Theories of Learning

Transcription

1 Theories of Learning

2 Learning Classical conditioning Classical conditioning in real life Operant conditioning Operant conditioning in real life Learning and the mind

3 Watson s Extreme Environmentalism Give me a dozen healthy infants, wellformed, and my own special world to bring them up in, and I ll guarantee to take any one at random and train him to be any type of specialist I might select - doctor, lawyer, artist, merchant-chief, and yes, beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. John Broadus Watson, 1928

4 Classical Conditioning Defining learning, behaviorism, and conditioning New reflexes from old Principles of classical conditioning What is actually learned in classical conditioning?

5 Defining Learning, Behaviorism and Conditioning Learning A relatively permanent change in behavior (or behavior potential) due to experience. Behaviorism Research on learning has been influenced by this approach to psychology that emphasizes the study of observable behavior and the role of the environment as a determinant of behavior. Conditioning The association between environmental stimuli and the organisms responses.

6 Social-Cognitive Learning Theories Do not omit mental processes from explanations of human learning. Learning is not so much a change in observable behavior as a change in knowledge that has the potential for affecting behavior. Emphasize learning by observation and imitation, positive consequences, and cognitive processes such as plans, expectations, and beliefs.

7 Classical Conditioning The process by which a previously neutral stimulus acquires the capacity to elicit a response through association with a stimulus that already elicits a similar or related response.

8 Pavlov s Apparatus Harness and fistula (mouth tube) help keep dog in a consistent position and gather uncontaminated saliva samples. They do not cause the dog discomfort.

9 New Reflexes from Old Unconditioned stimulus (US) Elicits a response in the absence of learning. Unconditioned response (UR) The reflexive response to a stimulus in the absence of learning.

10 New Reflexes from Old A neutral stimulus is then regularly paired with an unconditioned stimulus.

11 New Reflexes from Old Conditioned stimulus (CS) An initially neutral stimulus that comes to elicit a conditioned response after being paired with an unconditioned stimulus. Conditioned response (CR) A response that is elicited by the conditioned stimulus. Occurs after the CS is associated with the US. Is usually similar to US.

12 Principles of Classical Conditioning Extinction Higher-order conditioning Stimulus generalization Stimulus discrimination

13 Extinction The weakening and eventual disappearance of a learned response. In classical conditioning, it occurs when the conditioned stimulus is no longer paired with the unconditioned stimulus.

14 Acquisition and Extinction

15 Higher-Order Conditioning A neutral stimulus can become a conditioned stimulus (CS) by being paired with an existing conditioned stimulus (CS).

16 Stimulus Generalization In classical conditioning, occurs when a new stimulus that resembles the conditioned stimulus, elicits the conditioned response.

17 Stimulus Discrimination The tendency to respond differently to two or more similar stimuli. In classical conditioning, it occurs when a stimulus similar to the condition stimulus (CS) fails to evoke a conditioned response (CR).

18 What is learned in classical conditioning? For classical conditioning to be most effective, the stimulus to be conditioned should precede the unconditioned stimulus. We learn that the first event (stimulus) predicts the second.

19 Classical Conditioning in Real Life Learning to like Learning to fear Accounting for taste Reacting to medical treatments

20 Learning to Like Where do sentimental feelings come from? Objects have been associated in the past with positive feelings.

21 Learning to Fear Research suggests we can learn fear through association. Watson and Raynor conditioned Little Albert to be afraid of white rats by pairing the neutral stimulus (rats) with a unconditioned stimulus (loud noise). Within days, Albert was not only afraid of the rats, his fear had generalized to other furry objects.

22 Counterconditioning Unlearning Fear The process of pairing a conditioned stimulus with a stimulus that elicits a response that is incompatible with an unwanted conditioned response. Another child s fear of rabbits was removed by pairing the stimulus which elicited fear with a stimulus that elicited happiness.

23 Accounting for Taste Classical conditioning can also explain how we learn to like and dislike many foods and odours. Researchers have taught animals to dislike foods or odours by pairing them with drugs that cause nausea or other unpleasant symptoms. Humans also quickly learn to associate illness with food even when the food is not the cause of becoming sick.

24 Reacting to Medical Treatments Stimuli associated with drug treatments that produce nausea can become conditioned stimuli, creating problems for cancer patients undergoing chemotherapy. Non-drug treatments, such as placebos, are a beneficial application of classical conditioning, through association with real drugs.

