The effect of negation on deductive inferences.

Research shows that negation can suppress the activation of propositions presented explicitly in text, but does negation have a similar effect on propositions that can be inferred? That is, does negation inhibit the inference process? Four experiments investigated whether a deductive inference that produces a negated conclusion (therefore not a) is made as readily as a similar inference form that yields an affirmative conclusion (therefore a). A combination of naming latencies, verification times, and reading times indicate that negation does not affect the deductive inference process itself, although it may inhibit the activation of inferred concepts.