Have you ever felt drawn toward choices without knowing why? Or, as seen in the movie “Inception,” have you ever felt like you’ve woken up with a decision that’s already been made for you?
Neuroscience is beginning to demystify such feelings. Our agency and decisions, it turns out, can be measurably influenced by events that evade the conscious part of our brains. We’ll see three groundbreaking experiments that illustrate that influences we are unaware of in our waking life, during dreamless sleep, or even in our dreams can impact our memory and behavior.
Published on February 18, 2021, in the journal Current Biology, an international team of scientists have found a bridge to the dream world by showing that it’s possible to have a direct dialogue with someone in their dream—and NOVA’s Greg Kestin (host of “What the Physics?!”) was given exclusive access.
The scientific context and potential effect of this team’s work are built up in the film through two related groundbreaking experiments. These experiments also show how scientists can influence your decisions, desires, and habits without you being aware.
Dream Hacking: Decisions, Addictions, and Sleep
Published: February 18, 2021
Karen: They're communicating to us from a dream.
Greg: You're about to see three groundbreaking experiments...
Laura: When they woke up, they were actually less inclined to smoke.
Greg: ...that reveal, not only how hidden parts of your mind can control your decisions...
Nick: Seven times it happened? I thought it happened twice.
Greg: ...but also how scientists can manipulate your preferences, desires, and habits without you even being aware. So how do they do it?
Greg: Like in the movie Inception, they do it by sneaking ideas into people’s brains and by manipulating dreams. What you’re about to see may make you question what or who really controls your decisions.
Before getting to dream control, do you even control your decisions when you’re awake? Moran Cerf is a former hacker. And these days he hacks the brain. As a neuroscientist, he's attempting to implant an idea, a preference into these volunteers’ minds without them being aware it's happening. And while he does it, he monitors their brain with a device called an electroencephalogram or EEG.
Moran: The experiment is going to ask you to make a repeated decision. Each trial is going to have the following stages. First, you're going to see the choice, two options. Then you're gonna make a choice, left or right. And then we're going to ask you to explain to us.
Christina: She looks really intelligent.
Diara: The other one seemed a little bit more sad.
Nick: She looks like somebody who was fun and friendly.
Greg: After the participant makes several decisions, Cerf does something a little tricky. Pay close attention. The subject chooses the woman with the lighter hair on the right side. But five seconds later, when the card flips over, he's presented with the picture of the woman that was on the left.
Nick: I like this person's dimples.
Greg: Not only does he not remember that that wasn't the person he originally picked, a phenomenon called Choice Blindness, but he also comes up with a reason for why he did pick that person. So, could this actually change who he prefers in the future?
Moran: Part two, almost the same, just without the need to explain.
Greg: Now, when faced with the identical decision, will his preference be the same or different?
This time he chose the woman on the left. It appears that, without him being aware, his preference has successfully been changed.
The EEG gives Cerf a clue to what's happening in the subjects' brains.
Moran: So the way we think about it is that there are, in your brain, cells that code value or that code preferences. So imagine you have to choose between steak and a fish and you're about to make a choice. The fish cells on the left side of your brain are starting to fire, indicating, "we want fish." At the same time, the cells on the right are starting to fire, indicating, "we want the steak." And there is kind of a battle between those two. And at some point there's enough majority from one side, rather than the other. Then information gets sent to you, the conscious you, then says "Fish," not knowing that under the hood there was an entire battle going on.
Greg: This unconscious battle impacts how your brain actually decides between different foods, different videos, different faces.
But by explaining a false choice, that creates a false memory that influences the unconscious battle in one direction versus the other. Every once in a while, they'd actually catch the switch.
Nick: Thought I chose the other one.
Diara: I think I chose the other one.
Christina: Thought I chose the other image.
Greg: But most of the time this switch does go unnoticed.
Diara: Probably more the eyes on this one.
Greg: And it doesn't just work with faces.
