Dreams may serve an evolutionary purpose by simulating threatening situations, enhancing our ability to cope with real-world dangers.

The Threat Simulation Theory, proposed by Antti Revonsuo, posits that dreams are a ancient biological defense mechanism. By frequently rehearsing perilous scenarios – being chased, falling, confronting adversaries – in the safe confines of sleep, our brains can develop and refine coping strategies without actual risk. This 'practice field' for survival could have provided a significant evolutionary advantage, improving our responses to real threats and enhancing preparedness for dangerous situations encountered in waking life. This theory helps explain the high prevalence of negative and threatening content often reported in dreams.