Learning
Learning. Stimulus or Stimuli. Any event or object in the environment to which an organism responds. Learning. Relatively permanent change in behavior, knowledge, capability, or attitude acquired through experience & cannot be attributed to illness, injury, or maturation
Learning
E N D
Presentation Transcript
Stimulus or Stimuli • Any event or object in the environment to which an organism responds
Learning • Relatively permanent change in behavior, knowledge, capability, or attitude acquired through experience & cannot be attributed to illness, injury, or maturation • Why injury? Like when your behavior may change because you’ve had a brain injury. • Why maturation? Like when you talk in a deeper voice as a result of puberty.
Classical Conditioning • A stimulus comes to predict the occurrence of another stimulus and elicits a response similar to the response related by that stimulus. • A cat salivates when they see and smell their food; tap the can every time you are about to feed your cat & they will start to salivate when they hear the tapping.
Ivan Pavlov (1849-1936) • Russian scientist, studied physiology of digestion, won Nobel Prize in 1904 • Major contribution was the study of the conditioned reflex, which provided a model of learning called classical conditioning • Used dogs & a bell
Elements of Classical Conditioning Elements Stimulus & Response • Reflex: an involuntary response to a particular stimulus (eyeblink, salivation) • 2 kinds of reflexes: conditioned & unconditioned OR learned & unlearned • Unconditioned response (UR): response that is invariably elicited by the US without prior learning • Unconditioned stimulus (US): elicits a specific response without prior learning • Conditioned stimulus (CS): neutral stimulus after repeated pairing becomes associated with & elicits a conditioned response • Conditioned response (CR): response that comes to be elicited by a conditioned stimulus as a result of repeated pairing with US
Extinction & Spontaneous Recovery • Extinction: weakening & eventual disappearance of a learned response • Spontaneous recovery: reappearance of an extinguished response
Generalization • In classical conditioning, the tendency to make a conditioned response to a stimulus similar to the original conditioned stimulus
Discrimination • Learned ability to distinguish between similar stimuli so the conditioned response occurs only to the original conditioned stimulus but not the similar stimuli
Higher Order Conditioning • Conditioning that occurs when a neutral stimulus is paired with an existing conditioned stimulus, becomes associated with it, and gains the power to elicit the same conditioned response • For example, Pavlov could flash a light along with the tone he played & then the light flashing would also become associated with the stimulus
John Watson (1878-1958) • Demonstrated that fear could be classically conditioned by presenting a white rat along with a loud, frightening noise, thereby conditioning Little Albert to fear the white rat. • Fear generalized to a dog, a seal coat, Watson’s hair, and a Santa Claus mask • Formulated techniques to remove a conditioned fear
Classical Conditioning: Modern View • Rescorla: predicting the occurrence of the unconditioned stimulus • Rat experiment: tone (CS) & shock (US) = predict response BUT tone (CS) & shock (US) AND no shock (US) = not predictable response
Blocking • When previous conditioning to one stimulus prevents conditioning to a second stimulus with which it has been paired • Tone (CS), then Light (CS), but tone “trumped” CR because it was learned first, light (CS) was “blocked”
Taste Aversions • Intense dislike and/or avoidance of a particular food that have been associated with pain or discomfort • Can be generalized • Chemotherapy: “scapegoat” food before treatment
Everyday Classical Conditioning • Many emotional responses result from classical conditioning (positive and negative) • Fears & Phobias / dentist’s office • Drug Use / cues / soldiers & heroin use in Vietnam • Advertisements
Factors Influencing Classical Conditioning • How reliable a conditioned stimulus predicts the unconditioned response • The number of pairings of the conditioned stimulus and the unconditioned stimulus • Intensity of the unconditioned stimulus • Temporal relationship between the conditioned stimulus and the unconditioned stimulus
Operant Conditioning • The consequences of behavior are manipulated in order to increase or decrease that behavior in the future. • Voluntary responses (not reflexive) • Active state • Simple to highly complex responses
Thorndike & the Law of Effect • Edward Thorndike (1874-1949) • Trial-and-error learning: occurs when a response is associated with a successful solution to a problem after a number of unsuccessful responses. • Cats in the puzzle box, hitting lever for food • Law of effect: connection between a stimulus & response will be strengthened if the response is followed by a satisfying consequence or weakened it causes discomfort.
