PSY 456: Unit 2 Study Guide
PSY 456: Unit 2 Study Guide PSY 456
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This 15 page Study Guide was uploaded by Brianna on Saturday March 5, 2016. The Study Guide belongs to PSY 456 at Colorado State University taught by Amberg in Spring 2016. Since its upload, it has received 30 views. For similar materials see Sensation & Perception in Psychlogy at Colorado State University.
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Date Created: 03/05/16
Sensation & Perception Unit 2 Study Guide Chapter 5 Terms: ● Inverse Projection Problem: an image on the retina can be caused by an infinite number of objects ● Viewpoint Invariance: ability to recognize an object regardless of the viewpoint ● Illusory Contours: contours that appear real but have no physical edge ● Physical Regularities: regularly occurring physical properties ● Oblique Effect: people perceive horizontals and verticals more easily than other orientations ● Uniform Connectedness: objects are defined by areas of the same color or texture ● Lightfromabove Heuristic: light is natural environment comes from above us Visual Perception is like a Puzzle ● rules for organization, placement, and distance ● more than knowing something is there and being able to act on/relate to other experiences Why is it Difficult to Design a Perceiving Machine? ● stimulus on the receptors is ambiguous ○ Inverse Projection Problem: an image on the retina can be caused by an infinite number of objects ■ distance, size, angle ● objects can be hidden or blurred ○ occlusions are common in environment ● objects look different from different viewpoints ○ Viewpoint Invariance: ability to recognize an object regardless of the viewpoint Structuralism ● Wundt | Late 1800’s ● Major Premises ○ Sensations combine to create complex perceptions ○ Past experience also plays a role in perception ○ Consciousness broken down to basic components ○ Most research involved cataloging these basic elements via introspection ● Limitations ○ reliability with data ■ taugh everyone and only self report ○ illusions ■ apparent movement Gestalt Psychology ● Wertheimer, Koffka, Kohler | 1920s ● the whole differs from the sum of it’s part ○ perception is not built up from sensations, but a result of perceptual organization ● Principles ○ Good Continuation ■ perceive smoothly flowing or continuous forms rather that disrupted or discontinuous ones ○ Law of Pragnaz ■ stimuli is seen in simplest form possible ○ Similarity ■ similar things appear grouped ○ Proximity ■ things near each other are grouped ○ Common Fate ■ things moving the same direction are grouped together ○ Common Region ■ things within the same region appear grouped ○ Uniform Connectedness ■ connected region of the same visual properties is perceived as a unit ○ Closure ■ close up, or complete objects that are not complete ○ Figure Ground ■ figure prominent object ■ ground background ■ Segregation: determining what part of the environment is the figure ● Properties ○ the figure is more “thing like” and more memorable ○ the figure is seen in front of the ground ○ the ground is more uniform and extends behind figure ○ the contour separating figure from ground belongs to the figure (border ownership) ● Subjective Factors ○ experience and meaning ○ elements located in lower part of display ○ convex side of borders ○ Gibson ■ figure ground can be affected by meaningfulness or familiarity of stimuli ■ things that form meaningful patterns are likely to be grouped ● Illusory Contours: contours that appear real but have no physical edge Perceiving Scenes and Objects in Scenes ● A scene contains: ○ background elements ○ objects organized in meaningful ways with each other and the backgrounds ● Difference between objects and scenes ○ a scene is acted within ○ an object is acted upon ● Research on perceiving gists of scenes ○ Potter showed that people can do this when a picture is only presented for 1/4 second ■ given cue, able to identify picture ○ FeiFei used masking to show that the overall gist is perceived first followed by details ● Global image features of scenes ○ Degree of naturalness ■ is it manmade or naturally occurring ○ Degree of openness ■ are there vast open spaces in the picture ○ Degree of roughness ■ texture. smooth? grainy? ○ Degree of expansion ■ how much of the picture does it take up ○ Color ■ helps identify where objects starts and ends ○ holistic and perceived rapidly ● Physical Regularities: regularly occurring physical properties ○ Oblique Effect: people perceive horizontals and verticals more easily than other orientations ○ Uniform Connectedness: objects are defined by areas of the same color or texture ■ homogenous colors and nearby objects have different colors ○ Lightfromabove Heuristic: light is natural environment comes from above us ● Semantic Regularities: characteristics associated with the functions carried out in different types of scenes ○ Palmer ■ observers saw a context scene flashed briefly followed by a target picture ■ Results ● targets