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 that an object continues to exist when it is not in the baby's view. But in mid-1980s, new ways of doing experiments with babies found that they do, in fact, know that objects don't disappear when they do not look at them -- a concept known 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 John 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 _ 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 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 say. He thinks the brain has a structure that acts like a kind of pointer, a mental finger that points at an object. The study is beneficial to know   _   .
how the young brain deals with information about objects whether babies can remember features of hidden objects whether babies were surprised when they found the objects disappeared why babies less than two years did not understand a hidden object still existed