Without Time and Sleep, Facts Are Fragments

The ability to turn information into knowledge is powerfully influenced by reflection and rest, psychologists say.

In a study published today in the Proceedings of the National Academy of Sciences, researchers from two Boston hospitals showed pictures of abstract patterns to 56 college students.

The students were then told that some of the patterns were "correct" while others were "incorrect," for example, Shape A wins over Shape B, Shape B wins over Shape C, and so on. All of the students learned the individual pairs but were not told that there was a hidden "hierarchy" linking all five of the pairs together.

After a 30-minute study period, the students were separated into three groups to test their understanding of the larger "big picture" relationship between the individual patterns: Group One was tested after a period of 20 minutes; Group Two was tested after a 12-hour period; and Group Three was tested after a 24-hour time span. In addition, approximately half of the students in Group Two slept during the 12-hour period, while the other half remained awake. All of the students in Group Three had a full night's sleep.

The differences were clear. Kids in Group One were unable to infer the hierarchical relationships between the patterns. Groups Two and Three did much better.

"These individuals were able to make leaps of inferential judgment just by letting the brain have time to unconsciously mull things over," he says. But, perhaps most notable, he adds, when the inferences were particularly difficult, the students who had had periods of sleep in between learning and testing significantly outperformed the other groups.

"This strongly implies that sleep is actively engaged in the cognitive processing of our memories," notes Ellenbogen. "Knowledge appears to expand both over time and with sleep."

To understand the big picture, give it time -- and sleep [press release]

Image: Mary