Lecture 5 - Learning PDF

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Learning Learning – is any relatively durable change in behaviour or knowledge that is due to experience Classical Conditioning Conditioning – learning associations between events that occur in an organism’s environment Classical conditioning is a type of learning in which a stimulus acquires the capacity to evoke a response that was originally evoked by another stimulus Pavlovian condition 

Pavlov was studying the role of saliva in the digestive process of dogs

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He stumbled upon “Psychic reflexes”

He noticed that dogs accustomed to the procedure would start salivating before the meat powder was presented. For instance, they would salivate in response to a clicking sound made by the device that was used to present the meat powder. Intrigued by this unexpected finding, Pavlov decided to investigate further. He paired the presentation of the meat powder with various stimuli. In some experiments, he used a simple auditory stimulus— the presentation of a tone. After the tone and the meat powder had been presented together several times, the tone was presented alone. The dogs responded by salivating to the sound of the tone alone.

Terminologies Unconditioned stimulus (US) – stimulus that evokes an unconditioned response without previous conditioning Unconditioned response (UR) – an unlearned reaction to an unconditioned stimulus that occurs without previous conditioning Neutral Stimulus (NS) – a stimulus which does not originally produce a response to the unconditioned stimulus Conditioned stimulus (CS) – a previously neutral stimulus (NS) that has, through conditioning, acquired the capacity to evoke a conditioned response Conditioned response (CR) – a learned reaction to a conditioned stimulus that occurs because of previous conditioning, previously an UR

BEFORE: US  UR DURING: US + NS> CS AFTER: CS  CR

Classical conditioning in everyday life Conditioned fear & anxiety 

Phobias – are irrational fears of specific objects or situations.

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Everyday fear responses are also products of classical conditioning

Emotional Responses 

Pleasant emotional responses (E.g. Christmas music evokes positive emotions in many people)

Physiological Responses 

Functioning of the immune system

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Classical conditioning can lead to immunosuppression: a decrease in the production of anti-bodies

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Influence sexual arousal (E.g. Lingerie, candles, music)

Evaluative Conditioning of Attitudes 

Refers to changes in the liking of a stimulus that result from pairing that stimulus with a positive/negative stimulus

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Attitudes have to do with your preferences

Basic Processes in Classical Conditioning: 1. Acquisition: Forming New Responses 

The initial stage of learning a new response tendency

2. Extinction 

The gradual weakening and disappearance of a conditioned response tendency

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Extinction occurs when the conditioned stimulus is consistently presented alone, without unconditioned stimulus

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Conditioned fears are relatively hard to extinguish

3. Spontaneous Recovery 

The reappearance of an extinguished response after a period of no exposure to the conditioned stimulus

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Renewal effect – The phenomenon that occurs if a response is extinguished in a different environment than it was acquired; the extinguished response will reappear if the animal is returned to the original environment where acquisition took place

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Extinction does not appear to lead to unlearning

Stimulus Generalization 

Stimulus generalization – The phenomenon that occurs when an organism that has learned a response to a specific stimulus responds in the same way to new stimuli that are like the original stimulus

Stimulus Discrimination 

Stimulus discrimination – The phenomenon that occurs when an organism that has learned a response to a specific stimulus does not respond in the same way to new stimuli that are like the original stimulus

Higher-Order Conditioning 

In which a conditioned stimulus functions as if it were an unconditioned stimulus

Phase 1: -

A neutral stimulus is paired with an unconditioned stimulus, until it becomes conditioned

Phase 2: -

Another neutral stimulus is paired with the previously established CS

Operant Conditioning

Operant conditioning – A form of learning in which voluntary responses come to be controlled by their consequences 

Organisms tend to repeat responses that are followed by favorable consequences

Reinforcement – An event following a response that increases an organism’s tendency to make that response 

Everyday examples:

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Study to get good grades

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Work to get a paycheck Terminologies

Skinner Box (an operant chamber) – A small enclosure in which an animal can make a specific response that is systematically recorded while the consequences of the response are controlled 

The main response made available is pressing a small lever mounted on one side of the wall

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Because operant responses tend to be voluntary, they are said to be emitted than elicited

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To emit = to send forth

Reinforcement contingencies – The circumstances or rules that determine whether responses lead to the presentation of reinforcers 

The key dependent variable in most research on operant conditioning is the subjects’ response rate over time

Cumulative recorder – A graphic record of responding and reinforcement in a Skinner box as a function of time

Basic Processes in Operant Conditioning

1. Shaping 2. Extinction 3. Generalization 4. Discrimination Acquisition and Shaping 

Acquisition – is the initial stage of learning

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Procedures to create operant response is different from typical conditioned response

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Operant response – by shaping

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Shaping – which consists of repeatedly reinforcing closer and closer approximations of a desired response until the desired response is achieved

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Shaping is necessary when an organism does not, on its own, emit the desired response

Extinction 

Extinction begins in operant conditioning whenever previously available reinforcement is stopped

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Resistance to extinction – The phenomenon that occurs when an organism continues to make a response after delivery of the reinforcer for it has been terminated

