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Learning

Learning. Classical & Operant Conditioning Chapter 8. Associative Learning. Learning that certain events occur together. Our minds naturally connect two events that occur in sequence. Conditioning is the process by which we learn associations between two events.

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Learning

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  1. Learning Classical & Operant Conditioning Chapter 8

  2. Associative Learning Learning that certain events occur together. Our minds naturally connect two events that occur in sequence. Conditioning is the process by which we learn associations between two events Classical Conditioning – When two events occur together, the one occurring first predicts the other Operant Conditioning – A response (behavior) and its subsequent consequence Both types of conditioning provide an evolutionary benefit

  3. Classical Conditioning Pavlov’s Accidental Discovery • Actually interested in studying the digestive system. • “Psychic Secretions” • Sight of food, food dish or presence of person who brought food • Began pairing neutral stimuli with food • Dogs began salivating to previously neutral stimuli.

  4. Basic Terminology Unconditioned Stimulus (US) – A stimulus that unconditionally (naturally and automatically) triggers a response. Unconditioned Response (UR) – The unlearned, naturally occurring response to a given stimulus. Conditioned Stimulus (CS) – An originally irrelevant stimulus that, after conditioning with a UR, comes to trigger a conditioned response. Conditioned Response (CR) – The learned response to a previously neutral (but now conditioned) stimulus.

  5. Classical Conditioning Equations Before Conditioning US (Food)= UR (Salivation) CS (Neutral Stimulus) = No Response During Conditioning CS+ US = UR After Conditioning CS = CR (Salivation) Notice the actual response behavior (salivation) did not change between the UR and CR, only the terminology! It changes terminology because it is no longer naturally elicited, it is conditioned.

  6. 5 Major Conditioning Processes • Acquisition – First stage in conditioning process where the association is learned. • In Classical Conditioning: Associates neutral stimulus (CS) with US, so that neutral stimulus comes to elicit a response (CR). • In Operant Conditioning: Phase concerned with the strengthening of a reinforced (either positive or negative) response. • Extinction – The diminishing of a conditioned response. • In Classical Conditioning: Occurs when US does not follow a CS • In Operant Conditioning: Occurs when behavior is no longer reinforced.

  7. 5 Major Conditioning Processes • Spontaneous Recovery – The reappearance of an extinguished response after a pause in the conditioning response. • Generalization – The tendency, once a response has been conditioned, for stimuli similar to the conditioned response to elicit a similar response. • Discrimination – The learned ability to distinguish between conditioned stimulus and stimuli that do not signal a UR. • Early in conditioning, generalization takes place, followed by discrimination

  8. Acquisition (CS+UCS) Strength of CR Spontaneous recovery of CR Extinction (CS alone) Extinction (CS alone) Pause Visual Representation of Acquisition, Extinction and Spontaneous Recovery

  9. 60 Drops of saliva in 30 seconds 50 40 30 20 10 Hind paw Pelvis Shoulder Front paw 0 Thigh Trunk Foreleg Part of body stimulated Visual Representation of Generalization

  10. Cognitive Processes and Learning • Historically, behaviorists believed that learned behaviors could be reduced to mindless mechanisms. Simple organisms had no cognitive processes. • Two Challenges to this assumption • Predictability – When two events occur in proximal time, an organism uses the first event as a predictor of the second. • Expectancy – The more reliable the association, the greater the organism’s expectancy of the second event and therefore, the greater the organism's conditioned response.

  11. Biological Predispositions Can an organism be conditioned to ANY neutral stimulus? Garcia & Koelling rat & radiation experiment CS: taste, sight or sound US: drug or radiation UR: nausea Results: Rats avoided taste, but not sight or sound. Rats only associated taste with UR. Even though US was introduced HOURS after CS, rats still learned association. This violated basic assumption that CS & US had to be presented in proximal temporal relationship.

  12. Biological Predispositions Humans and Bad Dining Experience US: Eating muscles UR: Nausea Is the CS sight of restaurant, music you heard while dining, or sight/smell of muscles? We learn associations that infer a survival advantage. You are unlikely to get sick from the sight of a place or music you heard, but you are likely to get sick from bad muscles. Therefore, we make the association between sight/smell of food and nausea, not restaurant or music and nausea. Therefore: CS = sight/smell; CR = nausea

  13. Biological Predispositions • Major Principles: • Learning allows organism’s to adapt to their environment. Adaptation shows why animals would be responsive to stimuli that announce significant events (ex. food or pain). • Causes often immediately precede effects, thus the predisposition to associate CS with US that follows predictably, reliably and immediately. • We learn associations that make biological sense. This is why we associate sight/smell of muscles with nausea, not place or music.

  14. Operant Conditioning The type of learning in which behavior is strengthened (increases) if followed by a reinforcer, or diminished (decreases) if followed by punishment. Thorndike’s Law of Effect: Behaviors that are followed by favorable consequences become more likely to be repeated; behaviors that are followed by an unfavorable consequences are less likely to be repeated in the future.

  15. Respondent vs. Operant Behavior Respondent Behavior – Behavior that occurs as an automatic response to a given stimulus. (Skinner’s term for behavior learned through Classical Conditioning. Operant Behavior – Behavior that operates on the environment, producing consequences (ex. Kicking the dog). These two types of behavior allow us to distinguish between Classical and Operant Conditioning: Is the organism learning associations between events that it doesn’t or can’t control (acting in an automatic response)? = Classical Conditioning Is the organism learning associations between its behavior, which operates on the environment and produces the resulting events? = Operant Conditioning

  16. Reinforcement A reinforcement is any event that STRENGTHENS the behavior it follows. Positive Reinforcement – Increasing behaviors by presenting a positive stimulus Positive Reinforcer – Any stimulus that, when presentedafter a response strengthens the preceding behavior. Negative Reinforcement – Increasing behaviors by removing or reducing a negative stimulus. Negative Reinforcer – Any stimulus that, when removedafter a response strengthens the preceding behavior

  17. Reinforcement • Shaping – Procedure in which reinforcers guide behavior closer and closer to a desired behavior. • Example: Rat and bar pressing • Primary vs. Conditioned (Secondary) Reinforcers • Primary reinforcers: An innately reinforcing stimulus, such as one that satisfies a biological need. (ex. food) • Conditioned reinforcers: A stimulus that gains its reinforcing power through its association with a primary reinforcer. (ex. money, which can buy food) • Immediate vs. Delayed Reinforcement

  18. Reinforcement Schedules • Continuous: reinforce the desired response every time it occurs; learning occurs rapidly, but so does extinction • Intermittent (Partial): reinforcing a response only part of the time; results in slower acquisition of a response but has much greater resistance to extinction than does continuous reinforcement

  19. 4 Types of Intermittent Reinforcement Fixed-ratio (FR): Reinforces only after a specified number of responses. Produces high number of responses, because the more responses the more reinforcement Variable-ratio (VR): Reinforces a response after an unpredictable number of responses. Again, produces high number of responses, because the more responses the more reinforcement. Very resistant to extinction because reinforcement is hard to predict, therefore the next response may be the one that “pays off” (Classic example of VR is gambling)

  20. 4 Types of Intermittent Reinforcement Fixed-interval (FI): Reinforces a response only after a specified time has elapsed. Variable-interval (VI): Reinforces a response at unpredictable time intervals. Produces slow steady responding

  21. Number of responses Fixed Ratio 1000 Variable Ratio Fixed Interval 750 Rapid responding near time for reinforcement 500 Variable Interval 250 Steady responding 0 10 20 30 40 50 60 70 80 Time (minutes) Visual Representation of Reinforcement Schedules

  22. Punishment A punishment is any event that DECREASES the behavior that follows Positive Punishment – Administering an adverse stimulus after an undesired behavior. Negative Punishment – Withdrawing a desirable stimulus after an undesired behavior. Like reinforcement, punishment works best when it is administered strongly, immediately and consistently.

  23. Unintended Consequences of Punishment Punishment increases humans’ tendency to be aggressive. (ex. Most abusive parents and aggressive children come from families with abusive backgrounds) A child may learn to fear, not only the undesired behavior, but also the person administering the punishment. Punishment may not actually suppress the undesired behavior . (ex. A child may learn not to swear at home, but then swears when around his/her friends) If punishment is unpredictable and inescapable, humans and animals may develop a sense that events are beyond their control and may become helpless and depressed. “Learned Helplessness” Even though punishment suppresses unwanted behavior, it does not guide one to a desirable alternative behavior.

  24. Cognitive Processes Expectations – That animals use expectations to estimate when a reinforcement is likely to be presented shows evidence of cognitive processes in play. (Ex. animal on FI reinforcement schedule shows high rates of responding when time approaches when a response will produce a behavior. Cognitive Map – A mental representation of the layout of one’s environment. Rats use cognitive maps of mazes. After running the maze a few times, it knows where it is going. Latent Learning – Learning that occurs but is not apparent until there is an incentive to demonstrate it. (Ex. “Sightseer rats” Intrinsic vs. Extrinsic Motivation Over-justification effect

  25. Biological Predispositions Just as in Classical Conditioning, biological constraints apply to Operant Conditioning. Can Teach: Pigeon to flap wings to avoid shock Pigeon to peck button to receive food reward Can’t Teach Pigeon to flap wings to receive food reward Pigeon to peck to avoid shock Why?

  26. Applications of Operant Conditioning At School – Use of teaching machines (computers) and textbooks that provide immediate feedback would shape learning in small steps. In Sports – Golfers and Baseball athletes learning swing through small steps At Work – Profit sharing; when productivity increases, workers receive bonus check. At Home – Economic rule of thumb. Other examples: give children reinforcers for good behavior, ignore bad behavior. With Self – State goals, monitor, reinforce desired behavior (ex. snack after specified amount of study time has elapsed), decrease reinforcement as behavior becomes habitual.

  27. Observational Learning Modeling – Process of observing and imitating a specific behavior. Mirror Neurons – Frontal lobe neurons (adjacent to motor cortex) that fire when performing certain motor actions (such as grasping, holding or tearing) or when observing others doing so. The brain’s mirroring of another’s actions may enable imitation, language learning, empathy and theories of the mind. Observational Learning and Behavior Antisocial Behavior – Bandura’s Experiment: Bobo the doll Prosocial Behavior – Ghandi & Martin Luther King, Jr. Hypocritical Behavior – “Do as I say, not as I do” TV and Observational Learning – Aggressive Behavior

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