Interpretation of Optimal Signals
Michael Franke

Abstract:
According to the optimal assertions approach of Benz and van Rooij,
conversational implicatures can be calculated based on the assumption
that a given signal was optimal, i.e. that it was the sender's best
choice if she assumes, purely hypothetically, a particular naive
receiver interpretation behavior. This paper embeds the optimal
assertions approach in a general signaling game setting and derives
the notion of an optimal signal via a serious of iterated best
responses (c.f. Jager, 2007). Subsequently, we will compare three
different ways of interpreting such optimal signals. It turns out that
under a natural assumption of expressibility (i) the optimal
assertions approach, (ii) iterated best response and (iii) strong
bidirectional optimality theory (Blutner, 1998, 2000) all prove
equivalent. We then proceed to show that, if we take the iterated best
response sequence one step further, we can account for M-implicatures
(Horn's division of pragmatic labor) standardly in terms of signaling
games.