We Do Not Allow Suggestion or Suggestibility to Influence our Lab Results. – A Blog by Dr. M.A. Persinger

We take every measure to ensure that our subjects are not exposed to suggestions.
We take every measure to ensure that our subjects are not exposed to suggestions.

Our laboratory results are not due to suggestion or suggestibility – A blog by Dr. Michael A. Persinger.

We apply several procedures to guarantee that our subjects are not exposed to suggestions, have no expectations, so that our results are not influenced by subject suggestibility.

These procedures and analytical methods rule out suggestion as an explanation for the effects we have observed in our experiments.

Question: How do you ensure that subjects are not inadvertently given suggestions as to the purpose of your experiments and how do you respond to the claim that your results are due to suggestibility?

Answer: Human beings are remarkably sensitive to subtle cues in their environment. For example, specific areas of the human brain respond to alterations in structures of sentences while a person is reading even though the person is not “aware” of the change in sentence structure (Bern, 1997).

Thirty years ago when we were interested in the “subjective narrative” of people sitting in the dark in a quiet chamber we found that the music, e.g., a Gregorian chant or the bars from the movie Close Encounters of the Third Kind, compared to sitting in silence, affected the content of the “spontaneous” themes.  Sitting in silent darkness without previously hearing any music generated more “death” images, the pre-darkness listening to Gregorian chants was associated with more religious images and the movie score was associated with space themes.  We could influence what the subjects thought about by “priming” them with music with clear connotations.

Context is also important (Persinger, 1989; 1992). In a placebo-controlled experiment, we applied our magnetic signals, and immediately afterwards, the subjects listened to an ambiguous narrative (story) about a young boy who had night time anomalous experiences (“The Billy Story”) .  These were epileptic in origin, although this was never stated.  After the story and the stimulation was complete, we asked to subjects to listen to a brief story about either alien abduction or early sexual abuse.  The story was provided without any explanation.  The subjects were then asked to interpret the story about the boy’s night time experiences both immediately and a few days after.  We found that the subjects who heard the story about early sexual abuse interpreted the “Billy” story as one of sexual abuse, and the subjects who heard the story about alien abductions interpreted it as being about an interaction with aliens.   (Dittburner and Persinger, 1993; O’Gorman and Persinger, 1998). In this way, we verified how easily pseudomemories or false memories can be produced (Persinger, 1992; Healey and Persinger, 2001).

My critics who attribute God Helmet experiences to suggestibility have never directly tested this hypothesis. We have tested this potential confounding effect by psychometric inferences which are highly correlated with hypnotizability, such as the Wilson-Barber Imaginings Scale. We also have several experiments where we measured hypnotizibility directly with the Spiegel and Spiegel scale where the experimenter interacts with the subject directly (Ross and Persinger, 1987). The latter was administered after the exit questionnaire containing 20 questions about their experiences.

Interestingly, the last item in this questionnaire asks if the red light changed intensity even though for most studies there was no red light. Suggestible or highly hypnotizable individuals frequently respond “yes” to this item. However, even when the many suggestibility measures were taken into account during the statistical analyses, the sensed presence reports still occurred primarily when the “God Experience” protocol (Persinger, 2001) was used.

Dr. Linda St-Pierre and I explained this in our 2006 paper in the International Journal of Neuroscience, but online skeptics seem not to have read it.   Finally I reiterate that the volunteers do not know if they will receive a magnetic field or which field it might be and they are always told they are participating in a relaxation study.

We use questionnaires with our student subjects.  The questionnaires are applied at least six weeks before these students participate, and these are only some of the questionnaires they students fill out as they study psychological data gathering.  This gives them first hand experience with methods of gathering psychological data.  They have no idea that the questions have anything to do with the experiment.  The data is gathered under “blind” conditions.

We do not decorate our lab with any spiritual or religious imagery, and the researchers don’t discuss the specifics of the experiment with subjects until after all data have been gathered.