congruent with the context 80% ● targets incongruent with the context 40% ● Role of Inference ○ Unconscious Inference ■ created by Helmholtz to explain why stimuli can be interpreted in more than one way ■ Likelihood Principle: objects are perceived based on what is most likely to have caused the pattern ○ Modern research use Bayesian inference that take probabilities into account ● Connecting Neural Activity and Object Perception ○ GrillSpector ■ FFA in each monitored ■ shown: Harrison Ford, different face, random texture ■ shown for 50 ms followed by delay (masking task) ■ RegionofInterest Approach: the FFA for each person identified by ● showing faces and nonfaces and finding what responds to faces ■ Results: ● With Harrison Ford, FFA was ○ was greatest when correctly identified as Harrison Ford ○ was less when saw face but not Harrison ○ showed little response when there was no identification of face ● neural processing is associated with both the presentation of stimulus and the response to the stimulus ○ Brain Activity and Seeing ■ Sheinberg & Logothetis ● monkey trained to pull levers: one for sunburst one for butterfly ● Binocular Rivalry: each picture shown to one eye at the same time ● Neuron in the IT cortex that responded only to the butterfly monitored ○ firing was vigorous for the butterfly only ■ Tong ● binocular rivalry again ○ house to one, face to other ● pushed button to indicate perception ● fMRI showed increased activity in ○ parahippocampal place area for the house ○ fusiform face area for the face ○ Reading the Brain ■ Kamitani & Tong ● gratings with different orientations were presented to participants ● responses from fMRI voxels (cubicle areas of brain) were measured ● activity patterns across voxels varies by grating orientation ● orientation decoder used to analyze the voxel activity ○ decoder could accurately predict which orientation had been presented ○ Structural Semantic Encoding Model ○ Are Faces Special ■ FFA: responds only to faces ■ Amygdala: activated by emotional aspects of faces ■ Superior Temporal Sulcus: responds to where the person is looking and to mouth movements ■ Frontal Cortex: activated when evaluation facial attractiveness ○ Thatcher Illusion ■ Why does it occur? ● Barlett & Searcy ○ results supported the ‘configural processing hypothesis” ■ see faces as whole ■ unaware of grotesqueness ● Holistic Recognition ○ if we looked at individual features we would see problem Infant Face Perception ● understanding what an infant sees using preferential looking effect ● human faces are among the most important stimuli ● vision almost fully developed at 6 months ● object recognition more active than adults Chapter 6 Terms: ● Visual Scanning: looking from place to place ● Saccadic Eye Movement: fast voluntary movement of the eyes to accurately refix on target object ● Visual Search: looking for specific target ● Overt Attention: looking directly at the attended object ● Covert Attention: attention without looking ● Spatial Attention: attention to specific locations ● Illusory Conjunctions: features that should be associated with an object becomes associated with another ● Perceptual Capacity: capacity to do tasks ● Perceptual Load: amount of capacity needed to perform a task ● Habituation: the result when the same stimulus is presented repeatedly What Directs our Attention ● Characteristics ○ Stimulus Salience: areas of stimuli that attract attention due to their properties ■ ex; color, contrast, orientation, knowledge ● Selections Based on Cognitive Factors ○ picture meaning and observer knowledge ■ Scene Schema: prior knowledge about typical scenes ● fixations influenced by this, diversions from schemas ○ Shinoda et al. ■ measured fixations during simulated driving ■ more likely to detect stop signs at intersections ● Knowledge of Placement ○ Task Demands ■ task demands override stimulus saliency ■ eye movements and fixations linked to action person is about to take ■ Dynamic Environment ● Misic and Hayhoe ○ pedestrians walked loops ■ Rouge: walks towards other people ■ Risky: walked randomly ■ Safe: stayed away from people ○ Results: ■ paid most attention to rouge What Happens when We Attend? ● Spatial Attention: attention to specific locations ● Posner et al. ○ looked at fixation point, arrow indicated where stimulus might appear ■ consistent (valid trial) ■ inconsistent (invalid trial) ○ push button when target is seen ○ Results: ■ faster on consistent trials ■ information is processed better where attention is directed ● Egly et al. ○ viewed 2 rectangles, cued to where target may appear ○ press button when target appeared ○ Results: ■ fastest reaction time at targeted position ■ Enhancement Effect for nontarget within same field as the target rectangle ● Attention can Influence Appearance ○ Carrrasco et al. ■ looked at two grating stimuli ● different contrast or similar contrast ■ indicate orientation of bars with higher contrast ■ small dot flashed quickly on one side before choice ■ Results: ● large difference in contrast: dot