1. Sensation and Perceptiona. Sensation: the Conversion of the stimulus (e.g., photons) to neural impulsesi. Sensation is how we take in information about the worldb. Perception: interpreting information and making sense of itc. Three different steps in the processi. Stimulus Energy (e.g., a light Photon) impacts sense receptorsii. Sense Organ (e.g., eye transduces the stimulus energy into an electrical codeiii. This code is sent to the cerebral cortex, resulting in a psychologicalexperience (e.g., seeing something)1. Perceptions are created by our brains 9not always accurate)d. Psychophysics (Fechner) way of measuring strength of stimulus and theobserver’s sensitivity to iti. Absolute Threshold = the minimal intensity needed to just barely detect a stimulusii. Just Noticeable difference (JND) = minimal change in a stimulus that can just barely be detected1. Weber’s law  JND is a constant proportioniii. 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 stimulus2. Attentiona. Attention: selecting which information to ignore and which to process furtheri. Attention is a limited resourceii. We can only attend closely to a tiny fraction of itb. Change Blindness: the failure to detect large changes in a visual scene i. We do not process most sensory information deeplyc. Cocktail Party Phenomenon: People can tune out other info as they focusin on one thingi. Ex: you hear what you interaction partner says, but not what other people are sayingii. Does this mean that all other info is not processed at all?1. No, we unconsciously process peripheral info to a degree2. Ex: we frequently hear when somebody else says our name3. Visiona. Distal and Proximal stimulii. Distal Stimulus: External Object (e.g., a leaf)ii. Proximal stimulus: the stimulus energy that is transduced by the eye1. Image projected on the retina b. Color Vision:i. Rod & Cones: Two types of receptor cells in the retina1. Rods = 120 Milliona. Low light (night Vision)b. Black and Whitec. Periphery2. Cones = 6 milliona. Brighter lightb. Color visionc. Near fovea (centralized)3. Color vs. motion detectiona. Pen in peripheral visionc. After imagesi. Some colors seem to be oposites1. Red-green2. Blue-yellow3. Black and whiteii. When inundated with one colore (e.g., green), you adapt and those neurons stop firing as intensely1. 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 colord. Simultaneous contrasti. Our perception of color and darkness changes depending upon the surrounding colorse. Perceiving Depthi. Binocular disparity: a depth cue using both eyesii. Monocular depth cues1. Texture Gradient: Distant Objects are denser, less detailed2. Linear Perspective: Parallel lines appear to converge in the distance3. Relative size: Distant objects are smallera. If we lack sufficient depth cues, our visual system can be fooled4. Ames room examplea. Video Clipsb. Depth Cues are wrongi. The people appear to be equally far away, but they are notf. Context effects: when our expectations influence what we perceivei. The visual system “settles” on one or the other iinterpretation.4. Audition:i. Outer Ear- collects soundwavesii. Midle ear- transmites vibrations to inner eariii. Inner ear- vibrations transduced into neural impulses5. Toucha. Four different types of receptors under the skin enable us to sense pressure, pattern, texture & Vibrationb. Thermoreceptors6. Smella. Olfactory receptor neurons (ORNs) - receptor cells that initiate the senseof smelli. Axons go into the olfactory bulb in the brainii. Olfactory bulb sends outputs into many centers in the brainb. Smell and taste combine to produce our experience of flavorc. 5 taste sensationsi. saltii. souriii. bitteriv. sweetv. umami7.