25 Operant Conditioning Defining operant conditioning The consequences of behavior Reinforcers and punishers Principles of operant conditioning Schedules of reinforcement Shaping Operant conditioning in real life

26 Operant Conditioning The process by which a response becomes more or less likely to occur depending on its consequences.

27 Consequences of behavior A neutral consequence neither increases or decreases the probability that the response will recur. Reinforcement strengthens the response or makes it more likely to recur. Punishment weakens a response or makes it less likely to recur.

28 Reinforcement A stimulus strengthens or increases he probability of the response that it follows. Primary reinforcers are inherently reinforcing and typically satisfy a physiological need. Secondary reinforcers are stimuli that have acquired reinforcing properties through associations with other reinforcers.

29 Types of Reinforcement Positive reinforcement when a pleasant consequence follows a response, making the response more likely to occur again. Negative reinforcement when a response is followed by the removal of something unpleasant, making the response more likely to occur again.

30 Punishment The process by which a stimulus weakens or reduces the probability of the response that it follows. Primary punisher Something that is inherently punishing such as electric shock. Secondary punisher A stimulus that has acquired punishing properties through an association with other punishers.

31 Types of Punishers Positive punisher When something unpleasant occurs after a behavior. Negative punisher When something pleasant is removed after a behavior.

32 The Skinner Box

33 Principles of Operant Conditioning Extinction In operant conditioning, it occurs when a response is no longer followed by a reinforcer. Stimulus generalization Stimuli that are similar to the original stimulus are more likely to trigger a response. Stimulus discrimination The tendency of a response to occur in the presence of one stimulus but not another.

34 Schedules of reinforcement Continuous A particular response is always reinforced. Intermittent (Partial) A particular response is sometimes but not always reinforced. Fixed-ratio, variable-ratio, fixed interval, and variable-interval. Best choice for response to continue.

35 Schedules of Reinforcement Simple reinforcement schedules produce characteristic response patterns. Steeper lines mean higher response rates. Ratio schedules produce higher response rates than interval schedules.

36 Partial Reinforcement

37 Shaping To teach complex behaviors, may need to reinforce successive approximations of a desired response. For example, training animals, getting children to make their beds.

38 Biological Limits on Learning All principles of operant conditioning are limited by an animal s genetic dispositions and physical characteristics. During operant learning, organisms tend to revert to instinctive behavior, called instinctive drift.

39 Operant Conditioning in Real Life Behaviour modification the application of conditioning techniques to teach new responses or to reduce or eliminate undesirable ones. The pros and cons of Punishment When punishment works. When punishment fails. The problems with reward

40 When Punishment Works Immediately punishing a self-destructive behavior eliminates it. Milder punishments appear to work as well as harsh ones. Consistency is important.

41 When Punishment Fails People often administer punishment inappropriately or mindlessly. The recipient often responds with anxiety, fear, or rage. The effectiveness is often temporary. Most misbehavior is hard to punish immediately. Punishment conveys little information. An action intended to punish may instead be reinforcing.

42 Extrinsic and Intrinsic Reinforcers Extrinsic reinforcers. Reinforcers that are not inherently related to the activity being reinforced. Intrinsic reinforcers Reinforcers that are inherently related to the activity being reinforced. Extrinsic reinforcers may undermine intrinsic reinforcers.

43 Why Rewards Can Backfire Preschoolers played with felt-tipped markers and observed Divided into 3 groups: Given markers again and asked to draw Promised a reward for playing with markers Played with markers, then rewarded

44 Learning and the Mind Latent learning. Social-Cognitive learning theories.

45 Latent Learning (Tolman) Rats: one maze trial/day. One group found food every time (red line). Second group never found food (blue line). Third group found food on Day 11 (green line). Sudden change, Day 12. Learning isn t the same as performance.

46 Social-Cognitive Learning Social cognitive theories emphasize how behavior is learned and maintained: through observation and imitation of others, positive consequences, cognitive processed such as plans, expectations, and beliefs. Observational learning involves learning new responses by observing the behavior of another rather than through direct experience; sometimes called vicarious conditioning.

47 Bandura, Ross and Ross, Nursery school children watched a film of 2 men (Johnny and Rocky) playing with toys. Johnny refuses to share and Rocky hits him, ending up with all the toys. Children who watched the video were significantly more violent than children in a control group.

48 The Case of Media Violence. The greater the exposure to violence in movies or television, the stronger the likelihood of a person s behaving aggressively. This is not true for all children. Effects of violence are worse for children and adults already predisposed to aggressive behavior.