had no effect ● same contrast: reported grating with dot ● shift of attention led to effect on perception ● Attention can Influence Physiological Responding ○ O’Craven ■ present house or face ■ moving or stationary face: activity in FFA ■ moving or stationary house: activity in PPA ○ Datta and DeYoe ■ attention maps show directing attention to specific area of space activates specific brain area ○ Womelsdorf ■ showed that attention can cause a monkey’s receptive field to shift toward the place where the attention is directed What Happens when We Don’t Attend ● Inattentional Blindness: stimulus not perceived even when looking directly at it ● Simons and Chabris ○ film of passing basketball, told to count passes ○ someone walks through with umbrella or in gorilla suit ○ Results: ■ 46% don’t see the woman/gorilla ■ doesn’t fit schema, not asked to look for it ● Change Detection ○ Change Blindness: don’t notice a change in a scene ■ shown a picture with and without a missing element in alternating fashion ■ Results: ● pictures alternated multiple times before change is detected ● cued to indicate attention: change detected more quickly ● assume change isn’t going to happen unless we act on it ○ Continuity Issues in Films ■ don’t notice because objects in environment don’t change ● Is Attention Necessary for Perceiving Scenes ○ Li et al. ■ told to look at one point as a task occurred ● Central Task: letters flashed on screen ● Peripheral Task: picture of scene ● Dual Task: same as peripheral but determine color order on disc ■ Results: ● 90% on peripheral task | 50% on dual task ● easy to recognize simply things with covert attention, difficult to see details Distracting Effects of TaskIrrelevant Stimuli ● Task Irrelevant Stimuli: stimuli that doesn’t provide information relevant to the task ● Foster & Lavie ○ Load Theory of Attention ■ Perceptual Capacity: capacity to do tasks ■ Perceptual Load: amount of capacity needed to perform a task ■ Lowload tasks have high perceptual capacity ■ Highload tasks have low perceptual capacity ○ less capacity leads to less ability to ignore distractions ■ not able to determine relevant vs. non Attention and Experiencing a Coherent World ● Binding: features are combined to create coherent objects ○ Binding Problem: features of object are processed separately in different areas of the brain ○ How? ■ experience, knowledge, expectations ○ Why? ■ integrate nueron firing from movement, color, etc. together to perceive one thing ● Feature Integration Theory ○ Preattentive Stage ■ feature of objects are separated ■ register salient features automatically ■ lowlevel processing ○ Focused Attention Stage ■ features are bound into coherent perception ■ complex objects ○ Perceive Object ○ Compare to Memory ○ Illusory Conjunctions: features that should be associated with an object becomes associated with another ■ Treisman & Schmidt ● four shapes flanked by two numbers, flashed briefly followed by mask ● report numbers then shapes at four directions ● Results: ○ incorrect associations with objects 18% of the time ○ asked to focus on target eliminated this effect ○ brain does “reading” fist, then looks at details ● Visual Search ○ Conjunction Search: finding target with two or more features ■ patients with parietal lobe damage cannot perform conjunction searches well Attention and Autism ● Withdrawal from contact with people ○ can solve social situation reasoning problems, but function poorly when in these situations ● Klin et al. ○ autistic and non autistic watched movie while eye fixations were tracked ○ Results: ■ non autistic focus on eyes/faces, where people pointed, and who should reply ■ autistic focuses on socially irrelevant stimuli ● where autistic individuals focus leads to how they perceive the world ● Pelphrey et al. ○ measured superior temporal sulcus (STS) in autistic and non autistic while subjects watched character’s eyes ■ STS is sensitive to how gaze is directed in social situations ○ pressed button when character’s eyes moved toward checkerboard (congruent condition) or away from checkerboard (incongruent condition) ○ Results: ■ both groups detected eye movement 99% of time ■ STS of non autistic activated more in incongruent condition ■ STS of autistic activated same for incongruent and congruent conditions ○ Suggests ■ autistic individuals have problems identifying intentions ● high STS activity in non autistic because eye movement towards checkerboard was expected Chapter 7 Terms: ● Gradient of Flow: difference in flow in relation to distance from observer ● Focus of Expansion: point in distance where there is no flow ● SelfProduced Information: flow is created by the movement of the observer ● Invariant Information: properties that remain constant while the observer is moving ● Optic Flow Neurons: neurons in the medial superior temporal area (MST) that respond to flow patterns ● Optic Ataxia: inaccurate reaching movements towards a target or object in space ● Action Based Perception: purpose of perception is to create a representation of