1 Sensation and Perception a Sensation the Conversion of the stimulus e g photons to neural impulses i Sensation is how we take in information about the world b Perception interpreting information and making sense of it c Three different steps in the process i Stimulus Energy e g a light Photon impacts sense receptors ii Sense Organ e g eye transduces the stimulus energy into an electrical code iii This code is sent to the cerebral cortex resulting in a psychological experience e g seeing something 1 Perceptions are created by our brains 9not always accurate d Psychophysics Fechner way of measuring strength of stimulus and the observer s sensitivity to it i Absolute Threshold the minimal intensity needed to just barely detect a stimulus ii Just Noticeable difference JND minimal change in a stimulus that can just barely be detected 1 Weber s law JND is a constant proportion iii Signal Detection theory response to a stimulus depends on two things 1 Sensitivity to the stimulus despite noise 2 Your decision of whether you detected the stimulus 2 Attention a Attention selecting which information to ignore and which to process further i Attention is a limited resource ii We can only attend closely to a tiny fraction of it b Change Blindness the failure to detect large changes in a visual scene i We do not process most sensory information deeply c Cocktail Party Phenomenon People can tune out other info as they focus in on one thing i Ex you hear what you interaction partner says but not what other people are saying ii Does this mean that all other info is not processed at all 1 No we unconsciously process peripheral info to a degree 2 Ex we frequently hear when somebody else says our name 3 Vision a Distal and Proximal stimuli i Distal Stimulus External Object e g a leaf ii Proximal stimulus the stimulus energy that is transduced by the eye 1 Image projected on the retina b Color Vision i Rod Cones Two types of receptor cells in the retina 1 Rods 120 Million a Low light night Vision b Black and White c Periphery 2 Cones 6 million a Brighter light b Color vision c Near fovea centralized 3 Color vs motion detection a Pen in peripheral vision c After images i Some colors seem to be oposites 1 Red green 2 Blue yellow 3 Black and white ii When inundated with one colore e g green you adapt and those neurons stop firing as intensely 1 Leads to an imbalance e g too much red firing relative to green firing 2 When Shown a neutral color thereafter you see the opposite color d Simultaneous contrast i Our perception of color and darkness changes depending upon the surrounding colors e Perceiving Depth i Binocular disparity a depth cue using both eyes ii Monocular depth cues 1 Texture Gradient Distant Objects are denser less detailed 2 Linear Perspective Parallel lines appear to converge in the distance 3 Relative size Distant objects are smaller a If we lack sufficient depth cues our visual system can be fooled 4 Ames room example a Video Clips b Depth Cues are wrong i The people appear to be equally far away but they are not f Context effects when our expectations influence what we perceive i The visual system settles on one or the other iinterpretation 4 Audition i Outer Ear collects soundwaves ii Midle ear transmites vibrations to inner ear iii Inner ear vibrations transduced into neural impulses 5 Touch a Four different types of receptors under the skin enable us to sense pressure pattern texture Vibration b Thermoreceptors 6 Smell a Olfactory receptor neurons ORNs receptor cells that initiate the sense of smell i Axons go into the olfactory bulb in the brain ii Olfactory bulb sends outputs into many centers in the brain b Smell and taste combine to produce our experience of flavor c 5 taste sensations i salt ii sour iii bitter iv sweet v umami 7 7BdXb8bS