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:…activation patterns were consistent with the results of the previous studies on infants (Dehaene-Lambertz et al., 2002, 2004) and adults (Petersen et al., 1988; Price, 2000; Homae et al., 2002); all of these studies reported that the both hemispheres are involved in processing of speech sounds.
Category: