The MacDonald triad are three major personality traits in children that are said to be warning signs for the tendency to become a serial killer. They were first described by J. M. MacDonald in his article "The Threat to Kill" in the "American Journal of Psychiatry". * "Firestarting", invariably just for the thrill of destroying things. * "Cruelty to animals". Many children can be cruel to animals, such as pulling the legs off of spiders, … Wikipedia
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