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document
Motion aftereffects with horizontally moving sound sources in the free field . A horizontally moving sound was presented to an observer seated in the center of an anechoic chamber . The sound , either a 500-Hz low-pass noise or a 6300-Hz high-pass noise , repeatedly traversed a semicircular arc in the observer 's front hemifield at ear level ( distance : 1.5 m ) . At 10-sec intervals this adaptor was interrupted , and a 750-msec moving probe ( a 500-Hz low-pass noise ) was presented from a horizontal arc 1.6 m in front of the observer . During a run , the adaptor was presented at a constant velocity ( -200 degrees to +200 degrees/sec ) , while probes with velocities varying from -10 degrees to +10 degrees/sec were presented in a random order . Observers judged the direction of motion ( left or right ) of each probe . As in the case of stimuli presented over headphones ( Grantham & Wightman , 1979 ) , an auditory motion aftereffect ( MAE ) occurred : subjects responded " left " to probes more often when the adaptor moved right than when it moved left . When the adaptor and probe were spectrally the same , the MAE was greater than when they were from different spectral regions ; the magnitude of this difference depended on adaptor speed and was subject-dependent . It is proposed that there are two components underlying the auditory MAE : ( 1 ) a generalized bias to respond that probes move in the direction opposite to that of the adaptor , independent of their spectra ; and ( 2 ) a loss of sensitivity to the velocity of moving sounds after prolonged exposure to moving sounds having the same spectral content .
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Intervention_Other
horizontally moving sound
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Intervention_Other
500-Hz low-pass noise
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Intervention_Other
6300-Hz high-pass noise
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Intervention_Other
moving probe
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Outcome_Physical
auditory motion aftereffect ( MAE )
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Outcome_Physical
MAE
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Outcome_Physical
MAE