B.F. Skinner: Operant Conditioning Pioneer • Burrhus Frederic Skinner (1904-1990) • Believed behavior was shaped by the environment • Response first, then consequence • Skinner box: soundproof chamber with a device for delivering food & either a bar for rats to press or a disk for pigeons to peck
Shaping • An operant conditioning technique that consists of gradually molding a desired behavior (response) by reinforcing responses that become progressively closer to it
Extinction • Weakening & often eventual disappearance of a learned response (in operant conditioning, the conditioned response is weakened by withholding reinforcement)
Generalization • In operant conditioning, the tendency to make the learned response to a stimulus similar to the one that was originally reinforced
Discriminative stimulus • A stimulus that signals whether a certain response or behavior is likely to be followed by reward or punishment
Reinforcement • An event that follows a response and increases the strength of the response and/or the likelihood that it will be repeated
Positive Reinforcement • A reward or pleasant consequence that follows a response and increases the probability that the response will be repeated
Negative Reinforcement • The termination of an unpleasant stimulus after a response in order to increase the probability that the response will be repeated
Primary Reinforcer • A reinforcer that fulfills a basic physical need for survival & does not depend on learning • Eating, sleeping, drinking, stopping pain, & having sex
Secondary Reinforcer • A neutral stimulus that becomes reinforcing after repeated pairings with other reinforcers • Money, praise, good grades, attention, approval
Continuous Reinforcement • Administered after every desired or correct response; the most effective method of conditioning a new response • Rat got food every time it pressed bar
Partial Reinforcement • Pattern of reinforcement in which some portion, rather than 100%, of the correct responses are reinforced • More like real life, partial reinforcement is the rule
Schedule of Reinforcement • Systematic program for administering reinforcements that has a predictable effect on behavior • Distinct rates & patterns of responses
Fixed-Ratio Schedule • A fixed number of correct responses • Rat receives food after 5 pushes of lever • What would happen if the ratio was 100 pushes for each pellet of food? • If it was 1,000?
Variable-Ratio Schedule • Reinforcer is given after a varying number of nonreinforced responses based on an average ratio • Rat gets food after 30 lever pushes, then 20 pushes, then 50… averages to VR of 30 • Higher, more stable rates of responding than fixed-ratio schedules
Variable-Ratio Schedule • Real life example: Casino gambling • Variable-ratio: highest response rate & most resistance to extinction
Fixed-Interval Schedule • Reinforcer is given following the first correct response after a fixed period of time has elapsed • Working on salary: fixed-interval schedule • Food given every 60 seconds
Variable-Interval Schedule • Reinforcer is given after the first correct response following a varying time of nonreinforcement based on an average time. • Pop quizzes, cannot predict, so study responses should be more uniform
Partial Reinforcement Effect • Greater resistance to extinction • Reward not expected every time, so the learning does not become extinct • Strongest resistance to extinction observed by Holland & Skinner (1961): Fixed ratio of 900, pigeon emitted 73,000 responses during the first 4 ½ hours of extinction • Why parents should not give into nagging.
Influencers in Operant Conditioning • Magnitude • Immediacy • Level of motivation of the learner
Punishment vs. Negative Reinforcement • Punishment: adds a negative condition • Reinforcement: removes a negative condition • Punishment: Discourages a behavior • Reinforcement: Encourages a behavior
Problems with punishment • Does not extinguish undesirable behavior, it suppresses that behavior when they are being punished • Does not help people develop more appropriate behaviors • Often causes fear & anger • Can lead to aggression
Effective Punishments • Timing • Intensity • Consistency
Escape & Avoidance Learning • Escape learning: performing a behavior because it terminates an aversive event (running away, taking medicine) • Avoidance learning: first, an event signals a bad situation (classical conditioning); second, you avoid that situation (operant conditioning, negative reinforcement)
Learned Helplessness • A passive resignation to aversive conditions learned by repeated exposure to aversive events that are inescapable and unavoidable • Dogs; abused women
Applications • Training Animals • Biofeedback • Behavior modification
Learning by Insight: Aha! • Wolfgang Köhler (1887-1967) • Chimps, bananas, sticks, boxes & a flash of insight (not trial-and-error) • Solution gained through insight is more easily learned, less likely forgotten & more readily applied to new problems
Latent Learning & Cognitive Maps • Edward Tolman (1886-1959) • Latent learning: occurs without apparent reinforcement but is not demonstrated until sufficient reinforcement is provided • Rats, mazes, one rewarded, one not, one rewarded later. • Cognitive map: mental representation of a spatial arrangement
Observational Learning • Albert Bandura (1925-present) • Observational learning or modeling: learning by watching the behavior of others & the consequences of that behavior; learning by imitation • Fears acquired by observing behavior • Aggression acquired by observation
