Advertising already floods phones, televisions and laptops throughout the day. Now, some people online say commercial messages are following them into sleep, appearing as product placements or complete adverts woven into their dreams.

One person raised the issue on the Dreams subreddit by asking, “Has dream advertising started?” They said that “for the last year or so, every dream [they have had] has revolved over some kind of product”.

Another Reddit user described experiencing a “very specific” advert while dreaming. According to that person, the experience felt “almost like product placement”.

“Not the first time this has happened. I’ve had ads pop up right in the middle of a dream just like YouTube ads.”

“They’ve infiltrated the dream world. Honestly not surprised, it was gonna happen at some point.”

The same user suggested that falling asleep with the television on could be relevant. “Maybe it’s because I sleep with the TV on but it seems like this just started happening the past three or four days.”

Data from The Media Image released this year indicates that these reports are far from isolated. Six in 10 Americans, or 61%, said they had experienced dreams containing advertising content.

Among those respondents, almost two out of five, or 38%, said the experience occurred frequently, with reported intervals ranging from once a month to every day. Two in five respondents, or 41%, admitted they believed adverts were actively infiltrating their dreams.

Despite the concerns and the comparisons with Black Mirror, there is no suggestion that advertising executives have developed a way to enter people’s minds. Dr Daniel Atkinson, Clinical Lead at Treated, offered several explanations for why adverts might surface during sleep.

“One reason is exposure. Previously, adverts were something we consumed comparatively infrequently: when watching television, reading magazines or newspapers or travelling past a billboard. Now, we're seeing adverts much more often as we engage with social media and use online tools for day-to-day activities, at pretty much any time of day.”

Atkinson said novelty could also make modern advertising more memorable. “Another reason is novelty. Again, advertising has evolved to a point where elaborate, fantastical imagery is more common because it's easier to pull off from a production standpoint.”

He also described how the brain handles information and imagery encountered during waking hours. Catchy, repetitive or visually striking material may receive more attention as the brain processes the day’s experiences.

“The brain processes and catalogues images and and information during the day and stores this in the thalamus, and often more deeply processes data that's catchy or repetitive in the cerebral cortex,” he said.

“The prefrontal cortex and hippocampus effectively decide whether or not to 'keep' something for later, and it's at this point that associations with that memory begin to be matched to emotions and motivations ('I want to buy one of those'). When you enter REM sleep at night, the brain is working to further process this information, and this is why images might infiltrate dreams.”

Certain visual qualities may make an advertising campaign especially likely to stick in the mind. Atkinson pointed to animation, bright colours and stronger contrast as features that can increase how readily an image is recalled.

“Animated content, or campaigns utilising bright colours with a higher level of contrast, have a higher visual salience and are usually easier to recall, and these might be prioritised by the brain because they're more striking than other images we've seen throughout the day.”

For people who would prefer adverts to stay out of their dreams, Atkinson recommended limiting screen time. He also suggested setting a curfew and stopping device use at least one hour before going to bed.

“It might also help to do a mindful or 'meditative' activity before bed, (such as drawing, crafting or embroidery) to help give your brain the space and time it needs to filter out images and info you've taken in throughout the day,” he said.

“The task at hand may effectively replace advert content in your working memory - so you aren't as likely to dream about it.” That could offer people a simple way to give their sleeping minds a break from the advertising they encounter during the day.