Psych - Chapter 3 Sensation and Perception PDF

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Chapter 3 Sensation and Perception 1. Intro definitions a. Sensation (detect stimuli): process of receiving, converting, and transmitting raw sensory info from external and internal environments to brain. b. Perception (interpret stimuli): process of selecting, organizing and interpreting sensory info. 2. Understanding sensation: Thresholds a. Absolute Threshold: the smallest amount of stimulus that can be detected. (hearing/eye exams) b. Difference Threshold: minimal differences needed to detect stimulus change. (lip stick) c. Both thresholds apply to every sense. d. Thresholds vary by person, psychological state. (lack of food, drugs, environment, age) 3. Subliminal stimuli a. Stimuli just below level of conscious awareness b. Demonstrated in lab c. Not supported in persuasion, i.e. advertising 4. Habituation and Sensory Adaptation a. Habituation: Brain stops attending to constant, unchanging stimuli b. Sensory adaptation: Sensory receptors less responsive to constant stimuli 5. Sensory Adaptation (read more) a. All sensory systems allows attention to NOVEL stimuli; allows existence in wide range of stimuli b. Some senses adapt quickly (smell) others do not (pain, heat – DON’T want quick adaptation!) 6. Psychological Properties of Light a. Brightness: corresponds to amplitude of light waves (dim light, bright light) b. Color: corresponds to the length of light waves (reds, blues) 7. Light Traveling through the Eye a. Light enters eye through cornea b. From the cornea through pupil c. From pupil through lens d. Light falls on retina (area in back of the eye) e. Where photoreceptors (rods/cones) are stimulated. f. CouPLe Rhet and Tina Photos 8. Anatomy of the Eye a. Cornea: transparent bulge at front of the eye where light enters. b. Aqueous/Vitreous humor: clear fluid (behind cornea? Sclera) fills front chamber of eye, nourishes cornea. c. Pupil: opening surrounded by iris (color part of the eye): contains muscles that control the size of the pupil to regulate light entering the eye d. Lens: (behind iris) transparent elastic structure in the eye that focuses light on retina by changing shape i. Lens flatten to focus on far object ii. Lens bulge to focus on nearby objects e. Retina: area at back of eye – contains light receptors, rods and cones f. Fovea (center of retina): only cones, sharpest vision

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g. Blind spot: part of retina with no receptors; were optic nerve exits eye (not aware blind spot, eyes constantly move) h. Rods: most sensitive in dim light but loss of acuity; do not respond to color; 120 million rods i. Cones: respond to color, fine detail; 6 million cones i. More toward center of retina where fovea contains only cones ii. Function better in light, see fine details and color j. Optic nerve: nerve that carries info from retina to brain Light and Dark Adaptation a. Light adaptation (from dark to light): visual adjustment of rods/cones that reduces sensitivity to bright light/ 7-10 minutes. i. Ex. From dark theatre to bright day. Eyes hurt from glare. Wait 7-10 minutes before driving. b. Dark adaptation (from light to dark): visual adjustment of rods/cones that increases sensitivity to see better in dim light. 20-20 min i. Ex. Going into dark movie c. Normal vision: the image is focused on the retina d. Nearsightedness (myopia): the image is focused in front of the retina e. Farsightedness (hyperopia): the image is focused behind the retina The hearing sense a. Audition: sense of hearing, prominent sense like vision b. Sound: movement of air molecules in a particular wave pattern c. Sound waves vary in i. Pitch ii. Amplitude Psychological Properties of Sound a. Noise can affect, stress, learning, aggression…etc. 3 Sections of the Ear a. Outer ear: gathers and focuses sound waves b. Middle ear: transfer sound energy from air to liquid contained within the cochlea (located in inner ear) c. Inner ear: cochlea contains receptor cells that transduce sounds into neural impulses. Our Other sense a. Olfaction: receptors I olfactory epithelium b. 1,000+ receptors allow detection of 10,000 distinct smells. Smell and Taste – least critical sense (FDA) a. Smell and taste interact very closely b. Smell enhances taste c. Purpose to warn us about bad things d. The five basic tastes i. Bitter ii. Salty iii. Sweet iv. Sour v. Umami e. Taste buds are receptors for taste; located in papillae on surface of tongue Papillae a. Taste receptors

i. Also in roof/back of mouth ii. Chew slowly for max taste iii. Taste buds replaced 7 days in young kids iv. Older: more replacement time, decrease in taste v. Strong/unusual tastes too much for kids vi. Most food preferences are learned 16. Somesthetic Senses a. Skin sense (largest and heaviest organ): pressure, pain, temperature; protects internal organs. b. Vestibular sense: balance, body orientation to gravity and 3D space; allows walk, sit, bike,…movement WITH c. Kinesthesia sense: body posture/movement; receptors throughout muscles.

Perception 1. Perception: process of selecting, organizing and interpreting sensory information into useful mental representations. 2. Selection factor of perception a. Selection attention is first step. 3 factors: i. Physiological factors 1. Feature detectors: specialized brain cells – respond only to certain sensory interaction with environment b. 3. Organization a. perceptual constancy i. Size constancy ii. Shape iii. Brightness b. Figure ground c. Proximity: tendency to perceive objects that are close to one another as part of the same grouping d. Similarity: tendency to perceive things that look similar as being part of the same group; wearing uniforms. e. Closure: tendency to complete figures that are incomplete f. Continuity: tendency to perceive things as simply as possible with continuous pattern… g. Contiguity: tendency to perceive two things that happen close together in time as being related. Usually the first occurring event is seen as causing the second event. 4. Interpretation Factor of Perception a. Four major factors: i. Perceptual adaptation: brain adapt to changed environments (flashing lights at dance; get used to them) ii. Perceptual set (expectations): readiness to perceive in certain manner based on prior experiences (gossip) iii. Frame of reference (context): interpretation on context of situation (attractiveness influenced by who is next to us)

iv. Bottom-up or top-down processing: begins with raw sensory data (bottom-up) or with thoughts, expectations, and knowledge (top-down; faster); affects speed of processing....