Dreams have long served as an inspiration to history’s greatest artists: Fleetwood Mac, Beyoncé, Eurythmics. But what actually causes someone to have a sweet dream or a beautiful nightmare? Can the emotions we experience before sleep directly affect what we dream about? New research has found that the answer to that question is… probably, yes. Published in JNeurosci, the study found a pattern of brain activity that may predict angry dreams.
In the study, the researchers focused on frontal alpha asymmetry (FAA), defined as the difference between right and left activity in the frontal area of the brain. FAA is a useful marker of immediate, short-lived emotions and their regulation in someone who’s awake, and this new study investigated if FAA could also be a good marker of emotion during sleep, and whether a person’s emotions right before sleeping were related to the emotions they experienced in their dreams.
Over the course of two nights, the researchers recorded the participants’ EEG, measuring the subjects’ electrical brain activity before they went to sleep, while they were sleeping, and in the morning after they awoke. The study participants were woken up five minutes after the beginning of each REM stage (when humans tend to dream most intensely), and they gave a report describing the emotions and nature of their dream. The results indicated that FAA during sleep and in the evening minutes before sleep tended to predict experiences of anger in dreams, also demonstrating a pattern that’s previously been linked to anger and self-regulation during wakefulness.
“There are different theories regarding why people experience emotions, including anger, in their dreams,” Pilleriin Sikka, lead author of the study, told Newsweek. “Some theories argue that dreams may simply reflect our waking emotions and experiences. From this perspective, people who experience more anger and anger-related experiences in their waking life also experience more anger in dreams.”
Sikka added that other theories reason humans may actually process negative emotions in their dreams, which may help them cope during wakefulness. “From this perspective, individuals who experience anger in dreams may be better able to cope with such emotions and related situations in their daily waking life,” she said.
Previous research on the topic of dreams and aggression have found mixed results. One study found that anger and frustration were common themes among individuals who reported frequent nightmares, and another 2015 study found that anxiety levels and physical aggression within dreams were significantly higher for individuals who reported recurrent nightmares (versus people who didn’t suffer from recurrent nightmares). An article for the Harvard Mahoney Neuroscience Institute notes that nightmares in general can arise from a variety of sources, including medications, stress, anxiety, irregular sleeping patterns, and mental health disorders like PTSD.
One big caveat of the new study is that it was performed on a small group of 17 adult participants, meaning the results aren’t exactly generalizable. But the results suggest that FAA could potentially be a useful neural measure of emotion in both waking and dream states. The findings also encourage more research in the area, especially when it comes to understanding what might spur the content of peoples’ dreams (and nightmares).