The Postbag as a Research Instrument

The publicity that followed her husband's 1934 monograph had an unintended consequence: strangers began writing to Duke to describe things that had happened to them. Louisa Rhine took charge of that correspondence and turned it into an ordered collection, sorting each account by the form the experience took rather than by how impressive it was. Her categories were simple and have been reused since: intuitive impressions with no imagery, hallucinatory experiences in which something was seen or heard, realistic dreams, and unrealistic or symbolic dreams.

Cross-cutting these she recorded whether the experience concerned a past event, a present one or a future one, and whether the person had acted on it. This let her ask questions no laboratory could ask, such as which form of experience most often carried accurate detail and which most often prompted the recipient to do something about it, and to notice that the great majority of reported cases concerned death, injury or crisis rather than anything trivial. The archive she built was the largest of its kind and remains at the Rhine Research Center. Its value was never the individual letter. It was the shape of the distribution across many thousands of them, which is a different kind of evidence from a controlled trial and, as she said repeatedly, a weaker one.