Exam 2 Study Guide.pdf

9 Pages

Psychological & Brain Sciences
Course Code
CAS PS 101
Barry Grant

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Exam 2 Study Guide Saturday, October 27, 2012 6:32 PM Sensation and Perception Sensation: stimulation of the sense organs (one of the 5 sense) from physical stimuli Perception: selection, organization, and interpretation of sensory input (what we cometo know) Experienced at the same time but are two separate processes AbsoluteThreshold:the minimum amount of stimulus needed to perceive it (ie. Automatic headlights) Just Noticeable Difference(JND): smallest difference in stimulus intensity that a specific sense can detect Signal Detection Theory: in order to detect a signal, we need other factors that determine whether we perceive it: sensory informationand decision processes. The detection of stimuli involvesdetection and perception 4 responses: 1. A hit - correct about perceiving a stimulus 2. A false alarm - perceiving a stimulus that isn't there 3. A miss - not perceiving a stimulus that is present 4. Correct rejection - correctabout not perceiving a stimulus Subliminal perception: the registration of sensoryinput without conscious awareness, puts it below a threshold Sensory Adaption: a gradual decline in sensitivity to prolonged stimulation (ie. Getting into a pool of cold water and getting accustomedto the sense) Light • A form of electromagneticthat travels as a wave • Varies in two ways: amplitude (brightness) and wavelength (color) • The Visible Spectrum ranges from 400-1000nanometers Eye • A house for the retina, channels light towards the retina • Composedof ○ Cornea - transparent window where light enters the eye ○ Lens - behind the cornea, focuses light on the retina ○ Iris - colored ring of muscle around the pupil, reduce or increase mount of light coming into our eyes ○ Pupil - opening in the center of the iris that permits light to pass into the rear chamber of the eye ○ Retina - houses neuro tissue, channels the light to the optic disk, absorbs light, processes images, and send visual information to the brain  Two receptors that detect light: □ Rods - associatedwith night vision, sensitive to dim light □ Cones - daylight vision and color vision ○ Optic disk - hole in the retina where optic nerve fibers exit the eye, blind spot ○ Optic nerve runs through the Thalamus from the eye • Near-sighted = can see near ○ Light falls short of reaching the retina, cornea or lens bends light too much, too long of an eyeball, in front of retina eyeball, in front of retina • Far-sighted = can see far ○ Focus of objects fall behind the retina, short eyeball Perceiving Forms, Patterns, and Objects • Reversible figure: same visual input can result in radically different perceptions -- the shifting is caused by informationgiven about the drawing • Bottom-upprocessing theory: a progression from individual elementsto the whole ○ Feature analysis: process of detecting specific elements in visual input and assembling them into a morecomplex form • Top-Downprocessing:a progression from the whole to the elements Gestalt Principles • Proximity:things that are near one another seem to belong together (ie. Rows of dots vs. columns) • Closure: "complete"images in our minds • Similarity: similar elements are grouped together (ie. Hidden "2") • Simplicity: organize an image by grouping elements that combine to form a good figure (ie. Triangle and rectangle put together) • Continuity: follow the direction of the image to produce smooth continuation Perceiving Depth of Distance • Monocular cues - from either eye ○ Pictorial depth cues  Linear perspective: parallel lines that run away from the viewer seem to get closer together  Texture gradient: as distance increases, texture gradually becomesdenser and less distinct  Interposition: the shapes of near objects overlap or mask those of more distant ones  Relative size: assuming objects are the same size, the large images appear closer  Height in plane: near objects are low in the visual field  Light and shadow: patterns of light and dark suggest shadows that can create an impression of 3D forms • Binocular cues - from both eyes • Visual illusion - inexplicable discrepancy between the appearance of a visual stimulus and its physical reality ○ Muller-LyerIllusion: the lines on the end of the main line segment make us perceive the two as different lengths when they aren't The AuditorySystem: Hearing • Wavelengths -- pitch (high vs. low sound) Amplitudes -- volume(loud vs. quiet) Purity -- quality of sound • The cochlea is in the inner ear - the hearing part of the ear The Gustatory System: Taste • Cluster of