Sensation vs. PerceptionSensation- Basic processes by which sensory receptors and the nervous system: Receive and represent stimulus energies from environment, and entails basic psychological experiences.Bottom-Up Processing- Sensory detection and encoding; construction of whole from parts.This includes Lines, shapes, angels, colors, items/events that grab our attentionPerception- Interpretation and integration“Top Down” processing- conceptually driven organization & interpretation of infoExperiencesExpectationsAbsolute vs. Difference ThresholdsAbsolute threshold- Minimum stimulation needed to detect a particular stimulus 50% of the time1. Smallest detectable level of a stimulusDifference Thresholds- Minimum difference between two stimuli required for detection 50% of the time2. The measure of how different two stimuli have to be in order for the subject to notice that they are not the same.II. Signal-to-noise Ratio & Signal detection TheoryA. Signal detection theory- Predicts how and when we detect presence of a faint stimulus (signal) among background noise.B. Signal-to-noise ratio- It becomes harder to detect a signal as background noise increases. This depends on…1. Experience2. Expectations3. Motivation4. Level of fatigueIII. Sensory AdaptationA. Activation is greatest when a stimulus is first detectedB. Sensitivity diminishes as a consequence of constant stimulation1. (my socks are on, my socks are on…)IV. Sensory interactionsThe principle that one sensory system may affect another (cross-modal processing)1. Ex. Smell of food influences taste2. When Visual information influences auditory perception (McGurk effect)B. McGurk effect- Demonstrates that we integrate visual and auditory information when processing spoken language, and our brains automatically calculate the most probable sound given the info from the two sources.1. Saying “ba” seeing “ga”V. Parallel ProcessingA. Parallel Processing- The ability to attend to many sense modalities simultaneously1. Bottom-up processing- Construct a whole stimulus from its partsa) Perceptual Constancy2. Top-Down processing- Starts with beliefs and expectations, which we then impose on the raw stimuli we perceivea) Perceptual setB. Comes into play with ink blotsVI. Blindsight and Visual SystemA. Inattentional Blindness- Failure to detect stimuli that are in plain sight when our attention is focused elsewhereB. Selective attention- Process of selecting one sensory channel and ignoring or minimizing othersVII. Subliminal stimuliA. There is compelling evidence both ways that subliminal stimuli may have some influence, and the oppositeVIII. How we pinpoint soundsA. Place theory- Specific place along the basilar membrane matches a tone with a specific pitchB. Frequency theory- rate at which neurons fire the action potential reproduces the pitchC. We rely most on binaural cues to detect the source of soundsIX. PainA. Gate control model- Idea that pain is blocked or gated from consciousness by neural mechanisms in spinal cordB. Phantom pain- pain or discomfort in the missing limbC. Benefit of pain- protects our bodiesD. Things that may affect someone’s perception of pain:1. Culture2. Mind over matterX. Perceptual SetA. Perceptual set- set formed when expectations influence perceptionsB. We may expect to see either a woman or old lady, then see itXI. Perceptual constanciesA. Perceptual constancies- the process by which we perceive stimuli consistently across varied conditionsB. Without this, we’d be constantly confused, because we’d be seeing our worlds as continually changing.C. Brain allows us to fix minor changesD. Several types include: shape constancy, size constancy, color constancy, etc.XII. GestaltA. Gestalt principles- Rules governing how we perceive objects as wholes within their overall context. They help explain why we se much of our world as consisting of unified figures rather than lines and curves.XIII. Perception of motionA. The brain judges how things in our world are constantly changing by comparing visual frames, like those in a movie.B. Phi phenomenon- illusory perception of movement produced by the successive flashing of imagesXIV. IllusionsA. Illusions help us understand why we perceive the world the way we do.Chapter 4- Sensation and Perception Sensation vs. Perception Sensation- Basic processes by which sensory receptors and the nervous system: Receive and represent stimulus energies from environment, and entails basic psychological experiences. Bottom-Up Processing- Sensory detection and encoding; construction of whole from parts. This includes Lines, shapes, angels, colors, items/events that grab our attention Perception- Interpretation and integration “Top Down” processing- conceptually driven organization & interpretation of info Experiences Expectations Absolute vs. Difference Thresholds Absolute threshold- Minimum stimulation needed to detect a particular stimulus 50% of the time1. Smallest detectable level of a stimulus Difference Thresholds- Minimum difference between two stimuli required for detection 50% of the time2. The measure of how different two stimuli have to be in order forthe subject to notice that they are not the same.II. Signal-to-noise Ratio & Signal detection TheoryA. Signal detection theory- Predicts how and when we detect presence of a faint stimulus (signal) among background noise.B. Signal-to-noise ratio- It becomes harder to detect a signal as background noise increases. This depends on…1. Experience2. Expectations3. Motivation4. Level of fatigueIII. Sensory AdaptationA. Activation is greatest when a stimulus is first detectedB. Sensitivity diminishes as a consequence of constant stimulation1. (my socks are on, my socks are on…)IV. Sensory interactionsThe principle that one sensory system may affect another (cross-modal processing)1. Ex. Smell of food influences taste2. When Visual information influences auditory perception (McGurk effect)B. McGurk effect- Demonstrates that we integrate visual and auditory information when processing spoken language, and our brains automatically calculate the most probable sound given the info from the two sources.1. Saying “ba” seeing “ga”V. Parallel ProcessingA. Parallel Processing- The ability to attend to many sense modalitiessimultaneously1. Bottom-up processing- Construct a whole stimulus from its partsa) Perceptual Constancy2. Top-Down processing- Starts with beliefs and
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