Chapter 3: SENSORY PROCESSES

Transcription

1 Chapter 3: SENSORY PROCESSES SENSING AND PERCEIVING: A FEW BASIC CONCEPTS A. Sensation: is the conversion of energy from the environment into a pattern of responses by the nervous system. Perception: is making sense of that information (sensation) B. Transducer: a mechanism that converts energy from one form to another Problem: neurons use only chemical & electrical energy Outside World Sensory System Sensation/Perception Electromagnetic Vision Seeing Pressure Audition Hearing Chemicals Gustation Tasting Chemicals Olfaction Smelling Mechanic Somatosensation Touch Transduction C. SENSORY THRESHOLDS AND ADAPTATION: 1. Psychophysics: The study of how physical stimuli are translated into psychological (sensory) experiences 2. Absolute Thresholds: is the minimum amount of stimulation that an organism can detect 50% of the time.

2 Exam 2 Notes Difference Thresholds - Just Noticeable Difference (jnd): is the smallest difference in the amount of stimulation that a specific sense can detect 4. Signal Detection Theory: A decision making process 5. Sensory Adaptation: Involves a gradual decline in sensitivity to prolonged stimulation (you get use to it). Dark Adaptation: eyes become MORE SENSITIVE to light in low illumination. VISION THE EYE A. STRUCTURES THAT FOCUS VISUAL IMAGES 1. Cornea: serves as protection for the structures behind it 2. Lens: - Transparent eye structure - FOCUSES the light rays falling on the retina (focuses the visual image) 3. Iris: ring of muscle whose pigmentation gives the eye its characteristic color (blue, brown, hazel)

3 Exam 2 Notes -3- B. RETINA: neural tissue lining the inside back surface of the eye (light energy is changed to neural energy) 1. Photoreceptors: - Cells that are light-sensitive - Two types rods & cones a) Rods: specialized visual receptors that play a key role in NIGHT VISION and PERIPHERAL vision b) Cones: specialized visual receptors that play a key role in DAYLIGHT VISION and COLOR VISION 2. Optic Nerve: - Collection of axons from the retina that connect the eye with the brain. 3. Blind Spot: The area at which the optic nerve exits the retina. 4. Fovea: tiny spot in the center of the retina that contains PRIMARILY CONES III. THEORIES OF COLOR VISION: A. Trichromatic: (Young-Helmholtz) - The human eye has THREE TYPES of receptors with differing sensitivities to different wavelengths Primary Hues: red, green, & blue

4 Exam 2 Notes -4- B. Opponent-Process: - Color is perceived in three channels, where an eitheror-response is made to pairs of ANTAGONISTIC colors HEARING AND THE OTHER SENSES I. HEARING A. Cochlea (snail like structure): - Fluid filled B. Basilar Membrane: runs the length of the cochlea - Contains hair cells which convert physical stimulation into neural signals II. CHEMICAL SENSES A. Taste and smell are stimulated by chemical molecules B. Taste and smell are interrelated C. Taste Buds: Fire neural impulses when they absorb chemicals dissolved in your saliva D. Hair Cells:

5 Exam 2 Notes -5- III. POSITION SENSES: A. Vestibular Sense: Important for posture and SENSE OF BALANCE B. Kinesthetic Sense: monitors the POSITION of the VARIOUS PARTS of your body SELECTION AS PART OF ATTENTION A. STIMULUS FACTORS (Bottom up) Physical characteristics of the stimuli A) Contrast D) Motion B) Intensity E) Novelty-Familiarity C) Size F) Repetition B. PERSONAL FACTORS (Top-Down): Mental Set: Predisposed way to perceive something (an expectation). C. PERCEPTUAL ORGANIZATION 1. Contour: the point at which a change in brightness occurs. 2. Gestalt: Interested in how perception enable us to group and organize stimuli together

6 Exam 2 Notes Figure-Ground Relationship: Figure: Ground: Reversible Figure: drawing that is compatible with two different interpretations that can shift back and forth D. STIMULUS FACTORS: Characteristics of stimuli that help us perceive them as being organized together in one figure 1. Proximity (or contiguity): things that are near each other seem to belong together. 2. Similarity: We tend to group stimuli that are similar 3. Continuity: Principle of continuity reflects our tendency to follow in whatever direction we have been led. 4. Common Fate: Elements that move together tend to be grouped together. 5. Closure: Grouping of elements so that they create a sense of closure, or completeness. SUBJECTIVE CONTOURS: (special case of closure) 6. Simplicity: law of "pragnanz" we tend to group elements that combine to form a good figure.

