Bat sonar: an alternative interpretation of the 10-ns jitter result

In 1990 Simmons et al. reported evidence of a time resolution hitherto unknown in any animal, namely a 10-ns jitter detection threshold in echolocating bats. This result is discussed. The calibration data from the original papers are examined. Observations indicating other cues than delay being presented to the bats are given. We offer an alternative explanation for the psychometric jitter function, based on the assumption of a subtle distortion due to impedance mismatch in the delay-producing apparatus. We also report that effects of impedance mismatch are detectable by a human subject in a model experiment. Accepted: 3 September 1997