Discovery Lab Answers

Gertrude R. Schmeidler, PhD was a pioneering experimental parapsychologist whose systematic work on personality and belief effects in ESP shaped the modern understanding of individual differences in psi performance.

Experiments

Schmeidler’s research spanned several decades and lines of inquiry. Her foundational early work investigated how personality and belief predicted ESP performance in controlled laboratory settings. She conducted collaborative research with Gardner Murphy on what became known as the “sheep-goat effect” — the systematic finding that participants’ explicit beliefs about the possibility of ESP modulated their performance in ESP tasks.

Later in her career, she examined psi phenomena at multiple levels of analysis. A 2019 publication on studying individual psi experiences outlined her approach to understanding psi through sociology of psi (examining patterns across cultures and social groups), life histories, and laboratory investigation of spontaneous experiences ^[1]. She also engaged with methodological debates in the field; sources retrieved for this question include her participation in an edited ganzfeld debate with Hoyt Edge in 1999, examining whether ganzfeld research should remain central to psi methodology ^[2].

Methodology

Schmeidler’s methodological emphasis was on controlled experimental design paired with attention to individual and personality factors. Her early clairvoyance work (1943) used prediction methods — asking participants to predict their own performance — as a way to separate participants by belief and expectancy before the experiment ran, permitting analysis of whether believers (“sheep”) and skeptics (“goats”) differed in ESP scoring ^[3]. This approach became a standard tool in personality-based psi research and allowed her to isolate belief effects from other performance variables.

Her later work integrated multiple levels of analysis, from laboratory ESP tasks to field-based documentation of spontaneous phenomena. The sources retrieved do not detail her specific randomization, blinding, or pre-specification protocols, but they indicate she worked within the controlled experimental tradition and participated in methodological debates about which protocols (such as ganzfeld automation) best served replicability.

Data

The retrieved excerpts do not report specific effect sizes, hit rates, z-scores, or p-values from her experiments. To find those statistics, you would need to consult the primary papers directly or the ESP-Nexus studies section.

Skeptical critiques

The sources retrieved for this question do not include published criticism or skeptical engagement with Schmeidler’s work.

For a fuller account of her research program and its place in parapsychology, see the Gertrude R. Schmeidler profile page and the related work with Gardner Murphy on belief effects and personality correlates in ESP.