Role of masker predictability in the cocktail party problem

In studies of the cocktail party problem, the number and locations of maskers are typically fixed throughout a block of trials, which leaves out uncertainty that exists in real-world environments. The current experiments examined whether there is (1) improved speech intelligibility and (2) increased spatial release from masking (SRM), as predictability of the number/locations of speech maskers is increased. In the first experiment, subjects identified a target word presented at a fixed level in the presence of 0, 1, or 2 maskers as predictability of the masker configuration ranged from 10% to 80%. The second experiment examined speech reception thresholds and SRM as (a) predictability of the masker configuration is increased from 20% to 80% and/or (b) the complexity of the listening environment is decreased. In the third experiment, predictability of the masker configuration was increased from 20% up to 100% while minimizing the onset delay between maskers and the target. All experiments showed no effect of predictability of the masker configuration on speech intelligibility or SRM. These results suggest that knowing the number and location(s) of maskers may not necessarily contribute significantly to solving the cocktail party problem, at least not when the location of the target is known.