Chapter 4. Learning

CHAPTER FOUR LEARNING 1 What is learning? Learning occurs when experience causes a relatively permanent change in an individual's knowledge or behavior. The change may be deliberate or unintentional, for better or for worse, correct or incorrect, and conscious or unconscious. This change must be brought about by experience. Changes caused by maturation, such as growing taller, do not qualify as learning. Temporary changes resulting from illness, fatigue, or hunger are also excluded from a general definition of learning. 2 Con. •Learning is process through which experience causes permanent change in knowledge, thoughts, feelings or behavior. 3 Early explanations of learning Contiguity and classical conditioning One of the earliest explanations of learning came from Aristotle. He said that we remember things together (1) when they are similar, (2) when they contrast, and (3) when they are contiguous (connected). This last principle is the most important, because it is included in all explanations of learning by association. . 4 contiguity The principle of contiguity states that whenever two or more sensations occur together often enough, they will become associated. Later, when only one of these sensations ( a stimulus) occurs, the other will be remembered too (a response). Contiguity plays a major role in another learning process best known as classical conditioning. 5 Classical conditioning Classical conditioning builds on reflexes: We begin with an unconditioned stimulus (ucs) and an unconditioned response (ucr) -- a reflex! We then associate a neutral stimulus (ns) with the reflex by presenting it with the unconditioned stimulus. Over a number of repetitions, the neutral stimulus by itself will elicit the response! At this point, the neutral stimulus is renamed the conditioned stimulus (cs), and the response is called the conditioned response (cr). 6 Con. Or, to put it in the form that Pavlov observed in his dogs, some meat powder on the tongue makes a dog salivate. Ring a bell at the same time, and after a few repetitions, the dog will salivate upon hearing the bell alone -- without being given the meat powder! The dog associates the ringing of a bell with the presentation of food. The meat powder is the unconditioned stimulus and the salivating is, at first, the unconditioned responses. At first the bell is a neutral stimulus, but after conditioning, it becomes the conditioned stimulus and the salivating becomes the conditioned response. 7 Con. Classical conditioning can work on any reflex, including the orienting reflex (which makes you pay attention to new stimuli), the startle reflex (which makes you jump at disturbing stimuli), emotional reflexes (such as fear), and taste aversions (such as a distaste for sour or bitter). The first American follower of Pavlov was John Watson. His best known experiment was conducted in 1920. “Little” Albert B, an 11 month old child, was conditioned to fear a white rat by pairing it with a loud noise (which leads to the startle reflex, i.e. a good scare). 8 Con. His fear quickly generalized to white rabbits, fur coats, and even cotton. Later, another child, three year old Peter, was gradually “de-conditioned” from his fear of white rabbits by pairing white rabbits with milk and cookies and other positive things. But we should note that, even if they didn't "decondition" him, he would have eventually lost his fear, a process called extinction. 9 Operant Conditioning • a form of learning that takes place when an instance of spontaneous behavior is either reinforced by a reward or discouraged by punishment. The principles involved have had a strong influence on behavior modification as well as on other kinds of therapy. 10 Operant Conditioning (cont.) Operant conditioning is based on consequences: The organism is in the process of “operating” on the environment, which in ordinary terms means it is bouncing around it world, doing what it does. During this “operating,” the organism encounters a special kind of stimulus, called a reinforcer. This special stimulus has the effect of increasing the likelihood of the behavior which occurred just before the reinforcer. This is operant conditioning: “the behavior is followed by a consequence, and the nature of the consequence modifies the organism’s tendency to repeat the behavior in the future.” 11 Con. • A behavior followed by a reinforcing stimulus results in an increased probability of that behavior occurring in the future. • A behavior no longer followed by the reinforcing stimulus results in a decreased probability of that behavior occurring in the future. 12 Negative Reinforcement • Before heading out for a day at the beach, you slather on sunscreen (the behavior) in order to avoid getting sunburned (removal of the aversive stimulus). • You decide to clean up your mess in the kitchen (the behavior) in order to avoid getting in a fight with your roommate (removal of the aversive stimulus). 13 Shaping Shaping, or “the method of successive approximations.” Basically, it involves first reinforcing a behavior only similar to the one desired. Once that is established, you look out for variations that come a little closer to what you want, and so on, until you have the animal performing a behavior that would never show up in ordinary life. 14 Punishment Punishment usually involves an aversive stimulus is the opposite of a reinforcing stimulus, something we might find unpleasant or painful. A behavior followed by an aversive stimulus results in a decreased probability of the behavior occurring in the future. 15 Positive Punishment • You are probably thinking 'How can a punishment be positive?' Receiving a speeding ticket as a result of driving 20 miles over the speed limit is an example of a positive punishment. Positive punishments decrease behaviors by adding an unpleasant outcome or consequence after the undesirable behavior. When you were speeding, the cop wrote you a ticket in order to decrease the chances of you speeding again. 16 Negative Punishment • Examples of Negative Punishment • After getting in a fight with his sister over who gets to play with a new toy, the mother simply takes the toy away. • A teenage girl stays out for an hour past her curfew, so her parents ground her for a week. • 17 Negative Punishment • A third-grade boy yells at another student during class, so his teacher takes away "good behavior" tokens that can be redeemed for prizes. • Can you identify the examples of negative punishment? Losing access to a toy, being grounded and losing reward tokens are all examples of negative punishment. In each case, something good is being taken away as a result of the individual's undesirable 18 behavior. Con. On the other hand, if you remove an already active aversive stimulus after Ali performs a certain behavior, you are doing negative reinforcement. when the aversive stimulus stops, that this serves as a reinforcer! Behavior followed by the removal of an aversive stimulus results in an increased probability of that behavior occurring in the future. 19 Reinforcement Schedules There are two major types of reinforcement schedules: 1. Continuous reinforcement schedule: It means reinforcing every correct response. It is very important to condition a new response. After a response has been conditioned, partial or intermittent reinforcement is more effective. 2. Intermittent reinforcement schedule: It is called partial reinforcement which operates when some but not all responses are 20 reinforced. Reinforcement Schedules In intermittent reinforcement, the behavior may sometimes be rewarded and is not rewarded in some other times. Gambling is an example of this. There are four types of intermittent reinforcement schedules which are: 1. Fixed-interval 2. Variable-interval 3. Fixed-ratio 4. Variable-ratio 21 Reinforcement Schedules Fixed-interval schedule: In this type of schedule, a fixed period of time must elapse between one reinforced response and the next. Example of this (fixed-salaried employees). Variable-interval: • where a response is rewarded after an unpredictable amount of time has passed. This schedule produces a slow, steady rate of response. 22 Reinforcement Schedules Characteristics of this schedule: • Very resistant to extinction • The rate of response is relatively slow, but steady • Very minimal pause after reinforcement is given. Examples: - Checking Your Email: Typically, you check your email at random times throughout the day instead of checking every time a single message is delivered. - Your Employer Checking Your Work: 23 Reinforcement Schedules • Does your boss drop by your office a few times throughout the day to check your progress? This is an example of a variable-interval schedule. These check-ins occur at unpredictable times, so you never know when they might happen. 24 Reinforcement Schedules Fixed-ratio schedule: • It means that reinforcement should be delivered after a constant or “fixed” number of correct responses. For example, a fixed ratio schedule of 2 means reinforcement is delivered after every 2 correct responses. The chosen number could be 5, 10, 20 or it could be 100 or more; there is no limit but the number must be defined. It means to reinforce every two times response or every three times ..etc. 25 Reinforcement Schedules Variable-ratio Schedule: When using a variable-ratio (VR) schedule of reinforcement the delivery of reinforcement will “vary” but must average out at a specific number. Just like a fixed-ratio schedule, a variable-ratio schedule can be any number but must be defined. For example, a teacher following a “VR2” schedule of reinforcement might give reinforcement after 1 correct response, then after 3 more correct responses, then 2 more, then 1 more and finally after 3 more correct responses. 26 Problems Associated with the Use of Punishment • Punishment does not extinguish an undesirable behavior. It suppresses that behavior when the punishing agent is present. • Punishment indicates that a behavior is unacceptable but does not help people develop more appropriate behavior. If punishment is used it should be administered in conjunction with reinforcement or reward for appropriate behavior. 27 Problems Associated with the Use of Punishment • The person who is severely punished often becomes fearful and feels angry and hostile towards punisher. • Punishment frequently leads to aggression. 28 Making Punishment More Effective • Punishment is most effective when it is applied during the misbehavior or as soon afterword as possible. • Punishment should be of the minimum severity necessary to suppress the problem behavior. • Punishment must be applied consistently. Not to punish behavior once and ignore it some other time. 29 Steps in Observational Learning According to Bandura, observational learning takes place through four steps: • Attention to the model’s behavior. • Retention: after paying attention to the model’s behavior, mental image of the model’s behavior is stored in memory so that it can be retrieved later. • Reproducing the action: any specific situation similar to the one stored in memory may trigger the individual to convert remembered behavior into action. • Motivation: involves remaining motivated to learn and 30 carry out the behavior. Cognitive Views of Learning According to the cognitive view, Knowledge is learned, and changes in knowledge make change in behavior possible. Both behavioral and cognitive theorists believes reinforcement is important in learning. Cognitive view learning: A general approach that views learning as an active mental process of acquiring, remembering, and using knowledge. 31 Learning by Insight • According to Kohler, a sudden recognition of relationships lead to solution of complex problem. • His experiment with chimpanzees. • His theory remains particularly important to understand cognitive learning. • Cognitive view of learning is a general approach that views learning as an active mental process of acquiring, remembering, and using knowledge. 32