* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download half a second before
Survey
Document related concepts
Abnormal psychology wikipedia , lookup
Theory of planned behavior wikipedia , lookup
Insufficient justification wikipedia , lookup
Applied behavior analysis wikipedia , lookup
Neuroeconomics wikipedia , lookup
Theory of reasoned action wikipedia , lookup
Behavior analysis of child development wikipedia , lookup
Verbal Behavior wikipedia , lookup
Behaviorism wikipedia , lookup
Psychophysics wikipedia , lookup
Psychological behaviorism wikipedia , lookup
Transcript
Learning How does experience affect behaviors and/or attitudes? By Association!! • Our minds naturally connect events that occur in sequence. – Affects Behaviors By Association!! • Our minds naturally connect events that occur in sequence. – Affects Attitudes Sovfoto Pavlov and Classical Conditioning 5 Classical Conditioning • Unconditioned Stimulus (US) – A stimulus (an event) that triggers an unconditioned (involuntary) response. • Examples: food, loud noises, painful stimuli, bursts of air Classical Conditioning • Unconditioned response (UR) – An unlearned response to an unconditioned stimulus. • Examples: hunger -> food, jumping ->horror flick, blinking -> flying objects near eye Classical Conditioning • Conditioned stimulus (CS) – A neutral stimulus (an event) that comes to evoke a learned response due to being presented shortly before the US. • Ex: Bell ringing in high school, Fridays!!, Cologne Classical Conditioning • Conditioned response (CR) – A learned response to a classically conditioned stimulus (CS) • Ex: Salivation of Pavlov’s dog just to the bell, your mouth watering when you smell warm cookies, smiling when you hear a song that reminds you of someone (or frowning…depending) CC Check • Every time someone flushes a toilet in the apartment building, the shower becomes very hot and causes the person to jump back. Over time, the person begins to jump back automatically after hearing the flush, before the water temperature changes. – – – – – What is the: UCS UCR Neutral Stimulus/CS CR? Acquisition The initial stage in classical conditioning. during which association between a neutral stimulus and a US takes place. 1. Neutral stimulus needs to come before the US for conditioning to occur (most cases). 2. The time between the two stimuli should be about half a second. 12 Acquisition The CS needs to come half a second before the US to cause acquisition. 13 Extinction When a US (food) does not follow a CS (tone) CR (salivation) starts to decrease and at some point goes extinct. 14 Reinstatement After a rest period an extinguished CR (salivation) spontaneously recovers and if CS (tone) persists alone becomes extinct again. 15 Stimulus Generalization Tendency to respond to stimuli similar to CS is called generalization. • “Little Albert” – Conditioned to fear a white lab rat – Fear generalized to anything white and furry 16 Stimulus Discrimination Discrimination is the learned ability to distinguish between a CS and other stimuli that do not signal a US. 17 Applications of Classical Conditioning 1. Alcoholics can be conditioned (aversively) partly reversing their positive-associations with alcohol. 2. A drug (plus its taste) that affects the immune response, can lead the taste to invoke the immune response through classical conditioning. 18 Operant Conditioning Tilikum Attacks!! Operant & Classical Conditioning Classical conditioning forms associations between stimuli (CS and US). Operant conditioning on the other hand forms association between behaviors and resulting events. 20 Operant Conditioning • Cats in puzzle boxes – Time to escape decreased with practice – Thorndike’s “Law of Effect” • Responses followed by positive outcomes are repeated, whereas those followed by negative outcomes are not Shaping Operant conditioning procedure in which reinforcers guide behavior closer towards target behavior through successive approximations. Method used in training schools 22 Types of Reinforcers 23 Primary & Secondary Reinforcers 1. Primary Reinforcer: Innately reinforcing stimulus like food, drink, sex (depending). 2. Conditioned Reinforcer: Is a learned reinforcer. It gets its reinforcing power through its association with primary reinforcer. Ex. Money, praise, good grades, awards, gold stars 24 Immediate & Delayed Reinforcers 1. Immediate Reinforcer: A reinforcer that occurs closely to a behavior in time. Rat gets a food pellet for a bar press. 2. Delayed Reinforcer: A reinforcer that is delayed in time for a certain behavior. A paycheck that comes at the end of a week. We may be more inclined to engage in small immediate reinforcers (watching TV) than large delayed reinforcers (Getting A in a course) which requires consistent study. 25 Reinforcement Schedules 1. Continuous Reinforcement: Reinforcing the desired response each time it occurs. 2. Partial Reinforcement: Reinforcing a response only part of the time. Though results in slower acquisition in the beginning, shows greater resistance to extinction later on. 26 Ratio Schedules 1. Fixed-ratio schedule: Reinforces a response only after a specified number of responses e.g., like piecework pay, “I’m going to count to three.” 