Dr Amélie Gourdon, will be presenting the poster session at European Society of Philosophy and Psychology : August 10 -13th 2016
Wednesday 10th August -Saturday 13th, 2016
University of St Andrews, Scotland
DIRECTIONALITY OF PROBABILITY PHRASES IS NOT DETERMINED BY THEIR LINGUISTIC HEAD
Directionality of probability phrases is not determined by their linguistic head
Verbal probabilities (e.g., it is likely) are suggested to be preferred to numerical probabilities by speakers who express uncertainty (Erev & Cohen, 1990). These phrases are made of a modal adjective (e.g., it is possible) or noun (e.g., there is a possibility), sometimes a verb (e.g., it may be), with, in cases, the addition of a
modifier (e.g., there is a little possibility). In addition to conveying a quantity of uncertainty, verbal probabilities carry a directionality (Teigen, 1988), that focuses the receiver on the occurrence (positive directionality) or non-occurrence (negative directionality) of the outcome. As quantifiers, these modifiers carry their own directionality (e.g., a few and few; Sanford, Fay, Stewart & Moxey, 2002), which could be different to the modal itself (e.g., there is little certainty). Linguistic theory suggests that the head of a phrase determines its syntactic function and the semantic category (see e.g., Corbett, Fraser & McGlashan, 1993). In this perspective, in verbal probabilities, the modal is the head, and its directionality may prime, so that little certainty should have a positive directionality. However, directionality may have multiplicative properties: when a negative directionality introduced an uncertain event with a negative valence (e.g., it is unlikely that this car will break down in the next two years), participants showed similar probability judgements and behavioural intentions to when a positive directionality introduced an event with a positive valence (e.g., it is very certain that this car will run well for many years; Gourdon & Villejoubert, 2009). Therefore the directionality of the head (the modal phrase) could be cancelled by the directionality of the modifier, so that little doubt would focus a receiver on the occurrence of the uncertain event. In this study, we used the completion paradigm (Teigen & Brun, 1999) to test this competing predictions. Participants read 34 sentences presenting positive and negative modifiers (e.g., little vs a little) with positive and negative modals (e.g., doubt vs possibility), and completed these with reasons for explaining the sentence. For each sentence, they also provided a plausibility judgement and a probability judgement. Results indicated that directionality of the modal interacts with directionality of the modifier: a negative modifier associated to a negative modal were more often completed with a reason in favour of the uncertain event, similarly to when the directionality of both the modal and its quantifier is positive. In the contrary, a combination of negative and positive directionality led to more frequent completion with reasons against the uncertain event, when the negative directionality was carried by the modifier. These results provided empirical data to refine material construction in experiments on verbal probabilities, but also new insights about the linguistic perspective on heads. While the head determines the syntactic function and the semantic category of a phrase, it is suggested that it does not determine its pragmatic function and that probability phrases may be considered headless.
For further information about this event please visit ESPP16 website.