How do we perceive our acoustic world? This is a central issue of psychoacoustic research. It is of particular interest for non-stationary sounds which are strongly varying in their spectral content and intensity over time, such as speech and many other environmental sounds. This study presents some new results concerning the intricate interaction between the processing of intensity, spectral content and temporal effects in auditory psychophysics. It focuses on spectro-temporal effects in loudness perception and masking. It contains chapters on methodological factors in measurements of spectral loudness summation and the effects of duration on spectral loudness summation. Additional chapters discuss the impact of temporal effects on spectral masking as observed in conditions of "asymmetry of masking" and "comodulation masking release". The results have implications on several areas of applied psychoacoustics such as the further development of "intelligent" hearing aids, the research of annoyance and the development of speech recognition processors
