Nearly 10 years ago, Vanderbilt University cognitive neuroscientist Randolph Blake and his postdoc Duje Tadin needed to give their study participants the experience of complete darkness. They were testing their new transcranial magnetic stimulator (TMS) and developing protocols for a series of experiments involving the generation of phosphenes—light experienced by subjects when there is none. So the researchers ordered high-end blindfolds, designed to block all light from reaching the eyes.
When the blindfolds arrived, Blake tried one out. “I can’t remember what prompted me to do it, but on a lark, I put them on myself first and waved my hand in front of my eyes,” he recalls, “and had this faint sense that I could see my hand moving.”
Tadin then tried it and ...
