CHAPTER 6: SENSATION AND PERCEPTION  LECTURE NOTES- Chapter 6: Sensation and Perception- Thresholds and Signal Detectiono Absolute Sensory Threshold Intensity at which a given individual can detect a stimulus 50% of the timeo Response Ways _ 2 ways to be correct : Hit, Correct Rejection _2 ways wrong: False alarm_________ _misses_________o Signal-Detection Theory The study of people’s tendencies to make hits, correct rejections, misses, and false alarms In signal detection experiments, people’s responses depend on their willingness to risk a miss or a false positive- Experimento Scenario 1: _Light bulb dollar and penny__o Scenario 2: _Light bulb: dollar, penny and shock__- Subliminal Perceptiono The idea that a stimulus can influence our behavior even when it is presented so faintly or briefly or along with such distracters that we do not perceive it consciouslyo Myths Make you buy things Disney Movies- The Little Mermaid- The Rescuers- Who Framed Roger Rabbit- Aladdin- The Lion King Myths- Make you join a cult- Rock Songs- Barney Myths- Subliminal audiotapes can help you improve your memory, quit smoking, and lose weight… Truths- Emotions and facial expressions- Word Identification- Recognition of Patterns- Perceived Brightnesso Depends on _comparison to objects around ito Brightness Contrast The increase or decrease in an in an objects’ apparent brightness because of the effects of objects around it- Feature Detectiono Feature Detection Theory we begin recognition by breaking a complex stimulus into its component partso Feature Detectors Neurons in the visual cortex that respond to the presence of certain simple features, like lines and angles- Gestalt Psychologyo A field that focuses on our ability to perceive overall patterns German word that means “_Overall pattern or configuration__” Slogan was “__a whole is different from the sum of its parts_”o Visual perception is an active creation, not just the adding of lines or dots- Figure and Ground:o In order to perceive things, we must be able to separate figure and groundo We must be able to distinguish the __________ from the ____________________o We usually take this process for granted, except in situations when the task is difficult- Reversible Figureso Stimuli that can be perceived in more than one way.o In these cases, we have to test hypotheses to make sense of what we see- Gestalt Psychologyo Proximity-distance The tendency to perceive objects close to each other as forming a groupo Similarity-shapes Tendency to perceive objects that resemble ach other as forming a group_o Continuation Occurs when the eye is compelled to move through one object an continueto other objecto Closure _Imagine the rest of the figure that is missing_ Closer and continuation can work best together when something has blocked the presumed object in the background.- Perception of Movement and Deptho Visual Constancy Tendency to perceive objects as keeping their shape, size, and color, even though what actually strikes our retina changes from one moment to the next_- Perception of Movemento How do we distinguish between our own movements and that of other objects?o We know the object remains stationary for 2 reasons We perceive motion through the object’s background._ The vestibular system- Perception of Motiono Induced, or apparent movement When a background is moving and we incorrectly perceive as the object being in motion rather than the backgorund._- Stroboscopic movemento An illusion of movement created by rapid succession of stationary objects.__- Phi Effecto Illusion of movement created when _when two or more stationary light spearated by a short distance blink on and off at regular intevals.- Perception of Deptho Depth Perception Our perception of _ distances _ Retinal Disparity- The discrepancy between _the slightly different views the two eyessee becomes greater as the object comes closer. We use the amountof discrepancy to gauge distance. Convergence- The degree to which the eyes turn in to focus on a close object.o The closer the object, the more your eyes turn in- Binocular cueso Depend on both eyes- Monocular cueso Enable a person to judge depth and distance with just one eye or when both eyes see the same image, like a drawingo Depends on experience- Monocular Cueso Object size- a nearby produces a larger image than a distant one.o Linear Perspective-As parallel lines get further away, they appear to get closer togethero Detail- we see closer objects in more detailo Interposition-Closer objects tend to interrupt our view of more distant objects.o Texture Gradient- Distance btw evenly spaced items will appear to get shorter as distances increases.- Optical Illusionso Misinterpretation of a_ visual stimulus________________________ The relationship between size perception and depth perception helps us explain most optical illusions, yet not all.- Relationship between size and deptho If we can identify an object’s size, we can also judge its distance. Therefore, if we misjudge distance, we also tend to misjudge sizeo Ames