What is the physiological dream theory?

Psychologists, scientists, and even spiritual leaders have built theories around why we dream. While not all these theories are accepted anymore, the true nature of why we dream is a mystery. What we do know is that dreams can benefit us in many ways!

Índice Show

Ancient and Freudian Theories of Dreaming
Wish-Fulfillment
When Do We Dream?
Activation-Synthesis Theory
Information-Processing Theory and the Self-Organization Model
Threat-Simulation and Social-Simulation Theory
Social-Simulation Theory
Physiological-Functioning Theory
Which Theory is Correct?

Theories about why we have dreams include:

Ancient theories
Freud’s Wish-Fulfillment Theory
Activation-Synthesis Theory
Threat- and Social-Simulation Theory
Information-Processing Theory (Self-Organization Model)
Physiological-Functioning Theory

Ancient and Freudian Theories of Dreaming

“Why do we dream?” is a question that people have been asking since the dawn of time. In the earliest days of the study or contemplation of dreams, dreams had serious meaning. Humans are meaning-making creatures, so it’s natural for us to have a dream and ask “what does this mean?”

In the Bible, for example, dreams are often portrayed as messages from God. Mesopotamian kings took advice from their dreams. Ancient Egyptians wrote dream interpretations and what specific dreams meant for the dreamer. Medieval Europeans also wrote down how to interpret certain dreams.

Ancient cultures laid the foundation of this work, but one name is synonymous with dream interpretation: Sigmund Freud.

Wish-Fulfillment

Sigmund Freud, like many people, asked himself, “Why do we dream?” He believed he discovered the answer after, you guessed it, a dream. After dreaming about a patient whom he felt he had failed, Freud created the wish-fulfillment theory.

Freud’s wish-fulfillment theory suggests that we dream to fulfill repressed wishes. Often, these wishes are embarrassing. We wish to kill our father or have sex with our mother, for example. (Freud has some interesting theories.) That’s why, Freud believed, our dreams were so bizarre. We added unique elements so we could still fulfill our wish, but in a more palatable way. In Freud’s The Interpretation of Dreams, he interprets these unique elements. For example, he suggests interactions with sticks, trees, and other phallic-shaped items suggest…you can probably guess.

Freud’s theories of dream interpretation and wish-fulfillment are not accepted anymore. They have since been replaced by a variety of other theories about why we dream and how it benefits the dreamer.

When Do We Dream?

Before diving into more modern theories about why we dream, you should know when we dream. Dreaming takes place in the REM stage of sleep, or “rapid eye movement” stage. This name suggests exactly what happens during this stage. Although the rest of the body is close to paralyzation, our eyes rapidly move back and forth. The heart rate and breathing increases.

Brain activity is also especially high during REM sleep. REM sleep is crucial for the mind to recuperate, while other stages of sleep are vital for the body to do the same.

Knowing this, let’s dive into why modern psychologists think we dream.

Activation-Synthesis Theory

Remember when I said that humans are “meaning-making creatures?” Well, J. Allan Hobson and Robert McCarley took that into consideration. In 1977, they created the Activation-Synthesis Theory.

The Activation-Synthesis Theory suggests that dreams are the result of our brains attempting to make meaning from the brain activity that takes place during sleep. These dreams aren’t meaningless, necessarily, but they do not come from unconscious wishes or messages from the beyond. Just as we daydream to make sense of our social interactions, we dream to make sense of all the neurons firing in our brains during sleep.

Information-Processing Theory and the Self-Organization Model

Similarly, information-processing theory suggests dreams are just a part of our cognitive development. Cognitive psychology looks at how the brain makes decisions, solves problems, and stores memories. Memory storage is key to this study and why we dream.

Dreaming could just be a key part to how we convert our short-term memories into our long-term memory. And our minds don’t shove all long-term memories into one big storage container. Information-processing theory suggests that we organize our memories as we sleep. Our dreams, which often contain elements from what we experienced that day, are a byproduct of that process.

To illustrate this, psychologists developed the Self-Organization Model. While this model does not address the content of dreams itself, it looks at how dreams are formed.

A lot of dream theories explain why we might have nonsensical, yet pleasant, dreams. But what about nightmares? Why do we dream that we’re fired from our job, dumped by our partner, or taking a test without any pants on? Threat-simulation theory has a guess.

Finnish neuroscientist Antti Revonsuo suggested that nightmares are actually a biological defense mechanism. We simulate threats in our dreams so that we may be more prepared for them if we actually face them. Revonsuo theorized that the ancient humans that did “practice” facing these threats could fight them off and have children. Those children, too, simulated threats in their dreams and were more prepared to fight them.

The threats we face today are very different than what early humans faced. (We discuss this often when discussing fight-or-flight.) Whereas “threats” used to be carnivorous animals, now our bodies get just as stressed by pop quizzes and asking a cute girl out to the dance.

Could it be that all dreams, nightmarish or not, are practice? Some say yes! The social-simulation theory of dreaming suggests that all dreams are a defense mechanism of sorts. When we practice social situations, we are more prepared for them.

How many times do you prepare for a conversation with a friend, partner, or boss? Dreams are just our unconscious way of doing the same thing!

Physiological-Functioning Theory

One last theory about why we dream is known as the physiological-functioning theory. This theory suggests that dreams are pretty much meaningless, and that we dream to preserve neural pathways. Have you ever been told to run your car for ten minutes once a week to keep it working properly? The physiological-funtioning theory suggests that dreaming works the same way. We spend a lot of time sleeping. Brain activity during this time keeps us functioning and ready to process information when we wake up the next morning!

Which Theory is Correct?

Physiological-functioning theory was supported in a 2009 paper written by J. Allan Hobson.

Yes, the same J. Allan Hobson who wrote about activation-synthesis theory. Hobson has been a sleep researcher at Harvard for many years now. While he continues to assert that dreams are not some divine message, he has shifted his thoughts on why we dream.

The answer to the question “why do we dream” is like the answer of many deep questions in psychology and biology. It’s always evolving. The theories on this page are just the more popular theories that exist in psychology today! There are other theories, we dream to forget or to respond to what is happening in the outside world as we sleep. We cannot say for sure why we dream. With the help of modern theories and the creativity of ancient theories, we continue to get closer to the answer.

It’s snowing heavily, and everyone in the backyard is in a swimsuit, at some kind of party: Mom, Dad, the high school principal, there’s even an ex-girlfriend. And is that Elvis, over by the piñata?

Uh-oh.

Dreams are so rich and have such an authentic feeling that scientists have long assumed they must have a crucial psychological purpose. To Freud, dreaming provided a playground for the unconscious mind; to Jung, it was a stage where the psyche’s archetypes acted out primal themes. Newer theories hold that dreams help the brain to consolidate emotional memories or to work though current problems, like divorce and work frustrations.

Yet what if the primary purpose of dreaming isn’t psychological at all?

In a paper published last month in the journal Nature Reviews Neuroscience, Dr. J. Allan Hobson, a psychiatrist and longtime sleep researcher at Harvard, argues that the main function of rapid-eye-movement sleep, or REM, when most dreaming occurs, is physiological. The brain is warming its circuits, anticipating the sights and sounds and emotions of waking.

“It helps explain a lot of things, like why people forget so many dreams,” Dr. Hobson said in an interview. “It’s like jogging; the body doesn’t remember every step, but it knows it has exercised. It has been tuned up. It’s the same idea here: dreams are tuning the mind for conscious awareness.”

Drawing on work of his own and others, Dr. Hobson argues that dreaming is a parallel state of consciousness that is continually running but normally suppressed during waking. The idea is a prominent example of how neuroscience is altering assumptions about everyday (or every-night) brain functions.

“Most people who have studied dreams start out with some predetermined psychological ideas and try to make dreaming fit those,” said Dr. Mark Mahowald, a neurologist who is director of the sleep disorders program at Hennepin County Medical Center, in Minneapolis. “What I like about this new paper is that he doesn’t make any assumptions about what dreaming is doing.”

The paper has already stirred controversy and discussion among Freudians, therapists and other researchers, including neuroscientists. Dr. Rodolfo Llinás, a neurologist and physiologist at New York University, called Dr. Hobson’s reasoning impressive but said it was not the only physiological interpretation of dreams.

“I argue that dreaming is not a parallel state but that it is consciousness itself, in the absence of input from the senses,” said Dr. Llinás, who makes the case in the book “I of the Vortex: From Neurons to Self” (M.I.T., 2001). Once people are awake, he argued, their brain essentially revises its dream images to match what it sees, hears and feels — the dreams are “corrected” by the senses.

These novel ideas about dreaming are based partly on basic findings about REM sleep. In evolutionary terms, REM appears to be a recent development; it is detectable in humans and other warm-blooded mammals and birds. And studies suggest that REM makes its appearance very early in life — in the third trimester for humans, well before a developing child has experience or imagery to fill out a dream.

In studies, scientists have found evidence that REM activity helps the brain build neural connections, particularly in its visual areas. The developing fetus may be “seeing” something, in terms of brain activity, long before the eyes ever open — the developing brain drawing on innate, biological models of space and time, like an internal virtual-reality machine. Full-on dreams, in the usual sense of the word, come much later. Their content, in this view, is a kind of crude test run for what the coming day may hold.

None of this is to say that dreams are devoid of meaning. Anyone who can remember a vivid dream knows that at times the strange nighttime scenes reflect real hopes and anxieties: the young teacher who finds himself naked at the lectern; the new mother in front of an empty crib, frantic in her imagined loss.

But people can read almost anything into the dreams that they remember, and they do exactly that. In a recent study of more than 1,000 people, researchers at Carnegie Mellon University and Harvard found strong biases in the interpretations of dreams. For instance, the participants tended to attach more significance to a negative dream if it was about someone they disliked, and more to a positive dream if it was about a friend.

In fact, research suggests that only about 20 percent of dreams contain people or places that the dreamer has encountered. Most images appear to be unique to a single dream.

Scientists know this because some people have the ability to watch their own dreams as observers, without waking up. This state of consciousness, called lucid dreaming, is itself something a mystery — and a staple of New Age and ancient mystics. But it is a real phenomenon, one in which Dr. Hobson finds strong support for his argument for dreams as a physiological warm-up before waking.

In dozens of studies, researchers have brought people into the laboratory and trained them to dream lucidly. They do this with a variety of techniques, including auto-suggestion as head meets pillow (“I will be aware when I dream; I will observe”) and teaching telltale signs of dreaming (the light switches don’t work; levitation is possible; it is often impossible to scream).

Lucid dreaming occurs during a mixed state of consciousness, sleep researchers say — a heavy dose of REM with a sprinkling of waking awareness. “This is just one kind of mixed state, but there are whole variety of them,” Dr. Mahowald said. Sleepwalking and night terrors, he said, represent mixtures of muscle activation and non-REM sleep. Attacks of narcolepsy reflect an infringement of REM on normal daytime alertness.

In study published in September in the journal Sleep, Ursula Voss of J. W. Goethe-University in Frankfurt led a team that analyzed brain waves during REM sleep, waking and lucid dreaming. It found that lucid dreaming had elements of REM and of waking — most notably in the frontal areas of the brain, which are quiet during normal dreaming. Dr. Hobson was a co-author on the paper.

“You are seeing this split brain in action,” he said. “This tells me that there are these two systems, and that in fact they can be running at the same time.”

Researchers have a way to go before they can confirm or fill out this working hypothesis. But the payoffs could extend beyond a deeper understanding of the sleeping brain. People who struggle with schizophrenia suffer delusions of unknown origin. Dr. Hobson suggests that these flights of imagination may be related to an abnormal activation of a dreaming consciousness. “Let the dreamer awake, and you will see psychosis,” Jung said.

For everyone else, the idea of dreams as a kind of sound check for the brain may bring some comfort, as well. That ominous dream of people gathered on the lawn for some strange party? Probably meaningless.

No reason to scream, even if it were possible.