Tracking the neural dynamics of semantic composition through negation

Combining words and composing meanings lies at the basis of human language, but how the brain constructs meaning online is not well understood. We address this puzzle by exploiting the ubiquitous operation of negation. We track the compositional effects of negation (“not”) and intensifiers (“really”) on scalar adjectives (e.g., “good”) in parametrically designed behavioral and neurophysiological (MEG) experiments. The behavioral data show that participants first interpret negated adjectives as affirmative and then modify their interpretation towards the opposite meaning. Decoding analyses of neural activity further reveal that negation does not invert the representation of adjectives (i.e., “not bad” represented as “good”) but rather weakens their representation, at early semantic processing stages. This putative suppression mechanism of negation is supported by increased synchronization of beta-band neural activity in sensorimotor areas. The analysis of semantic composition through negation provides a steppingstone to understand how the human brain combines words into meaning. ### Competing Interest Statement The authors have declared no competing interest.