Theories & Concepts
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Theories & Concepts Selective Attention Theory x x x x x
Cocktail party phenomenon: Ability to focus on a single conversation in the midst of a chaotic cocktail party. Attention selection is not an all or none process that eliminates unattended stimuli Filter theory: A Theory that people have a limited capacity for sensory information and thus a screen of incoming information, letting in only the most important. Early selection theory: A Theory that we can choose the stimuli to which we attend before we process their basic features. Late selection theory: A theory that people take in the sensory information, process it, and then select which aspects of the stimuli should be attended after processing.
Automatic Recognition Theory x x x
Different visual features of objects are analyzed by different systems Time it takes to find target increases linearly with the number of distractions (more distractions = more time to analyze) Attention helps integrate features so that we can correctly perceive objects faster
Gate-Control Theory x x x
In order for us to experience pain, pain receptors must be activated an v µo^P _]v the spinal cord must allow these signals through to the brain. d}o} Z]^P _Ç}µv]uµo }Z Z] }Z}À ÁZ ou ]Pvo from the pain receptor (ex. Rubbing leg when bruised, causing it to not be as painful One region of the midbrain influences this gate, and endorphins are believed to act on this region to block pain.
Signal-Detection Theory x x x
Detecting a stimulus requires making a judgment about its presence or absence based on a subjective interpretation of ambiguous information. People sometimes believed they saw a weak stimulus when there was none, and sometimes failed to detect a stimulus that was presented. False alarm t Ç]vPZ Á]PvoÁZ vZ Áv[UZ]t correctly detecting signal, miss t failing to detect signal that was present, correct rejection t saying that there was no ]PvoÁZ vZ µooÇÁv[X
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What Versus Where Concept x x
Ventral Stream: Specialized for object perception so it tells you WHAT an object is Dorsal Stream: Specializes in spatial perception so it tells you WHERE an object is Job of taste/gestation t to keep poison out and to let food in Stimuli for taste are chemical substances in food. Taste receptors are part of taste buds that are on the toungue/mouth. Microvilli come into contact w/ saliva and send electrical signals to brainstem region called medulla and from there to thalamus and cortex, producing sensation of taste. Sense of smell/olfaction involves sensing chemicals from outside body. Odorous particles pass into nose and upper and back portions of nasal cavity. They come into contact w/ the olfactory epithelium, a layer of tissue embedded w/ smell receptors. The particles dissolve in solution surrounding the epithelium and cause reaction that triggers chemical receptors. These nerve impulses convey information to olfactory bulb just below frontal lobes. Smell bypasses thalamus. Olfactory stimuli can evoke powerful emotions & memories. Pheromones are chemicals released by animals that trigger physiological or behavioural reactions in others. Haptic/touch sense t conveys sensations of pain, temp. and pressure. Anything that makes contact w/ skin provides tactile stimulation. Haptic receptors terminate outer layer of skin. Their lonhg axons enter the central nervous system by way of spinal or cranial nerves. Some of the receptors t nerve fibres at the base of hair follicles that respond to hair movement. Others tcapsules in skin that respond to vibration, sudden movements and steady pressure. Pain is part of a warning system that stops you from continuing activities that may harm you. Two kinds of nerve fibers have been identified for pain: fast fibers for sharp, immediate pain, and slow fibers for chronic pain. Distinction b/w two fibers is the myelination of their axons that travel from pain receptors to spinal cord. Gate control theory t Á Æ ] v ]vl^v µoP _Zoo}Á]v]Pvo}P} through spinal cord to brain. To close this gate, we must activate other haptic receptors. Stimulus for hearing is displacement of air molecules caused by changes in air pressure. Pattern of changes = sound wave. Amplitude t loudness, frequency t pitch, sound is measured in hertz (vibrations/second) we can detect sound waves with freuquencies of 20hz to 20000 hz. Sound waves arrive at outer ear and travel down the auditory canal to eardrum which marks the beginning of the middle ear. Changes in AP make eardrum vibrate vibrations are transferred to 3 bones called ossicles (hammer, anvil, stirrup). Ossicles transfer vibrations of eardrum to oval window, a membrane of the cochlea. The cochlead (inner ear) is a fluid filled tube that curls into a snail like shape. The ossicles amplify the vibrations so that they can reach
