The Man on the Other End of the Distance Series

Pratt's name is attached to the Duke laboratory's most famous result because he was the one physically handling the cards. In the distance series of 1933 and 1934, Pratt sat in the Social Sciences building turning cards at agreed one-minute intervals while the subject Hubert Pearce sat in the library across the quadrangle recording his calls, each man sealing and dating his own record before the two were compared in front of J. B. Rhine. The design was intended to remove every channel that had been complained about in the earlier work at once: the experimenter could not see the subject, the subject could not see the cards, and neither record could be adjusted after the other was known.

The scores that came back were far above chance and became the single result the Duke group leaned on hardest for the next thirty years. Pratt spent much of his career defending the details of that afternoon's arrangements, because the criticism of the series has always turned on architecture rather than statistics, on where the doors and windows were rather than on the arithmetic. He was, by most accounts including hostile ones, meticulous in reporting what he had actually done, which is a large part of why the argument about the series has stayed technical instead of collapsing into accusation.