LAWRENCE — There are a few reasons why we might dream, say the neuroscientists. Even dreams that are scary may serve a purpose: One prevalent idea is fear in dreams could help people deal with fear in waking life, much like exposure therapy.
One University of Kansas researcher tested this concept and recently published results in the peer-reviewed journal Sleep . Garrett Baber, a KU doctoral student in clinical psychology, sought to test whether emotions experienced within dreams — like fear and joy — change feelings the following morning.
“The idea I’ve been most interested in was whether emotions in our dreams have any impact on our emotions in the day,” Baber said. “We’re in a safe environment in our dreams. We cannot technically be harmed. If all goes wrong in a dream, we wake up. As long as sleep is not really disrupted, if it’s not rising to the level of a nightmare, fear in our dreams might actually help us better deal with our emotions in the day.”
To find out, Baber and his co-authors analyzed dream reports from more than 500 people, employing machine learning to sort emotions reported in dreams. Then they compared those dreamt emotions to participants’ emotional states the following day.
“We wanted to apply new methods with bigger data,” he said. “We had a much larger sample than a lot of studies use and used some advanced statistics to apply a more rigorous approach to testing why we dream. I didn’t reinvent the wheel in terms of creating a theory. I just wanted to put them to the test.”
With the larger datasets, the researchers applied a customized large-language model to classify and quantify dreamt emotions, according to Baber.
“I trained it to measure fear as well as joy,” he said. “I asked it to read the dream text and produce a number for how afraid the person was in their dream, as well as how much positive emotion was present.”
The KU researcher said if the “exposure therapy” idea held, more fear in dreams should predict a better mood the following day.
“But we found two different results,” Baber said. “On the day-to-day level, more fear in dreams was associated with worse mood in the morning. However, people who reported using more adaptive emotion regulation strategies — such as acceptance rather than suppression — showed higher levels of fear in their dreams on average.”
In other words, Baber said there was a discrepancy in the findings.
“In the short term, more fear in dreams is associated with worse mood,” he said. “But at the individual level, people who are better at handling their emotions tend to have more fear in their dreams.”
Another finding involved the researchers measuring joy in dreams as well as fear.
“We examined whether emotional complexity — experiencing multiple emotions at once — had any effect,” Baber said. “We found when dreams contained both fear and joy at the same time, people were less likely to report negative mood in the morning. This was a novel finding. It suggests that emotional complexity in dreams may have a protective effect.”
But when does the “emotional processing” or “regulation” take place: during a dream or when we reflect upon a dream?
“There is no consensus on when emotional processing happens,” Baber said. “Early work assumed it occurs during the dream itself. I am testing whether it may be more important how dreams affect us later in the day. This study focused on the morning, but it may be that effects unfold much later. An emerging theory suggests that changes within the dream itself may reflect emotional regulation. The presence of both fear and joy may be an example of this.”
Baber’s KU co-authors were Nancy Hamilton, associate professor of psychology; Jeffrey Girard, associate professor of psychology; Amber Watts, associate professor of clinical psychology; Daiil Jun, doctoral researcher in psychology; Matthew Gratton, researcher in the Department of Psychology; Anna Quesada, graduate researcher in psychology; and Elijah Nichols, a doctoral researcher in the department. They were joined by Pilleriin Sikka of Stanford University, the University of Skövde in Sweden and the University of Turku in Finland; Jamie Cohen, an independent researcher in Lawrence; and Tony Cunningham of Beth Israel Deaconess Medical Center and Harvard Medical School.
The next step, according to Baber, is testing whether there is a difference between dreams that involve fear, or a mixture of fear and joy, and clinical nightmares.
“Nightmares are typically defined as dreams that are so distressing they wake the person up, versus bad dreams where the person remains asleep,” he said. “There are effective therapies for chronic nightmares, particularly for people with PTSD, where nightmares about traumatic experiences are common. There may be nuance in whether some forms of distressing dreams represent the brain trying to process emotions.”
Baber noted that while chronic nightmares are associated with negative outcomes like mental and physical health challenges which warrant attention, the average bad dream might actually be a sign of the brain's resilience.
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