Human languages can express opposite
propositions by means of the negative operator “not,” which
turns affirmative sentences into negative ones. Psycholinguistic research
has indicated that negative meanings are formed by transiently
reducing the access to mental representations of negated conceptual
information. Neuroimaging studies have corroborated these findings,
showing reduced activation of concept-specific embodied neural systems
by negative versus affirmative sentences. This “disembodiment
effect” of sentential negation should have two distinct consequences:
first, the embodied systems should be computationally more free to
support concurrent tasks when processing negative than affirmative
sentences; second, the computational interference should only be reduced
when there is a strict semantic congruency between the negated
concept and the referent targeted by concurrent tasks. We tested these
two predictions in two complementary experiments involving the
comprehension of action-related sentences and kinematic measurements
of its effects on concurrent, congruent actions. Sentences
referred to actions involving either proximal or distal arm musculature.
In experiment 1, requiring a proximal arm movement, we found
interference reduction for negative proximal sentences. In experiment
2, requiring a distal arm movement, we found interference reduction
for negative distal sentences. This dissociation provides the first
conclusive evidence in support of a disembodiment theory of negation.
We conclude that the computational cost resulting from the
insertion of an additional lexical item (“not”) in negative sentences is
compensated by solely storing a concept in affirmative form in
semantic memory, since its negative counterpart can be produced by
transiently reducing the access to such stored semantic information.
negation; concept; semantic memory; embodied systems; disembodiment