Radioactive Decay as an Unguessable Target

Schmidt's innovation was to choose a target that physics says cannot be predicted. Card guessing had always been open to the objection that a deck carries traces of its own order, in the shuffling, the wear on the cards, the habits of the person handling them, and that a subject might exploit those without anyone intending it.

Schmidt, working as a physicist at the Boeing Scientific Research Laboratories in the late 1960s, built machines whose output was determined by the timing of individual radioactive decay events, a quantum process for which no theory permits a predictive shortcut. A subject pressed a button to try to make the machine favour one outcome, or tried to guess which outcome was coming, and the device recorded everything automatically without a human scorer. He reported that subjects could do it, at rates a fraction of a percent above chance sustained over very large numbers of trials. The design was widely admired on its merits even by those who did not accept the results, because it removed at a stroke several of the loopholes that had dogged the Duke work, and it set the template for everything that followed in micro-psychokinesis, including the Princeton programme a decade later.