Minimum audible movement angle thresholds at low velocities Free

Auditory resolution of a moving sound source was determined in a real motion paradigm. Minimum audible movement angle (MAMA) and minimum visible movement angle (MVMA) thresholds were obtained for five subjects in a two‐alternative, forced‐choice, three‐up/one‐down, adaptive procedure as a function of velocity. Velocities from 0.15°/s to 40°/s were utilized to give a wide range of motion thresholds. The low‐ended velocities are of particular interest because in a previous study Saberi and Perrott showed an increase of approximately 4–5 deg for velocities below 1°/second indicating a U‐shaped function in the detection of MAMA thresholds [Saberi and Perrott, J. Acoust. Soc. Am. 88, 2639–2644 (1990)]. The results of the current study suggest that MAMA thresholds flatten or decrease for velocities below 1°/s. However, it should be noted that in the current study, real motion was employed in contrast to that of simulated motion which utilized a 1.8‐ms click train with 5.7‐cm speakers in the Saberi and Perrott study. In addition, when MAMA and MVMA thresholds are compared at the lowest velocities, MAMA thresholds are at or below MVMA thresholds. Implications of results will be discussed. [Work supported by NSF (BNS‐9025118).]