7 Exam 2 Notes -7- PERCEPTION OF DEPTH AND DISTANCE + We do not directly sense Depth and Distance; it is something we PERCEIVE. + Rely on indirect predictors of distance (binocular & monocular cues) + Construction of three-dimensional vision is one of the brain s most important activities. A. BINOCULAR CUES (ocular cues): are cues about distance that one obtained by comparing the differing views of the two eyes. a) Retinal Disparity: (Principle Binocular depth cue) Objects project images to slightly different locations on your right and left retinas. b) Convergence (Another Binocular cue): Sensing your eyes converging toward each other as they focus on closer objects. c) Accommodation: is the changing of the shape of the lens by the ciliary muscles to focus images on the retina. B. MONOCULAR CUES (Pictorial Cues): are depth cues that can be seen with ONE eye a. Linear Perspective: parallel lines that run away from the viewer seem to get closer together b. Interposition: The shapes of near objects overlap or mask those of more distant ones.

8 Exam 2 Notes -8- c. Relative Size: If separate objects are expected to be of the same size, the larger ones are seen as closer. APPARENT MOTION Image moves across the retina (stimulates successive rods & cones) CONSTANCY OF PERCEPTIONS - Organize & Interpret stimuli 1. Size Constancy: Our tendency to view objects as stable in size even though the size of their image changes when they are viewed from different distances. 2. Shape Constancy: compensates for distortions due to the three dimensional nature of the world (e.g. door) 3. Brightness Constancy: white shirt sensed as gray at night but perceived as white. GEOMETRIC ILLUSIONS & IMPOSSIBLE ILLUSIONS Illusion: perception that is at odds with what we know as physical reality. 1) They do not depend upon our ignorance 2) They do not "occur" at the retina 3) They do not depend on movement of the eye.

9 Exam 2 Notes -9- Chapter 5: CLASSICAL CONDITIONING I. Learning: is a relatively durable change in behavior or knowledge that is due to experience. II. Reflex: unlearned automatic response that occurs in the presence of a specific stimulus III. CLASSICAL CONDITIONING (Pavlovian Conditioning OR Respondent Conditioning): is a type of learning in which a neutral stimulus acquires the ability to evoke a response that was originally evoked by another stimulus. Example of classical conditioning

10 Exam 2 Notes -10- A. Conditioning: is the simplest form of learning it involves learning associations between stimuli and responses. 1) Unconditioned Stimulus (UCS): Is a stimulus that evokes an unconditioned response without previous conditioning. 2) Unconditioned Response (UCR): Is an unlearned reaction to an unconditioned stimulus that occurs without previous conditioning. 3) Conditioned Stimulus (CS): Is a previously neutral stimulus that has, through conditioning, acquired the capacity to evoke a conditioned response. 4) Conditioned Response (CR): Is a learned reaction to a conditioned stimulus that occurs due to previous conditioning. B. Orienting Reflex: a simple, unlearned response of orienting toward, or attending to a new or unusual stimulus. C. Habituation: is when an organism comes to ignore a stimulus of no consequence.