what we are looking at Perception Reconsidered ● J.J. Gibson’s Ecological Approach ○ most perception studies are too artificial ■ ex; labs, artificial stimuli, restricted responses ○ perception is not a stationary experience ○ perception should be studied as it occurs naturally ○ Optic Flow: appearance of objects as the observer moves past them ■ helps keep your balance ■ Gradient of Flow: difference in flow in relation to distance from observer ■ Focus of Expansion: point in distance where there is no flow ● fixed; destination point ■ SelfProduced Information: flow is created by the movement of the observer ● skilled actions partly arise from establishing a coordination between sensory and motor systems ○ ex: somersaulting ● Bardy & Laurent ○ expert gymnasts performed worse with eyes closed ○ use vision to correct trajectory ○ no effect on novice gymnasts ■ Invariant Information: properties that remain constant while the observer is moving ● ex; color of sky, gradient information, information you pick up without trying to process ● Senses do not Work in Isolation ● Lee and Aronson ○ 1316 mo old children placed in swinging room ■ floor stationary but walls and ceiling swung backward and forward ■ movement creates optic flow patterns ○ children swayed back and forth in response to flow patterns ○ adults show same response ○ Results: ■ vision has powerful effect on balance, overrides other senses Navigating Through the Environment ● Optic Flow Neurons: neurons in the medial superior temporal area (MST) that respond to flow patterns ● Britten & Van Wezel ○ monkeys trained to respond to flow of dots on a computer screen ■ indicated direction of flow ○ stimulated MST neurons ■ judgment shifted to direction of stimulated neuron ● Land and Lee ○ car fitted with instruments to measure ■ angle of steering wheel, speed, and direction of driver's’ gaze ○ Results: ■ when driving straight, driver looks straight but not at focus of expansion ■ when driving around a curve, looks at point at side of the road ○ Suggests that drivers use other information in addition to optic flow to determine where their headed ■ noting the position of car in relation to center line/side of road ● Walking ○ Visual Direction Strategy: observers keep their body pointed toward a target ■ walkers correct when target drifts to left or right ○ Blind Walking Experiments ■ people can navigate without any visual stimulation ● Wayfinding ○ landmarks involved taking routes the involves making turns ○ landmarks are object on the route that serve as cues to indicate where to turn ■ depends on how important landmark is ○ Janzen & Van Turennout ■ studied film that moved through a virtual museum tour ■ told they should be able to be a guide ■ exhibits appeared both at decision points and nondecision points ■ given recognition task in a fMRI ■ Results: ● showed greater activation for objects at decision points in parahippocampal gyrus ○ Brain Damage ■ retrosplenial cortex damage ■ Maguire et al. ● virtual tour of town, put in PET scanner, asked to navigate ● Results: ○ navigating activated hippocampus and parietal cortex ■ greater activation when navigation was accurate ● Suggests ○ hippocampus and parietal lobe form “navigation network” ■ Patient T.T. ● damage in parahippocampal gyrus, retrosplenial cortex, hippocampus Affordances ● class of ecological properties that concern the goals and utilities ○ ex; edible, obstacle, weapon, shelter, dangerous, potential mate ● perception involves processes that relate the environment to the perceivers potential for action ● same environment looks different depending on perceivers abilities and intentions ○ subjective ● Physiology of Reaching and Grasping ○ neurons in parietal lobe fired when the monkeys reached to press a button to receive food ■ only happened when reaching to achieve a goal ○ Links Between Sensory and Motor Functions ■ Optic Ataxia ● damage to parietal lobe ● inaccurate reaching movements towards a target or object in space ● Schindler et al. ○ visual or reaching problem? ○ 2 tasks ■ Bisection Task: point to position between cylinders ■ Reaching Task: reach between and touch grey strip ○ Results: ■ Bisection: damage and control equally accurate ■ Reaching: damaged kept reaching in same place even though cylinders were shifted ○ Suggests ■ parietal lobe provides guidance for movement ■ mechanism operate unconsciously ■ movement different from perception ■ Mirror Neurons ● respond to particular kind of action and observing someone doing the action ● Functions: ○ understand another’s actions and react appropriately ○ imitate the observed action ○ help link sensory perceptions and motor actions ○ predicting people’s intentions ● Audiovisual Mirror Neurons: respond to action and the accompanying sound ● What are they for? ○ Learning by Imitation ■ language development ■ skill learning ○ Social Interaction ■ empathy ■ connecting with others ● autism may be related to deficiency in mirror neurons Action Based Accounts of Perception ● Traditional Approach: focused on how the