The preparedness model is an evolutionary theory suggesting that the human brain is predisposed to more readily associate certain stimuli with fear. This theory explains why phobias of ancestral dangers, such as snakes, spiders, and heights, are more common than phobias related to modern dangers like motorcycles or weapons, despite the latter posing a greater objective threat. It argues that over the course of evolutionary history, the mind adapted to quickly and easily develop fears of these historically threatening stimuli.