The threat stimulation theory of why we dream states that dreams allow us to prepare for threats or danger. Finnish researchers at the University of Turku found that threat simulations during dreams allow a person to rehearse the required cognitive mechanisms for proper threat perception and avoidance, leading to increased reproductive success. They studied this claim by investigating the dreams of children in both threatening and nonthreatening households.
They found that those living in an environment where their physical well-being is constantly threatened tended to have wild dreams and a great threat simulation system, whereas those living in a safe household had a weakly activated system and much calmer dreams, free of threat cues.
They followed this study with another one done on traumatized and non-traumatized children. Their results concurred with those obtained from the previous study. They found that traumatized children tended to have a significantly greater number of dreams and that their dreams were plagued with threats and violence. On the other hand, the mentally healthy children had dreams that were less severe in nature than those of the traumatized children, and they dreamed much less frequently.
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