The semantic negation scope account for the influence of expression form of negation on possibility judgments from external negated disjunctions

The reading of external negated disjunctions (a disjunction as a clause is externally negated) is an interdisciplinary issue addressed by logic, linguistics, and psychology. For external negated disjunctions, we investigated how their possibility judgments varied with their two expression forms: NTSs (not-true sentences) with the form <i>It is not true that p or q or both</i> versus DSs (deny-sentences) with the form <i>Someone denied that p or q or both</i>). We propose the semantic negation scope account for the question with the hypothesis of the effect of expression form of negation that a NTS will more often elicit the weak local negation strategy that people consider cases negating at least one of the disjuncts as possible, and judge <i>p¬q</i>, <i>¬pq</i>, and <i>¬p¬q</i> as possible; while a DS will more often elicit the strong global negation strategy that people consider only cases negating all disjuncts as possible, and judge only <i>¬p¬q</i> as possible. Experiments 1 and 2 tested the hypothesis in verbal and pictural scenarios, respectively. Both experiments exhibited the effect of expression form of negation that DSs more often elicited the strong global negation strategy, while in conversational and non-conversational contexts, NTSs more often elicited the weak local negation strategy, as favoring the semantic negation scope account over the alternative accounts. The effect of expression form of negation suggests that there seems no unified mental mechanism of the reading of external negated disjunctions with different expression forms.