Discovery Lab Answers

Marilyn J. Schlitz, PhD — Experiments and Data

The studies currently in the ESP-Nexus library represent a sample of Schlitz’s published work, and the library’s share of the full published literature on this question has not been measured. What follows reflects what the library holds, not a settled account of the field. The evidence across that sample is mixed: several lines of work produced null results, and the directional signals that do appear are uneven across conditions and investigators.

Experiments

Schlitz’s experimental record spans at least four distinct research programs, each documented in the sources retrieved for this question.

Retroactive (time-reversed) priming — Schlitz led a large multi-site replication study testing whether future stimulus presentation could prime a participant’s current response — a design originating with Daryl Bem. The 2021 paper involved a collaboration of eighteen researchers across multiple institutions and was explicitly framed as a confirmatory replication effort, with pre-specified primary outcomes.

Distant mental interactions with living systems (DMILS) / remote staring — Schlitz conducted and co-conducted a series of electrodermal activity (EDA) experiments testing whether a distant “sender” staring at a receiver, or directing intention toward them, produces measurable physiological responses. This line includes a 1997 and a 1999 study conducted jointly with Richard Wiseman, designed specifically to test whether the experimenter’s orientation (skeptic vs. proponent) affected outcomes. A 1997 meta-analytic summary pooled thirty EDA distant-intentionality experiments.

Distant healing intention (DHI) and transpersonal healing — Schlitz co-authored and co-led clinical and laboratory studies examining whether healer intention directed at surgical patients affected wound healing (specifically collagen deposition) and psychological outcomes. A 2012 study with Hopf, Eskenazi, Vieten, and Dean Radin examined expectation and belief as variables in DHI effects on surgical wound recovery.

Consciousness and worldview transformation — Schlitz co-authored a community-based trial examining whether engagement in an integral practice program enhanced well-being, measured across spiritual, psychological, and self-transcendence dimensions.

Methodology

Retroactive priming (2021) — The protocol required participants to view a picture and judge its emotional valence before a prime was randomly selected and displayed. The key test was whether response times on trials where the subsequently presented prime was congruent differed from incongruent trials — a temporally reversed priming design. The 2021 study was explicitly confirmatory: primary outcomes were pre-specified, and the paper distinguishes these from exploratory analyses. The sample of 493 participants was assembled across multiple sites and languages. Expectancy and belief were assessed via self-report scales including the Revised NEO Personality Inventory and Zuckerman’s Sensation Seeking Scale.

DMILS / remote staring — In the Schlitz–Wiseman joint studies (1997, 1999), a critical methodological innovation was the deliberate crossing of experimenter identity with participant assignment. Each experimenter (Wiseman, a declared skeptic; Schlitz, a declared proponent) ran their own separate participant groups using an otherwise identical EDA protocol. In 1999 this was extended to a 2×2 crossover design varying both the greeter and the sender roles. EDA was recorded during alternating stare/non-stare epochs; participants were isolated from the sender. The design was conceived to test whether experimenter effects — a documented concern in parapsychology — could account for the divergence between Schlitz’s prior positive results and Wiseman’s null replications.

DHI / collagen deposition (2012) — Participants were surgical patients (wound healing context) randomly assigned across three groups, receiving distant healing intention under blinded conditions. Outcomes included objective measures (collagen deposition) and psychosocial measures. The 2015 overview notes methodological concerns common across the DHI literature more broadly, including inadequacy of blinding and lack of independent replication in many studies.

Data

The evidence table below accompanies this answer; the chart beneath it plots Cohen’s h effect sizes against publication year for the studies on that metric. Key patterns across the library’s holdings:

Retroactive priming (2021, N = 493): The confirmatory pre-specified test returned a null result.

DHI / collagen deposition (2012, N = 66): The main effect across three groups was null.

Remote staring / DMILS — the experimenter-effect pattern is the most structurally notable signal in this dataset. In the 1997 joint study, Schlitz’s participants produced a positive result while Wiseman’s did not. In 1999, the same directional split replicated — Schlitz’s participants again showed a positive result while Wiseman’s showed null — but the direct comparison between the two sets of participants was itself null in both years. A 2×2 crossover ANOVA on the greeter variable in the 1999 study also returned null.

A note on metrics: the table mixes Cohen’s h, Cohen’s d, and Pearson r — these are not comparable, and no pooled overall effect size across them can be stated.

Unsettled signals the evidence requires surfacing: directional results disagree across studies; eight of the thirteen result rows report null or below-chance outcomes; and the experimenter-condition pattern — Schlitz positive, Wiseman null, but no statistically significant difference between their participant sets — remains without a definitive structural explanation in the sources retrieved.

Skeptical critiques

What critics argue. Wiseman, Smith, and Milton (1998) raised the experimenter-effect hypothesis as a primary concern: that the divergence between Schlitz’s positive DMILS results and Wiseman’s null results could reflect systematic differences in how each experimenter conducted sessions rather than genuine psi — differences in demeanor, instruction delivery, or unintended cueing that the shared protocol did not fully control. Wagenmakers et al. (2011) and Schimmack (2012) raised methodological concerns about the Bem time-reversed priming paradigm specifically — arguing that analyses were partly exploratory and that studies were underpowered, raising the false-positive risk; these concerns apply directly to replications of that paradigm, including the 2021 Schlitz et al. study. The 2015 overview of DHI research identified methodological flaws across the broader literature — inadequate blinding, dropped data, poor outcome measures, absence of power estimates, and absence of independent replication — and concluded that no firm conclusions could be drawn.

What the experimental data show. The 1997 and 1999 joint studies were specifically designed to test the experimenter-effect hypothesis by crossing experimenter identity with participant assignment. In both years, Schlitz’s participants produced a directional result consistent with prior positive findings, and Wiseman’s did not. In 1999, the full 2×2 crossover ANOVA on the greeter variable returned p =.50, and the direct comparison of detect scores between Schlitz’s and Wiseman’s participant groups returned p =.44 — neither comparison yielded a statistically significant difference. The 2021 confirmatory retroactive priming replication returned a null confirmatory result (Cohen’s d = 0.03, p =.22), though an exploratory analysis of the English-language subsample differed from non-English samples. The DHI collagen deposition study returned a null main effect (p =.46).

Analysis. The 1997 and 1999 joint studies constitute a rare attempt to run a controlled within-protocol comparison of experimenter effects in parapsychology, with two named investigators using the same design. The directional split between Schlitz’s and Wiseman’s participant groups appeared in both studies, yet neither the between-group detect-score comparison nor the crossover ANOVA reached significance. No third-laboratory independent replication of the joint-experimenter design, with a pre-specified experimenter-effect hypothesis, has been published in the sources retrieved for this question. The 2021 multi-site replication addressed some reproducibility concerns by using a large pre-specified confirmatory design, though its confirmatory result was null. The DHI literature, as Schlitz and co-authors themselves note, contains methodological heterogeneity that has prevented firm conclusions.

For a broader view of Schlitz’s research profile and related topic pages, see Marilyn J. Schlitz.