Remembering and Forgetting
Why dreams are lost, who keeps them, and what the journal does.
Most dreams are gone within minutes of waking. The adult average is about one remembered dream a week (Schredl, 2008, in a representative German sample), with women recalling somewhat more than men, the young more than the old, and the gap between people enormous: some recall a dream every morning, some none in a year. The forgetting has physiology behind it. The noradrenaline system that stamps waking experience into memory is silent in REM, and the hippocampus, which does the stamping, is partly disconnected from the cortex, so that the dream is lived without being filed.
Who remembers? High recallers (five dreams a week) differ from low recallers (two a month) in measurable ways: Eichenlaub et al. (2014), with positron emission tomography in 41 subjects, found higher resting activity in the medial prefrontal cortex and the temporo-parietal junction in high recallers both awake and asleep, and more brief awakenings through the night; a later study found more white matter in the medial prefrontal region (Vallat, 2018). The regions are the ones whose damage abolishes dreaming in Solms’s patients. The high recaller wakes more, and attends more to the inner world when awake.
What raises recall is known and simple. Waking from REM, which is why the dream of the alarm clock is remembered and the dreams of the night are not; lying still on waking, since the memory is fragile and the first movement displaces it; the intention to remember, set at bedtime; and above all the journal by the bed. In every laboratory study subjects asked to keep a dream diary recall more within days, and the frequency keeps rising for weeks. Interest in dreams, openness to experience, and a thin boundary between fantasy and reality (Hartmann, 1991) predict recall across people; stress and the mood disorders raise it, and the drugs that suppress REM (most antidepressants) lower it and bring vivid dreams when stopped.
The forgetting is not total. Dream content incorporates the day before most, and then again, oddly, the events of five to seven days before, the dream-lag (Nielsen and Powell, 1989; Blagrove et al., 2011), which tracks the time the hippocampus takes to hand a memory to the cortex. And the dream that is gone on waking is sometimes recovered by a cue hours later, a sign that it was stored and not retrieved. A journal read back over a month shows the dreamer dreams that were never consciously recalled on the morning they were written.
Sources
- Schredl, M. (2008). “Dream recall frequency in a representative German sample.” Perceptual and Motor Skills 106.
- Eichenlaub, J.-B., et al. (2014). “Resting brain activity varies with dream recall frequency between subjects.” Neuropsychopharmacology 39.
- Vallat, R., et al. (2018). “Dream recall frequency is associated with medial prefrontal cortex white-matter density.” Frontiers in Psychology 9.
- Hartmann, E. (1991). Boundaries in the Mind. Basic Books.
- Blagrove, M., et al. (2011). “A replication of the 5–7 day dream-lag effect.” Consciousness and Cognition 20.
A review of the literature for readers; not medical advice.