Joint Influence of Metaphor Familiarity and Mental Imagery Ability on Action Metaphor Comprehension: An Event-Related Potential Study

The present study investigates whether an individual's mental imagery ability, in addition to metaphor familiarity, affects the degree of sensory-motor involvement during action metaphor comprehension. We assessed participants' mental imagery ability using the Vividness of Mental Imagery Questionnaire-2 (VVIQ-2) and recorded the participants' event-related potentials (ERPs) while they read (1) Literal, (2) Familiar Metaphor, (3) Unfamiliar Metaphor, and (4) Abstract sentences. The ERP mental imagery effect (200-750 ms) in the Literal relative to the Abstract condition was reliably correlated with participants' VVIQ scores. A median split based on the VVIQ scores showed that high-VVIQ participants elicited ERP frontal imagery effects that were more prolonged in the Unfamiliar Metaphor condition (350-550 ms) than in the Familiar Metaphor condition (350-450 ms), suggesting that people with high imagery ability tend to routinely recruit sensory-motor experiences to facilitate metaphor comprehension, and to a greater extent for unfamiliar metaphors than for familiar ones. On the other hand, low-VVIQ participants with less effective mental imagery abilities showed no imagery effects in either metaphor conditions, but an early posterior N400 mismatch effect (200-350 ms) in the Unfamiliar Metaphor condition. The results suggest that low-VVIQ participants tend to rely on more general semantic access mechanisms during metaphor comprehension that detect the semantic mismatch between the unintended literal meanings of the metaphors and the context. Both processing styles are affected by metaphor familiarity and lead to successful metaphor comprehension in the current study. However, whether these processing styles lead to comprehension differences for metaphors appearing in discourses or conversations will require further research.