For the first time, researchers have got evidence that dreams help soothe the impact of emotional events in our lives, acting like overnight therapy

Manipulating dreams could help us come to terms with trauma Jasper James/Millennium Images, UK

DREAMING really does help us process our memories and come to terms with our daily lives. That might sound uncontroversial but we have never had clear evidence that this is the case – until now. The finding raises the prospect of hacking our dreams to boost learning, memory and emotional well-being.

Mark Blagrove at Swansea University in the UK and his colleagues have found that the emotional strength of the experiences we have when we are awake is linked to the content of our dreams, and the intensity of our dreaming brainwaves.

The team asked 20 student volunteers to keep a detailed diary of their daily lives for 10 days, logging the main things they had done, any personally significant events that had taken place, and any major concerns or worries they had had. Where appropriate, the students noted any accompanying emotion, and scored it for intensity.


On the evening of the tenth day, the volunteers slept in the team’s dream lab while wearing an EEG cap that measured their brainwaves. Each person was woken during rapid eye movement (REM) sleep, and if they had been dreaming, a report of the dream was recorded. The team then compared the content of such dreams with the daily logs, looking for links. For example, you might have a scary near miss while cycling, and later dream about riding a bike.

During REM sleep, electrical activity in the brain oscillates at a frequency between 4 and 7 hertz, generating a type of brainwave known as theta waves. Blagrove’s team found that the intensity of a person’s theta waves was positively correlated with the number of diary items that appeared in their dreams.

The researchers also discovered that events that had a higher emotional impact were more likely to become incorporated into a person’s dreams than blander, more neutral experiences (Social Cognitive and Affective Neuroscience, doi.org/gdn49v).

Together, these findings suggest that the most intense dreaming activity occurs when our brains are working hard to process recent, emotionally powerful experiences.

“If dreams soothe the emotional impact of our experiences, we could hack them to dream better”

“This is the first finding that theta waves are related to dreaming about recent waking life, and the strongest evidence yet that dreaming is related to the processing that the brain is doing of recent memories,” says Blagrove.

It is a very original result, says Tore Nielsen at the Dream and Nightmare Laboratory in Montreal, Canada. “This study could provide us with some effective and non-invasive measures that could eventually help uncover the functions and mechanisms of dreaming,” he says.

Nielsen’s team has previously found that theta activity is higher in people who have frequent nightmares. It might be that such people put more brain effort into processing their emotions and experiences during dreaming.

Boosting brainwaves

If dreams do act as a sort of overnight therapy to soothe the emotional impact of our experiences, it raises the prospect of manipulating our sleeping brains to improve this process. We know that people who have more REM sleep and more intense theta activity during REM are better able to consolidate emotional memories, says Blagrove. If we attempt to hack our dreams by artificially increasing theta waves, it might lead to the incorporation of more waking experiences into our dreams, says Blagrove. This could help us learn better.

One way to do this may be to force brainwaves to the theta frequency. Blagrove says it is possible to drive brainwaves into this using sound, and the team is planning to test this. “If we stimulate and increase theta activity, do we start dreaming more of recent waking life experiences?” he says.

This may boost the effectiveness of dreaming or even let us manipulate our own dreams. It could also have therapeutic uses, including helping people come to terms with traumatic experiences. Techniques that boost theta waves during sleep could also open the door to improving our ability to store memories, says Nielsen.

This article appeared in print under the headline “Dreams act as overnight therapy”

Read more: Why dreaming is vital: Unlocking the power of REM sleep