When the circles were small and defined, participants relied on their sight rather than their hearing to gauge the direction of movement. But, intriguingly, when the circles were large and fuzzy, observers were more likely to believe their ears over their eyes, and used the sound to judge the direction of movement. The authors call this effect "reverse ventriloquism", and it occurs because large, blurred blobs are perceived as being less trustworthy than small, sharply defined ones.