Brain asymmetries in figurative language comprehension.

This chapter reviews the literature concerning the neural basis of three types of figurative expressions, namely, idioms, metaphors, and irony. Besides these three forms of language, which are the most investigated, many other types exist, differing in their linguistic structure and, consequently, in the corresponding comprehension processes. After defining the most common figurative expressions and showing how they differ in terms of linguistic properties, the chapter presents early studies that focused on the role of the right hemisphere (RH) in figurative language comprehension in general, without a clear distinction among different forms. Later literature shows how evidence has been accumulated, suggesting that both hemispheres are involved in figurative language processing. Therefore, a sharp distinction between the left hemisphere (LH) and the RH, the first involved in literal language and the second in figurative language, is not tenable. Idioms, metaphors, and irony will be considered separately, demonstrating that different expressions rely on the LH and RH to a different degree.