Researchers at the University of Huelva in Spain are about to commence an experiment to study the effects of transcranial direct-current stimulation (tDCS) on the brains of violent convicts. Over a course of a few days, a dozen convicted murderers will get electrodes strapped to their brains in the hopes of finding a way to zap the violent urges out of their heads. Afterwards, the subjects will donate some of their drool and receive a questionnaire asking how stabby they're feeling on a scale of 1 to "having 'Baby Shark' stuck in your head."
But before you start picturing Nicolas Cage / John Travolta getting the contents of their skull turned into that of an Edison elephant, tDCS is actually more of a brain massager than a fryer, using very low levels of direct current to painlessly "stimulate" the mind. That's why tDCS gained popularity during the late '00s brain health fad, when people got way into Sudoku and brain-training video games became so popular that they could afford to get Nicole Kidman to shill for them. You can even buy your own tDCS kit for a couple of hundred bucks online. It's that harmless. So harmless, in fact, that most scientists think you'd get more measurable results hot-wiring a potato to your nipples.