title: Is the basic conditional probabilistic?
abstract: Nine experiments examined whether individuals treat the meaning of basic conditional assertions as deterministic or probabilistic. In Experiments 1-4, participants were presented with either probabilistic or deterministic relations, which they had to describe with a conditional. These experiments consistently showed that people tend only to use the basic if p then q construction to describe deterministic relations between antecedent and consequent, whereas they use a probabilistically qualified construction, if p then probably q, to describe probabilistic relations-suggesting that the default interpretation of the conditional is deterministic. Experiments 5 and 6 showed that when directly asked, individuals typically report that conditional assertions admit no exceptions (i.e., they are seen as deterministic). Experiments 7-9 showed that individuals judge the truth of conditional assertions in accordance with this deterministic interpretation. Together, these results pose a challenge to probabilistic accounts of the meaning of conditionals and support mental models, formal rules, and suppositional accounts.
authors.affiliation: University of Pennsylvania.
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Goodwin
mesh_terms: D000328:Adult; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008128:Logic; D011336:Probability; D055815:Young Adult