The effect of distraction on sensitivity to syntactic structure in schizophrenic and affective disorders

This study was designed to determine whether the presence of a distracting message would interfere with schizophrenics' ability to utilize syntactic structure in processing information from a relevant sentence. Seventeen schizophrenics, 17 patients with affective disorders, and 16 normals were given a word recognition task in both the presence and absence of auditory distraction. None of the patients was hospitalized at the time of testing. Subjects listened to a sequence of sentences which consisted of two clauses. Immediately following each sentence, the subject heard a probe word and was required to indicate whether it had been part of the preceding sentence. In the neutral condition, the recognition latencies of subjects in all three groups were shorter if the word came just after, rather than just before, the clausal boundary of the preceding sentence. In the presence of a distracting message, the normals and affective patients continued to exhibit this same effect. The schizophrenics did not. The latency of their responses in the distractor condition was not influenced by the location of the target word relative to the clausal boundary. This result indicates that although schizophrenics are sensitive to syntactic structure, their ability to organize verbal messages into meaningful grammatical units may be relatively fragile and subject to disruption by auditory distraction.