Why Dreaming Can Sometimes Be Harmful

Fantasies are a double-edged sword. On one hand, they help us understand ourselves better, clarify our values, or practice certain skills. On the other, they can deceive our motivation and prematurely create the illusion of success.

Imagine you need to move several heavy boxes or have a serious conversation with your boss. In both cases, your body enters a state of readiness: adrenaline is released, your heart beats faster, and your blood pressure may rise. After the real action—when the boxes are moved or the conversation is over—relaxation sets in, and your body needs rest because the goal has been achieved. Interestingly, a similar state can occur when you mentally rehearse such scenarios.

For example, in a study by Kappes & Oettingen, 30 participants who imagined drinking a refreshing beverage showed decreased systolic blood pressure. Without any physical action, their bodies decided it was time to rest. The researchers believe that simply imagining actions can consume energy as if the action had actually been performed. And this isn’t the only unusual effect of fantasies.

How Imagination Affects the Brain and Body

In her book “Neurologic,” Eliezer Sternberg describes two interesting cases. In the first, she discusses how patients who have had limbs amputated cope with phantom limb syndrome—a phenomenon where a person continues to feel sensations in a missing limb. An elderly man who had both feet amputated due to circulation problems suffered from unbearable itching in his missing feet. He was advised to vividly imagine scratching his feet as if they were still there. He bent his fingers and scratched the air where his feet would have been, which helped relieve the phantom itch. Through imagination, he activated the same brain areas that would have been involved if he were scratching real feet.

In the second case, Sternberg describes a study by California neurologists comparing brain activity during real and imagined movements. Participants sat in front of four numbered buttons and were asked to press them in a specific sequence: 4, 2, 3, 1, 3, 4, 2. As they pressed each button, an MRI scanner recorded their brain activity. Then, with their hands on their laps and eyes closed, they imagined pressing the buttons in the same sequence. The MRI showed that the motor cortex—the area controlling finger movements—was activated almost as much during imagined movements as during real ones.

In another experiment, participants who imagined eating 30 M&M’s (enough to feel full) actually ate fewer candies during the experiment than those who imagined eating only 3 or none at all (Morewedge, Huh, & Vosgerau, 2010). This suggests that mentally simulating the feeling of fullness can help control appetite. On the other hand, if you fantasize about tasting different dishes at a feast, your appetite may increase. The researchers suggest that, just like with real actions, the Zeigarnik effect may apply to imagined actions: people remember interrupted actions better and are motivated to complete them. So, imagining the start of an action can motivate you to finish it, but visualizing the goal as already achieved can serve as a substitute for real achievement—making you feel better but reducing your drive to actually reach the goal.

The Double-Edged Sword of Positive Fantasies

This can have various effects. For example, imagining that you’ve already completed a workout can lower your motivation to actually exercise. Or, if a woman compares herself to a thin model in a picture (when the comparison isn’t in her favor), it can cause negative emotions. But if she imagines herself as the model, she may feel better—yet this positive effect can become an obstacle to actually getting in shape (Tiggeman, Polivy, & Hargreaves, 2009). The mind gets the signal that everything is fine, dissatisfaction is suppressed, and motivation drops.

The link between fantasies and motivation can be illustrated with another example: weight loss. People who are overweight often complain about a lack of motivation to get in shape. In one study, 25 women with obesity participated. At the start, they determined how many pounds they wanted to lose and how confident they were in their ability to do so. Each participant was then asked to imagine herself as the main character in four different weight loss scenarios.

Here’s an example of one scenario:

You’ve just finished a weight loss program and tonight you’re meeting a friend you haven’t seen in about a year. While waiting, you imagine that…

The goal was to identify which types of fantasies dominated and how they affected results. It turned out that the more positive the women’s fantasies about their lost weight and physical shape after the program, the less weight they lost. Conversely, participants with more negative fantasies achieved better results. The researchers explained that negative fantasies allowed participants to mentally rehearse difficult scenarios, helping them cope with challenges during the program. Those who imagined themselves as already successful didn’t prepare for difficulties. Positive fantasies left no room for obstacles, making it seem like achieving results required little effort.

Rethinking Positive Psychology

These findings offer a new perspective on the principles of positive psychology, which has inspired countless books. The main recommendation of this approach is to think positively about everything. For example, a sick person is encouraged to frequently imagine themselves healthy and victorious over illness. While this can be helpful—since despair and a bad mood are the last things a patient needs—it’s not so simple.

Gabriele Oettingen, a psychology professor at New York University and the University of Hamburg, and Doris Mayer, in their research, highlight the difference between two types of thoughts about the future: expectation of success (assessing the likelihood of an event) and fantasies (what we imagine about the future). Belief in success is crucial for planning (if people didn’t believe space travel was possible, we wouldn’t have built spaceships). American psychologist Albert Bandura notes:

Belief in one’s inability to succeed weakens motivation and hinders behavior. A person’s beliefs about their own effectiveness influence the actions they choose, the effort they put in, how long they persist in the face of obstacles and failures, and how flexible they are in dealing with difficulties.

However, Oettingen and Mayer argue that positive fantasies about the end result (e.g., being healthy) or the process (e.g., successfully recovering) are a motivational burden because they suppress the drive to achieve the desired outcome and hide the need for effort.

In their study, people who had undergone hip replacement surgery participated. Psychologists first assessed how much patients believed recovery was possible (expectation of success) and their fantasies about the result. Participants were asked to imagine themselves in five different situations and write down their fantasies—for example, picturing themselves walking to the hospital newsstand, going for a walk with friends, cooking dinner, cleaning, and imagining themselves three months after surgery. They rated how positive or negative their fantasies were. The results were surprising: positive fantasies correlated with a more difficult recovery, while negative expectations also had a negative effect. Not believing recovery was possible weakened motivation, but positive fantasies created the illusion that the result would be easy. Positive fantasies can give us the false impression that no effort is needed, making it seem easy to reach the goal and reducing the energy we generate for hard tasks.

Despite the popular belief in the power of visualization, constant positive fantasies about the future also reduce the need for careful planning. Thinking through future obstacles and strategies to overcome them is crucial for success. For example, a student who fantasizes about acing an exam may not make a thorough study plan, spend less time reviewing notes, and not bother to get a good night’s sleep. In contrast, imagining potential mistakes can actually help achievement. In a study by Kappes & Oettingen, participants were asked to imagine successfully solving an anagram and explain how they did it. These participants performed worse than those who were asked to imagine and explain their failure in solving the anagram.

Imagining that a goal is already achieved is much more pleasant than planning, focusing on upcoming difficulties, or—according to the Zeigarnik effect—thinking about the goal but focusing on its incompleteness. The creators and fans of the pseudoscientific film “The Secret” claim that dreams come true if you imagine yourself as already having achieved everything. According to them, this works thanks to the law of attraction, not daily hard work. So, what’s wrong with picturing yourself as successful? It lifts your mood and brings a smile, but most likely, dreams remain just dreams.