2. Variable-ratio schedule: Reinforces a response after an unpredictable number of responses. Hard to extinguish because of unpredictability, e.g., behaviors like gambling, fishing. 27 Interval Schedules 1. Fixed-interval schedule: Reinforces a response only after a specified time has elapsed e.g., preparing for an exam only when the exam draws close, getting a raise every year and not in between. 2. Variable-interval schedule: Reinforces a response at unpredictable time intervals. produces slow steady responding, e.g., pop quiz, boss checking on you 28 Punishment 29 Motivation Intrinsic Motivation: The desire to perform a behavior for its own sake. Extrinsic Motivation: The desire to perform a behavior due to promised rewards or threats of punishments. How “rewarding” is it for an orca to leap in the air for [already] dead fish from a bucket? THIS is how orca’s feed: http://www.youtube.com/watch?v=k5M3gs76fzA http://www.youtube.com/watch?v=p3xmqbNsRSk 30 This 14-month-old child imitates the adult on TV in pulling a toy apart. Meltzoff, A.N. (1998). Imitation of televised models by infants. Child Development, 59 1221-1229. Photos Courtesy of A.N. Meltzoff and M. Hanuk. Imitation Onset-Learning via Observation Bandura's Bobo doll study (1961) indicated that individuals (children) learn through imitating others who receive rewards and punishments. Courtesy of Albert Bandura, Stanford University Bandura's Experiments Latent Learning Such cognitive maps are based on latent learning, which becomes apparent only when an incentive is given (Tolman & Honzik, 1930). Biological Predisposition Photo: Bob Bailey Biological constraints predispose organisms to learn associations that are naturally adaptive. Breland and Breland (1961) showed that animals drift towards their biologically predisposed instinctive behaviors. Marian Breland Bailey Skinner’s Legacy Skinner argued that behaviors were shaped by external influences instead of inner thoughts and feelings. Critics argued that Skinner dehumanized people by neglecting their free will. Falk/ Photo Researchers, Inc . Motivation Motivation is a need or desire that energizes behavior and directs it towards a goal. Aron Ralston AP Photo/ Rocky Mountain News, Judy Walgren Aron Ralston was motivated to cut his arm in order to free himself from a rock that pinned him down. 36 Perspectives on Motivation Four perspectives used to explain motivation include the following: 1. Instinct Theory (replaced by the evolutionary perspective) 2. Drive-Reduction Theory 3. Arousal Theory 4. Hierarchy of Motives 37 Instincts & Evolutionary Psychology Instincts are complex behaviors that have fixed patterns throughout different species and are not learned (Tinbergen, 1951). Tony Brandenburg/ Bruce Coleman, Inc. © Ariel Skelley/ Masterfile Where the woman builds different kinds of houses the bird builds only one kind of nest. 38 Drives and Incentives When the instinct theory of motivation failed, it was replaced by the drive-reduction theory. A physiological need creates an aroused tension state (a drive) that motivates an organism to satisfy the need. 39 Incentive Where our needs push, incentives (positive or negative stimuli) pull us in reducing our drives. A food-deprived person who smells baking bread (incentive) feels a strong hunger drive. 40 Optimum Arousal Human motivation aims to seek optimum levels of arousal, not to eliminate it. Young monkeys and children are known to explore the environment in the absence of a need-based drive. Randy Faris/ Corbis Harlow Primate Laboratory, University of Wisconsin 41 Hunger When do we eat? When we are hungry. When are we hungry? When there is no food in our stomach. How do we know when our stomach is empty? Our stomach growls. These are also called hunger pangs. The Physiology of Hunger Stomach contractions (pangs) send signals to the brain making us aware of our hunger. Stomachs Removed Tsang (1938) removed rat stomachs, connected the esophagus to the small intestines, and the rats still felt hungry (and ate food). Body Chemistry & the Brain Levels of glucose in the blood are monitored by receptors (neurons) in the stomach, liver, and intestines. They send signals to the hypothalamus in the brain. Rat Hypothalamus Hypothalamic Centers The lateral hypothalamus (LH) brings on hunger (stimulation). Destroy the LH, and the animal has no interest in eating. The reduction of blood glucose stimulates orexin in the LH, which leads rats to eat ravenously. Hypothalamic Centers The ventromedial hypothalamus (VMH) depresses hunger (stimulation). Destroy the VMH, and the animal eats excessively. Richard Howard Hypothalamus & Hormones The hypothalamus monitors a number of hormones that are related to hunger. Hormone Orexin increase Tissue Response Hypothalamus Increases hunger Ghrelin increase Stomach Increases hunger Insulin increase Pancreas Increases hunger Leptin increase Fat cells Decreases hunger PPY increase Digestive tract Decreases hunger