Dreaming may be an evolutionary technique that helped humanity survive by allowing us

to practice responses to threatening situations while we sleep. This would explain why our

dreams are often made up of events far more threatening than our waking lives.

Finnish scientist Antti Revonsuo has shown that while we are dreaming, the part of our

brain that determines ‘fight or flight’ is more active than usual.

In addition, the area of the brain that practices motor activity - such as running and punching

- is also extremely active, despite bodies being paralyzed during Rapid Eye Movement

(REM) sleep, the period when dreaming takes place.

9) Dream Gender Differences

Studies have found that there are significant gender differences in dream content.

One study analyzed 100,000 people’s reported dreams and found that while men often dream

of cars, weapons & violence, women’s dreams center around familiar situations such as

home or the workplace.

Women's sexual dreams were likely to be of someone they knew in real life, whereas male

sex dreams tended to be about characters they’d invented.

This is assumed to be due to both environmental and biological gender differences, with male

testosterone thought to contribute to thoughts of aggression and sex that are played out

in dreams.

8) Dream Déjà Vu

The feeling of a new situation being familiar, known as Déjà Vu, is a similar process to

what occurs during dreaming.

When dreaming about real places such as our home, it can often look like a completely

different house, but because of a feeling of familiarity that comes with the dream,

we know where the dream is taking place.

This is because dreaming, like déjà vu, is created by a network of memory traces that

can evoke the feeling of familiarity, allowing us to recognize a situation without a clear

memory or understanding of why.

Alternatively this sensation could be due to precognitive dreams: the experience of

living future events while in a dream state. Although more than 50% of people claim to

experience precognitive dreams, science has yet to prove this phenomenon.

7) Do Animals Dream?

Most land mammals and birds have dreams.

While pet owners may have noticed their cats or dogs appearing to act out their dreams

in their sleep, scientists have determined that even rats have complex dreams and replay

events in the same way humans do.

Researchers got rats to perform specific tasks in a maze and found that this produced distinctive

patterns of brain activity. While the rats were sleeping, the exact same brain patterns

were reproduced, suggesting that the rats were dreaming of navigating the maze.

A similar observation has been made in Zebra Finches. An analysis of the order their brain

neurones fired while dreaming indicated that they were practicing birdsong in their sleep.

6) Black & White Dreams

Reportedly 12% of sighted people dream exclusively in black and white.

Research by the University of Dundee has shown that the type of television watched in childhood

determines the color of dreams.

A study found that thousands of people over 55 who'd been raised watching black and white

television often dreamed in monochrome, while almost all people under 25 dream in color.

This suggests that there could be a critical period in childhood when watching films has

a big impact on the way dreams are formed.

5) Dream-reading Machines

Japanese scientists are in the first stages of developing ‘dream-reading machines’.

They developed a computer-learning algorithm that was able to match visualisations with

the corresponding brain activity.

By showing volunteers images and recording their responding brain activity, the scientists

were able to predict with a 60% accuracy the broad category of what their participants

were dreaming about - for example, whether it was a person or building.

Future benefits of these kinds of machines could include the ability to read the minds

of people unable to communicate, such as coma victims.

Although for now these machines are limited in the brain activity they can detect, future

studies may implant electrodes deep into the brains of subjects to enable a closer reading

of individual neutrons.

4) Sleepwalking

Sleepwalking occurs when our body’s natural defense fails during deep sleep. Sufferers

can end up acting out their dreams, hurting themselves or others.

British man Brian Thomas was arrested for murder after strangling his wife to death

as she lay in bed with him. He claimed that he’d strangled her while dreaming she was

an intruder.

The murder charges were withdrawn when it was discovered that Mr. Thomas had a history

of suffering from sleepwalking and night terrors. The judge ruled that Mr Thomas couldn’t

be held responsible for his actions, as his mind wasn’t in control of his body at the

time of the attack.

3) Musical Dreams

Beatles singer Paul McCartney reportedly wrote the band’s hit song ‘Yesterday’ after

hearing it in a dream.

Researchers at the University of Florence found that musicians dream of music more than

twice as much as non-musicians. The younger the musicians had learnt their craft, the

more frequent their musical dreams.

Almost half of the songs the musicians reported having dreamed were completely new to them.

McCartney's fellow Beatle John Lennon also performed a song he'd dreamed up while sleeping.

1974 single Number 9 Dream even included made-up words he remembered from his dream.

2) Cheese Dreams

It’s an urban myth that eating cheese at night causes nightmares. In fact the amino

acid tryptophan, which is found in cheese, is known to reduce stress and induce sleep.

However, a recent study did find that different types of cheese could affect the types of

dreams we experience.

Eating Stilton before bed was found to cause bizarre dreams, including talking soft toys.

Red Leicester creates nostalgic dreams, while participants that ate cheddar before sleep

dreamed about celebrities.

1) Lucid Dreams

Lucid dreaming is when the dreamer is aware that they are in a dream state and can influence

what happens during it.

It is thought that anyone can learn and practice the ability to lucid dream, though those who

spend hours playing video games are more likely to be able to control their dreams, as both

activities require being in an artificial world.

Full lucid dreaming can benefit athletic performance. By practicing running during a lucid dream,

the neural pathways needed to run become strengthened, making the sport easier by morning.