Spain is not Greece: how metaphors are understood.

Metaphoric expressions are pervasive and powerful communication tools. The present report sheds light on two questions: how do we extract meaning from metaphors and similes, and are these two tropes interchangeable? Existing models propose different mechanisms for metaphor comprehension: comparison, categorization, and a shift from comparison to categorization as metaphors become conventionalized. While the categorization model allows for the possibility that metaphors and similes are not always interchangeable, all the variants of the comparison model assume equivalence of meaning between the two tropes. The findings reported here rule out this assumption: they show that metaphors and similes may express different, and even incompatible meanings. Aptness, rather than conventionalization, seems to determine processing mechanisms: apt metaphors, both novel and conventionalized, are understood as categorizations, while similes and inapt metaphors are understood as comparisons.