Hemispheric Processing of High and Low Familiarity Metaphors

The aim of the present study is to provide a neurocognitive perspective on the processing mechanisms used to comprehend high and low familiarity metaphors utilizing the divided visual-field paradigm. The Fine-Coarse Semantic Coding Theory proposes that, during language processing, the left hemisphere activates only highly relevant meanings, whereas the right hemisphere activates both relevant and irrelevant meanings (Beeman, 1998). In the present study, participants read a centrally presented high or low familiarity metaphor (e.g., The baby is an angel), or a literal sentence prime (e.g., The soup is a bisque), and then, after a delay (600 ms), a word or non-word letter string was presented to the left visual field (right hemisphere) or right visual field (left hemisphere). Participants performed a lexical decision task in response to the letter string. Letter strings belonged to one of three categories: (1) a word associated with the figurative meaning of the metaphor (e.g., SWEET), (2) a word associated with the literal meaning of the metaphor (e.g., HEAVEN), (3) or a non-word (e.g., THASE). For targets presented to the left hemisphere, I expected to find evidence of inhibition of the literal meaning of target words following low familiarity metaphor primes and facilitation of the figurative meaning of targets following low and high familiarity metaphor primes. I also predicted that for targets presented to the right hemisphere, there would be facilitation of both the figurative and literal meanings of targets following both low and high familiarity metaphors. I did not find significant facilitation (positive priming) or inhibition (negative priming) for targets presented to the left hemisphere. The only significant facilitation found was for figurative and literal target following low familiarity metaphors presented to the right hemisphere. This finding supports previous research that highlights a right hemisphere advantage in novel metaphor processing.