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:By pooling the feedforward inputs, a small proportion of V2 cells (Figure 3) and a large proportion of V4 cells (Chen et al., 2014) in the superficial (output) layers start to signal the global contour.
Category: