Chapter Six. Learning. Classical Conditioning Operant Conditioning Observational Learning

Transcription

1 Chapter Six Learning Classical Conditioning Operant Conditioning Observational Learning

2 Part One: Classical Conditioning Classical Conditioning is conditioning by association, such as a pet getting excited whenver she hears a certain car arriving because she associates it with her owner coming home. Pavlov (1906) fundamental concepts further concepts Watson & Rayner (1920) influencing factors Rescorla (1968) special cases Garcia & Koelling (1966)

3 Pavlov (1906) Ivon Pavlov 24 gave dogs specific stimuli, such as the ringing of a bell, several times, each immediately prior to providing them with food. The dogs salivated because of the food. Later, the dogs would salivate at the sound of the bell, in anticipation of the food.

4 Fundamental concepts of classical conditioning Term Definition Example Unconditioned Stimulus stimulus that naturally causes The smell of food is a natural (UCS) an unconditioned response stimulus for dogs. (without need for conditioning) Unconditioned Response (UCR) natural response to a stimulus (without need for conditioning) Dogs will naturally salivate when they smell food. Conditioned Stimulus (CS) Conditioned Response (CR) stimulus that does not naturally cause a given response but does after being paired sufficiently with an unconditioned stimulus response to a stimulus that does not naturally elicit that response The sound of a bell was paired with food for Pavlov s dogs. The sound of a cart does not naturally elicit salivation, but it did for Pavlov s dogs.

5 Further concepts of conditioning Term Definition Example Acquisition creating a conditioned behavior Pavlov s dogs heard the bell by pairing a CS with a UCS each time right before being Stimulus Generalization Stimulus Discrimination Extinction Spontaneous Recovery responding to stimuli similar but not identical to the CS not responding to stimuli different from the CS eliminating a CR by consistently presenting the CS without the UCS regaining a CR after a rest period following extinction fed. Pavlov s dogs would salivate even if the bell-ringing was louder or higher pitched. Pavlov s dogs would not salivate to the sound of a horn. After receiving no meat powder after several bell ringinings, Pavlov s dogs would unlearn the CR. Days after the CR was extinguished, a ringing bell may again elicit a CR.

6 Watson & Rayner (1920) John Watson 17 and Rosalie Rayner let an 11- month-old infant, Little Albert, play with a fluffy white rat. Each time he reached for it, they scared him with a very loud noise from a hammer and metal. Later they gave him the rat unaccompanied by the noise, and did the same with similar items. Term Unconditioned Stimulus Unconditioned Response Conditioned Stimulus Conditioned Response Stimulus Generalization Stimulus Discrimination Extinction For Little Albert The loud noise was naturally scary. He naturally experienced fear from the noise. The noise elicited fear now that it was paired with the rat. He developed a fear of the rat. He also showed a fear response to a fluffy rabbit, a Santa Claus mask, Watson s white hair, etc. He showed less fear response to a dog, and none to people s hair that wasn t white. Eventually his conditioned fear of rats and related things might fade as he experienced them not paired with scary noises.

7 Factors influencing classical conditioning In most cases, there are two factors that are essential for classical conditioning to take place: The unconditioned stimulus should be more likely to occur after an occurance of the conditioned stimulus than at another random time, and it should be immediate rather than delayed. As an example, consider the episode from The Office in which Jim offered Dwight an altoid each time his computer made a restart sound. Term Optimal conditions How Jim could have failed Temporal Contiguity The UCS immediately follows the CS. letting time elapse between the sound and the altoid offering Contingency The UCS has a higher probability following an instance of the CS than at another random time. sometimes not offering an altoid after the tone, and sometimes offering an altoid without the tone

8 Rescorla (1968) Participants: 24 rats Procedure: Over a five-day conditioning period, rats experienced a series of 12 two-minute tones, each followed by eight minutes without a tone. During some of these tones they received a ½-second shock. Independent Variable: contingency received no additional shocks, or also received shocks at random times without the tone Dependent Variable: conditioned fear of the tone Results: The rats that experienced shocks only when they heard the tone were conditioned to fear the tone, but the others were not. Conclusion: For the rats to be conditioned to fear the tone, they had to know that the shock would not happen without it.

9 Special cases of classical conditioning Term Definition Distinction Example Higher-Order Conditioning using a CS as a UCS to create a CR to a new CS The CS is never actually paired with a true UCS. A rat conditioned to fear a red light because an electric shock will follow can be conditioned to fear a blue light because a red Conditioned Taste Aversion conditioning pairing taste or smell with nausea The UCS can happen long after the CS, and can be effective after just one pairing. light will follow. Carli got sick after drinking tequila; now she feels sick at the smell of it.

10 Garcia 86 & Koelling (1966) Participants: 10 rats Procedure: Punishment was applied for drinking water with a specific characteristic. Independent Variable I: unique aspect of water gustatory or audio-visual Independent Variable II: type of punishment nausea or shock Independent Variable III: delay before punishment none or 20 minutes Dependent Variable: avoidance of water Results: In the audio-visual condition, only shock caused avoidance, and only minimally so in the delayed punishment condition. In the gustatory condition, only nausea caused avoidance, but did so equally in the immediate and delayed condition. Conclusion: When punishment results from eating, making the results not immediately known, the effects were linked even though they did not occur until much later. Without this, it would be impossible to learn what is dangerous and should be avoided.

11 Part Two: Operant Conditioning Operant Conditioning is conditioning through reinforcement and punishment, such as circus animals learning tricks by getting treats when they perform a desired behavior. It is called operant conditioning because it is based on organisms operating on their enviornment to effect a desired outcome (or avoid an undesired one), as opposed to classical conditioning which is more automated. fundamental concepts Project Pigeon special cases Seligman & Meier (1967)

12 Fundamental concepts of operant conditioning B. F. Skinner 1 developed an operant chamber (later commonly called a Skinner Box) in which reinforcements and punishments could be administered to an animal in response to specific behaviors. Term Definition Skinner Box Example Positive Reinforcement making a behavior more likely A rat gets food by pushing a by adding a desirable stimulus lever whenever a green light Negative Reinforcement making a behavior more likely by removing an undesirable stimulus comes on. A rat prevents getting shocked by pusing a lever whenever a green light comes on. Punishment making a behavior less likely A rat gets shocked whenever he pushes a lever while a red light is on.

13 Project Pigeon B. F. Skinner 1 headed a World War II effort to create a missile-guidance system operated by pigeons (Skinner, 1960). The pigeons were trained to steer the missile by pecking at a target projected onto a touch screen triggered by interruptions in airflow. Test simulations showed the system to be highly effective.

14 Special cases of operant conditioning Term Definition Distinction Example Shaping conditioning successively more specific behaviors Learned Helplessness conditioned failure to attempt to remedy unpleasant situations due to previous exposure to other unpleasant situations in which the organism had no control The criterion required for reinforcement gradually increases in scope. The organism is conditioned to be helpless in general, including in contexts unrelated to the original conditioning. A bear is reinforced for coming near a tricycle until he learns to do so; then he is rewarded for sitting on it, then for putting his feet on the pedals, then for pushing the pedals. A student who loses her job and is unable to get a new one gives up in general and stops studying for her midterms.

15 Seligman 31 & Maier (1967) Participants: 24 dogs of no specific breed Procedure: Each dog in the two experimental conditions was placed in a box in which the lights would periodically go out, signaling an oncoming shock. In the escape condition, the dog could avoid the shock by pressing a panel. In the learned helplessness condition, the dog could not control the shocks, which were matched in duration to those received in the escape condition. The next day, each each dog was placed in a different box. For each of 10 trials, the dog would be shocked if he did not jump to the other side of this box when the lights went out. Independent Variable: original conditioning none, escape, or learned helplessness Dependent Variable: learning to escape the shock in the second box Results: Dogs that learned they had no control in the first situation did not attempt to learn how to escape the shocks in the next situation. Conclusion: Appropriate feelings of helplessness can carry over to contexts in which they are not appropriate. shocks avoided later 100% 75% 50% 25% 0% none escape learned helplessness original conditioning

16 Part Three: Observational Learning Observational Learning is learning by observing others behaviors and their consequences. A person being observed in this way is called a model. Bandura, Ross, & Ross (1961) fundamental concepts statement on media violence

17 Bandura 31, Ross & Ross (1961) Participants: 36 boys and 36 girls, ages 3 to 5, from Stanford Nursery Procedure: While the child did artwork in one corner of a room, an adult played with tinker toys in another. In the aggressive condition, after a minute the adult attacked a bobo doll. After 10 minutes, the experimenter took the child to a new toy room, but after allowing a moment s play induced frustration by stating that these toys were reserved for others. Finally, the child was taken to a room with a bobo doll and other toys. Independent Variable I: aggression of model none or bobo doll attack Independent Variable II: sex of child Independent Variable III: sex of model same as child or different Dependent Variable: aggressive acts imitating the model Results: Children tended to imitate adults aggressive behaviors, especially physical aggression for boys and verbal aggression for girls. Both sexes were more likely to imitate same-sex models. Conclusion: Children learn by watching others. mean physical imitative aggression score aggressive model nonaggressive model 0 child: male female model: same different same different sex

18 Fundamental concepts of observational learning Term Definition Example from Bobo doll Attention being aware of another s behavior and its consequences The kids watched the adult s aggressive behavior. Retention remembering what was observed The kids remembered the adult s general aggression and details of it. Ability being able to reproduce the observed behavior The kids could easily mimic the adult s behavior. Motivation believing that reproducing the behavior will provide positive consequences The kids had an outlet for their frustration of having toys taken away.

19 Joint statement to congress on media violence In 2000, the six major organiztions listed below provided a joint statement to congress on the effects of media violence, including the excerpts quoted below. At this time, well over 1000 studies point overwhelmingly to a causal connection between media violence and aggressive behavior in some children. The conclusion of the public health community, based on over 30 years of research, is that viewing entertainment violence can lead to increases in aggressive attitudes, values and behavior, particularly in children. In particular, exposure to media violence is believed to increase acceptance of Children who see a lot of violence are more likely to view violence as an violence effective way of settling conflicts. emotional Viewing violence can decrease the likelihood that one will take action on desensitization behalf of a victim when violence occurs. fear Viewing violence increases fear of becoming a victim of violence, with a resultant increase in self-protective behaviors and a mistrust of others. acts of violence Children exposed to violent programming at a young age have a higher tendency for violent and aggressive behavior later in life than children who are not so exposed. American Medical Association American Psychiactric Association American Psychological Association American Academy of Pediatrics American Academy of Family Physicians American Academy of Child & Adolescent Psychiatry