Sounds mask both preceding and following sounds but forward masking dominates.

Evidence

The masking effect has been discussed so far only for continuous sounds. Sounds mask each other in time as well; that is, a sound affects the audibility of a preceding or following sound. A conceptual illustration of temporal masking is shown in Figure 9.10, both for a sound occurring before the masker, called backward masking, or pre-masking, and after the masker, called forward masking, or post-masking. Such thresholds of audibility are measured using psychoacoustic tests, where the listener hears a masker sound long enough (>200 ms), which is preceded or followed by a short burst of sound. Forward masking is, in general, more significant and more consistent a phenomenon than backward masking. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1016

Categorization

• DEFINE: Defines temporal — backward vs forward — masking, extending the classical simultaneous-masking picture.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1016