Understanding Speech With Our Ears and Eyes

Understanding people when they are speaking seems to be an activity that we do only with our ears. Why, then, do we usually look at the face of the person we are listening to? Could it be that our eyes are also involved in understanding speech? We designed an experiment in which we asked people to try to comprehend speech in different listening conditions, such as someone speaking amid loud background noise. It turns out that we can use our eyes to help understand speech, especially when that speech is difficult to hear clearly. Looking at a person when they speak is helpful because their mouth and facial movements provide useful clues about what is being said. In this article, we explore how visual information influences how we understand speech and show that understanding speech can be the work of both the ears and the eyes!