environment is represented in the nervous system ● Action Based Perception: purpose of perception is to create a representation of what we are looking at ○ perceive environment in terms of ability to act on it ● Embodied Perception ○ body movements and interaction with the environment shape perception of world ■ perception is body reacting ■ reaction is to bodily cues not visual stimuli ● bodily state, emotional state ○ Proffit ■ judge slant of hill ● haptic, verbal, visual ■ Results ● Before Fatigue ○ Haptic: best estimation ○ Verbal and Visual: overestimated ● After Fatigue ○ Haptic: little increase ○ Verbal and Visual: increase significantly ○ Strack et al. ■ smiling pen study ■ conditions ● in hand, in lips, in teeth (smiling) ■ rate funniness of cartoon ■ Results: ● lips: lowest ● teeth: highest Chapter 8 Terms: ● Attentional Capture: motion attracts attention ● Akinetopsia: blindness to motion ● Apparent Motion: perception of motion when there is none ● Apparent Movement: stationary stimuli presented in slightly different locations ● Real Motion: an object physically moving ● Induced Motion: movement of one object results in the perception of movement in another object ● Optic Array: structure created by surfaces, textures, and contours (enviro) ● Local Disturbance in Optic Array: something moving in environment ● Global Optic Flow: movement caused by observer ● Reichardt Detectors: neurons that fire to movement in one direction ● Corollary Discharge Theory: movement perception depends on three signals Functions of Movement Perception ● Survival in Environment ○ Attentional Capture: motion attracts attention ■ freezing in place eliminates attention attracting effects ○ Akinetopsia: blindness to motion ■ bilateral damage to V5 (MT) ● Perceiving Objects and Events ○ movement of objects or movement of observer through objects assists in organization of stimuli ○ Apparent Motion: perception of motion when there is none Studying Motion Perception ● Real Motion: an object physically moving ● Illusory Motion ○ Apparent Movement: stationary stimuli presented in slightly different locations ■ basis of movement in movies/TV ● Induced Motion: movement of one object results in the perception of movement in another object ● Motion Aftereffect ○ observer looks at movement of object for 3060s ○ look at stationary object, movement appears to occur in opposite direction ● Comparison of Real and Apparent Motion ○ Larsen et al. ■ scanned by fMRI while viewing ● Control: two dots in different position flashed simultaneously ● Real Motion: a small dot is moved back and forth ● Apparent Motion: dots are flashed so they appear to move ■ Results: ● Control: each dot activated a separate area of visual cortex ● Apparent and Real: activation of visual cortex from both sets of stimuli was similar ■ Suggests ● perception of motion in both cases is related to same brain mechanism ● motion is constructed not perceived ● What we Want to Explain ○ an object moves, and the observer is stationary ■ movement creates an image that moves on the retina ○ an object moves, and observer follows object with eyes ■ movement is tracked so that the image is stationary on retina ○ an observer moves through a stationary environment ■ image of environment moves across retina but environment is stationary ● Information in the Environment ○ Ecological Approach ■ information is directly available in the environment for perception ■ Optic Array: structure created by surfaces, textures, and contours (enviro) ● changes as move through the environment ■ Local Disturbance in Optic Array: something moving in environment ■ Global Optic Flow: movement caused by observer ● indicates observer is moving and not environment ● changes perceived are because of observer not enviroment ● Retina/Eye Information ○ Reichardt Detectors: neurons that fire to movement in one direction ○ Corollary Discharge Theory: movement perception depends on three signals ■ Image Displacement Signal (IDS): movement of image stimulating receptors across the retina ■ Motor Signal (MS): signal sent to eyes to move eye muscles ● ex; tracking ■ Corollary Discharge Signal (CDS): split from the motor signal, gets signal from brain to move eye ■ Comparator: relays information back to the brain that the eye is moving ○ Behavioral Evidence for Corollary Discharge Theory ■ Afterimage ● stare at stimulus for 60s then move to dark room, image of stimulus remains on retina ● no IDS, only the CDS reaches the comparator so the afterimage moves ■ Pushing on Eyeball ● movement is seen while lightly pushing on eyelid and focusing on one point ● eye muscles push back against finger to keep eye in place ● MS to keep eye in place created CDS which reached comparator and the scene moves ○ Physiological Evidence for Corollary Discharge Theory ■ Vertigo (Patient R.W.) ● IDS with eye movement but no CDS, so illusion of movement when there is no movement ■ RealMotion Neuron ● responds only when stimulus moves, not when eye moves
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