Operant conditioning is different from classical conditioning in a very specific way.
If we consider the dogs in Pavlov’s classic study of salivation at the sound of the bell, it was unnecessary for the dogs to do anything but respond as normal.
Consider this to Skinner’s box where rats would operate a lever to gain some reward such as a food pellet. Skinner sees the individual or organism as operating directly on the environment to achieve some goal or attain some reward.
This would be termed positive reinforcement.
However, another type of reinforcement is negative reinforcement which is not the same as punishment. Rather negative reinforcement refers to the rat pressing a lever to remove or avoid an aversive stimulus such as shock.
A key similarity between operant and classical conditioning is that they are associative.
Interestingly, Thorndike also investigated the use of puzzle boxes in which cats could escape by pressing or activating the right lever.
The textbook Gross Psychology on Thorndike:
“…one of the boxes, the average time of escape was 5 minutes, but after 10-20 trials this was reduced to about 5 seconds.”
Here we see rats and cats exhibiting learning by associating a lever or button with having a specific outcome.
Gross, R. Psychology: The Science of mind and behaviour 2015 - Hodder Education