Liang Li’s group has studied why spatial separation between the target-speech source and masking-speech sources is still able to improve recognition of the target speech under reverberant conditions, where both the head-shadowing and interaural-interaction unmasking cues are limited by numerous reflections. It is the fast decaying primitive auditory memory (PAM) that forms the basis of perceptual integration between the direct wave and the correlated reflections of a speech source, leading to perceptual segregation between different speech sources.

Li, H., Kong, L., Wu, X., and Li, L. (2013). Primitive auditory memory iscorrelated with spatial unmasking that is based on direct-reflection integration. PLoS One  8:e63106.