<i>A priori</i> knowledge about the signal and binaural processing capabilities

Various factors play a significant role in determining a listener's effectiveness in understanding the speech of the target talker in complex auditory contexts including similarity and spatial relationship between speech sources, the listener's age, and hearing acuity, among others. Previous research indicates that directing attention to a specific location in space—especially when the listener is aware of the speaker and/or has prior knowledge of the target stimulus—can greatly improve speech understanding in the presence of competing talkers. A priori knowledge regarding the spatial location of the target yielded significantly improved speech understanding under conditions of high acoustic ambiguity. However, there is no information about how a priori information about the quality of the signal affects speech identification. Here, we present data on reported listening effort and speech understanding while manipulating the spatial location of the target and the maskers and the a priori information available to the listeners. Preliminary analyses indicated no effect on speech understanding based on the available a priori information for both colocated and separated conditions. However, perceived listening effort varied as a function of spatial location and available a priori information. Also, the effects of aging and hearing impairment on these measures will be discussed.