Ivan pavlov discovered while conducting research on digestion in dogs.

classical conditioning.

Explanation:

Classical conditioning refers to a process of learning developed by Russian physiologist Ivan Pavlov that takes place by associations between an external stimulus and a naturally occurring stimulus. In order to create a new conditioned response, the conditioned stimulus has now been combined with the unconditioned stimulus. It is a form of learning that has had a major influence on the psychological school of thought popularly called behaviorism.

all of them lol cause theres no map

experiments.

surveys.

questionnaires.

interviews.

case studies.

participant and non-participant observation.

observational trials.

studies using the delphi method.