Sound changes that lead to seeing longer-lasting shapes.

To survive, people must construct an accurate representation of the world around them. There is a body of research on visual scene analysis, and a largely separate literature on auditory scene analysis. The current study follows up research from the smaller literature on audiovisual scene analysis. Prior work demonstrated that when there is an abrupt size change to a moving object, observers tend to see two objects rather than one-the abrupt visual change enhances visible persistence of the briefly presented different-sized object. Moreover, if a sequence of tones accompanies the moving object, visible persistence is enhanced if the tone frequency suddenly changes at the same time that the object's size changes. Here, we show that although a sound change must occur at roughly the same time as a visual change to enhance visible persistence, there is a fairly wide time frame during which the sound change can occur. In addition, the impact of a sound change on visible persistence is not simply matter of the physical pattern: The same pattern of sound can enhance visible persistence or not, depending on how the pattern is itself perceived. Specifically, a change in a tone's frequency can enhance visible persistence when it accompanies a visual size change, but the same frequency change will not do so if the shift is embedded in a larger pattern that makes the change merely a continuation of alternating frequencies. The current study supports a scene analysis process that is both multimodal and actively constructive.