Exposed 6 male albino rats to 6,900 Hz tone pulses with durations of .25-64 msec. and intensities of 80-125 db. re .0002 dyne/cm2. Startle amplitudes increased with duration in a manner suggestive of an exponential function distorted by the failure of the auditory system to reflect faithfully prolonged intense sounds. 5 other male albino rats were exposed to pairs of 1-msec pulses at 125 db., having interpulse intervals ranging 1-11 msec. For pulses separated by 3 msec. or more, response amplitudes demonstrated a decaying exponential summation function with a time constant of 3 msec. Results are in accord with established principles of reflex function and organization. (PsycINFO Database Record (c) 2006 APA, all rights reserved)