The Day’s Events are Incorporated Into That Night’s Dreams

Published: September 6, 2010

THE FACTS In the world of sleep research, dreams are something of a black box. But one tidbit that scientists have discerned is the peculiar but predictable pattern in which dreams tend to occur.

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Christoph Niemann

Research suggests that much of what happens in a dream is unique to that dream. But some events from a person’s day can be incorporated into dreams in two stages.

First there is the “day residue” stage, in which emotional events may work their way into a person’s dreams that night. But that is followed by the more mysterious “dream lag” effect, in which those events disappear from the dream landscape — often to be reincorporated roughly a week later. This lag has been documented in studies dating to the 1980s.

A 2004 study in The Journal of Sleep Research began to shed some light on this cycle. Researchers reviewed the journals of 470 people who recorded their dreams over a week. The dream-lag effect was strongest among people who viewed their dreams as a chance for self-understanding; their dreams often involved the resolution of problems or emotions tied to relationships.

The researchers speculated that the delayed dreams were the mind’s way of working through interpersonal difficulties and even “reformulating” negative memories into more positive ones. Other studies have also shown a connection between dreams and this type of emotional memory processing.

THE BOTTOM LINE The dream cycle can be much longer than a single night.

ANAHAD O’CONNOR