I am in the process of reviewing literature related to the effects of "informational" and/or "perceptual" masking on speech understanding. I have found the use of these terms in isolation to describe the additional masking effects of a two (or several) talker babble/interferers above that of a spectrally matched modulated (or unmodulated) noise. In my cursory review I have noticed several authors use the term "perceptual masking" to describe this phenomenon (e.g. Carhart and colleagues, 1966, 1968, 1975; Hall, et al., 2002), while others use the term "informational masking" to describe a seemingly similar phenomenon (e.g. Freyman, et al., 1999; Brungart and colleagues, 2001a, 2001b, 2002).
The terms seem to have come from different camps of researchers that were investigating the impact of the same phenomenon on somewhat different aspects of auditory perception. Carhart et al., were looking at additional masking effects (above simple power summation) of two (multi)-talker maskers compared to steady state (or modulated) noise maskers and used the term "perceptual masking" to describe the effects. In contrast, Pollack (1975), Watson and colleagues (1975,1976) and others have examined the impact of stimulus uncertainty on various detection tasks and used the term "informational masking" to describe the additional masking effects of uncertainty above that of traditional "energetic masking". More recent papers (e.g. Freyman, et al., 1999; Brungart and colleagues, 2001a, 2001b, 2002 and others I'm sure) have used this term to describe additional masking in some speech understanding tasks similar to that described by Carhart.
Sorry for the long post but I am simply trying to confirm the history and usage of the terms. Any comments regarding how to best combine/differentiate these terms would be helpful.