Ever woken up after an erotic dream completely freaked out?

About eight in 10 people at some point dream about having sex with people who they don't even find attractive — often friends and colleagues.

It can cause an overwhelming sense of guilt in some cases: if the dream involved a friend's partner, for example, or if the dreamer was cheating on their spouse.

For others it can be deeply confusing — it is not uncommon for straight people to have erotic dreams about someone of the same sex.

Now a new book has sought to explain why we dream about certain individuals and assure people that sex dreams are not always the result of our subconscious desires.

Dreamers typically imagine someone they know - even if they are exceedingly ordinary or unattractive (stock image)

Neuroscientist Dr Rahul Jandial says there are generally two types of sex dreams, and their causes are completely different.

A sex dream involving someone who you are attracted to and fantasize about regularly while awake can often manifest in our dreams.

But the other type of sex dream stars seemingly random people, even if the dreamer dislikes them or finds them unattractive. 

All dreams are the product of the Imagination Network in our brains, unbound by the rules and logic of our waking life. 

When we’re dreaming, the imagination is unfettered, free to find loose associations and connections in our memories.

It can lead us to think about the people in our lives in surprising, disturbing and even erotic ways.

Because the logical Executive Network in our brains is shut down during dreaming, we can’t stop these erotic flights of fancy before they take off. They are also free from judgment — even our own.

In erotic dreams we are liberated to imagine sexual encounters that would be taboo or inconceivable in our waking lives. 

They will probably not involve our current partner. Instead, we have much more of an inclination toward bisexuality and novel sexual interactions generally.

Dr Jandial says: 'This moderating influence on our erotic imagination when we're awake is gone when we dream, allowing our erotic dreams to be wildly creative and exploratory.' 

That same moderating influence becoming idle allows us to dream of flying at great heights or breathing underwater, or any number of creative scenarios.  

Dr Jandial adds: ‘If our daytime fantasies are visions of some desired, if improbable, sexual outcome, erotic dreams are more like a prurient thought experiment.

'We can switch genders or become bisexual in our dreams, even if it never crosses our minds during the day or in our most liberated fantasy.' 

Neuroscientist Dr Rahul Jandial posits that sex dreams are a benign product of unfettered imagination and not something to feel shame over

Dr Jandial's new book explains why we dream about certain individuals and assures people that erotic dreams are not always the result of subconscious sexual desires

And whether a person experiences a sex dream has little to do with how sexually active they are in waking life, how much porn they watch, or how much they masturbate. 

The best predictor of sex dreams is how often a person daydreams or fantasizes about sex.

Dr Jandial says: ‘If our erotic imagination is more active when we’re awake, it is highly possible that we become more open to erotic dreams at night.'

It may come as a surprise to know that the mind does not typically conjure up the ideal sexual mate to star in one’s erotic dreams; it rarely includes the ultimate dream partner. More often than not, the dreamer knows the star of their erotic dream personally.

Dreamers typically imagine someone closer to home, someone exceedingly ordinary, unattractive, or even repellant.

This is why sex dreams often star ex-partners, ex-bosses, co-workers, friends, neighbors, and even family members, and often take place in familiar settings.

Scientists posit that sex dreams have a basis in evolution, preparing early humans (and animals) to adapt to the unexpected, like the sudden death of a mate.

As Dr Jandial puts it: ‘This may help explain why erotic dreams tend not to look outside “the tribe” but stick close to home.’

Women are having three times as many sex dreams, new study shows 

The latest study, conducted by researchers from the University of Freiburg in Germany, asked 2,907 men and women aged between 16 and 92 about their dreams. 

The major role that familiarity plays in devising erotic dreams could also explain the number of times one might fantasize about Halle Berry, Ryan Gosling, Jennifer Anniston, or any number of attractive celebrities.

Dr Rodrigo Quian Quiroga of the University of Leicester in England determined that celebrities are deeply entrenched in our brains at a cellular level, and become as familiar to us as our own grandmother.

Dr Quiroga connected wire-thin electrodes inserted into the cerebral cortexes of people’s brains to see how individual neurons were firing, and discovered that specific neurons responded to pictures of celebrities.

In one patient, a single neuron responded to a photo of Halle Berry and ignored picutres of other people. It responded to pictures of her on the red carpet, in costume, even just her written name.

In another patient, Dr Quiroga saw that a specific neuron fired in response to seeing photos of Jennifer Anniston, and ignored photos of other people, animals, and buildings.

Dr Jandial writes: Celebrities have literally taken root in our neural architecture. Our response to them suggests they are as familiar to us as a long-time friend or neighbor.’

The star of the erotic dream, whether it’s an ex-lover or a supervisor at work, is less important than what the dream symbolizes.

For instance, a dalliance with the boss in a dream might be less about how attractive you find them, and more about wanting to wield more power at work or recognizing your own professional ambitions.

Dr Jandial says: ‘In this way, erotic dreams are more than our true desires: They are the embodiment of desire itself.

‘Erotic dreams prime us for sexual exploration… This makes sense when we remember the essential biological imperative of life is to survive at least long enough to procreate.’