What Went Wrong, and What Rhine Changed

Three objections arrived almost immediately and none was frivolous. The first concerned the cards themselves: early Zener decks were printed thinly enough that a symbol could sometimes be made out from the back under the right light, and the edges of a card carry information about how it has been handled. The second concerned recording, since in much of the early work the person who knew the target also wrote down the call, which allows small unconscious corrections to accumulate in one direction. The third concerned selection, both of which subjects to keep testing and of when to stop a series.

To these was added the plain fact of failed replication, most publicly the Princeton series run by W. S. Cox, over twenty-five thousand trials with 132 subjects and no effect at all. Rhine's response was to change the procedure rather than to argue: opaque screens between the parties, mechanical shuffling, duplicate independent scoring, greater physical distance between subject and cards. He also founded the Journal of Parapsychology in 1937 so that criticism and negative results would have a home inside the field. Critics answered, and still answer, that the effect shrank each time a control was added, which is the pattern an artefact produces and not the pattern a phenomenon produces.