The Case for Caution: Contamination, Leading Questions, and Confirmation Bias

Stevenson's fieldwork was unusually rigorous by the low standard set by most anecdotal psychic testimony, he traveled to interview witnesses directly, sought corroborating family statements, and attempted to document a case before verifying the deceased person's identity where possible. Critics have nonetheless identified structural problems that run through the method itself. Champe Ransom, a researcher who worked with Stevenson early in his career, and later critics including psychologist James Alcock, have argued that in the substantial majority of cases the child's family and the deceased person's family lived near enough to each other, or were connected closely enough through community ties, that information could have passed between them well before Stevenson's investigation began, undermining the independence his cross-checking method depended on.

Reviewers have also pointed to leading questions in interviews with young children, a research population already known in psychology to be highly susceptible to suggestion, the substantial gap in time between the child's statements and Stevenson's formal documentation of them, during which memories and family retellings could drift, and a general absence of the blinded, controlled conditions that would let an outside party rule out coaching, embellishment, or simple coincidence in matching biographical details. No mainstream scientific body has accepted Stevenson's case collection as evidence for reincarnation, and the research is generally treated, even by scholars sympathetic to psychical research, as suggestive fieldwork rather than confirmed proof.