A ttendees of a new immersive exhibit in New York City of the most infamous murder scenes in history must sign a waiver before they enter to acknowledge the risk of “emotional distress”. A severed head propped in a refrigerator. Bodies wrapped in plastic, hanging from the ceiling. A bathtub sloshing with blood. The Mind of a Serial Killer: The Experience — which opened April 17 in Greenwich Village — depicts the aftermath of crimes by Jeffrey Dahmer , Ted Bundy , and others that still haunt the public imagination. Why do visitors, who must be 18 or older due to the graphic content, want to delve into the minds of serial killers and wander their crime scenes? The popularity of exhibits like this – and the explosion of true crime podcasts and documentaries – points to something deeper, experts say. “The first comparison that came to mind was roadkill,” Stephanie Johnson, a clinical psychologist who has experience treating acute psychiatric disorders, trauma, and PTSD, told The Independent.…