Stimulus Control: Generalization and Discrimination 

Stimuli that precede a response can influence operant behavior

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Discriminative stimuli – Cues that influence operant behavior by indicating the probable consequences (reinforcement or nonreinforcement) of a response

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Reactions to a discriminative stimulus are governed by the processes of stimulus generalization and stimulus discrimination, just like reactions to a CS in classical conditioning

Reinforcement Behaviorists say reinforcement is not a reward because the experience of pleasure is an unobservable event that takes place within an organism 

The central process in reinforcement is the strengthening of a response tendency

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Reinforcement is defined after the fact, in terms of its effect on behavior

Primary reinforcers – Events that are inherently reinforcing because they satisfy biological needs Secondary (conditioned) reinforcers – Events that acquire reinforcing qualities by being associated with primary reinforcers A schedule of reinforcement determines which occurrences of a specific response result in the presentation of a reinforcer Continuous reinforcement occurs when every instance of a designated response is reinforced Intermittent, or partial, reinforcement occurs when a designated response is reinforced only some of the time

Ratio schedules require the organism to make the designated response a certain number of times to gain reinforcement 

With a fixed-ratio (FR) schedule, the reinforcer is given after a fixed number of nonreinforced responses

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With a variable-ratio (VR) schedule, the reinforcer is given after a variable number of nonreinforced responses

Interval schedules require a time period to pass between the presentation of reinforcers 

With a fixed-interval (FI) schedule, the reinforcer is given for the first response that occurs after a fixed time interval has elapsed

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With a variable-interval (VI) schedule, the reinforcer is given for the fi rst response after a variable time interval has elapsed

Positive/Negative Reinforcement •

Purpose of reinforcement – to desire and increase good behaviour

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Purpose of punishment – to reduce bad behaviour

Positive reinforcement occurs when a response is strengthened because it is followed by the presentation of a rewarding stimulus Negative reinforcement occurs when a response is strengthened because it is followed by the removal of an aversive (unpleasant stimulus)  Negative reinforcement plays a key role in both escape learning and avoidance learning  In escape learning, an organism acquires a response that decreases or ends some aversive stimulation  In avoidance learning an organism acquires a response that prevents some aversive stimulation from occurring Punishment occurs when an event following a response weakens the tendency to make that response

Negative reinforcement involves the removal of an aversive stimulus, thereby strengthening a response. Punishment, on the other hand, involves the presentation of an aversive stimulus, thereby weakening a response. Thus, punishment and negative reinforcement are opposite procedures that yield opposite effects on behavior!!

Changing Directions in the Study of Conditioning Recognizing Biological Constraints on Conditioning 

Conditioned Taste Aversion  Natural selection favors organisms that quickly learn what not to eat  Thus, evolution may have biologically programmed some organisms to learn certain types of associations more easily than other types

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Preparedness and Phobias  Preparedness – Species-specific predisposition to be conditioned in certain ways and not others  Phobias that are more common than others were once genuine threats to our ancient ancestors Recognizing Cognitive Constraints on Conditioning

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Latent Learning and Cognitive Maps  Latent learning – Learning that is not apparent from behavior when it first occurs  Findings suggested that learning can take place in the absence of reinforcement  Findings suggested that the rats who displayed latent learning had formed a cognitive map of the maze (a mental representation of the spatial layout)

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Signal Relations  Studies of signal relations have shown that the predictive value of a CS is an influential factor governing classical conditioning  These studies suggest that classical conditioning may involve information processing rather than reflexive responding

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Response-Outcome Relations and Reinforcement  Studies of response-outcome relations and reinforcement highlight the role of cognitive processes in conditioning  Skinner argued that “superstitious behavior” could be established through noncontingent reinforcement, which occurs when a response is accidentally strengthened by a reinforcer that follows it, even though delivery of the reinforcer was not a result of the response  Researchers eventually failed to replicate Skinner’s findings  Superstitious behavior is extremely common  Accidental reinforcements may sometimes contribute to these superstitions, along with various types of erroneous reasoning  Reinforcement is not automatic when favorable consequences follow a response Observational Learning

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A type of learning that occurs when an organism’s responding is influenced by the observation of others, who are called models

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Four key processes are crucial in observational learning

1. Attention. To learn through observation, you must pay attention to another person’s behavior and its consequences 2. Retention. A stored mental representation of what you have witnessed in your memory 3. Reproduction. The ability to reproduce the response by converting your stored mental images into overt behavior 4. Motivation. You are unlikely to reproduce an observed response unless you are motivated to do so. Your motivation depends on whether you encounter a situation in which you believe that the response is likely to pay off for you

Observational Learning and the Media Violence Controversy 

In Bandura’s research, children were more aggressive after watching violent videos (Eg. Bobo doll)

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Observational learning plays an important role in regulating behavior

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Media violence desensitizes people to the effects of aggression in the real world

Heredity and environment jointly influence behavior  All aspects of behavior could be explained in terms of environmental determinants  In recent decades, evidence on conditioned taste aversion and preparedness has shown that there are biological constraints on conditioning Psychology evolves in a sociohistorical context  Skinner’s ideas on the power of positive reinforcement have influenced patterns of discipline in American society  Research on operant conditioning has affected management styles in the business world, leading to an increased emphasis on positive reinforcement...