One experiment made it clear that our effects were not coming from suggestion.  After experimenting for several years with a burst-firing pattern, and seeing repeated results telling us that it generated higher pleasantness ratings when applied over the left hemisphere (see example; Persinger & Healey, 2002), we began to investigate another signal (derived from hippocampal tissues during long-term potentiation).  In that case, and in a few since, we have seen that this signal is more pleasant over the right hemisphere (Persinger, et al., 1994).  If our effects were due to suggestion, these results should have been the same in all cases, but they weren’t.  We’ve also had many other results (for example, with lab rats) that simply cannot be explained by suggestion or suggestibility.

I hope this blog clarifies that we are aware of experimental factors that allow suggestions and suggestibility to confound experimental results, and that we take all necessary steps to prevent their occurrence.

Dr. Michael A. Persinger
Full Professor
Behavioural Neuroscience, Biomolecular Sciences and Human Studies
Departments of Psychology and Biology
Laurentian University,
Sudbury, Ontario, Canada P3E 2C6
Email: mpersinger@laurentian.ca and drpersinger@neurocog.ca
NOTE: This blog is hosted by a colleague.


Berns, Gregory S., Jonathan D. Cohen, and Mark A. Mintun. “Brain regions responsive to novelty in the absence of awareness.” Science 276.5316 (1997): 1272-1275.

Dittburner, T.-L. and Persinger, M. A. (1993). Intensity of amnesia during hypnosis is positively correlated with estimated prevalence of sexual abuse and alien abductions: implications for false memory syndrome. Perceptual and Motor Skills, 77, 895-898.

Healey, F. and Persinger, M. A. (2001). Experimental production of illusory (false) memories in reconstructions of narratives: effect size and potential mediation by right hemispheric stimulation from complex, weak magnetic fields. International Journal of Neuroscience, 106, 195-207.

O’Gorman, K. A. and Persinger, M. A. (1998). Hypnotic Induction profiles, contextual innuendo and delayed intrusion errors for a narrative: searching for mediating variables. Perceptual and Motor Skills, 87, 587-593.

Persinger, M. A. (1989). Geophysical variables and behavior: LV. Predicting the details of visitor experiences and the personality of experients. Perceptual and Motor Skills, 68, 55-65.

Persinger, M. A. (1992). Neuropsychological profiles of adults who report “suddenly remembering” of early childhood memories: implications for claims of sexual abuse and alien visitations/abduction experiences. Perceptual and Motor Skills, 75, 259-266.

Persinger, M. A. (1996). Subjective pseudocyesis in normal woman who exhibit enhanced imaginings and elevated indicators of electrical lability within the temporal lobes: implications for the “Missing Embryo Syndrome”. Social Behavior and Personality, 24, 101-112.

Persinger, Michael A. “The neuropsychiatry of paranormal experiences.” The Journal of neuropsychiatry and clinical neurosciences 13.4 (2001): 515-524..


Ross, J. and Persinger, M. A. (1987). Positive correlations between temporal lobe signs and hypnosis induction profiles: a replication. Perceptual and Motor Skills, 64, 828-830.

St-Pierre, L. S. and Persinger, M. A. (2006). Experimental facilitation of the sensed presence is predicted by specific patterns of applied magnetic fields not suggestibility: re-analysis of 19 experiments. International Journal of Neuroscience, 116, 1-8.

Spiegel, H. and Spiegel, D. (1978). Trance and treatment: clinical uses of hypnosis. New York: Basic Books.

Persinger, Michael A., and Faye Healey. “Experimental facilitation of the sensed presence: Possible intercalation between the hemispheres induced by complex magnetic fields.” The Journal of nervous and mental disease 190.8 (2002): 533-541.

Persinger, Michael A., Pauline M. Richards, and Stanley A. Koren. “Differential ratings of pleasantness following right and left hemispheric application of low energy magnetic fields that stimulate long-term potentiation.” International journal of neuroscience 79.3-4 (1994): 191-197.

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