Learning

Learning

Dr Nesif Al-Hemiary

Learning refers to relatively permanent changes in behavior resulting from practice or experience
Learning can be unlearned
Observation can lead to learning
Learning requires an operational memory system

Definition

classical conditioning
instrumental( operant) conditioning.
complex learning
Basic types of learning

Classical conditioning is learning by association

it is sometimes called “reflexive learning”
The Russian physiologist, Ivan Pavlov
discovered classical conditioning by serendipity
received the Nobel Prize in science for discovery


Classical conditioning

Pavlov’s experiment

Association: the KEY element in classical conditioning

Pavlov considered classical conditioning to be a form of learning through association, in time, of a neutral stimulus and a stimulus that incites a response.
Any stimulus can be paired with another to make an association if it is done in the correct way (following the classical conditioning paradigm)

Classical conditioning

Unconditioned Stimulus (UCS): any stimulus that will always and naturally ELICIT a response
Unconditioned Response (UCR): any response that always and naturally occurs at the presentation of the UCS
Neutral Stimulus (NS): any stimulus that does not naturally elicit a response associated with the UCRConditioned Stimulus (CS): any stimulus that will, after association with an UCS, cause a conditioned response (CR) when present to a subject by itself
Conditioned Response (CR): any response that occurs upon the presentation of the CS
Certain stimuli can elicit a reflexive response
Air puff produces an eye-blink
Smelling a grilled steak can produce salivation
The reflexive stimulus (UCS) and response (UCR) are unconditioned
The neutral stimulus is referred to as the conditioned stimulus (CS)


Terminology of Classical Conditioning

That’s all there is to it. I’ll show you a fleshed-out example on the next slide

Here’s a fleshed out example:
UCS----------------->UCR
(food powder) --------------> (salivating)
NS--------------->UCS----------------->UCR
(Bell)---> (food powder) -----> (salivating)
CS---------------------------------------->CR
(Bell)-------------------------------> (salivating)
Here’s another example:
UCS------------------>UCR
(onion juice) -----------------> (crying)
NS --------------> UCS ----------------->UCR
(whistle)----->(onion juice)--------> (crying)
CS ---------------------------------------->CR

In classical conditioning, the CS is repeatedly paired with the reflexive stimulus (UCS)

Conditioning is best when the CS precedes the UCS
Eventually the CS will produce a response (CR) similar to that produced by the UCS
The Classical Conditioning “paradigm”
“paradigm” is a scientific word similar to using the word “recipe” in a kitchen, i.e., this is how you do it
UCS--------------------->UCR
NS------------->UCS--------------------->UCR
CS------------------------------------------>CR


NS and UCS pairings must not be more than about 1/2 second apart for best results
Repeated NS/UCS pairings are called “training trials”
Presentations of CS without UCS pairings are called “extinction trials”
Intensity of UCS effects how many training trials are necessary for conditioning to occur

Some pointers on effective conditioning

Operant conditioning

Organisms make responses that have consequences
The consequences serve to increase or decrease the likelihood of making that response again
The response can be associated with cues in the environment
We put coins in a machine to obtain food
But we refrain when an Out of Order sign is placed on the machine

Definition

Operant conditioning is simply learning from the consequences of your behavior
the “other side” of the psychologist’s tool box, operant conditioning is a form of learning in which the consequences of behavior lead to changes in the probability of a behavior’s occurrence.


In operant conditioning, the stimulus is a cue, it does not elicit the response
Operant responses are voluntary
In operant conditioning, the response elicits a reinforcing stimulus, whereas in classical conditioning, the UCS elicits the reflexive response
Key aspects of operant conditioning

Reinforcement is any procedure that increases the response

Punishment is any procedure that decreases the response
Types of reinforcers:
Primary: e.g. food or water
Secondary: money or power
The Operant Conditioning paradigm:
SD ------> Response -----> Consequence
where “SD” is the “discriminative stimulus”
where “Response” is the subject’s behavior
where “Consequence” is what happens to the subject after EMITTING the response

What consequences can follow a subject’s response?

Consequences to behavior can be:
nothing happens: extinction
something happens
the “something” can be pleasant
the “something” can be aversive
Consequences include positive and negative reinforcement, time out, and punishment. We’ll examine each of these now.