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the oval window from the eardrum. Vibrations of oval window create pressure in fluid of inner ear and these waves stimulate hair cells - primary auditory receptors. In vision, the eye detects light waves: receptors (rods and cones) in the retina detect different forms of light waves. The lens helps the eye focus the stimulation on the retina for near versus far objects.. color is determined by wavelengths of light activating certain types of cones, by the absorption of wavelengths by objects or the mixing of wavelengths of light. Perception occurs in the brain: primary auditory cortex handles hearing. Touch is handled by primary somatosensory cortex. Vision results primarily in the occipital lobe. Object perception requires construction: by using the gestalt principles of stimulus organization, we are able to perceive our world. We use cues about similarity, proximity, form, figure, and background properties and shading. Perception involves the dual processes: bottom up (sensory information) and top down (brain organization) Fusiform gyrus t specialized in perceiving faces. Prosoagnosia t inability to recognize faces. Binocular depth cues t cues of depth that arise from the fact that we have 2 eyes Monocular depth cue t cues of depth perception available to each eye alone. Binocular disparity t µ }( Z ]}vZ]µ Ç]v lÁ }v[ Ç X Ventral stream t specialized for object perception and recognition Dorsal stream t specialized for spatial perception ^ÁZ_v^ÁZ _ZÁÇs Object agnosia t inability to recognize objects Principle of proximity t the closer 2 figures are to each other, the more likely we are to group them together Good continuation t the tendency to interpret intersecting lines as being continuous rather than changing direction radically. Closure t tendency to complete figures that have gaps. Geon theory t objects can be represented as an assemblage of primitive parts called geons. Monocular depth perception: Occlusion t v }i }oµ ~o}l}i Z[(µZ ÁÇ Relative size t far off objects project similar retinal image than close objects Familiar size t we know how large familiar objects are so we can tell how far away they are Linear perspective t parallel lines appear to converge in the distance. Texture gradient: as surface recedes, texture becomes denser.
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Position relative to horizon t objects below horizon that appear higher in the visual field are perceived as being further away. Objects above horizon that appear lower in visual field are perceived as being further away. Akinsetopia t inability to perceive motion Induced movement illusion t looking up at the sky and it looks like the u}}v]u}À]vPµ]]v[ Stroboscopic movement t 2 or more slightly different images are presented in rapid succession Unconscious inferences: the brain is actively connected the dots provided to it by sensation bia automatic and unconscious gestalt grouping procedures and prior assumptions that it has learned or inherited. Direct perception: the visual system is not built to enable us to see an exact copy of the real world; it is built to interpret cues that maximize its function. Stimuli already have info for us to perceive them t Á }v[]]}vou u}Çloµo]}v}µv vZ X
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Theories & Concepts Selective Attention Theory x x x x x
Cocktail party phenomenon: Ability to focus on a single conversation in the midst of a chaotic cocktail party. Attention selection is not an all or none process that eliminates unattended stimuli Filter theory: A Theory that people have a limited capacity for sensory information and thus a screen of incoming information, letting in only the most important. Early selection theory: A Theory that we can choose the stimuli to which we attend before we process their basic features. Late selection theory: A theory that people take in the sensory information, process it, and then select which aspects of the stimuli should be attended after processing.
Automatic Recognition Theory x x x
Different visual features of objects are analyzed by different systems Time it takes to find target increases linearly with the number of distractions (more distractions = more time to analyze) Attention helps integrate features so that we can correctly perceive objects faster
Gate-Control Theory x x x
In order for us to experience pain, pain receptors must be activated an v µo^P _]v the spinal cord must allow these signals through to the brain. d}o} Z]^P _Ç}µv]uµo }Z Z] }Z}À ÁZ ou ]Pvo from the pain receptor (ex. Rubbing leg when bruised, causing it to not be as painful One region of the midbrain influences this gate, and endorphins are believed to act on this region to block pain.
