Verbal probability expressions convey both a more or less precise
numerical meaning, and they have a positive or negative
directionality. 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 participants
primarily would interpret specific verbal probability expressions as
conveying a numerical meaning, or if they would focus on the
directionality of the verbal phrases. The results indicate that
participants primarily have treated the verbal phrases as conveying
probabilistic information, and seem to have been less influenced by
the semantic clues inherent in the positive or negative
directionality of the phrases. This does not mean that
participants have treated the phrases as exclusively conveying a
numerical meaning, but rather that they seem to have weighted the
probabilistic content more than the semantic content.
The second part of this paper compares how people assign verbal and
numerical probability estimates to uncertain outcomes.
The saliens of different state space partitions are manipulated, and we see if
participants are consistent in the way they assign verbal and
numerical estimates to the same situation. It is argued that asking
for numerical estimates puts a stronger emphasis on the rule-based
aspect of assigning probabilities, and leads to more participants assigning probabilities in accord with the formal rules of probability.