Moran: It works to an extent with choices that we think are not just arbitrary and small, but ones that define who we all like political choices. So, you can't easily take a Democrat and make it a Republican or vise-versa. But you can take definitely a person who says that they're going say 9 on how liberal they are, and in a small manipulation, make them shift to scoring 6.
Greg: But for someone to dramatically change your habits or even addictions, your memories may need to be even more vulnerable to manipulation.
Moran: We can actually find moments in your life where your guards are down. One of those moments is when we're sleeping.
Greg: A study was done by a research group at Israel's Weizmann Institute. They took habitual smokers and asked them to track how much they smoked over a particular week. Then at the end of that week, they asked the smokers to come into the lab for a night of sleep. Then over the following week, they tracked how much they smoked again. It turned out that over that following week, they smoked significantly less. So, what happened to the smokers when they slept in the lab? It all comes down to what they smelled during the night.
Laura Shanahan is a neuroscientist at Northwestern University who does similar research studying sleep and odors.
Laura: Sleep is really important for consolidating our memories. What if we could actually go in and manipulate that process? The sense of smell is often a really underappreciated sense.
Greg: So, when the smokers in this study slept in the lab, they were equipped with an odor delivery system and an EEG to track what stage of sleep they were in.
Laura: When they fell asleep researchers presented two different smells to their noses repetitively: cigarette smoke and the smell of rotten eggs. They had no idea that they had smelled the smells during sleep ...
Greg: Without their awareness their sleeping brains, by some mysterious process, associated cigarette smell with the rotten egg smell, and as a result...
Laura: They were less inclined to smoke cigarettes for the following week.
Greg: Laura was intrigued by research like the Israeli study, and wanted to understand the mechanism that makes such a powerful transformation, during sleep, possible.
Laura: What we wanted to understand was what happens in your brain when you smell an odor during sleep.
Greg: She designed a study wherein the subjects played a simple memory game involving pictures of animals, buildings, faces and tools.
Laura: They were learning the locations of these pictures on a four by four grid.
Greg: Before their memories of those locations were tested, they were hooked up to a machine that delivers odors to their noses.
Laura: Most of us have a particular scent that evokes a very specific memory. In our study, we decided to take advantage of this system. So, for instance, they might learn that cedar odor belonged with pictures of animals and that rose odor was associated with pictures of buildings.
Greg: So the cedar smell goes with animals, the scent of roses, buildings. Then the participants went to sleep in the MRI machine. During deep sleep, Shanahan presented them with cedar odor, but not rose odor. From the MRI, she could see just how much the cedar odor reactivated, in their brains, images of animals. Now it was time for the participants to wake up and take the memory test. Would that unremembered mental replay of animals during sleep improve their memories of the animal pictures?
Laura: So people had a better memory for those locations that were reactivated by odors during sleep.
Greg: Without knowing why, they were better at remembering the locations of the animal pictures compared to the building locations. Similarly, in the Israeli study, the subjects' memories of smoking and rotten eggs were presumably retriggered, reducing their desire to smoke. What's strange, though, is that these memory manipulations, which can profoundly impact our behavior, only work if the subject is sleeping . So, what if you could actually control the images that appeared in your sleeping mind?
Professor Ken Paller and Karen Konkoly are conducting some of the first experiments in real-time two-way dream communication , and the first step is training their subjects to access their own dreams.
Ken: So lucid dreams have been known for a long time. There is a special category of dreams where the dreamer understands that they're dreaming. Once you understand that you're dreaming, there's the possibility of controlling what is happening in the dream. So lucid dreamers enjoy doing this. They love to go and fly.
Greg: Before training the subject to lucid dream, Karen places an EEG on her.
Karen: We can use EEG to see what stage of sleep somebody is in and we can also use it to see where they're looking with their eyes.
Ken: In their dream, their body is paralyzed. So they're not moving. But the eyes are an exception.
Greg: Knowing where they're looking is important because the subjects aren't asked to, say fly in their dreams, which they might only be able to describe after waking up, but rather to demonstrate control of their dreams by having a real-time conversation with researchers with their eyes, from within the dream.
