Directional selectivity of auditory spatial attention in multi-talker environment

When people direct their auditory selective attention in a specific direction, the information from that direction can be perceived easily, even in a noisy environment. Understanding how this effect is distributed spatially is important. The extent of spatial distribution may depend on the direction of the attention focus, and thus may differ between the frontal and oblique directions. In the present study, we investigated the dependence of the spatial extent of auditory selective attention on the focus azimuthal direction. To examine the spatial extent, speech intelligibility was measured in a multi-talker environment. In the experiment, a target sound and multiple distracting speech sounds were presented simultaneously from loudspeakers surrounding observers. By manipulating the probability of the target presentation directions, the listener's auditory spatial attention was directed to a specific loudspeaker. The attracted direction was one of three directions: -30, 0, or +30 degrees. The results showed that the greatest improvement in intelligibility was observed at the attracted direction, for all attracted directions. The spatial extent of the auditory selective attention seems identical for all attracted directions. This means that the attention spotlight is not modulated by the direction of the attention.