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:…and high levels of defecation are interpreted as indicators of high levels of emotionality (DeFries, Wilson, & McClearn, 1970; Flint et al., 1995; Gervais, 1976), although the validity of ambulation and defecation as indexes of emotionality has been questioned (Lister, 1990; Ramos & Mormède, 1998).
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