10 things you may not know about dreams

What are dreams? Strictly speaking, dreams are images and thoughts, sounds, voices and subjective sensations that we experience when we sleep. They may include people we know and strangers, places we know and places we have never seen before. Sometimes they just remind us of the events that happened during the day. Other times they can also remember our darkest secrets, fears and most intimate fantasies.

Sigmund Freud believed that dreams were a window to our unconscious, and some studies say they could be. But there are hundreds of competing theories about what dreams are and their purpose.

1. You can't read in your sleep.

If you're not sure if you're dreaming or not, try reading something. Most people are unable to read in their sleep. The same goes for watches: every time you look at a watch, it will tell you a different time.

2. When you dream

Until a few years ago, it was believed that one only dreamed during the so-called REM sleep phase. But some research says that we dream even during non-REM sleep (NREM). However, REM sleep is the closest stage of waking up, so you are more likely to remember REM dreams than NREM dreams. Each phase of sleep would correspond to different dreams. During REM sleep, for example, people usually report interacting with 2-3 characters, usually people they know in real life. The NREM phase, on the other hand, can host multiple characters, even strangers, like in a movie.

3. Painful dreams

Some studies suggest that pain enters dreams, overcoming the barrier between waking and sleeping. Intense pain can give rise to real nightmares, but a study conducted at the Montreal Hospital in Canada has shown that even the simple fact of inducing a tingling sensation in the foot makes someone dream of discomfort in their feet.

4. A memory aid

An experiment by Harvard Medical School neuroscientist Robert Stickgold confirmed that they remember more those who immediately after reading fall into a dream dream than those who, while asleep, do not have many dreams. This is because the brain would work hard during deep sleep to find links between things it has just learned and things it has already stored.

5. Dreams of color

80% of dreams are in color, but a small percentage of people say they dream in black and white. In some studies, newly awakened dreamers were asked to select from a table the colors that corresponded to their dreams. Pastel colours are the most frequently chosen.

6. Dream control

A lucid dream is defined as one in which you realize you are dreaming, even if you are still awake. During this type of sleep you can check the contents of the sleep for up to 30 minutes. Lucid dreamers dream mostly of things like flying, going through walls and travelling through time.

7. Famous dreams

Many authors and inventors have declared that their creations were born from a dream. Among them are the writer Mary Shelley, who dreamt of Frankenstein, the physicist Nikola Tesla (whose dreams continue to fascinate mystery lovers today), Elias Howe, who was inspired by dreams to invent the sewing machine, and the scientist Friedrich August Kekulé, who in his dreams discovered the chemical structure of benzene. And it seems that the dream inspired Larry Page to create a search engine like Google.

8. Negative emotions

American researcher Calvin S. Hall has collected more than 50,000 dream descriptions of college students over 40 years. These reports were made available to the public in 1990 and reveal that in dreams we live many emotions, such as joy, happiness and fear. However, the most common emotion in dreams is anxiety: negative emotions usually outweigh positive ones.

9. Universal dreams

Dreams are often influenced by our personal experiences, but researchers have found that some issues are common to all individuals at different latitudes, such as being chased, attacked, or falling. Other common sleep experiences include school exams, feeling paralyzed, being late, flying, and being naked in public.

10. Premonitions

Are they possible? According to a friend's story, U.S. President Abraham Lincoln dreamt of his assassination 10 days earlier. However, some historians are skeptical. According to them, Lincoln himself had a curiosity for dreams, which he recognized as premonitory abilities, and this could have inflated the legend.