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Conditions under which the Haas precedence effect may or may not occur
D R Perrott1, T Z Strybel, C L Manligas
1Department of Psychology, California State University, Los Angeles 90032.
The Journal of Auditory Research
|January 1, 1987
Summary
The Haas precedence effect, crucial for sound localization, is primarily observed with very short interstimulus onset intervals (ISO-Is). Further research is needed to fully define the conditions under which this auditory perception occurs.
Area of Science:
- Auditory Perception
- Psychoacoustics
- Acoustic Signal Processing
Background:
- The Haas precedence effect describes how the first arriving sound signal influences perceived sound location.
- Understanding the boundaries of this effect is crucial for audio technology and understanding human auditory processing.
Purpose of the Study:
- To investigate the stimulus conditions that define the existence region of the Haas precedence effect.
- To determine the influence of interstimulus onset intervals (ISO-Is) and noise correlation on auditory image perception.
Main Methods:
- Five normal-hearing adults listened to 50-ms broadband noise bursts from two loudspeakers with varying ISO-Is (0-50 ms).
- Two conditions were tested: uncorrelated noise (separate generators) and correlated noise (single generator split).
- Participants classified their auditory experience into five categories and indicated perceived motion direction.
Main Results:
- At 0 ms ISO-I, correlated noise yielded a single image (71%), while uncorrelated noise produced two distinct images (68%).
- A weak precedence effect (single image perception) was observed for correlated noise at 2 ms ISO-I.
- Single image perception decreased significantly with increasing ISO-I, becoming dominated by dual source perception by 8+ ms.
Conclusions:
- The Haas precedence effect appears to be confined to very brief ISOIs.
- Further experimental investigation is required to define the precise boundaries of the precedence effect.
- It is premature to propose neurophysiological mechanisms underlying the precedence effect.