Syntactic and semantic factors in the classification of nonspeech transient patterns

Three experiments were conducted to investigate the role of both syntactic (i.e., temporal structure) and semantic (i.e., knowledge of the source events) factors in a two-alternative (target/ nontarget) categorization task involving patterns of nonspeech acoustic transients. The results demonstrated that both factors can play an important role in the classification of such patterns. Although pattern syntax influenced performance in all three experiments, the effects of syntactic structure were clearest in Experiment 1, in which listeners categorized meaningless tonal patterns. Listeners who categorized a syntactically structured target set performed better than did those with an unstructured set. Experiments 2 and 3 were similar to Experiment 1, but listeners classified patterns of familiar, brief-duration, complex sounds rather than tones. When listeners in Experiment 3 were given explicit descriptive information about the pattern components in their instructions, performance actually improved for interpretable, but not for uninterpretable, patterns. This suggests that syntactic and semantic factors interact in an important way to influence performance. It was argued that many complex nonspeech patterns have both syntactic and semantic structure, which is determined by the sequence of source events that produce them. In classifying such patterns, as in the case of speech, listeners rely on their knowledge of these factors as well as on the perceptual information in the sound itself.