Discovery Lab Answers

The Schlitz–Wiseman Experimenter-Effect Studies

Coverage note: The figures below reflect studies currently in the ESP-Nexus library. The library’s share of the published literature on this question has not been measured, so treat this as a summary of what the library holds rather than a settled account of the field. The library’s holdings on this topic skew toward the Schlitz–Wiseman joint series itself; broader DMILS and remote-staring literature from other labs is less fully represented here.

What the research program is

Marilyn Schlitz and Richard Wiseman conducted a systematic, three-experiment joint series to test whether the same protocol, run by a proponent and a skeptic simultaneously, would yield different outcomes — making the studies as much a test of experimenter effects as of remote staring itself. Schlitz brought a track record of positive findings in electrodermal activity (EDA) staring research; Wiseman brought consistent null results. The collaboration, documented across,, and, was designed to hold everything equal — same equipment, same participant pool, same randomization — while varying only the experimenter.

The 2002 and 2005 interviews conducted by Caroline Watt probed a specific candidate explanation: tacit knowledge — the idea that one experimenter might, through subtle behavioral or attitudinal cues during setup, inadvertently signal expectation to participants in ways the other did not.

The quantitative picture

The evidence table the reader sees below carries the full figures; here is the pattern in prose.

Several things stand out:

• In both 1997 and 1999, Schlitz’s participant arm reached or approached significance while Wiseman’s did not — but the direction reversed between years. In 1997, Schlitz’s participants showed elevated EDA during staring epochs (the expected psi direction). In 1999, the effect ran in the opposite direction: EDA was lower during staring, yet still technically significant at p = .05.
• Neither year’s between-experimenter comparison reached significance (p = .17 in 1997; p = .44 in 1999), meaning the difference between the two arms was not itself statistically demonstrated in either study.
• The 2006 study, which added a 2×2 cross-over design varying who acted as both greeter and sender, found no significant effect for either experimenter and no main effect of greeter condition.

The broader DMILS meta-analysis Schlitz co-authored with William Braud — covering 30 EDA distant-intentionality experiments — reported an overall positive pooled effect (z = 6.17, mean r = 0.25), but that result comes from a different and wider evidence base than the joint series alone.

The tacit-knowledge question

The Watt interviews pursued a concrete hypothesis: that Schlitz and Wiseman interacted differently with participants during setup in ways that could account for the divergent outcomes without invoking psi. Wiseman reported doing nothing to prepare before sessions. Schlitz described a more engaged pre-session interaction and, in the 2005 interview, acknowledged that her general orientation included an expectation of success grounded in past positive findings. The 2006 study was designed partly to test this by having each experimenter serve as both greeter and sender in separate conditions — an attempt to isolate the preparation effect. That design found no significant result in any cell.

Whether tacit knowledge explains the 1997 and 1999 divergences, or whether some other mechanism was at work, the 2006 data do not adjudicate.

Skeptical critiques

What critics argue. The central skeptical position — articulated by Wiseman himself as a named co-author throughout the series — is that the divergence between the two experimenters’ arms is more parsimoniously explained by conventional social-psychological mechanisms than by psi. Specifically: experimenter-expectancy effects, differential pre-session rapport, or subtle behavioral cues during setup could produce the EDA differences observed in Schlitz’s participant arm without requiring any anomalous influence. The 2002 and 2005 interview transcripts make Wiseman’s own skeptical framing explicit and on the record.

What the experimental data show. The 2006 study was the direct empirical response to this critique — it varied the greeter/sender role in a 2×2 design to see whether Schlitz’s involvement at the greeting stage was a necessary condition for a positive result. Neither condition produced a significant effect, and the ANOVA main effect of greeter was null (p = .50). The between-experimenter comparisons in 1997 (p = .17) and 1999 (p = .44) were also non-significant, so the claim that Schlitz’s arm differed significantly from Wiseman’s was not established by either study’s own statistics.

Analysis. The direction reversal between 1997 and 1999 — with Schlitz’s arm positive in both years but in opposite directions — was not predicted by any prior hypothesis, psi or conventional. No published independent replication of the joint design by a third research group appears in the sources retrieved for this question. The three-study series leaves the tacit-knowledge account neither confirmed nor ruled out by the data it generated.

For the full curated treatment of Schlitz’s work, including her broader DMILS and distant healing research, see Marilyn J. Schlitz and the spoke page Remote Staring Detection and Autonomic Nervous System Activation.