Absolute thresholds were measured for 5-, 30-, and 200-ms stimuli using an adaptive, forced choice procedure. Temporal integration of loudness for these durations was also measured for a 1-kHz tone and for broadband noises over a range of 5-80 dB SL (noise) and 5-90 dB SL (tones). Results show that temporal integration (defined as the level difference between equally loud 5- and 200-ms stimuli) varies non-monotonically with level. The temporal integration is about 10-12 dB near threshold, increases to 18-19 dB when the 5-ms signal is about 56 dB SPL (tone) and 76 dB SPL (noise), decreases again around 100 dB SPL to about 10 dB (tones) and 13 dB (noise). The data for tones are in good agreement with the majority of existing data. The data for noises are within the range of the few previous data, but the effect of level differs from that obtained in previous studies. The present results indicate that the growth of loudness may, at least in part, be consistent with the nonlinear input/output function of the basilar membrane.