In a series of experiments at the Hebrew University of Jerusalem, more than 300 student participants were unconsciously exposed to words and equations through a research technique known as Continuous Flash Suppression (CFS). With this method, a static image appears in front of one eye while rapidly changing pictures flash in front of the other eye. The changing pictures dominate awareness at first, letting the still image register subliminally before popping into consciousness.
In the first part of the study, one eye was presented with a static phrase or sentence, which was “masked” by changing colorful shapes flashing in front of the other eye. The students were instructed to press a button as soon as they became aware of the words. It usually took about a second, but negative phrases like “human trafficking” and jarring sentences such as “I ironed the coffee” typically registered quicker than positive expressions and more coherent phrases such as “I ironed clothes,” the study found.