when you dive into a swimming pool filled with cold water. At first, the water seems frigid, but if you stay in for a while you’ll eventually “get used to it.” In other words, you’ll adapt to the constant stimulation of the cold water. ▪ You can also adapt to hot water, of course, or an odor, or the feel of an article of clothing, or a constant noise like the hum from an air conditioner. SELECTIVE ATTENTION ▪ Selective attention - Focusing conscious awareness on a particular stimulus to the exclusion of others. SELECTIVE ATTENTION ▪ Selective attention to a small number of stimuli lets you function in a busy, noisy world. ▪ Right now, you are effectively blocking out a variety of stimuli in your environment—the feel of the clothes you are wearing, the temperature of the air around you, the noises outside the room you are in, and so on. ▪ https://www.youtube.com/watch?v=fHd6XqnbEpU PERCEPTION The process of selecting, organizing, and interpreting sensory information, which enables us to recognize meaningful objects and events (Top down processing). 12 ORGANIZATIONAL PRINCIPLES 14 SELECTIVE ATTENTION We can perceive different forms of the Perceptions about objects Other examples: the Necker cube; however, change from moment to Stroop Task, dichotic we can only pay attention moment. listening to one aspect of the object at a time. Necker Cube 15 SELECTIVE ATTENTION ▪Stress narrows attention ▪OTHER EXAMPLES: ▪ Cell phones in car ▪? 16 COUNT THE NUMBER OF TIMES THE BALL IS PASSED: ▪ http://www.youtube.com/watch?v=vJG698U2Mvo 17 CHANGE BLINDNESS ▪ http://www.youtube.com/watch?v=-HVw9kWkPX0 ▪ https://www.youtube.com/watch?v=vBPG_OBgTWg 18 GESTALT ▪ The “whole,” or the organizational patterns that we tend to perceive ▪ Gestalt psychologists stressed that the whole is greater than the sum of its parts. ▪ By breaking experiences into their basic parts, something important is lost. A GESTALT ORGANIZATIONAL PRINCIPLES: FIGURE-GROUND RELATIONSHIPS FIGURE-GROUND The perceptual tendency to organize stimuli into objects (the figures) that stand out from their surrounding (the ground) The figure is the object(s) that stands out or draws one’s attention. The ground is the background. ORGANIZATIONAL PRINCIPLES: GROUPING PRINCIPLES  The perceptual tendency to organize stimuli into understandable groups GROUPING Several principles of grouping include: Similarity Proximity Closure Continuity  The tendency GROUPING - to place items that look SIMILARITY similar into a group  ▪ The tendency to place objects that GROUPING - are physically close to each other PROXIMITY in a group  ▪ The tendency to look at the whole GROUPING by filling in gaps in a perceptual field – CLOSURE  ▪ The tendency to perceive that movement of an object continues GROUPING – once it appears to move in a CONTINUITY particular direction DEPTH PERCEPTION  ▪ The ability to see in three DEPTH dimensions and judge distances PERCEPTION  ▪ A laboratory device for testing depth perception in infants and young animals VISUAL ▪ Infants are reluctant to crawl past the “edge” of the visual cliff CLIFF ▪ Other animals had similar results. ▪ Suggests that depth perception, to some extend, is inborn VISUAL CLIFF DEPTH PERCEPTION: BINOCULAR DEPTH CUES  ▪ Depth cues that require the use of BINOCULAR both eyes CUES  ▪ A binocular depth cue resulting from slightly different images produced by the separation of the RETINAL retinas in the left and right eye DISPARITY ▪ Is most effective when the item is quite close to the person BINOCULAR DEPTH CUES: FINGER SAUSAGE  CONVERGENCE ▪A binocular depth cue related to the tension in the eye muscles when the eyes track inward to focus on objects close to the viewer ▪The more tension in the eye muscle, the closer the object is ▪Works best at close distances DEPTH PERCEPTION: MONOCULAR DEPTH CUES  MONOCULAR CUES ▪Depth cues that require the use of only one eye ▪Monocular depth cues include: relative size, relative motion, interposition, relative height, texture gradient, relative clarity, and linear perspective.  MONOCULAR DEPTH CUES – RELATIVE SIZE ▪Using the perceived size of a familiar object to determine depth ▪The larger the object appears, the closer the object is to the viewer  MONOCULAR DEPTH CUES – RELATIVE MOTION ▪A person who is moving can determine depth by focusing on a distant object. ▪Objects further away than the object of focus will appear to move in the same direction as the subject is moving. ▪Objects closer than the object of focus will appear to move in the opposite direction. RELATIVE MOTION  MONOCULAR DEPTH CUES – INTERPOSITION ▪Method of determining depth by noting that closer objects partially obstruct the more distant objects ▪Also called “overlap”  MONOCULAR DEPTH CUES – RELATIVE HEIGHT ▪Method of determining depth by noting that distant objects appear higher in your field of vision than do closer objects  MONOCULAR DEPTH CUES – TEXTURE GRADIENT ▪Method of determining depth by noting that distant objects have a smoother texture than nearby objects  MONOCULAR DEPTH CUES – RELATIVE CLARITY ▪Method of determining depth by noting that distant objects are less clear than nearby objects ▪Tends to work outdoors  MONOCULAR DEPTH CUES– LINEAR PERSPECTIVE ▪Method of determining depth by noting that parallel lines appear to converge in the distance ▪The lines appears to eventually merge on the horizon. MOTION PERCEPTION  STROBOSCOPIC MOTION ▪The illusion of motion by the rapid projection of slightly changing images ▪The concept a motion picture uses  PHI PHENOMENON ▪The illusion of motion when fixed lights are turned on and off in a sequence PERCEPTUAL CONSTANCY  PERCEPTUAL CONSTANCY ▪Perceiving the size, shape, and lightness of an object as unchanging, even as the retinal image of the object changes ▪The understanding that objects usually remain the same PERCEPTUAL CONSTANCY: SIZE CONSTANCY  SIZE CONSTANCY ▪A person’s understanding that as an object moves further or closer to them its actual size stays the same ▪As an object appears to become larger we realize it is getting closer, not bigger. ▪As an object appears to become smaller we realize it is moving farther away, not getting smaller. SIZE DISTANCE RELATIONSHIP SIZE DISTANCE RELATIONSHIP SIZE DISTANCE RELATIONSHIP PERCEPTUAL CONSTANCY: SHAPE CONSTANCY  SHAPE CONSTANCY ▪The understanding that an object’s shape remains the same even though the angle of view makes the shape appear changed SHAPE CONSTANCY PERCEPTUAL CONSTANCY: LIGHTNESS CONSTANCY  LIGHT CONSTANCY ▪The ability to see an object as having a constant level of lightness no matter how the lighting conditions change PERCEPTUAL SET  PERCEPTUAL SET ▪ A mental predisposition to perceive something one way and not another ▪ Example of top-down processing ▪ Influence of the “power of suggestion” (subliminal perception) ▪ Guided by schemas: concepts or mental frameworks that organize and interpret information CONTEXT  CONTEXT ▪The setting or environment in which we interpret sensory stimuli ILLUSIONS  ILLUSIONS ▪Misinterpreting sensory stimuli ▪Help researchers understand how sensation and perception normally works MÜLLER-LYER ILLUSION  MÜLLER-LYER ILLUSION Most people think segment AB equals BC. In reality AB is much longer than BC. MÜLLER-LYER ILLUSION MÜLLER-LYER ILLUSION MÜLLER-LYER ILLUSION AMES ROOM ILLUSION: SECRET REVEALED