The third one
not the first or the second one
I am not 100 percent sure, but double-blind placebo testing is a good standard in medicine.
Classical conditioning is a type of learning that had a major influence on the school of thought in psychology known as behaviorism. Discovered by Russian physiologist Ivan Pavlov, classical conditioning is a learning process that occurs through associations between an environmental stimulus and a naturally occurring stimulus.
Classical conditioning involves placing a neutral signal before a naturally occurring reflex. In Pavlov's classic experiment with dogs, the neutral signal was the sound of a tone and the naturally occurring reflex was salivating in response to food. By associating the neutral stimulus with the environmental stimulus (food), the sound of the tone alone could produce the salivation response.
In order to understand how more about how classical conditioning works, it is important to become familiar with the basic principles of the process. Classical conditioning involves forming an association between two stimuli resulting in a learned response. There are three basic phases of this process.
The first part of the classical conditioning process requires a naturally occurring stimulus that will automatically elicit a response. Salivating in response to the smell of food is a good example of a naturally occurring stimulus.
During this phase of the processes, the unconditioned stimulus (UCS) results in an unconditioned response (UCR).
For example, presenting food (the UCS) naturally and automatically triggers a salivation response (the UCR).
At this point, there is also a neutral stimulus that produces no effect yet. It isn't until this neutral stimulus is paired with the UCS that it will come to evoke a response.
