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:Because females perform phonotaxis or courtship solicitation displays, while males respond to social signals with evoked calling and call timing, females are generally found to be the more discriminating sex (Brenowitz 1982; Searcy and Brenowitz 1988; Bernal et al. 2007; Danner et al. 2011).
Category: