PSYC1010 Learning - Week 7 Slides PDF

PSYC1010 LEARNING Learning is.. What does it mean to learn something? How do we learn new things? What helps us learn and what hinders our learning?  Pavlov’s Unexpected Discovery  Pavlov was studying the secretion of stomach acids and salivation...

PSYC1010 LEARNING Learning is.. What does it mean to learn something? How do we learn new things? What helps us learn and what hinders our learning?  Pavlov’s Unexpected Discovery  Pavlov was studying the secretion of stomach acids and salivation in dogs in response to the ingestion of food.  Noticed the dogs secreted stomach acids and salivated even in the absence of food (sometimes to the sound of the experimenter’s footsteps or their mere presence).  He recognized that the dogs had learned an association between the stimuli that surrounded food and the food itself.  The dogs were responding not only based on biological need, but also as a result of learning (classical conditioning).  Classical Conditioning Type of learning in which a neutral stimulus (NS) comes to bring about a response after it is paired with an unconditioned stimulus (UCS) that would naturally bring about that response Involves 5 primary components: Neutral stimulus (NS) Unconditioned stimulus (UCS) Unconditioned response (UCR) Conditioned stimulus (CS) Conditioned response (CR)  The Basics of Classical Conditioning Neutral stimulus (NS): A stimulus that, before conditioning, does not naturally bring about the response of interest. Unconditioned stimulus (UCS): A stimulus that naturally brings about a particular response without having been learned. Unconditioned response (UCR): A response that is natural and needs no training (e.g., salivation at the smell of food). Conditioned stimulus (CS): A neutral stimulus that has been paired with an unconditioned stimulus to bring about a response formerly caused only by the unconditioned stimulus. Conditioned Response (CR): A response that, after conditioning, follows a previously neutral  Classical Conditioning Steps 1. Neutral stimulus (NS): does not elicit a particular response (e.g.,. metronome or bell) 2. Pair the NS repeatedly with unconditioned stimulus (UCS), which elicits an unconditioned response (UCR) Meat powder (UCS) and salivation (UCR) 3. Eventually, the NS becomes a conditioned stimulus (CS), eliciting a conditioned response (CR) Metronome or bell elicits salivation The Basics of Classical Conditioning  Remember:  Conditioned = learned; unconditioned = not learned.  An unconditioned stimulus leads to an unconditioned response.  An unconditioned stimulus triggers the unconditioned response innately (it is unlearned and untrained).  During conditioning, a previously neutral stimulus is transformed into the conditioned stimulus because it is being repeatedly paired with the unconditioned stimulus. The Basics of Classical Conditioning  Neutral stimulus & conditioned stimulus are the same stimulus.  Once the neutral stimulus triggers a response we no longer call it neutral. After conditioning has occurred we refer to the (previously) neutral stimulus as the conditioned stimulus.  Unconditioned response & conditioned response are the same response.  The difference between them is what triggers the response: the unconditioned response is triggered by the unconditioned stimulus while the conditioned response is triggered by the conditioned stimulus. Unlearning? What if we want to unlearn something? What if there is an association between two things that we don’t want to continue? How do we break that association?  Extinction  Occurs when a previously conditioned response decreases in frequency and eventually disappears.  To produce extinction, one needs to break the association between the CS and UCS.  Extinction occurs when the conditioned stimulus is presented repeatedly without the subsequent unconditioned stimulus.  E.g., the bell followed by no meat, over and over = extinction  However, sometimes extinction isn’t permanent, as spontaneous recovery can occur.  Stimulus Generalization & Discrimination  After a stimulus has been conditioned to produce a particular response, stimuli that are similar to that original stimulus produce a very similar response.  The greater the similarity between two stimuli, the greater the likelihood stimulus generalization will occur.  By contrast, if a stimuli is very different from the original conditioned stimulus, it will not produce a similar response.  Aka we are able to discriminate between the original conditioned stimulus and the new stimulus.  Evaluative Conditioning (a form of CC)  Changing the liking of a stimulus that results from pairing that stimulus with other positive or negative stimuli.  NS paired with UCS that triggers positive reactions, such that the NS becomes a conditioned stimulus that also elicits positive reactions.  e.g., marketing/advertising!  Conditioned Fears & Phobias Watson’s Little Albert experiment Initially, Albert showed no reaction to the rat other than interest, which meant the rat could be considered a (NS). Experimenters made a loud noise as they showed Albert a white rat and the noise (UCS) evoked fear (UCR). After a few pairings of the noise and rat, Albert began to show fear of the rat by itself, bursting into tears when he saw it. The rat had become a CS that elicited the CR, fear. The effects generalized, as Albert reacted with fear to objects that looked like the rat, e.g., a white rabbit, a white coat, and white Santa Claus mask. Conditioned Fears & Phobia Classical conditioning can lead to the development of fears (e.g., of the dentist, dog bites) and phobias, which are intense, irrational fears (e.g., insects). Posttraumatic stress disorder (PTSD), suffered by some people who have had traumatic experiences, can also be explained by classical conditioning. Even years after their traumatic experience, a stimulus such as a loud noise may trigger an emotional response of fear or panic.  Conditioned Taste Aversions  People develop aversions to food that was followed by nausea or illness.  E.g., Seligman’s “sauce Bearnaise syndrome”  Seems like straightforward classical conditioning, but is it?  Lengthy delay between food and illness  Why only the sauce as a CS?  Biological Preparedness Theory = our propensity to learn certain classically conditioned associations over others that is linked to our evolutionary history. OPERANT CONDITIONING The Powerful Role of Rewards and Punishments  Operant Conditioning  Learning in which a voluntary response is strengthened or weakened, depending on its favourable or unfavourable consequences.  This is contrary to classical conditioning in which the original behaviours are the natural, biological responses to the presence of some stimulus such as food, water, or pain (and are thus involuntary).  Thorndike’s Law of Effect  Responses that lead to satisfying consequences are more likely to be repeated (responses followed by negative outcomes are less likely to be repeated. He believed that this would operate automatically & over time and through experience the organism would make a direct connection between the stimulus and the response without any awareness that the connection  The Basics of Operant Conditioning  Thorndike’s research influenced B. F. Skinner, who created the The Skinner box: a chamber with a highly controlled environment used to study operant conditioning processes with lab animals.  Thorndike’s goal was to get his cats to learn to obtain food by leaving the box, animals in a Skinner box learn to obtain food by operating on their environment within the box.  Skinner became interested in specifying how behaviour varied as a result of alterations in  Reinforcement  Process by which a stimulus increases the probability that a preceding behaviour will be repeated.  A reinforcer is any stimulus that increases the probability that a preceding behaviour will occur again.  Primary reinforcer: satisfies biological need and works naturally, regardless of a person’s prior experience (ex. food, warmth).  Secondary reinforcer: a stimulus that becomes reinforcing because of its association with a primary reinforcer (ex. money).  Shaping  Process of teaching a complex behaviour by rewarding closer and closer approximations of the desired behaviour.  You start by reinforcing any behaviour that is similar to the behaviour you want the person to learn.  Later, you reinforce only responses that are closer to the behaviour you ultimately want to teach.  Finally, you reinforce only the desired response.  Positive Reinforcers & Negative Reinforcers  Positive reinforcer: a stimulus added to the environment that brings about an increase in a response.  Negative reinforcer: an unpleasant stimulus whose removal increases the probability that a response will be repeated in the future.  Like positive reinforcers, negative reinforcers increase the likelihood that certain behaviours will be repeated.  Positive Reinforcers & Negative Reinforcers Pressing the snooze button is so Companies use positive negatively reinforcing that many of us reinforcement in like points and have been conditioned to do it in our rewards to encourage brand sleep. The negative reinforcement of loyalty. Points are awarded to unpleasant sound of your reinforce the behaviour of alarm stopping is very powerful. purchasing their products. Pressing the snooze button is reinforced by the stopping the sound of the alarm.  Positive Punishment & Negative Punishment  Punishment is a stimulus that decreases the probability that a prior behaviour will occur again.  Positive punishment: introducing an unpleasant stimulus decreases the likelihood that a certain behaviour will be repeated in the future.  Negative punishment: removing a pleasant stimulus decreases the likelihood that a certain behaviour will be repeated in the future.  Positive Punishment & Negative Punishment A speeding ticket is positive punishment Being towed from an illegal parking spot by application—you receive something is an example of negative punishment. unpleasant (the ticket) as a punishment Your car is removed to punish the for the behaviour of speeding. behaviour of parking illegally.  More Examples of Reinforcements and Punishment The Pros and Cons of Punishment  Several disadvantages to use of punishment.  It is frequently ineffective, particularly if the punishment is not delivered shortly after the target behaviour.  It may fail to produce long-lasting behavioural change.  Physical punishment conveys the idea that physical aggression is acceptable, even desirable.  It can decrease the self-esteem of recipients.  Reinforcing desired behaviour is a more appropriate technique for modifying behaviour than punishment. Schedules of Reinforcement  Different patterns of frequency and timing of reinforcement following desired behaviour.  Continuous reinforcement: Reinforcing a behaviour every time it occurs  Ex. Working on an hourly based wage.  Partial (intermittent) reinforcement: Reinforcing a behaviour some, but not all of the times it occurs.  Ex. Working on a commission-based wage.  Behavior learned under partial reinforcement is more robust and longer lasting than behaviour learned under continuous reinforcement. Schedules of Reinforcement Two main categories: Fixed-ratio & Variable-ratio schedules: Schedules that consider the # of responses made before reinforcement is given. Fixed-interval & Variable-interval schedules: Schedules that consider the The variable-ratio schedule of a slot amount of time that elapses before machine means that gamblers will develop reinforcement is given. a high-frequency, extinction-resistant behaviour. This is why gambling can become an addiction that is hard to treat.  Fixed- and Variable-Ratio Schedules  Fixed-ratio schedule: A schedule by which reinforcement is given only after a specific # of responses are made.  Variable-ratio schedule: A schedule by which reinforcement occurs after a varying #of responses.  Variable-ratio schedules produce a high rate of response & more resistant to extinction than fixed-ratio schedules.  Fixed- and Variable-Interval Schedules  Fixed-interval schedule: a schedule that provides reinforcement for a response only if a fixed time period has elapsed, making overall rates of response relatively low.  Variable-interval schedule: A schedule by which the time between reinforcements varies rather than being fixed.  Variable-interval schedules are more likely to produce steady rates of responding than are fixed-interval schedules & responses take longer to extinguish after reinforcement ends.  Discrimination and Generalization  Like CC, OC involves of processes of discrimination and generalization.  Stimulus control training: process by which people learn to discriminate stimuli, where a behaviour is reinforced in the presence of a specific stimulus, but not in its absence.  A discriminative stimulus signals the likelihood that reinforcement will follow a response. ▪ e.g., pigeons learn that when a green light is on, food will follow, but when a red light is on, no food will follow.  Latent Learning (Tolman) Tolman challenged behaviourist view of learning, arguing that: We engage in latent learning: learning that isn’t apparent from behaviour when it first occurs. Learning can take place in absence of reinforcement! Rat Maze Study of Latent Learning: 3 conditions to experiment, rats to go through maze over 3 weeks: C1) Rats got cheese as reward at end of maze each day. C2) Rats received no reward. C3) Rats received no reward for first 10 trial days, then reinforced from 11th trial day onward.  Observational Learning Learning by observing the behaviour of another person and by watching whether they are rewarded or punished for it. Bandura’s Famous Bobo Doll experiments! Demonstrated the importance of models (particularly same sex models), and of whether the model is rewarded for their behaviour. Q - What do think this suggests about the risks of childhood exposure to violent media?  Violence in Television and Video Games: Does the Media’s Message Matter? Experiencing high levels of media violence makes viewers more susceptible to behaving aggressively.  It lower inhibitions against carrying out aggression.  It distorts our understanding of the meaning of others’ Illustrating observational learning, this infant behaviour. observes an adult on the television and then is able to imitate his behaviour. Learning has obviously occurred through the mere  It desensitizes us to observation of the television model. violence.