Verbal probability expressions convey both a more or less precisenumerical meaning, and they have a positive or negativedirectionality. Positive phrases, such as possible and likely , focus on the occurrence of the target event, negative phrases, such as uncertain and unlikely , focus on it's non-occurrence.
The first part of this paper investigates whether participantsprimarily would interpret specific verbal probability expressions asconveying a numerical meaning, or if they would focus on thedirectionality of the verbal phrases. The results indicate thatparticipants primarily have treated the verbal phrases as conveyingprobabilistic information, and seem to have been less influenced bythe semantic clues inherent in the positive or negativedirectionality of the phrases. This does not mean thatparticipants have treated the phrases as exclusively conveying anumerical meaning, but rather that they seem to have weighted theprobabilistic content more than the semantic content.
The second part of this paper compares how people assign verbal andnumerical probability estimates to uncertain outcomes. The saliens of different state space partitions are manipulated, and we see ifparticipants are consistent in the way they assign verbal andnumerical estimates to the same situation. It is argued that askingfor numerical estimates puts a stronger emphasis on the rule-basedaspect of assigning probabilities, and leads to more participants assigning probabilities in accord with the formal rules of probability.