This is indicative of classical conditioning as studied by Pavlov. There is an unconditioned stimuli, in this case, Kendra’s nausea wherein nausea is not often associated with alcohol. The conditioned stimuli here is the smell of liquor which does not normally associate with nausea in other humans. In this case, Kendra’s nausea is now associated with the smell of liquor; yet another possible conditioned stimuli such as the sight of bottle was not associated.