 It is, of course, controversial to claim that monkeys have rule-governed propositional social knowledge systems as claimed in (iv) and (v). For instance, Tomasello’s (2008) ‘Cooperative Communication’ approach makes a case for primate intentional systems not based on their vocalizations but on their gestural systems. Therein he claims that “great ape gestural communication shares with human linguistic communication foundational aspects of its manner of functioning, namely, the intentional and flexible use of learned communicative signals” (2008: 21).