Choosing to presuppose: strategic uses of presupposition triggers
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Date
15/11/2022Author
Lorson, Alexandra
Metadata
Abstract
This PhD project investigates the discourse structuring and managing properties of presupposition
triggers. Specifically, the thesis is a theoretical and experimental investigation of what motivates
speakers to presuppose as opposed to assert content, and how this decision influences the course of
the subsequent discourse. This thesis is divided into three parts: (I) the negotiation of new content
that is introduced by presuppositions versus assertions [experiment 1], (II) the communication of
degrees of beliefs via factive presupposition triggers in contrast to uncertainty expressions and the
bare assertion [experiments 2–5], and (III) the signalling of parallel information via additive pre-supposition triggers [experiments 6–7].
The first part of the thesis teases apart the distinction between presupposed/asserted and at-issue/not at-issue content by investigating whether (i) presupposed at-issue content is inaccessible
or less accessible for interlocutors than asserted at-issue content, and (ii) in what way interlocutors
address presupposed content in the subsequent discussion if the presupposed content is indeed
less accessible. The experimental results suggest that, when material is relevant to the discourse
question, it can be challenged directly by a subsequent speaker whether it is formally asserted or
presupposed. However, expressing relevant material through presupposition rather than assertion
may reduce the frequency of such challenges. Thus, a speaker-hearer model would have to include
interlocutors’ expectations both about information packaging and about the overall discourse topic,
in order to determine which content material may be discussed further.
The second part of the thesis focuses on the factive presupposition trigger know and its discourse
structuring properties. For this purpose, experiments [2–3] investigated the speakers’ motivations
in choosing between uncertainty expressions such as think, believe or the factive verb know in co-operative versus uncooperative scenarios. The results of both experiments suggest that speakers’
choice of formulation is influenced by (i) how likely they estimate an event to be and (ii) strategic
considerations relating to the communicative context in which they are working. More specifically,
speakers uttered know more frequently and for lower degrees of belief in uncooperative settings
than in cooperative settings. Experiments [4–5] explored whether the strategic use of know in the
uncooperative setting has to do with its discourse structuring properties as a presupposition trigger:
By presupposing content speakers assume or act as if the conveyed information was already shared
knowledge and not up for debate. Thus, hearers might be more inclined to accept and accommodate presupposed content than asserted content. For this purpose, speakers’ production choices and
hearers’ interpretations of know versus the bare assertion were assessed. The results suggest that
presupposing might have an advantage over asserting when speakers want to avoid further discussion of a topic. However, there was no evidence that hearers consider the speakers’ strategies when
assessing their degrees of belief, which may mean that speakers can employ these communicative
strategies successfully, though this point requires further investigation.
The third part of the thesis investigates the discourse managing properties of additive particles
such as too, which are argued to presuppose a propositional alternative. If a suitable antecedent
for the presupposition is present in the preceding dialogue, the production of too has been argued
to be obligatory. Experiments [6–7] test (i) the potential obligatoriness and discursive functions
of additives by manipulating the antecedents’ salience focusing on the factors Similarity and Turn
Distance; and (ii) whether speakers would purposely violate the obligatoriness of too and with that
avoid signalling similarity between what they and the antecedent speaker said in order to socially
distance themselves from the antecedent speaker. Overall, the results of experiments [6–7] suggest that while the production of additives seems to depend on the antecedent’s salience, additive
production was not as frequent as expected if additives were indeed obligatory. More specifically,
participants were found to utter additives more frequently when their utterance’s content matched
the content of a previously formulated utterance and when the matching utterance directly preceded
their utterance. Furthermore, results of experiment [7] suggest that speakers deliberately drop the
use of additives when wanting to diverge from an impolite speaker.
This project sheds more light on the speakers’ motivation to presuppose rather than assert content and on the way their production choices influence the preceding dialogue and the hearers’
interpretation. Overall, the results suggest that the speakers’ choice to either assert or presuppose
content depends on (i) what content is part of the common ground, and (ii) speakers’ communicative goals: specifically in whether or not they are being maximally informative and cooperative. The
thesis draws parallels between the discursive properties of di↵erent kinds of presupposition triggers
while at the same time also highlighting possible di↵erences between them, in particular between
factive and additive presupposition triggers. By demonstrating the strategic use of presupposition
triggers, this thesis informs theories on presupposition accommodation, the common ground, and
communicative strategies in cooperative and uncooperative contexts.