According to Bart Geurt’s recent work, we, animals, use signals when we want others to behave in a certain way. Others, of course, need to also be motivated if we want them to do what we want. Thus, when we use signals we do not only express our desire to have others do something, but also our willingness to do something that would somehow compensate and thus motivate others to do what we want. This is how we generate collective commitments. That is how communication supports cooperation.
But notice that we could tell the same story without attributing assertive content to those so-called communicative acts. Thus, we could say that when we use signals our goals is to have others do something, but our action does not causes others to do this directly but instead generates a conditional commitment to do something that would compensate and thus motivate and justify others to do what we want. This creates a social fact that makes it more likely that others do what we want. Hence, there is no need to talk about communication as sharing some sort of mental content or the like. Furthermore, the plan that is generated is collective but what is planned need not be an irreducibly collective action, it can be just the conjunction of two or more individual actions.
Notice that we could accomplish something very similar without signals if we just did what would motivate others to do what we want. That is what happens when some apes groom others, for example: it motivates others to groom them. But this can only work when the time span between what one does and what the others do is quite short. Thus we have devised a lot of mechanisms to overcome this limitation. Some of them are simple like sanctions, and do not require communication. But others, like rebuking and reminding are more complex, for they require communication.
In geurts’ theory, actions in a social setting bring about commitments and other normative facts. Thus, norms are grounded in acts. For example, successfully performing a promise generates the obligation to keep the promise. The utterance of the promise counts as the undertaking of an obligation to do what is promised. (Searle 1965, 1969) Joining a team to play a friendly match of street soccer is another example of an action that generates and grounds the implementation of rules, i.e., the loose set of rules that define street soccer.
To make a promise is a clear example of a speech act that grounds a set of normative acts. But the second example, joining a team, according to Geurts, should also be conceived fundamentally as a sort of speech act, for it would be impossible without the use of language. How else could we arrange in teams with different roles and rules applied to them, how else could we concur on our allegiance on such complex normative systems as the rules of soccer, furthermore, given the loose nature of these rules in a street setting, how else could we negotiate these rules and apply them in our particular circumstances?