Answer:unconditioned stimulus;conditioned stimulus.
Step-by-step explanation:
What is meant by unconditioned stimulus?
Unconditioned stimulus is a stimulus that unconditionally triggers responses without an intervention of an outside source so it occurs in a natural way.
Let us say you like a particular flavour of pizza and whilst walking in the mall you smell it eventually you will feel hungry .
This smell of your favourite pizza is the unconditioned stimulus which triggers your hunger.
Other examples of the Unconditioned Stimulus
According to Ivan Pavlov's experiment of classic conditioning when a dog smells it's food and it starts to drool, this is its natural response to the unconditioned stimulus which is a smell of food.
These kinds of responses are the ones that a person does not need to be taught about because they happen naturally without an influence or previous training or lessons.
Onion above is the unconditioned stimulus because it's naturally triggers those tears in Bert's eyes and to anyone else who cuts onion.
What is a conditioned stimulus?
The conditioned stimulus is a previously neutral stimulus which one links to the known unconditioned stimulus due to the fact that there has been an association between this previous neutral stimulus and the unconditioned stimulus due to that association when one sees or touches this stimulus it will trigger the same response as that triggered by the unconditioned stimulus .
An example made by Ivan Pavlov who is the founder of these classic conditions is a dog response to the smell of food (unconditioned response) it drools but also since they know the person who delivers their food; over time when they see that person who delivers their food they will start to drool (triggered response) at his sight.
This person who delivers the food is now a conditioned stimulus.
So the person who delivers the dog food as they are the previous neutral stimulus but now have been linked to the unconditioned stimulus (food or smell of food) they will eventually trigger the natural response previously triggered by the unconditioned stimulus.
When the previous neutral stimulus begin to be linked to the unconditioned stimulus it then becomes conditioned stimulus.
The knife above is a previous neutral stimulus because Bert uses it all the time when she cuts onion and now she associates it with onion which is an unconditioned stimulus; due to that association the knife now triggers the same response as does onion (unconditioned stimulus).
The knife is now a conditioned stimulus.