Sound localization acuity in the cat: effect of azimuth, signal duration, and test procedure

The sound localization acuity of cats was determined at 0 degrees, 30 degrees, 60 degrees, and 90 degrees from the median sagittal plane for four durations of noise bursts using two behavioral procedures. Similar thresholds were also obtained for humans. The cats' average thresholds for a 40 ms noise burst ranged from 4.8 degrees at 0 degrees azimuth to 9.0 degrees at 90 degrees azimuth. Comparable thresholds for humans ranged from 1.3 degrees at 0 degrees to 9.7 degrees at 90 degrees. The fact that humans and cats had similar thresholds at 90 degrees azimuth suggests that the mobile pinnae of the cat are not an advantage in localizing sound in the lateral fields. Varying the duration of the stimulus from 10 ms to 'continuous' had little effect on threshold. No difference was found between the results of the two behavioral procedures.