Object Persistence

Suppose that while playing tennis, an unfortunate swing propels your tennis ball out of the court and into some bushes. When you go to retrieve it, you find two tennis balls there. Which is yours? This is a type of correspondence problem: You must determine which of the two tennis balls corresponds to the one that you just hit out of the court. Though we are seldom explicitly aware of it, the visual system faces this type of problem thousands of times per day, whenever we encounter an object. On every such encounter, the visual system must determine whether a current bit of visual stimulation reflects a new object in the field of view or an object that was already encountered a moment ago. This ...