In the study of psychology, conditioning is the process of pairing two stimuli together so that if one stimulus can trigger a reaction, the other can do the same, too, simply by learned association.
Classical conditioning, also called Pavlovian conditioning and respondent conditioning, is learning through the association of a neutral stimulus with a biologically potent stimulus.
A harsh and strict teacher (US) makes students feel bad (UR).Students associate going to school (CS) with the harsh teacher and learn to feel bad about going to school (CR).