Six-month-old babies are strictly limited in what they can remember about the objects they
see in the world. If you hide several objects from babies, they will only remember one of those
objects. But a new study, which was published in an issue of Psychological Science, a journal
of the Association for Psychological Science, finds that when babies “forget” about an object,
not all is lost. Researchers used to think that babies less than two years old did not understand
than an object continues to exist when it is not in the baby’s view. But in the mid-1980s, new
ways of doing experiments with babies found that they do, if fact, know that objects don’t
disappear when they are not looking at them- a concept know as object permanence. But it
was still unknown what babies needed to remember about objects in order to remember their
existence.
     Now Melissa Kibbe, of Johns Hopkins University, and Alan Leslie, of Rutgers University, are
working to figure out exactly what it is that babies remember about objects. For the new study,
they showed six-month-old babies two objects, a disk and a triangle. Then they hid the objects
behind small screens, first one shape, then the other. Earlier research has shown that young babies
can remember what was hidden most recently, but have more trouble remembering the first object
that was hidden. Once the shapes were hidden, they lifted the screen in front of the first object.
Sometimes they showed babies the shape that was hidden there originally, but sometimes it was
 the other shape, and sometimes the object had vanished completely.
     Psychologists measure how long babies look at something to see how surprised they are. In
Kibbe and Leslie’s study, babies weren’t particularly surprised to see that the shape hidden behind
the screen had changed, for example, from a triangle to a disk. But if the object was gone altogether,
the babies looked significantly longer, indicating surprise at an unexpected outcome. “This shows
that even though babies don’t remember the shape of the object, they know that it should continue
to exist,” Kibbe says. “They remember the object without remembering the features that identify that
object.”
     This helps explain how the young brain processes information about objects, Leslie says. He
thinks the brain has a structure that acts like a kind of pointer, a mental finger that points at an object.