ABSTRACT
We all know that we cannot listen to what two people are saying, or to any other two auditory signals at once. Although we can detect the location of a variety of auditory objects in the environment, it is not possible to listen to them all at the same time. The separate sounds are analysed from the auditory input, and we considered some of the problems of auditory analysis in Chapter 7. However, attentional
processes are also involved in allowing us to selectively listen to one source of sound rather than other. Walking in the garden you can intentionally control what you listen to. You may listen to the birds, then switch attention to listening to the wind in the trees, then back to your friend’s chatter. Most of the time one sound source is the focus of attention, and is in the foreground, which other sources merge into the background. As you switch between the sounds, what appears to be in the background or foreground changes places. However, if there is a sudden noise, for example an apple falling to the ground, this will automatically capture your attention. We have already looked at endogenous and exogenous control of attention in Chapter 5, concerning visual attention. While there are some important differences between hearing and vision, these modalities interact in some interesting ways. For example, if you are trying to hear what someone is saying to you in a noisy environment it helps if you can see their lips moving, so attending to sounds can be improved if we also attend to visual properties of the same object.
