Yeah, they didn’t propose how those sets of calls appear; only that they’re there, in other primates. So no, you aren’t missing it.
What I’m going to say is just a guess from my part. Those sets would appear like this:
Simple call, conveying some simple info (for example: ook = “threat”)
Call gets repeated to ensure others got the message. (for example: ook ook ook = “threat, threat, threat”)
The number of repetitions gets associated with some additional info. (for example: ook ook = small threat, ook ook ook = big threat).
The repetitions get some rhythm structure, to ensure others got the whole thing.
On #4 you already got a set. But all steps are on their own advantageous for the survival of the group.
However, once you got through all those steps, a problem appears: since the set itself is conveying info, how to ensure the info is not missed? Then you go back to #2, repeating the whole set to ensure others got the message.
Yeah, they didn’t propose how those sets of calls appear; only that they’re there, in other primates. So no, you aren’t missing it.
What I’m going to say is just a guess from my part. Those sets would appear like this:
On #4 you already got a set. But all steps are on their own advantageous for the survival of the group.
However, once you got through all those steps, a problem appears: since the set itself is conveying info, how to ensure the info is not missed? Then you go back to #2, repeating the whole set to ensure others got the message.