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Unformatted text preview: 1) Sensation VS Perception a) Measuring Sensation i) Theories of sensation measurement (1) Absolute Threshold – Smallest intensity that can be detected (2) Difference Threshold (TV volume example) (a) Just-Noticeable Difference (JND): the point at which a person is able to determine the difference between 2 stimuli (3) Signal-Detection Theory: A theory explaining why people detect signals in some situations but miss them in others. (a) Hits: When a stimulus is correctly detected (b) Misses: when a stimulus is not detected (c) Correct Rejection: correct rejection of a stimulus that has not been presented. (d) False Harm: when stimulus is said to have been presented but it was not. b) Organizing our sensory imputs i) Stages of processing (1) Bottom Up Processing: organizing perceptions by beginning with low level features (2) Top Down Processing: interpreting objects and events based on our knowledge, beliefs, and experiences. c) Vision (Source: Light) i) Visual Pathway (1) Light enters cornea (2) It passes thru the pupil: an opening which is controlled by iris (3) It enter the lens: focus is fine-tuned (4) It reaches the retina (a) Photoreceptors: Transduction begins (i) Rods – detect light (ii) Cones – detect color – (helps w/visual accuitity/sharpness) (b) Bipolar and ganglion cells: send neural impulse via the optic nerve to thalamus then visual cortex. (5) Visual Cortex (a) Feature detectors; (i) Simple Cells: small receptive fields that detect lines in a particular location (/or\) (ii) Complex Cells: large receptive fields detect lines and movement in a particular location(/ moving ↓ or \ moving ↑) 1. receiving input from combinations of simple cells (iii) Hyper complex cells: detect combinations of lines angles corners, and movement (/ moving ->) ii) Theories of processing color (1) Trichromatic Theory (a) 3 wavelengths: 3 groups of cones (the absorption amount produces the group of cones’ sensitivity to a short, medium, or long wavelength of light) (i) Violet/blue - short (ii) Green - medium (iii) Orange - long (b) Weaknesses: could not explain (i) After images (ii) Seem to be 4 primary colors not 3 (iii) Partial color blindness (2) Inability to perceive color differences (a) Genetic factor (i) Lacking short, medium, or long wavelength cones (ii) Some lack two types of cones (iii) Some have low number of all three (b) Inability to distinguish red from green is most common deficiency (i) Recessive x chromosome (ii) 8% in men and 1% in women (3) Opponent process theory (Ewald Hering) (a) Brain sees color on a continuum from red to green and another from yellow to blue (b) Perceive color in “paired opposites” red-green, black-white, and yellow-blue....
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- Spring '07
- Classical Conditioning, neutral stimulus, Stimulus Positive Positive, Stimulus Negative Negative