title: A Priori True and False Conditionals.
abstract: The theory of mental models postulates that meaning and knowledge can modulate the interpretation of conditionals. The theory's computer implementation implied that certain conditionals should be true or false without the need for evidence. Three experiments corroborated this prediction. In Experiment 1, nearly 500 participants evaluated 24 conditionals as true or false, and they justified their judgments by completing sentences of the form, It is impossible that A and ___ appropriately. In Experiment 2, participants evaluated 16 conditionals and provided their own justifications, which tended to be explanations rather than logical justifications. In Experiment 3, the participants also evaluated as possible or impossible each of the four cases in the partitions of 16 conditionals: A and C, A and not-C, not-A and C, not-A and not-C. These evaluations corroborated the model theory. We consider the implications of these results for theories of reasoning based on logic, probabilistic logic, and suppositions.
authors.affiliation: William James Center for Research, ISPA-Instituto Universitário.
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Quelhas
authors.affiliation: William James Center for Research, ISPA-Instituto Universitário.
authors.forename: Célia
authors.initials: C
authors.lastname: Rasga
authors.affiliation: Department of Psychology, Princeton University.|Department of Psychology, New York University.
authors.forename: Philip N
authors.initials: PN
authors.lastname: Johnson-Laird
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008128:Logic; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D011340:Problem Solving / Q000502:physiology*; D011582:Psychological Theory; D055815:Young Adult
keywords: Conditionals; Deductive reasoning; Logic; Mental models; Modulation; Possibilities