11 Exam 2 Notes -11- IV. CLASSICAL CONDITIONING PHENOMENA A. Acquisition: Is the formation of a new conditioned response tendency. B. Extinction: The GRADUAL WEAKENING and DISAPPEARANCE of a conditioned response tendency. C. Spontaneous Recovery: is the reappearance of an extinguished response AFTER a period of NONEXPOSURE to the conditioned stimulus. D. Generalization: occurs when an organism responds to new stimuli that are SIMILAR to the ORIGINAL STIMULUS used in conditioning E. Discrimination (OPPOSITE OF GENERALIZATION): Occurs when one DOES NOT RESPOND to stimuli that are similar to the original stimulus used in conditioning. V. CLASSICAL CONDITIONING IN EVERYDAY LIFE: A. ADVERTISING CAMPAIGNS SOMETIMES TRY TO TAKE ADVANTAGE OF CLASSICAL CONDITIONING: Unconditioned Stimulus: Unconditioned Response: Conditioned Stimulus: Conditioned Response:

12 Exam 2 Notes -12- B. PHOBIC DISORDERS: - Example of Classical Conditioning in everyday life. C. Systematic Desensitization: the use of classical conditioning in which a state of relaxation is paired with anxiety-producing stimuli to alleviate irrational fears. D. CONDITIONED TASTE AVERSION: Conditioned ONLY through the pairing of taste stimuli & nausea. VI. JUST WHAT IS LEARNED IN CLASSICAL CONDITIONING? * Conditioning is now viewed as the LEARNING OF RELATIONSHIPS that exists among events in the world. VII. APPLYING CLASSICAL CONDITIONING TO YOUR STUDY OF PSYCHOLOGY - Find a special place to study - RESERVED ONLY for studying. - Common locations can act as conditioned stimuli and come to elicit conditioned responses.

13 Exam 2 Notes -13- OPERANT CONDITIONING I. OPERANT CONDITIONING (Instrumental Learning): is a form of learning in which voluntary responses come to be controlled by their consequences. Law Of Effect (Thorndike): if a response in the presence of a stimulus leads to satisfying effects, the association between the stimulus and the response is strengthened. II. COURSE OF CONDITIONING: A. Shaping: The reinforcement of closer & closer approximation of the desired response B. Acquisition: an increase in response rate due to the process of operant conditioning. C. Extinction: Gradual weakening & disappearance of a response tendency because the response is no longer followed by a reinforcer. D. Spontaneous Recovery: extinguished response returns after a rest interval.

14 Exam 2 Notes -14- III. REINFORCEMENT A. Reinforcement: occurs when an event following a response strengths the tendency to make the response & can be thought of as a reward. 1) Positive Reinforcer: occurs when a response is strengthen because it is followed by the arrival of a (presumably) pleasant stimulus. 2) Negative Reinforcer: a response is STRENGTHENED because it is followed by the removal of a (presumably) unpleasant stimulus. TWO WAYS TO INCREASE A BEHAVIOR: we can a. give someone something that they "like" (positive reinforcement) OR b. take away something that they "dislike" (negative reinforcement) 3) Primary Reinforcers: are stimulus events that are inherently reinforcing because they satisfy biological needs for humans. 4) Secondary Reinforcers: are stimulus events that acquire reinforcing qualities by being associated with primary reinforcers. 5) Continuous Reinforcement Schedule (CRF): EVERY instance of a designated response is reinforced.

15 Exam 2 Notes -15-6) Intermittent Reinforcement Schedules: Occurs when a designated response is reinforced only some of the time. a) Fixed-Ratio Schedule (FR): the reinforcer is given after a FIXED number of non-reinforced responses b) Fixed-Interval Schedule (FI): reinforcement is given for the FIRST RESPONSE that occurs AFTER a FIXED INTERVAL has elapsed. c) Variable-Ratio Schedule (VR): the reinforcer is given after a VARIABLE NUMBER of non-reinforced responses. d) Variable-Interval Schedule (VI): The reinforcer is given for the first response after a variable time interval has elapsed. B. PUNISHMENT: Occurs when an event that follows a response weakens or suppresses the tendency to make the response. 1) Positive Punishment: a response is followed by the presentation of aversive stimulus 2) Negative Punishment: a response is followed by the removal of a pleasant stimulus. Reinforcement Punishment Positive Negative

16 Exam 2 Notes -16- C. GENERALIZATION: D. DISCRIMINATION: E. Instinctive Drift: occurs when an animal's innate response tendencies interfere with conditioning processes. Walden Two B. F. Skinner You can reinforce your own actions for studying! COGNITIVE APPROACHES TO LEARNING COGNITIVE APPROACHES TO LEARNING: Learning that need not involve an observable behavior. Latent Learning: learning that is NOT shown in behavior at the time it occurs. Cognitive Map: a mental representation or a mental picture of a physical environment due to learning.

17 Exam 2 Notes -17- Social Learning Theory: learning can take place through imitation and observation of models Learning the consequences of one's behavior by observing the consequences of someone else's behavior Vicarious Reinforcement: Vicarious Punishment:

18 Exam 2 Notes -18- Chapter 4: LEVELS OF CONSCIOUSNESS A. Consciousness: all mental experiences B. Three Levels of Consciousness (Freud): 1) Conscious: 2) Preconscious: 3) Unconscious: C. Subliminal Perception: stimulus presented below the threshold for conscious perception. VARIETIES OF CONSCIOUSNESS A. SLEEP 1. Electroencephalogram (EEG): a) BETA Activity: Wide awake b) ALPHA Activity: EEG pattern, eyes closed, not a sleep, calm and relaxed state 2. Electromyogram:

19 Exam 2 Notes STAGES OF SLEEP Stage 1: Brief transitional stage usually last 5-10 min. * ALPHA waves give way to THETA waves. Stage 2: Characterized by brief burst of higher-frequency brain waves, sleep spindles-> fairly regular intervals * START to get DELTA WAVES Stage 3: 20% of EEG activity DELTA WAVES Stage 4: More than 50% of EEG DELTA WAVES REM Sleep (Rapid Eye Movement): * Deep stage of sleep Difficult to awaken a person * EEG activity dominated by BETA WAVES * Stage where most dreaming occurs. Atonia: Muscle tone is extremely relaxed, bodily movement are minimal & sleeper is virtually paralyzed. ENTIRE SLEEP CYCLE RUNS ABOUT 90 Min. 6. Dreams: Nightmares: are anxiety arousing dreams that lead to awakening (usually from REM sleep). Night Terrors: Abrupt awakening from Non-Rem sleep accompanied by intense autonomic arousal & feelings of panic. 7. Somnambulism (sleepwalking): occurs when a sleeping person arises and wanders about in deep Non-REM sleep (stage 3 or 4).

20 Exam 2 Notes -20- VOLUNTARY ALTERATIONS OF CONSCIOUSNESS A. HYPNOSIS: an altered state of consciousness one enters voluntarily. * Can produce sensory distortions & hallucinations HALLUCINATIONS: are perceptual experiences that occur without sensory input. 1) SPECIAL PROCESS THEORY: Hidden Observer Theory: HIGHWAY HYPNOSIS: person drives a great distance responding to traffic signals & other cars with no recall of any consciousness effort to do so. 2) NONSTATE-VIEW THEORY: B. MEDITATION: self-induced state of altered consciousness C. ALTERING CONSCIOUSNESS WITH DRUGS PSYCHOACTIVE DRUGS: Psychoactive Drugs are chemical substances that modify mental, emotional, or behavioral functioning. Dependence: Tolerance: Withdrawal: Addiction: Drug Abuse:

21 Exam 2 Notes -21-1) STIMULANTS: are drugs that tend to increase central nervous system activation and behavioral activity. a) Caffeine: found in may foods as well as many varieties of pain killers. b) Nicotine: activate excitatory synapse in both CNS & PNS c) Cocaine: elevates blood pressure & heart rate, d) Amphetamines: (Norepinephrine & Dopamine) 2) DEPRESSANTS: reduces one's awareness of external stimuli, Alcohol: 3) Opiates, Heroine, & Barbiturates: a) Opiates (Narcotics): can reduce or eliminate sensation of pain, tend to ignore real-world stimuli. Examples: Heroin & Morphine b) Barbiturates: synthetically produced sedatives 4) HALLUCINOGENS: Are a diverse group of drugs that have a powerful effect on mental and emotional functioning. - Distortions in sensory and perceptual experiences. LSD (Lysergic Acid Diethylamide): 5) MARIJUANA: A mild, relaxed euphoria, accompanied by enhanced sensory awareness and a distorted sense of time.