Knowledge and strategies for processing lexical metaphor after right or left hemisphere brain damage.

This study was designed to assess how unilateral right hemisphere brain damage (RHD) affects the knowledge and processing of metaphoric aspects of word meaning. Ambiguous adjectives that could convey either a metaphoric or a literal meaning were used as target words in auditory lexical decision tasks. Targets were preceded by primes that were valid (related to the target's metaphoric or literal meaning), neutral, or unrelated. Prime-target pairs were presented in two attention conditions, designed to favor either relatively automatic or relatively effortful mental processing, and reaction time data were gathered. RHD stroke patients performed similarly to left-brain-damaged and normal control subjects in the automatic condition, and when provided with specific processing strategies, indicating that they retained some knowledge of metaphoric word meanings. When left to glean strategies for themselves, however, both brain-damaged groups had difficulty. These results and others from the RHD literature are discussed in terms of attentional resource capacity and attentional allocation models.