Stimulus
Anything that causes a reaction or response in an organism.
Ex: Taste, touch, smell, sound, sight.
Response
The behavior or reaction caused by a stimulus.
Ex: A dog salivating when it sees food, or blinking when air is puffed into its eye.
Acquisition
The initial learning stage when a response is first established and strengthened.
Ex: When Pavlov rings the bell (NS) and gives food (US) over and over, the dog learns to associate them.
Unconditioned stimulus (US)
A stimulus that naturally and automatically triggers a response—no learning required.
Ex: Food automatically causes a dog to salivate.
Unconditioned response (UR)
The unlearned, natural reaction to the unconditioned stimulus.
Ex: Salivating when seeing or smelling food.
Neutral stimulus (NS)
A stimulus that initially produces no response before learning takes place.
Ex: The sound of a bell before it’s ever paired with food.
Conditioned stimulus (CS)
A once neutral stimulus that, after being paired with the unconditioned stimulus, now triggers a learned response.
Ex: The bell, after it has been associated with food, now makes the dog salivate even without food present.
Conditioned response (CR)
The learned response to the conditioned stimulus.
Ex: The dog salivates when hearing the bell, even when no food is shown.
Generalization
The tendency to respond in the same way to different but similar stimuli.
Extinction
When a conditioned response fades because the stimulus is no longer reinforced.
Spontaneous Recovery
The reappearance of a weakened conditioned response after a pause.
Discrimination
The ability to distinguish between similar stimuli and respond only to the specific one.
Primary Reinforcer
A stimulus that satisfies a basic biological need
Ex: Food, water, or warmth given to an animal after it performs a desired behavior
Secondary Reinforcer
A learned reinforcer associated with a primary reinforcer
Ex: Money, grades, or praise — they have value because they’re linked to basic rewards like food or success