EFFECT OF PARALLEL/OPPOSITE FREQUENCY MOVEMENTS ON PERCEPTUAL INTEGRATION OF INHARMONIC COMPONENTS
We investigated whether perceptual integration of inharmonic components is affected by parallel/opposite frequency movements (FMs) of the components. Recognition thresholds (RTs) of a target component embedded in background components were measured. In the parallel-FM condition, the target and the background always moved in the same direction on logarithmic frequency. In the opposite-FM condition, they moved in opposite directions. When all the components ascended or descended monotonically, the RTs in the opposite-FM condition were 2-4 dB lower than those in the parallel-FM condition. This benefit increased to 4-5 dB when a target consisted of ascending or descending inharmonic components with vowel-like formants. These results suggest that a target is more easily heard out from a background in the opposite-FM condition than in the parallel-FM condition because perceptual integration between the target and the background is attenuated by different frequency movements. As the shape of FM became more complex, however, this effect was limited to certain conditions and eventually disappeared.