Sleep facilitates consolidation, particularly for information important to the learner. For example, in a 2012 study, participants studied pictures of buildings and furniture. Participants had their memory for those items tested immediately. Researchers then told half of the participants that they would have their memory of furniture items tested in 14 hours. They told the other half of participants that they would have their memory of buildings tested in 14 hours. Within each group of participants, half did their initial learning early in the day and were retested at the end of the day. The other half did their initial learning toward the end of the day and were retested after getting a typical night of sleep. During the restesting period, all participants were tested for their memory of both furniture and buildings. People who slept before retesting remembered more items from the category on which they expected to be tested. In other words, those who expected to be tested on their memory of furniture remembered more furniture items than buildings. People who did not sleep before retesting remembered fewer items overall and were equally likely to remember expected and unexpected items. In other words, regardless of whether they expected to be tested on furniture or buildings, people had equal difficulty remembering all pictures.
People typically are better at remembering information consistent with their schemas. But schemas can also lead people to remember features that were not actually present. For example, in 1981, American cognitive psychologists William Brewer and James Treyens had people wait in a professor's office for 35 seconds. After exiting the room, the people were asked to list everything they could recall seeing. People were better at recalling objects that fit their schema of "professor's office" (such as a chair and desk) than unusual objects (such as a skull). Some people also recalled seeing objects that had not been present but were consistent with their schema for "professor's office," such as books.