Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:For instance, Murphy, Baker, and Fouquet (2001) used an
appetitive Pavlovian conditioning procedure to explore context conditioning in a predictive relative validity paradigm with rats, finding that the net conditioned response to a conditioned stimulus was determined not only by the stimulus, but…
Category: