5.1 Learning, Experience and Change

What is Learning?

Two different psychology fields provide these two definitions

Behaviorists: a relatively permanent change in behavior that results from practice or experience.

Cognitive Psychologist: the process by which organisms change the way the represent the environment because of experience.

• The main difference between the two views is that one defines it as a change in behavior and the other defines it as a change of the way the organism sees the environment.

One of the main contributors to the field of Learning in Psychology was Ivan Pavlov .

• His research in learningwith dogs helped us understand how we, and other animals, learn. 
• We will study his research on Classical Conditioningthe next sections.

Classical Conditioning: A simple form of learning in which a neutral stimulus comes to evoke response, usually evoked by another stimulus by being paired repeatedly by the other stimulus.

Example:  We are conditioned to cringe in anticipation of thunder when we see lighting.  This is something we have learned!!

Stimulus 1: Lighting +  Stimulus 2: Thunder

Stimulus: We see lighting | Response: We wince, anticipating thunder.

But… what is a stimulus?

The definition of a stimulus is an environmental condition that elicits a response.  In the previous example lighting and thunder are the stimuli.

5.2 Classical Conditioning

Classical Conditioning (note: Conditioning = Learning): a simple form of learning in which a neutral stimulus comes to evoke response, usually evoked by another stimulus by being paired repeatedly by the other stimulus.

It is also known as Pavlovian conditioning, after the famous scientist Ivan P. Pavlov (1849-1936), who is credited with being the first who systematically studied this type of learning.  In Pavlov’s experiments, he conditioned dogs to salivate at the sound of a metronome. In this example we will substitute the sound of a metronome with the sound of a bell.

There are three  stages of Classical Conditioning:

1. BeforeConditioning (Before Learning)
2. DuringConditioning (During Learning)
3. AfterConditioning (After Learning)

This is how classical conditioning works:

1. Before Conditioning (learning) Occurs:

• • In this example the  Bell or Neutral Stimulus (NS)means nothing to the dog, which triggers NO RESPONSE
  • However the Meat which is an Unconditioned Stimulus (UCS)makes the dog salivate which elicits an Unconditioned Response (UCR).
  • Note that they are named UNconditioned(“Un-Learned”) because the stimulus have not been paired with anything and the response has not been learned. It is a “natural response” for the dog to salivate in the presence of meat. In other words, food evokes a reflex: a biological response that it is NOT learned.
  • And also note that the bell means nothing to the dog, which leads to no response.

2. During Conditioning (During Learning): In this stage the dog is conditioned (learns) that every time the bell sounds or (NS) the meat (UCS) will be presented.

• • This pairing happens several times, while the dog learns.
  • This pairing produces salivation.
  • The once Neutral Stimulus (NS), the bell, is now the Conditioned Stimulus (CS)

3. After Conditioning (After Learning): The formerly Neutral Stimulus now elicits the response, which is now a learned or conditioned response (CS).

• At this point  that the meat is Not Present anymore, but …..
• …the dog still salivates!!! Note that this response is now called: Conditioned Response (CR) because the dog had learned (or conditioned) that the sound of the bell means that food is soon coming.

A few definitions and their abbreviations:

• Neutral Stimulus (NS)–   A stimulus that elicits no response before conditioning (learning). Ex. Bell tone
• Unconditioned Stimulus (UCS)– A stimulus that elicits a response before conditioning (learning). Ex. Meat
• Unconditioned Response (UCR) – An unlearned response to an unconditioned stimulus. Ex. Salivation to Meat
• Conditioned Stimulus (CS)– A previously neutral stimulus that elicits a Conditioned Response, because it has been paired repeatedly with a stimulus that already elicited a response. Ex. Bell tone, after conditioning have occurred
• Conditioned Response (CR)– a learned response to a Conditioned Stimulus. Ex. Salivation in response to the Bell Tone.

5.2a Explaining Classical Conditioning

There are two views on how Psychologists explain classical conditioning.

• Behaviorist Psychologists:publicly observable conditions of learning.
  • Dog learned to salivate in response to the tone because the tone had been paired with meat powder.
• Cognitive Psychologists:the relationship between events allows the organisms to mentally represent their environment and make predictions
  • Dog salivated in response to the tone since the tone became mentally connected with the meat.

NOTE: The following are some of the abbreviations used in this chapter (NS, UCS, UCR, CS, CR) refer to this page if you forget what they mean.

By using Pavlov’s Example:

• Neutral Stimulus (NS) – A stimulus that elicits no response before conditioning (learning)
  • Bell tone
• Unconditioned Stimulus (UCS)– A stimulus that elicits a response before conditioning (learning)
• • Meat
• Unconditioned Response (UCR) – An unlearned response to a unconditioned stimulus
• • Salivation to Meat
• Conditioned Stimulus (CS) – A previously neutral stimulus that elicits a Conditioned Response, because it has been paired repeatedly with a stimulus that already elicited a response
• • Bell tone, after conditioning have occurred
• Conditioned Response (CR) – a learned response to a Conditioned Stimulus
• • Salivation in response to the Bell Tone

5.2b Stimuli and Responses in Classical Conditioning – Example

Consider this example:

• Dan takes a shower in his family’s new apartment. He gets the water perfect—not too hot, because that hurts! Then Dan hears his son flush the toilet. The water gets very hot, which makes Dan feel a lot of pain.  After this happens a few times, Dan feels afraid when he hears a toilet flush while he is in the shower.  In this example Dan is subjected to classical conditioning. Could you identify the following?

• • unconditioned stimulus (UCS)
  • conditioned stimulus (CS)  
  • unconditioned response (UCR)
  • conditioned response (CR)

5.2c Extinction and Spontaneous Recovery

In some instances the learning could appear to disappear.

For example, if the CS is no longer paired with the UCS, after a period of time the learning could be extinguished.

Extinction

• • CS no longer elicits the CR 
    • The bell no longer produces the dog’s salivation.
  • Because the CS is no longer associated with the UCS!
    • The bell is no longer paired with the meat.

In other words, if the bell is no longer paired with the meat, after a period of time the dog doesn’t see the relation between the meat and the bell.  Therefore the dog will no longer salivate with just the bell tone.

But… learning could reappear due to a phenomena called Spontaneous recovery. 

Spontaneous recovery happens if:

• • Time passes
    • Let’s say you don’t present the sound of the bell to the dos for a few days.
  • CS is presented again and elicits the CR
    • Then you suddenly sound the bell again in the presence of the dog!
    • After extinction has occurred, the the dog hears the bell again, and it will salivate!!
  • Spontaneous recovery helps organisms adapt to situations that recur from time to time

5.2d Generalization and Discrimination

Generalization

Tendency for CR to be evoked by stimuli similar to the stimulus to which the response was conditioned.  The more similar the stimuli, the stronger the generalization.

Ex. In a variation of  Pavlov’s experiments, he  conditioned dogs to expect food when a circle was presented.  The dogs would salivate when presented with any closed geometric figures was presented, even squares. The dogs generalized that any closed geometric figure could mean that food will be presented.

Organisms must learn that:

• • • Even though the could be similar stimuli, they could have different functions
    • The organism must respond adaptively to different stimuli.
    • They do so by discrimination.

Discrimination: in conditioning the tendency for an organism to distinguish between a CS and a similar stimulus that do not forecast a UCS.  

Ex. Pavlov conditioned his dogs to salivate with only circles and not ellipses. He would present ellipses to the dogs and no food will follow.  The dogs learned to discriminate between circles and ellipses.

Recall the story about Dan’s  being classically conditioned?  Let’s use it again to the describe some of these new concepts.

• Dan notices that when he is in the shower and hears water running through the pipes, he feels afraid. Dan is now most likely experiencing learning through: stimulus generalization. He generalized that any sound similar to the toilet flush, could mean that the water would turn hot.
• Dan asks his son to flush the toilet many times when Dan is showering with very cold water so that Dan no longer feels afraid of the toilet flushing. Dan is attempting to perform on himself a learning procedure called: extinction by not pairing the NS with the UCS (see previous page).

5.2e Higher order Conditioning

Higher order Conditioning: A previously neutral stimulus becomes a CS after being repeatedly paired with that CS.

Ex. Demonstrated by Pavlov when he conditioned a dog to salivate to a tone

• • • • • Repeatedly paired a lightwith the tone
        • After several pairings, the presence of the light (with no sound), evoked salivation!

5.3 Applications of Classical Conditioning (5.3a Taste Aversion)

Taste Aversion: when people can’t face a type of food for a prolonged period of time.

Ex. The author of your textbook described how after being forced to eat two bags of popcorn, he could not eat popcorn again for a year. After a few decades have passed, he still feels nauseated by the smell of popcorn!

Some characteristics are:

• Adaptive
• Motivates organisms to avoid harmful foods
• Differs from other kinds of classical conditioning in that it doesn’t require several pairings.
  • May require only a single association!

Ex.  A single nauseating meal can give rise to a taste aversion that lasts for years

Ex. UCS  (nausea) can occur hours after the CS (taste of food) –  Even  if you don’t get sick right after eating the meal you can still develop a food aversion.

5.4 Operant Conditioning: Learning what does what | Edward L. Thorndike’s Law of Effect

Difference between: Operant Conditioning vs Classical Conditioning 

• In Operant Conditioning organisms learn to do things-  or not do things – because of the consequences of their behavior.
• In classical conditioning the behavior learned is NOTassociated with consequences.

Law of effect: Thorndike’s view that pleasant events stamp in responses and unpleasant events stamps them out.

What does this mean?

• Response is strengthened by a reward
• Response is ended by a punishment
• Organisms learn to avoid behaviors that would result in punishment

5.4b B. F. Skinner and Reinforcement

Skinner taught pigeons to engage in operant behavior

Operant behavior (operant): Behavior that operates on, or manipulates, the environment

Operant conditioning: Organisms learn to engage in behavior that is reinforced

• • Voluntary responses are acquired or conditioned

Skinner focused on measurable behaviors.

• Skinner box
  • Animal cage (operant chamber) devised to study operant behavior
  • Permits careful introduction and removal of experimental conditions
  • Provides observable effects on laboratory animals
• reinforce: to follow a response with a stimulus that increasesthe frequency of the response

5.4d Types of Reinforcers

Positive Reinforces: Increase the probability of a behavior to occur when applied

Negative Reinforces: Increase the probability of a behavior to occur when removed

• • Note that INCREASE probability of a behavior to occur!
  • Positive or negative refers to the action of removing (negative) or adding (positive) a stimulus.

On the other hand, Punishments: decrease the frequency of the behavior and suppress undesirable behavior

Positive Punishment: application of an aversive stimulus decrease unwanted behavior

Negative Punishment: removal of a pleasant stimulus  decrease unwanted behavior

• • Note that a punishment,DECREASES the probability of a behavior to occur!
  • Positive or negative refers to the action of removing (negative) or adding (positive) a stimulus.

Let’s watch this video:

Immediate versus Delayed Reinforcers

• Immediatereinforcers are more effective than delayed reinforcers
  • –Short-term consequences of a behavior provide more of an incentive than the long-term consequences

Consider this example:

Fred racked up a $200 cell phone bill from his texting last month, and his parents are furious. They take away his phone for two weeks to teach him that he must reduce his texting. Fred’s parents are using:

1. positive reinforcement.
2. negative reinforcement.
3. positive punishment.
4. negative punishment.

5.4h Schedules of Reinforcement

The answer is d. negative punishment! 

• Continuous reinforcement:Reinforcement for every correct response
• Partial reinforcement:Not every correct response is reinforced
  • • • Partially reinforced responses are more resistant to extinction

Fixed-ratio schedule: Reinforcement is provided after a fixed number of correct responses or instances.

• • Enables organisms to make several responses before the next reinforcement
  • Example:  After submitting her 2nd article to the newspaper, Alicia looks at her bank account.  She always gets paid once the newspaper receives 2 articles. 

Variable-ratio schedule: Reinforcement is provided after an indefinite number of correct response!

• • Example: After submitting her 2nd article to the newspaper, Alicia looks worried at her bank account.  She is not sure when the newspaper will deposit her next paycheck.   

Fixed – interval schedule: a schedule in which a fixed amount of time must elapse between the previous a subsequent times that reinforcement is available.

• • Example: After the 15th of the month, Alicia looks at her bank account and is always excited to see her paycheck deposited.

Variable – interval schedule: a schedule in which a variable amount of time must elapse between the previous a subsequent times that reinforcement is available.

• • Example: Alicia submits several articles to the newspaper with the hope that eventually she will get paid.

5.5b Shaping

Shaping: Reinforces progressive steps toward a behavioral goal

• As training proceeds, successive approximations to the goal are reinforced
• Successive approximations: Behaviors that are progressively closer to a target behavior
• Watch this video to see how to use shaping to train your dog to turn on a light switch!