Ken: One way to have a two-way conversation would be to ask them to solve little math problems. And we've already agreed on a code for those where one is moving left-right wants to is moving twice, three, moving three times and so forth.
Greg: Now, the first step in training is to teach the participant various eye signals.
Karen: If you become lucid in a dream, then you want to look all the way to your left ear, all the way to the right, all the way left, all the way to the right, as fast as you can.
Greg: Now the participant goes into the sleep room, which is equipped with a red light and a speaker so that Karen can communicate with them. As they get ready to sleep. Karen starts the second step of training by flashing a faint light or playing a faint sound over the speaker, followed by directions.
Karen: As you notice the signal, bring your attention to your thoughts and notice where your mind has wandered.
Greg: She directs them to practice what's called a reality check.
Karen: Reality check is when you ask yourself very sincerely, am I awake or am I dreaming?
Greg: In the movie Inception, unique objects called totems were used to distinguish reality from dreams. But Karen and Ken have some tricks anyone, including you, can use to check if they’re in a dream.
Karen: If you study your hands a lot of times in dreams, they become really strange.
Ken: The storyline just is bizarre sometimes, and that's a hint that you're dreaming and actually not awake.
Karen: If you read something, look away, and then read it again, a lot of times in a dream, the words will change.
Karen: The best reality check is just to become really critically aware of your environment.
Karen: Remain lucid, critically aware, and notice how aspects of this experience are in any way different from your normal waking experience.
Greg: After about 20 minutes of similar training, the participant begins to fall asleep.
Karen: When their eyes start moving and they're completely paralyzed, you know that they're in REM sleep.
Greg: As the subject enters REM sleep, the phase of sleep where narrative dreams occur, Karen again softly plays that violin sound or flashes the dim red light, hoping that the subject will become aware of the signal from within the dream.
Michelle: I was looking at my old house. I saw the light cue; that flashed kind of like intertwined with my dream.
Karen: We're waiting for her to give a left, right, left, right eye signal after one of the light cues that we give her, or one of the violin sounds. In lucid dreaming, it's certainly true, wherever you're looking in the dream corresponds to where your eyes are looking in your waking body.
Michelle: I acknowledge that there was a light cue. I was also dreaming at the same time.
Karen: So now we know, okay, our participant’s having a lucid dream. So, we quietly celebrate and then we try to communicate by giving them an easy math problem.
Karen: Two plus one.
Michelle: So then I incorporated by envisioning the math problem on the house number plate.
Greg: While this is happening, Karen carefully monitors the EEG to make sure the subject is still asleep. One reliable indication that the subject is sleeping is a reduction of electrical signals coming from the chin, confirming that the body is still paralyzed.
Michelle: I would transform that into the math problem.
Greg: She now signals from her dream, the number three with her eyes.
Karen: It seems like we've successfully communicated, so we're gonna wake her up and see what she remembers.
Greg: This live dream communication shows that we can control the images that occur to our, malleable, sleeping minds. This opens the door to training ourselves, in our dreams, to make better choices. And it may even help us solve difficult problems in our lives.
Ken: We're planning to do the same experiments with problem solving. If you're struggling with something, you might decide that your lucid dream would be a good chance to revisit that problem and see if you can come up with a more creative answer to that problem.
Greg: So, the unconscious forces from your sleeping or wake mind, can really impact your habits and decisions. But really understanding these forces could change even more than that...
About 400 years ago, when we began to accept that we on the Earth weren’t at the center of the solar system , a revolution in understanding our universe began.
Moran: Our coming years will allow us to explore not just the conscious us, but the other parts, if we begin to understand that we are not the center of our own universe. In understanding that, we will not only uncover a lot of things about how we think, how we decide, how emotions work, how dreams work, how memories work, but we'll understand essentially how all of those become what we call "me."
Produced & Directed by:
Senior Digital Producer:
Julia Cort and Chris Schmidt
Craig Newmark Graduate School of Journalism at the City University of New York
Sound Effects: Freesound.org
Stock footage: Videoblocks, Pond 5
© WGBH Educational Foundation 2021