14Difference Threshold (Just Noticeable Difference) the smallest possible change in a stimulus that can be detected half the time.True OR false? ……. Our sensory experiences depend more on changes than the absolute size of the stimulus.
15Difference Threshold (Just Noticeable Difference) TrueSensory experiences depend more on changes than the absolute size of the stimulus.
16Difference Threshold (Just Noticeable Difference) Example – What do you notice more?3# brick into an empty backpack?OR3# brick into a 100# backpack ?
17Weber’s lawThe larger or stronger a stimulus, the larger the amount of change required for an observer to notice a difference.Doubling sweetness takes 3x the sugar2x the light < doubly bright
18Sensory Adaptation-Our sensory receptor cells become less responsive to a constant stimulus.-This allows us to quickly notice new or changing stimuli.
19Sensory Adaptation Give me an example: Movie theater lighting pressure of your clotheshot / cold (esp. water)Odors in a labStreet noise (background)
21Signal Detection Theory Studies the relationship between:Motivation, Sensitivity &, Decision MakingDifferent thresholds depending on the circumstances (importance of the detection matters)Radar operator “looking” for a blipExpecting to see someone at a party
42Vestibular Mechanical / gravitational forces operate on inner ear Controlled by: cerebellum & parietal lobeRegulates the body’s sense of balance by sending messages from semicircular canal fluid to brain.
61Perceptual inferencePerception based on sensory input and past experience.Mostly automatic & unconsciousFill in the gaps of what you sense!
62Perceptual inference Auditory – hear a bark & assume it’s your dog Visual –driving over a hill, you ASSUME the road continues
63We learn to perceive Learned – babies learn to recognize faces Interaction with our environment is necessary for the development of perception. (Kitten example)Influenced by-needs-beliefs-expectationsCan’t just RIDE in the car…….you must DRIVE!
64We learn to perceive Perceptual Set- You tend to believe/see what you expectheuristics lead topre-judging (mis-judging)racism
85Convergence Eyes turn inward to look at an object. As the eyes turn inward, the muscles of the eyes send messages to the brain telling it the object is near.
86Retinal Disparity / Binocular Fusion The two eyes see different images, the brain recognizes this, and then calculates distance.The two images are “fused” into one, creating one large, coherent image in your brain.
87ConstancyThe tendency to perceive certain objects in the same even though light, angle, or distance may change.3TypesSize/distanceShape/angleBrightness/color
88Size constancy: all the same size but pilots know this better than you!
89Shape constancyPerceive the shape of a known object as remaining unchanged although we may perceive it from different angles(different images cast on our retina)
90Brightness constancyPerceive the brightness of an object as stable or unchanging regardless of a change in lighting.Objects in sunlight & shade
91IllusionsIllusions occur when we misperceive the true characteristics or properties of an object.
92IllusionsSpatial summation – A collection of individuals = a different whole
93Sunday Afternoon on the Island of Grand Jatte by Georges Seurat (1884-1886)
97Subliminal Perception subliminal means literally “below the threshold.”-1957 movie theater experiment-subsequent experiments do NOT support this!-There IS evidence that we can detect subliminal information-Word Recognition experiment-Explanation for déjà vu?
98Extra Sensory Perception Receiving info. From channels other than the “normal” senses-Clairvoyance: perception w/o sensory input-Telepathy: mind reading / thought transference-Psychokinesis: moving objects w/mind-Precognition: foretelling of events