Cerebral asymmetry for aspects of sentence processing: A replication and extension

In an earlier study by this author it was found that when subjects hear a monaurally presented two‐clause sentence immediately followed by a probe word, they are faster at indicating that the probe had occurred in the sentence (Identical Word Recognition) with left ear (right hemisphere) presentation than with right ear (left hemisphere) presentation. This was interpreted as support for the idea that the left hemisphere is particularly efficient at transforming linguistic, auditory stimuli into an abstract representation of the meaning. The main purpose of the present study was to test the idea that the left hemisphere is particularly good at semantic analysis during initial sentence processing. The Identical Word Recognition condition was replicated and a new task which required semantic matching (Say‐a‐Synonym) was employed. As predicted, the structural task produced a left ear/right hemisphere advantage as before, and the semantic task produced a right ear/left hemisphere advantage. The effect of ear upon reaction time varied as a function of task and clause position of the target. Overall, these findings suggest that behavioral asymmetries associated with the cerebral hemispheres are powerfully affected by task demands.