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:Note that Drieghe et al. (2008) have proposed that parafoveal-on-foveal effects (i.e., an effect of the word to the right of fixation that appears in the eye movement record before the eyes have actually left the fixated word) may be likely to arise in cases in which the saccadic targeting system…
Category: