Non-simultaneous masking lets sounds mask others at temporal offsets, not only together

Evidence

The masking effects considered so far are known as “simultaneous masking” because the masking effect on the maskee by the masker occurs when both sound together (or simultaneously). Two further masking effects are important for the perception of music when the masker and maskee are not sounding together; these are referred to as “nonsimultaneous masking.” These are “forward masking” or “postmasking,” and “backward masking” or premasking. In forward masking, a pure tone masker can mask another tone (maskee) that starts after the masker itself has ceased to sound. In other words the masking effect is “forward” in time from the masker to the maskee. Forward masking can occur for time intervals between the end of the masker and the start of the maskee of up to approximately 30 ms. In backward masking, a maskee can be masked by a masker that follows it in time, starting up to approximately 10 ms after the maskee itself has ended. It should be noted, however, that considerable variation exists between listeners in terms of the time intervals over which forward and backward masking takes place. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1606

Categorization

• DEFINE: Defines forward/backward masking as the two nonsimultaneous masking effects, with their defining time intervals.
• QUESTION: What are the perceptual/evolutionary explanations for why masking works backward in time at all? Worth chasing.