Continuous: reinforcement occurs after every response

Produces rapid acquisition and is subject to rapid extinction
Partial: reinforcement occurs after some, but not all, responses
Responding on a partial reinforcement schedule is more resistant to extinction

Schedules of reinforcement

What is a reinforcer?
Definition: a reinforcer is any stimulus which, when delivered to a subject, increases the probability that a subject will emit a response.
Primary reinforcers, e.g., food
Secondary reinforcers, e.g., praise
One can only know if a stimulus is a reinforcer based on the increased probability of occurrence of a subject’s behavior

Positive reinforcement

What is positive reinforcement?

a procedure where a pleasant stimulus is delivered to a subject contingent upon the subject’s emitting a desired behavior
Schedules of reinforcement
reinforcement schedules may be used to decrease the probability that a response pattern in a subject will extinguish

the use of positive reinforcement in the differential reinforcement of successive approximations is called “shaping”
shaping can be used to create a new response pattern in a subject
shaping must be done carefully and one must rely on the differential reinforcement of successive approximations to the target behavior

Shaping behaviors

a procedure where an aversive stimulus is removed from a subject contingent upon the subject’s emitting a desired behavior
the reinforcing consequence is the removal or avoidance of an aversive stimulus
Escape conditioning: the behavior is reinforced because it stops an aversive stimulus
Avoidance conditioning: behavior reinforced because aversive stimulus is prevented

Negative reinforcement

Examples of negative reinforcement in the real world include:
taking out the trash to avoid your mother yelling at you
taking an aspirin to get rid of a headache
paying your car insurance on time to prevent cancellation of your policy

a procedure where an aversive stimulus is presented to a subject contingent upon the subject emitting an undesired behavior.
punishment should be used as a last resort in behavior engineering; positive reinforcement should be used first
examples include spanking, verbal abuse, electrical shock, etc.

Punishment

punishment is often reinforcing to a punisher (resulting in the making of an abuser)
punishment often has a generalized inhibiting effect on the punished individual (they stop doing ANY behavior at all)
we learn to dislike the punisher (a result of classical conditioning
what the punisher thinks is punishment may, in fact, be a reinforcer to the “punished” individual
punishment does not teach more appropriate behavior; it merely stops a behavior from occurring
punishment can cause emotional damage in the punished individual (antisocial behavior) punishment only stops the behavior from occurring in the presence of the punisher; when the punisher is not present then the behavior will often reappear and with a vengeance
the best tool for engineering behavior is positive reinforcement

Dangers in use of punishment

use the least painful stimulus possible; if you spank your child, do it on the child’s bottom with an open hand never more than twice and NEVER so hard as to leave any marks on your child. That would be classified as child abuse.
reinforce the appropriate behavior to take the place of the inappropriate behavior
make it clear to the individual which behavior you are punishing and remove all threat of punishment immediately as soon as the undesired behavior stops.
do not give punishment mixed with rewards for a given behavior; be consistent!
once you have begun to administer punishment do not back out but use punishment wisely

How to use punishment

Extinction is the process of unlearning a learned response because of a change on the part of the environment (reinforcement or punishment or stimulus pairing contingencies)
Removing the source of learning
in CC, not pairing the NS with the UCS will result in extinction
in OC, not providing consequences causes extinction

Extinction : the process of unlearning

According to the cognitive perspective ,the crux of learning lies in an organism’s ability to mentally represent aspects of the world and then operates on these mental representations rather than on the world itself.
In classical & instrumental conditioning what is represented is an association between events.

Complex learning

In other cases what is represented seems more complex : It might be a map of one’s environment or an abstract concept like the notion of cause. The operations performed on mental representations are more complex than associative processes.
the operations may take the form of mental trial & error , in which the organism tries out different possibilities in its mind.
Or the operations may be a strategy in which we take some mental steps only because they make possible subsequent steps.


Edward Tolman : his research dealt with the problems of rats learning their way through complex mazes. In his view, a rat running through a complex maze was not learning a sequence of right & left turning responses but rather was developing a cognitive map: a mental representation of the layout of the maze.
More recent research provides strong evidence for this view.
Experiments on rats and chimpanzees : Chimpanzees can acquire abstract concepts that were once believed to be the sole province of humans.

COGNITIVE MAPS AND ABSTRACT CONCEPTS

Insight learning involves three critical aspects:

1. suddenness
2. its availability once it is discovered.
3. transferability
These aspects are at odds with trial & error behaviors of the type observed by Thorndike ,Skinner, & their students.
Complex learning involves two phases :
1. Initial phase :problem solving is used to arrive at a solution.
2. Second phase :the solution is stored in memory & retrieved whenever a similar problem is faced.
So, complex learning is intimately related to memory & thinking.
Insight learning