An Act regarding human nature

This bill (HD 1748) allows defendants in Massachusetts criminal cases to present neuroscience evidence about involuntary "fight or flight" stress responses to show they temporarily lost the ability to control their actions or make reasoned decisions at the time of an alleged crime. It specifically makes such evidence admissible to address issues of criminal intent, culpability, or self-defense, and requires courts to instruct juries on how this neuroscience relates to legal standards. The bill does not create new defenses but clarifies that existing evidence about stress-induced cognitive impairment can be considered under current law. It directly affects criminal defendants and courts handling cases involving claims of impaired judgment due to acute stress responses.