69 Distance Perception

Imagine an angry customer at a retail store yelling that he can’t find the swim shorts he wants in his size (the ones with the smiling sharks). You’re annoyed, but you can tell that the 28-year-old is far away from you just by how loud he is to you, so you just steer clear of the children’s swim section. This is an example of a direct-to-reverberant sound. When we listen to something, that is the direct source, and the reflection of the sound to us allows us to gain information about the location and distance of said object. The direct-to-reverberant sound is the ratio of a sound’s reverberation time to when we hear it. The ratio also includes the amount of that reflected sound we are not picking up and is lost.

Our expectations about sounds helps us understand the distance of the sound we are hearing. For instance, we know a whisper is quiet, so if we were to hear the whisper loudly, we would know the distance of the sound is shorter and closer to us than if a whisper was more quiet, meaning it’s further away from us. This is the same with louder sounds as well. For example, we know that train noises are loud, so when we hear the train more quietly, we know the train or the source of the sound is much further away.

It is useful to compare optical distance estimation to sound-based distance perception. While auditory perception depends on the direct-to-reverberant sound ratio, visual estimation is dependent on cues such as perspective and size. Auditory signals center on sound purity and intensity, whereas visual cues are more concerned with size and depth. Nonetheless, our expectations have a major impact on both, forming how we perceive distances based on various sensory data.