Double Negation Without Double Effort: ERP Evidence From Mandarin Chinese.

Accounts of negation processing, including two-step simulation, pragmatic, and monotonicity-based accounts, differ in their predictions about whether double negation requires additional cognitive effort relative to affirmation. Using event-related potentials, we investigated a Mandarin Chinese double-negation structure ("méiyǒu X bù Y") that is logically equivalent to its affirmative counterpart ("suǒyǒu X dōu Y"). Forty native speakers read context sentences (double negation vs. affirmation) followed by critical sentences containing semantically congruent or incongruent target words. Crucially, the target word appeared in a separate sentence, downstream from the negation operators; the design, therefore, tests whether a pragmatically licensed double negation establishes a discourse representation functionally equivalent to affirmation at the point of propositional evaluation. At the critical word, incongruent words elicited larger N400/P600 amplitudes, and these congruency effects did not differ between contexts, indicating equivalent representations and no detectable downstream cost. Post-critical analyses, however, revealed context-specific differences: the affirmation context showed a prolonged negativity to incongruency-plausibly reflecting sustained engagement with its more salient violation-whereas the double negation context did not. A representational similarity analysis (RSA) further showed greater neural tracking of incongruency magnitude in the double negation context at a later window (726-798 ms). Together, these findings indicate that a pragmatically licensed double negation supports downstream semantic integration as efficiently as affirmation, while later processing remains context-sensitive. Because this early equivalence is also consistent with a monotonicity-based account, we frame the early-equivalence/late-divergence pattern as a tentative dual-stage characterization to be tested in future work, rather than a decisive adjudication between theories.