This research project explores the effect of conviction severity and conviction base rate on numerical estimates of the uncertainty conveyed by verbal probability phrases.
Research on linguistic probabilities has shown that phrases such as possible can be attributed higher numerical estimates in severe or high base rate events. Research has also built on the pragmatic account of linguistic probabilities, which shows that when verbal probability expressions are interpreted as politeness devices, events are estimated as more likely to occur and as denoting higher risks.
This research project aims to expand upon previous findings in a new area of application; namely the communication of uncertainty in a legal setting. It examines how conviction severity and conviction base rates may influence the interpretation of verbal probability phrases (as a risk communication or a face-management linguistic device) and assessed the degree to which the type of linguistic interpretation favored might influence the perceived likelihood of a suspect’s guilt and of his conviction.
So far, our findings show that whereas an event base rate might have a strong influence on the numerical and linguistic interpretation of verbal probability phrases such as “it is possible that…”, evidence for the impact of severity seems to depend on base-rates.
Bonnefon, J. F., & Villejoubert, G. (2006). Tactful, or doubtful? Expectations of politeness explain the severity bias in the interpretation of probability phrases. Psychological Science, 17, 747-751. doi: 10.1111/j.1467-9280.2006.01776.x
Ms Egle Butt (PI)
Prof Gaëlle Vallée-Tourangeau
Dr Marie Juanchich
Dr Miroslav Sirota
Butt, E., Sirota, M., Juanchich, M., & Vallée-Tourangeau, G. (2016, June). When Are Severe Outcomes More Probable? – Role of Base Rate. Paper presented at the FUR 2016 Conference, Warwick, United Kingdom.
Butt, E., Vallée-Tourangeau, G., Juanchich, M., & Sirota, M. (2015, August). Communicating probability of environmental risk: Accounting for face-threatening contexts. Paper presented at the 25th Subjective Probability, Utility and Decision Making Conference, Budapest, Hungary.
Butt, E., Villejoubert, G., Juanchich, M., & Vallée-Tourangeau, F. (2013, August). The effect of conviction severity and base-rate in interpreting linguistic probability expressions. Paper presented at the 24th Subjective Probability, Utility and Decision Making Conference, Barcelona, Spain.