ORGANIZATION IN AUDITION BY SIMILARITY IN RATE OF CHANGE - EVIDENCE FROM TRACKING INDIVIDUAL FREQUENCY GLIDES IN MIXTURES

In audition, sound energy is assigned to separate auditory ''streams'' following principles of organization that closely parallel the visual gestalt principles that guide the perception of distinct forms or obj ects. Metzger (1934) provided evidence for organization in vision base d on similarity in the velocity of moving forms. If two dots approach one another along one spatial dimension, they may appear to cross and continue beyond their meeting point if their velocities differ; otherw ise, they usually appear to change direction abruptly and retrace thei r movements. If an analogous auditory principle exists, with rate of c hange in frequency substituted for velocity of movement, two frequency glides that sweep through the same frequency range in opposite direct ions should be able to perceptually cross if their rates of change dif fer; otherwise, they should usually appear to change direction and ret race the same frequency region. Four experiments provided data in supp ort of this hypothesis, and the results were consistent across experim ents with varying stimuli and methods of presentation. When properties of the stimuli favored organization according to a principle of frequ ency proximity, the effect of a principle of rate similarity was atten uated but still evident.