Evolutionary Approach

Cognitive Neuroscientist Antti Revonsuo, a Finnish philosopher and professor at the University of Turku, is an active proponent of the evolutionary function of dreams. According to his theory, we are biologically wired to have threatening dreams, thus preparing us for such situations in the conscious state.  (Valli, 2005). So, this means that the reason we are here is because our ancestors were able to rehearse the skills needed for survival.

Threat Rehearsal Theory

Revonsuo believes our brains are actively presenting the world into elements that we normally would not experience in waking life. This is because situations that are “underrepresented” are brought to life when we are asleep. In his work during the year 2000, The Reinterpretation of Dreams: An Evolutionary Hypothesis of The Function of Dreaming, Revonsuo hypothesizes that dreaming is a biological function of the brain to present us with situations that “rehearse threat perception and threat avoidance”. This theory has been known as “threat rehearsal theory”.

Not Just Humans

The theory applies primarily to human dreaming, however, Revonsuo (2000) suggests that threat rehearsal theory can also be found in other mammals. The dreams that they would have would specific to their nature of survival. There is evidence to support that cats may have threatening dreams to prepare them for threatening situations. This supports that every persons/mammals dreaming experience is subjective to their own personal experiences. Although, according to the TRT theory, the way that we dream now has been shaped by the way that our ancestors have dreamed before us. If our ancestors did not have this practice, they were likely to not live long enough to bear offspring. The key element to this theory is also realizing that the neural production of dreams are innate (Revonsuo,2000 ).

Its More Important Than Random Firing!

Revonsuo rejects the theory of random activation, stating the the human brain is much too complex and organized to have such random neural firings. Our dreams have the commonality of being able to resemble our waking life so well, evidence of predictable and organized system (Revonsuo,2000) .

Why We Remember Nightmares

Another argument that Revonsuo makes is that our dreams have a tendency to under- represent neutral or positive emotions, and over-represent emotions that feel negative to us (Revonsuo,2000 ) For example, you might not remember typing or writing in your dreams, but you are much more likely to remember something that made you feel highly emotional, such as having a gun pointed at your head or falling off a cliff. Studies support that negative emotions are far more frequent than positive ones, with fear and anger being the most typical emotional experiences ( Hall &Van de Castle, 1966). It is also interesting to note that dreamers are involved in aggressive behaviors 80%, depicted as the victim more than the aggressor( Domhoff, 1996), the aggressors are often wild animals or male strangers and female encounters are more likely to have a happy or positive nature (Domhoff, 1966). This theory states that most dreams that we remember are stressful and filled with conflict and negativity (Valli, 2005).

Research on The Dreams of Traumatized Children

In 2005, Revonsuo and his team studied the dream recall of traumatized vs. non-traumatized children. The traumatized group consisted of children who had experienced an overwhelming amount of military violence and/or lost their guardian in war or military attacks. The non-traumatized group consisted of children who had been brought up in relatively safe environments with no encounter of military violence. Revonsuo hypothesized that the severely traumatized children would report more dreams than those who were not/less traumatized due to higher activation of the dream production system, as well as report more threatening situations in their dreams (Revonsuo, 2000). They hypothesized correctly, and they found that kids who had trauma in their life were indeed much more likely to have more threatening dreams, rather than the kids with no trauma in their life. They noticed that the nature of the events during the dream were similar in both groups, each having to do with aggression(figure 1). The trauma group also had dreams where the target of threats were more self and people centered, rather than resource centered (figure 2) and the severity of the threatening effects were much higher for the trauma group than the control group(figure 3) (Revonsuo, 1995).



figure 1



figure 2





figure 3


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