Most of us have been faced with major life decisions. What college to attend? What job to take? Whether to buy that new car?

Some of these choices can be slam-dunks. But more often, the tally of pros and cons related to a decision can be roughly equal, making for a tougher choice.

For those moments, there’s a time-tested strategy: “Sleep on it.”

Now scientists affiliated with Harvard Medical School have shown that relational memory… the ability to see the big picture instead of just assessing isolated pieces of information… is enhanced by taking some time away from the task at hand… and, if possible, getting a good night’s sleep.

The researchers showed college students five pairs of abstract shapes. For each pair, the researchers told the students shape A was superior to shape B. The researchers did not reveal, however, that there was a hierarchy among all the shapes combined.

Later, the students were divided into three groups to test their understanding of what they’d seen. One group was tested almost immediately, a second group after twelve hours, and a third twenty-four hours later, after a full night’s rest. Students in the second and third groups were far better at discerning the overall pattern in the various shapes.

The researchers likened the process to a mental jigsaw puzzle… the subconscious mind continues to work on the puzzle even during sleep. Of course, their focus was more on memory than decision-making, but you get the picture.