Psychology Exam 2 Study Guide Sensation Perception Skin can perceive pressure temperature and pain Phantom limb pain clear and realistic sensation that missing limb is present when sensory and pain neurons from one part of the body have been cut the somatosensory cortex for the severed area begins to receive input from areas that activate nearby areas of the somatosensory cortex Gestalt Principles of Perception 1 Figure ground center of attention and background can be reversed and still make sense 2 Continuity we perceive lines or patterns that go straight as being part of a single unit 3 Proximity things close together are usually perceived as belonging together 4 Similarity similar things are perceived as being related 5 Closure missing sensory info of familiar things is filled in to create a complete and whole perception Perceptual Constancies perceptions of objects remain relatively unchanged in spite of changes in raw sensations 1 Brightness the lighting of a room doesn t change our perception of an object 2 Color constancy colors do not appear to change much in spite of different light conditions 3 Size constancy familiar objects do not change in perceived size at different distances we know that even if things change in brightness color or size because of distance etc it s the raw sensations and conditions changing and the actual object is the same Monocular Cues of Depth Perception perceived by one eye 1 Texture Gradient We perceive that things that are slanted are curved away from us and so create the illusion of depth 2 Linear perspective objects cast smaller images on the retina when farther away from us and so creates the illusion of depth 3 Superposition closer objects tend to partially cover up more distant objects 4 Shadowing shadows and highlights of objects suggest depth 5 Speed of movement objects farther away move across field of vision more slowly than closer objects 6 Aerial perspective water vapor and pollution in air scatter light waves and make objects in the distance look hazy and blue 7 Accommodation the shape of the lens of the eye changes to focus on stimuli that are different distances from the eye Kinesthetic receptors in the ciliary muscles provide info about distance of different objects up to 4 feet away 8 Vertical Position objects on the ground are closer to us when farther below the horizon objects in the air are closer to us when farther above the horizon Binocular Cues of Depth Perception perceived using both eyes 1 Convergence eye muscles move inward when looking at something in the center of vision closer to you and move farther apart when looking at something far away Eye muscles provide info 2 Retinal Disparity difference in retinal images because eyes are a couple of inches apart Illusions Taste Smell 5 tastes sweet salty sour bitter umami fatty 10 000 taste buds bunched together into papillae each contains approximately 12 sensory receptors taste cells Taste buds respond to thousands of chemicals but sensations of taste result from different combinations of taste receptors being stimulated only a few types of taste receptors and each only responds well to one class of chemicals There are no taste receptors in the middle of the tongue Touch temperature pain sight smell of food also greatly influence our perception of it Olfactory epithelium dime sized mucous coated sheet of olfactory receptors located at the top of the nasal cavity Hundreds or thousands of different receptors Almost all chemicals humans can detect are organic compounds There is a link between smell and Alzheimer s disease Consciousness Drugs Hallucinogens most powerful conscious altering drugs create psychological dependency Amphetamines increased energy alertness euphoria stimulants risk for amphetamine psychosis Cocaine similar to amphetamines psychologically and physiologically addicting Marijuana risk of schizophrenia if predisposed genetically Alcohol most widely used depressant Caffeine increased risk of heart disease if consumed in high amounts Read application section Cocktail party phenomenon focusing attention of the person you are talking to and excluding all of the other voices sounds Divided consciousness 2 conscious activities that occur simultaneously driving and thinking about something else Day dreams conscious dreamlike state of wishful fantasizing Sleep Hypnagogic state twilight state between being awake and asleep Myoclonia normal jerks usually accompanied by hypnagogic state brief seizure like states of the brain REM dreaming occurs here presence of conscious awareness Autonomic storms autonomic nervous system and other parts of the PNS are very active during dreams blood flow to brain increases heartbeat and breathing becomes irregular muscles of face and fingers twitch voluntary control of large muscles lost accompanied by activation of adrenal glands Differences between REM and non REM sleep non REM dreams are less negative and bizarre Circadian rhythms and sleep body temperature falls as you begin to feel sleepy and continues to fall until middle of sleep Reasons for Sleep Sleep debt not getting enough sleep leads to sleeping longer to make up for it Memory consolidation REM activates expression of genes that control changes in the connections between neurons that are involved in memory Day residue content of dreams directly related to things going on in our lives during the day Stimulus incorporation something going on in the outside world represents itself in dreams Ex telephone ringing Restorative rest the inhibiting system of sleep Protective can t get hurt in the dark if sleeping Latent content hidden meaning of dreams Manifest content literal meaning of dreams Learning Classical conditioning learning by association unconditioned stimulus elicits inborn response without any learning unconditioned response unlearned inborn reaction to unconditioned stimulus conditioned stimulus acquires ability to elicit unconditioned response conditioned response response elicited by conditioned stimulus o similar to or same as unconditioned response operant conditioning learning by consequences of behavior consequences lead to changes in probability of behavior occurrence Positive Reinforcement something is added that causes behavior to increase o timing positive reinforcer must be given within a short time following behavior o consistency positive reinforce must be given after every response Schedules of Positive Reinforcement 1 Fixed ratio given only