The authors conclude that listening chimpanzees could use the acoustic information
in these calls to infer the role of the individuals involved in a conflict. Listeners who
move to intervene in agonistic encounters may base their decisions on this acoustic
information. It is possible that these agonistic screams are functioning as referential
calls, i.e. they contain specific information that can be of use to other individuals listening.
However, the authors acknowledge that playback experiments, testing the hypothesis that
listeners take advantage of the information available in the calls, need to be conducted
before these calls can be labelled as functionally referential.
144 Social behaviour and relationships