classical/pavlovian conditioning: BASICS

classical conditioning

A learning process in which a previously neutral stimulus (CS) becomes associated with an unconditioned stimulus (US) to elicit a conditioned response (CR).

Example: A bell (CS) rings before food (US), causing salivation (CR).

conditioned stimulus

A previously neutral stimulus that, after being paired with an unconditioned stimulus, triggers a conditioned response.

Example: The bell in Pavlov's experiment.

unconditioned stimulus

A stimulus that naturally and automatically triggers a response without prior conditioning.

Example: The food that causes salivation in dogs.

unconditioned response

The natural, unlearned reaction to the unconditioned stimulus.

Example: Salivation in response to food.

conditioned response

The learned response to the conditioned stimulus after conditioning has taken place.

Example: Salivation in response to the bell alone.

general phenomena

General patterns observed in classical conditioning that apply across different scenarios.

Example: Animals learning to associate different stimuli with food.

acquisition

The initial stage of learning when a response is first established and gradually strengthened.

• the process of learning the association between the CS and US

Example: A dog begins to salivate to the sound of a bell after several pairings with food.

stimulus generalization

The tendency to respond similarly to stimuli that resemble the conditioned stimulus.

• Organisms will respond most strongly to the CS used
  during training

Example: A child conditioned to fear a white rat may also fear a white rabbit.

generalization gradient

The less similar the stimulus is to the training stimulus, the less vigorous the response will be.

• The dog salivates strongly to the bell (CS) but less to a similar sound, like a ringing phone (less similar)

generalization decrement

The decrement in the response when the stimulus is changed.

Example: The dog salivates less to a sound that is not very similar to the bell, like a honking horn.

summation

If two separate stimuli are conditioned separately to elicit the same CR, the intensity of the response will double (summate) when the two stimuli are presented together.

Example: If a dog hears a bell and a whistle at the same time, it may salivate more than if it hears just one of them alone.

second-order conditioning

A new stimulus, when paired with an established CS (one that already elicits the CR), will also begin to elicit the conditioned response.

Example: If the bell (CS1) is paired with a light (CS2), the light alone can eventually cause salivation, even though it was never directly paired with food.

extinction

The process where the conditioned response diminishes when the conditioned stimulus is no longer paired with the unconditioned stimulus.

Example: A dog stops salivating at the bell when it no longer receives food afterward.

what is being learned during extinction?

During extinction, the CS is learned to no longer predict the US, leading to inhibition of the response rather than unlearning.
Example: The dog learns that the bell no longer means food, so it stops salivating.

Evidence that CS → no US creates inhibition (not unlearning)

when a CS is repeatedly presented without its associated US, the resulting change in behavior is due to inhibition rather than unlearning. The organism retains the original learning but learns to suppress the response in the absence of the US.

Example: If a dog learns to salivate to the sound of a bell when food is presented, and then the bell rings multiple times without food, the dog will eventually stop salivating in response to the bell. This is not because the dog has forgotten the original association but because it has learned to inhibit its response to the bell in that specific context.

disinhibition

The recovery of a conditioned response when a new or novel stimulus is introduced after extinction.

Example: A dog that has stopped salivating at the bell begins to salivate again when a new sound is introduced.

spontaneous recovery

The reappearance of a conditioned response after a period of rest following extinction.

Example: After a break, the dog may suddenly salivate again to the bell even though it has not heard it for a while.

discrimination learning

The ability to distinguish between different stimuli and respond only to the conditioned stimulus.

Example: A dog learns to respond only to the specific tone of a bell used in training.

• A dog learns to salivate to the bell (CS+) but not to a buzzer (CS-) because it doesn’t predict food

CS+ and CS-

CS+ (Conditioned Stimulus Positive) signals the presence of the unconditioned stimulus, while CS- (Conditioned Stimulus Negative) signals its absence. Example: A bell (CS+) paired with food (US) vs. a different sound (CS-) that does not predict food.

CS+

Conditioned Stimulus Positive signals the presence of the unconditioned stimulus

CS-

Conditioned Stimulus Negative signals its absence