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:Action-based models of selective attention have done a good job of explaining interference effects associated with competing targets (Meegan and Tipper1998,1999) as well as negative priming (Tipper et al.2002) and IOR in a cue-target task (Briand et al.2000; Welsh and Elliott 2004b).
Category: