What Is the Activation-Synthesis Theory of Dreaming?

Dreams are a form of a mental phenomenon that many people experience. They consist of images, ideas, and emotions. These dreams can differ in quality, but the dreamer usually cannot wake up during the dream and cannot control it.

One theoretical model that attempts to show the function of dreams is the activation-synthesis model of dreaming. The model has undergone many revisions but remains today’s dominant theory of dreaming. Let’s understand the theory of dreaming in detail.

What Does Activation Synthesis Model of Dreaming State?

The activation-synthesis model of dreaming is a theory that posits that dreams are the result of brain activity during sleep. In other words, it is based on the idea that we do not dream because we are asleep but rather because our brain is active during sleep.

The activation-synthesis model of dreaming was first proposed by psychologist J. Allan Hobson of Harvard Medical School and neuroscientist Robert McCarley of Boston University School of Medicine.

Origin of Activation Synthesis Model of Dreaming

The Activation-synthesis hypothesis was developed as an alternative to Freud’s psychodynamic dream theory, which proposed that dreams were expressions of unconscious wishes. Hobson and McCarley argued that dreams do not have an underlying meaning or purpose; instead, they are simply a result of random neural activity during sleep. They also suggested that dreams are formed through two processes:

  1. Neurons fire randomly during sleep and cause activation patterns in the brainstem (the part of the brain located at the base of the skull). These activation patterns can be translated into images that we perceive while sleeping.
  2. The activation patterns are then interpreted by higher brain parts and made into stories or images that make sense to us when we are awake. This results in bizarre and incoherent dream imagery that reflects spontaneous neural activity.

They argued that dreams result from an interaction between two brain systems: a limbic system (the emotional system), which generates random neural activity during REM sleep; and a prefrontal cortex (the executive control system), which attempts to make sense of this neural noise through the construction of images, sounds, smells and other sensory experiences.

Difference Between Activation Synthesis Theory and Freud’s Model of Dreams

Freud’s psychoanalytic model of dreams is based on the theory that dreams are a form of wish fulfillment. According to Freud, the unconscious mind uses the process of displacement to disguise its wishes from the conscious mind. The activation-synthesis model states that dreams are created by an interaction between REM sleep and sensory input; during REM sleep, neurons fire randomly, creating a chaotic network that sensory inputs can reorganize.

There are several differences between these two models:

  • Freud believed that dreams were a manifestation of repressed desires that could be traced back to childhood experiences. He thought dreams were disguised memories or wishes evoked by external events. In contrast, Hobson believes that dreams are formed during REM sleep as part of an ongoing process of brain maturation.
  • Freud believed that dreams were mainly driven by unconscious forces, while Hobson believes they are primarily influenced by external stimuli and learning during waking hours.

Criticisms of Activation Synthesis Theory

The activation-synthesis theory is a cognitive and neurobiological model of how we experience dreams. It stated that dreaming results from the brain’s attempt to synthesize random signals from the cortex during REM sleep into meaningful experiences.  That said, the hypothesis has been highly debated. Many studies have been done to find evidence for this theory. Still, none have ever yielded results accepted by the scientific community and have been criticized for being unable to account for certain features of dreams. 

For example, if dreams were simply random signals generated by the brain during REM sleep, people would be more likely to have lucid dreams than nonlucid ones. But most people don’t have lucid dreams or any knowledge that they are having until after they’ve woken up. Another problem with this theory is that it doesn’t explain why dreams have such emotional intensity and vividness compared with other types of mental activity that occur during sleep (such as hypnagogic hallucinations).

Further, Hobson believes that dreams occur only during REM sleep and not during non-REM sleep because there is no evidence that people can dream during non-REM sleep. However, studies have shown that people report having dreams at various stages throughout their sleep cycle.

Final Words

One thing that sets us apart from all the other animals is our ability to imagine a reality, picture a scenario, or envision certain events or ideas. We can process information in our sleep and dream about events, which ultimately helps us in the long run with our survival as human beings. Dreams are also a source of mental renewal and help keep our brains functioning at optimal levels for longer periods of time.

Overall, evidence supports the view that dreams are essential at a functional and adaptive level. Consideration of dream content and constructive emotions in dreams may play an integral role in a healthy night’s sleep. In this way, dream states play an integral role in psychological and physiological well-being.


Hi, I am Happy. I'm a professional writer and psychology enthusiast. I love to read and write about human behaviors, the mind, mental health-related topics, and more.