The perceptual simultaneity range for complex tones

Separating concurrent sounds is fundamental for a veridical perception of one's auditory surroundings. Sound components that are harmonically related and start at the same time are usually grouped into a common perceptual object, whereas components that are not in harmonic relation or have different onset times are more likely to be perceived in terms of separate objects. Here we tested whether neonates are able to pick up the cues supporting this sound organization principle. We presented newborn infants with a series of complex tones with their harmonics in tune (creating the percept of a unitary sound object) and with manipulated variants, which gave the impression of two concurrently active sound sources. The manipulated variant had either one mistuned partial (single-cue condition) or the onset of this mistuned partial was also delayed (double-cue condition). Tuned and manipulated sounds were presented in random order with equal probabilities. Recording the neonates' electroencephalographic responses allowed us to evaluate their processing of the sounds. Results show that, in both conditions, mistuned sounds elicited a negative displacement of the event-related potential (ERP) relative to tuned sounds from 360 to 400 ms after sound onset. The mistuning-related ERP component resembles the object-related negativity (ORN) component in adults, which is associated with concurrent sound segregation. Delayed onset additionally led to a negative displacement from 160 to 200 ms, which was probably more related to the physical parameters of the sounds than to their perceptual segregation. The elicitation of an ORN-like response in newborn infants suggests that neonates possess the basic capabilities of segregating concurrent sounds by detecting inharmonic relations between the co-occurring sounds.

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Dynamic Pitch Perception for Complex Tones of Periodic Spectral Patterns

Music Perception An Interdisciplinary Journal ◽

10.2307/40285504 ◽

1991 ◽

Vol 8 (3) ◽

pp. 291-314 ◽

Cited By ~ 4

Author(s):

Yoshitaka Nakajima ◽

Hiroyuki Minami ◽

Takashi Tsumura ◽

Hiroshi Kunisaki ◽

Shigeki Ohnishi ◽

...

Keyword(s):

Paired Comparison ◽

Fixed Ratio ◽

Pitch Perception ◽

The Other ◽

Complex Tones ◽

Logarithmic Frequency ◽

Human Ear ◽

Spectral Patterns ◽

Pitch Movement

Pitch circularity as found in Shepard tones was examined by using complex tones that had various degrees of exactness in their spectral periodicities on the logarithmic frequency dimension. This dimension was divided into periods of 1400 cents by tone components, and each period was subdivided into two parts of a fixed ratio of 700:700, 600:800, 550:850, 500:900, 450:950, 400:1000, or 0:1400. Subjects made paired comparison judgments for pitch. When the subdividing ratio was 0: 1400 or 400:1000, the subjects responded to the spectral periodicity of 1400 cents, and, when the ratio was 700:700 or 600:800, they responded to the periodicity of 700 cents. Some seemingly intermediate cases between these two extremes or some qualitatively different cases were obtained in the other conditions. As we have asserted before, the human ear appears to detect a global pitch movement when some tone components move in the same direction by similar degrees on the logarithmic frequency dimension.

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