Signal-Detection Theory x x x
Detecting a stimulus requires making a judgment about its presence or absence based on a subjective interpretation of ambiguous information. People sometimes believed they saw a weak stimulus when there was none, and sometimes failed to detect a stimulus that was presented. False alarm t Ç]vPZ Á]PvoÁZ vZ Áv[UZ]t correctly detecting signal, miss t failing to detect signal that was present, correct rejection t saying that there was no ]PvoÁZ vZ µooÇÁv[X
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What Versus Where Concept x x
Ventral Stream: Specialized for object perception so it tells you WHAT an object is Dorsal Stream: Specializes in spatial perception so it tells you WHERE an object is Job of taste/gestation t to keep poison out and to let food in Stimuli for taste are chemical substances in food. Taste receptors are part of taste buds that are on the toungue/mouth. Microvilli come into contact w/ saliva and send electrical signals to brainstem region called medulla and from there to thalamus and cortex, producing sensation of taste. Sense of smell/olfaction involves sensing chemicals from outside body. Odorous particles pass into nose and upper and back portions of nasal cavity. They come into contact w/ the olfactory epithelium, a layer of tissue embedded w/ smell receptors. The particles dissolve in solution surrounding the epithelium and cause reaction that triggers chemical receptors. These nerve impulses convey information to olfactory bulb just below frontal lobes. Smell bypasses thalamus. Olfactory stimuli can evoke powerful emotions & memories. Pheromones are chemicals released by animals that trigger physiological or behavioural reactions in others. Haptic/touch sense t conveys sensations of pain, temp. and pressure. Anything that makes contact w/ skin provides tactile stimulation. Haptic receptors terminate outer layer of skin. Their lonhg axons enter the central nervous system by way of spinal or cranial nerves. Some of the receptors t nerve fibres at the base of hair follicles that respond to hair movement. Others tcapsules in skin that respond to vibration, sudden movements and steady pressure. Pain is part of a warning system that stops you from continuing activities that may harm you. Two kinds of nerve fibers have been identified for pain: fast fibers for sharp, immediate pain, and slow fibers for chronic pain. Distinction b/w two fibers is the myelination of their axons that travel from pain receptors to spinal cord. Gate control theory t Á Æ ] v ]vl^v µoP _Zoo}Á]v]Pvo}P} through spinal cord to brain. To close this gate, we must activate other haptic receptors. Stimulus for hearing is displacement of air molecules caused by changes in air pressure. Pattern of changes = sound wave. Amplitude t loudness, frequency t pitch, sound is measured in hertz (vibrations/second) we can detect sound waves with freuquencies of 20hz to 20000 hz. Sound waves arrive at outer ear and travel down the auditory canal to eardrum which marks the beginning of the middle ear. Changes in AP make eardrum vibrate vibrations are transferred to 3 bones called ossicles (hammer, anvil, stirrup). Ossicles transfer vibrations of eardrum to oval window, a membrane of the cochlea. The cochlead (inner ear) is a fluid filled tube that curls into a snail like shape. The ossicles amplify the vibrations so that they can reach
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the oval window from the eardrum. Vibrations of oval window create pressure in fluid of inner ear and these waves stimulate hair cells - primary auditory receptors. In vision, the eye detects light waves: receptors (rods and cones) in the retina detect different forms of light waves. The lens helps the eye focus the stimulation on the retina for near versus far objects.. color is determined by wavelengths of light activating certain types of cones, by the absorption of wavelengths by objects or the mixing of wavelengths of light. Perception occurs in the brain: primary auditory cortex handles hearing. Touch is handled by primary somatosensory cortex. Vision results primarily in the occipital lobe. Object perception requires construction: by using the gestalt principles of stimulus organization, we are able to perceive our world. We use cues about similarity, proximity, form, figure, and background properties and shading. Perception involves the dual processes: bottom up (sensory information) and top down (brain organization) Fusiform gyrus t specialized in perceiving faces. Prosoagnosia t inability to recognize faces. Binocular depth cues t cues of depth that arise from the fact that we have 2 eyes Monocular depth cue t cues of depth perception available to each eye alone. Binocular disparity t µ }( Z ]}vZ]µ Ç]v lÁ }v[ Ç X Ventral stream t specialized for object perception and recognition Dorsal stream t specialized for spatial perception ^ÁZ_v^ÁZ _ZÁÇs Object agnosia t inability to recognize objects Principle of proximity t the closer 2 figures are to each other, the more likely we are to group them together Good continuation t the tendency to interpret intersecting lines as being continuous rather than changing direction radically. Closure t tendency to complete figures that have gaps. Geon theory t objects can be represented as an assemblage of primitive parts called geons. Monocular depth perception: Occlusion t v }i }oµ ~o}l}i Z[(µZ ÁÇ Relative size t far off objects project similar retinal image than close objects Familiar size t we know how large familiar objects are so we can tell how far away they are Linear perspective t parallel lines appear to converge in the distance. Texture gradient: as surface recedes, texture becomes denser.
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Position relative to horizon t objects below horizon that appear higher in the visual field are perceived as being further away. Objects above horizon that appear lower in visual field are perceived as being further away. Akinsetopia t inability to perceive motion Induced movement illusion t looking up at the sky and it looks like the u}}v]u}À]vPµ]]v[ Stroboscopic movement t 2 or more slightly different images are presented in rapid succession Unconscious inferences: the brain is actively connected the dots provided to it by sensation bia automatic and unconscious gestalt grouping procedures and prior assumptions that it has learned or inherited. Direct perception: the visual system is not built to enable us to see an exact copy of the real world; it is built to interpret cues that maximize its function. Stimuli already have info for us to perceive them t Á }v[]]}vou u}Çloµo]}v}µv vZ X
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