Cecilia Paasche, Honors Neuroscience

Metaphors Make the Brain Work Harder

Metaphor is frequent in human language and essential to communication. But how does the brain process metaphor differently from literal language? We measured electrophysiological activity at the scalp while participants processed metaphorical and literal language. Results show no difference between metaphorical and literal stimuli at the N400, a negative electrical signal, 400 ms after stimuli, that corresponds to semantic access. Divergence occurred at the P600, a positive electrical signal 600 ms after stimuli that typically responds to grammatical errors; metaphorical stimuli elicited larger P600 amplitudes. This suggests that compared to processing literal language, metaphor requires an additional reanalysis step, despite being understood comparably well. Results support the theory that metaphorical language is effective for communication partly because it increases depth of processing, leading to more meaningful representations.