People who frequently recall their dreams show different brain reactivity compared to those who rarely recall dreams, both while awake and asleep. In a study of 18 high-recall and 18 low-recall participants, brain responses to hearing first names (ignored during a silent movie or sleep) were measured. During wakefulness, high-recall individuals had larger attention-orienting brain responses (P3a) and a late parietal response. During sleep, differences appeared at the P3a latency during N2 sleep and at later latencies across all sleep stages. These findings indicate that dream recall ability is linked to a particular functional organization of the brain that persists regardless of whether the person is awake or asleep.
People who often remember their dreams (high-recallers, averaging 4.42 dream recalls per week) show a more sustained decrease in alpha brainwave activity (8–12 Hz) in response to hearing their own first name during wakefulness compared to low-recallers (0.25 recalls per week). This alpha decrease, measured at the Pz electrode site 1000–1200 milliseconds after the sound, suggests deeper processing of complex sounds in high-recallers, possibly reflecting a longer release of inhibition in brain regions not needed for the task. No group difference in alpha reactivity was found during REM sleep. High-recallers also experienced more time awake during the night (30 vs. 14 minutes), supporting the idea that trait differences in brain physiology underlie dream recall frequency.