cells=tastebuds, absorb chemicals, trigger neural impulses which send information through the thalamus to the cortex The OlfactionSystem: Smell • Humans can distinguish among 10,000odors because we have 350 different types of olfactory receptors • Smell is the only sensory system that doesn't run through the thalamus - runs directlyto the temporal lobe temporal lobe Variations in Consciousness The Nature of Consciousness • Subjective and private • Dynamic ○ William James - constant flux/stream of consciousness • Self-reflective(sense of self) • Electroencephalograph (EEG):records activityin the cortex,quantify the activityof brain waves ○ Beta waves: 15-30 cycles/second,alert and awake ○ Alpha waves: 8-12 cycles/second,drowsy and relaxing ○ Theta waves: 4-7 cycles/sec,falling asleep ○ Delta waves: <4 cycles/sec,asleep CircadianRhythms • 24-hours biological clocks • Core Body Temp (elevates during the day, drops at night) • During the day: active SEN neurons, less melatonin (alertness) secreted through pineal gland At night: melatonin increases (drowsiness/relaxation/sleepiness) • Easier to travel westward - lengthen the day harder to travel eastward - shorten the day Stages of Sleep 1. Light sleep. Theta waves 2. Appearance of a sleep spindle (1-2 second bursts of rapid brain activity),deeper sleep 3. Appearance of Delta waves 4. Delta waves dominate the patterns 5. REM, most active period of sleep (dreaming), Beta waves (like being awake) Cellular Waste Theory: There is a chemical/cellularwaste product adenosine: accumulatesduring the day (inhibiting brain circuits) slows the body down. Decreasesduring sleep Children sleep in REM 50%. Adults 20%-25% Sleep Disorders • Dyssomnias - disturbances in the amount, timing, and quality of sleep ○ Insomnia: most commonsleep disturbance  Predominatecomplaint: difficulty initiating sleep/falling asleep (normal is 15 min, bad is typically more than 30 min); maintaining sleep/wakeup frequently or too early and trouble falling back to sleep  Sleep reasonable amount but does not feel rested  40% of those who suffer from depression are co-morbid (?) to suffering from insomnia  Potential Causes: pain/physical discomfort,physical inactivity during the day, respiratory problems, high stress  1/3 of the population reports some symptomsof insomnia, high prevalence rate in children (24-40%) ○ Narcolepsy  Irresistible attacks of sleep, unintentional  Lasts 1 min-1 hour  Cataplexy: individuals can lose complete muscle tone, often preceded by a strong emotion • Parasomnias- disturbances in arousal and sleep stage transitions ○ Nightmares  Repeated awakenings from REM sleep with detailed recall of extended and extremely frightening dreams  Usually involve threats to survival, security, and self-esteem  Upon awakening, individuals are aware, awake, and alert  In general, most nightmares don't recount actual events ○ Sleep terrors  Recurrent episodes of abrupt awakening from NotREM sleep  Intense fear and signs of autonomicarousal  Relativelyunresponsive to efforts of others to comfortthe person  No detailed dream is recalled and there is amnesia for the episode  Don't fully wake up, easy to fall back asleep ○ Sleep walking (stage 3/4)  Repeated episodes of rising from bed during NREM sleep and walking about  15-30%of children experience a sleep walking episode  While sleepwalking, person: blank face, relatively unresponsive, can be awaken (with difficulty)  On awakening: amnesia for the episode  Confusional arousal: when you wake up but do not rise from the bed, can be referred to as a mild sleepwalking episode Dreams • Freud's Dream ProtectionTheory: manifest content (dream's details) and latent content (dream's true hidden message) • Activation Synthesis Theory: dreams reflect the brain's attempt to make sense of signals/brain activity during REM sleep Drugs Drug Dependence: Tolerance:the need for increased amount of drug to attain the desire effect Withdrawal:what happens when you don't have the drug for a while • Substance is taken in a larger amount than intended • Continued use, despite physical and psychological problems from using the drug Drug Abuse: • Does not include tolerance and withdrawal • Recurrent substance use, despite potential hazardous situations Psychoactivedrugs Affect your state (mental, emotional,etc) Narcotics: Heroin, morphine, oxycodone(reduce pain, induce sleep, sense of euphoria, "who cares" mentality [inhibitions]) • High on physical dependency risk, psychological dependency risk, and high risk for overdose also infectious diseases • Side effects: lethargy, nausea, impaired mental and motor f
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