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:…that there is ample evidence from functional magnetic imaging experiments that in humans prediction errors are indeed encoded in the dorsal striatum (e.g. Valentin & O’Doherty, 2009; Cooper et al., 2011), including regions of dorsal putamen most comparable to rat DLS (e.g. Garrison et al., 2013).
Category: