The dependence of the absolute auditory threshold on signal duration was measured by means of behavioral methods in the house mouse (Musmusculus). Twelve frequencies between 1 kHz and 120 kHz and white broad‐band noise were tested while seven pulse durations between 1 and 3000 msec were used. In any case temporal summation follows the functionI⋅tb=const until, at a critical durationtc, a constant value is reached where thresholds become independent from signal duration. The critical durations are frequency‐dependent following the general function:tc=p⋅fq(withq<0). This frequency‐dependent nonlinearity could alos be extracted from available data on human hearing. The present results and respective data of the human ear are discussed with reference to a critical‐band‐related summation theory assuming fixed critical bands even for very short signal durations.Subject Classification: [43]65.68, [43]65.75, [43]65.35; [43]80.50.