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Are “Group Hallucinations” Possible? The Case of Mary.

Several people have asked me about my claim that “group hallucinations” are possible – that is, that a “vision” can be seen by many people at once.  It seems counter-intuitive: aren’t hallucinations by definition the inner workings of a person’s mind?  How can more than one person have the same hallucination at the same time?

Well, I’m not sure how that works, psychologically.  My guess is that there is a strong sociological component as well – i.e., that something weird is seen by a number of people, one of the persons in the group nterprets it, and the rest agree that Yes, that is indeed what they saw.  But that’s just my guess.  Maybe some of the trained psychologists on the blog can tell us.

But in any event, it is a well-documented phenomonen.  Here is the query from one of the people who asked the question, specifically with respect to the modern-day appearances of Jesus’ mother, Mary, followed by a brief discussion of the phenomenon taken from my book How Jesus Became God.



QUESTION:  Bart, when you refer above to “the hundreds of people who say they have, at one and the same time, seen the Blessed Virgin Mary” what apparition or apparitions are you referring to? Can you give some background details please? Thank you!


RESPONSE:  Here is a brief discussion taken from my book:


The Blessed Virgin Mary

René Laurentin is a modern-day Catholic theologian and expert on modern apparitions, who has written many books on the topic.[1]  He has a degree in philosophy from the Sarbonne in Paris, and two PhDs, one in theology and one in literature.  He is not your average intellect.   And he deeply and sincerely believes that Mary – the mother of Jesus who died 2000 years ago — has appeared to people in the modern world and that she continues to do so.  Here I give just two examples from his writings.

In Cua, Betania, in Venezuela, a woman named Maria Esperanza Medrano de Bianchin received peculiar spiritual powers: she could tell the future, levitate, and heal the sick.  The Virgin Mary appeared to her…

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On the Accuracy of Oral Traditions
Upcoming Debate!



  1. Avatar
    gdb620  February 9, 2016

    Mentalist “The Amazing Kreskin” did not believe in hypnosis, but he often demonstrated what he called “the power of mass suggestion.” I remember him convincing a dozen or so volunteers from his TV audience that they had seen a UFO. Their excitement as they described their visions seemed genuine. Kreskin also cited mass suggestion as a possible reason several people became ill on two occasions within four days, at the courthouse in Monmouth County, New Jersey in June, 2012. The courthouse was closed for a week, but no physical cause for the illness was ever found.

  2. Avatar
    thelad2  February 9, 2016

    Good morning, Bart. For a fascinating account of group hallucinations, read Stacy Schiff’s new book, “The Witches – Salem, 1692.” A massively researched work detailing the infamous Salem Witch Trials. The well chronicled inquiries and witch trials are full of eye witness accounts from the locals, many well educated, as to the witchcraft they experienced first hand and to their experience of the witches responsible.

  3. Avatar
    Alfred  February 9, 2016

    I think it is important to distinguish between what people say they are experiencing ‘now’ and what they say they remember later. There may be two different processes at work.

    And in the biblical accounts, we don’t know that anyone actually reported their experiences ‘at the time’. Just that so,some said they did.

  4. Avatar
    stokerslodge  February 9, 2016

    Thank you, Bart. Maybe you can enlighten me on the following: is it the consensus view among the experts that all of the apparitions referred to above were nothing more than hallucinations? Or are there other equally qualified people who arrived at a different conclusion?

    • Bart
      Bart  February 10, 2016

      The scholar I cite in the post thinks they are real.

  5. Avatar
    Searching_For_Truth  February 9, 2016

    Here are some other interesting group hallucinations (or miracles if you’re a believer):

    Three early leaders of the Mormon church claimed that they saw an angel come down from heaven and present a book of gold plates to them (the golden plates Joseph Smith claimed to have translated the Book of Mormon from). The Mormon church relies heavily on this miracle as evidence that the Book of Mormon is true. It’s printed in the front of every Book of Mormon. (https://www.lds.org/scriptures/bofm/three?lang=eng)

    Another example is from a Mormon break off religion called the True and Living Church of Jesus Christ of Saints of the Last Days. Here’s an excerpt about a vision by two people:

    “I had my head bowed, and my eyes were closed. And when I opened my eyes and was wondering why he was pausing. And then I closed my eyes again and I saw three men walk through the wall. It was Joseph Smith and Brigham Young and Heber C. Kimball who came through the veil. And they placed their hands upon my head and revealed many things concerning my life and my [UNINTELLIGIBLE] to certain things upon this earth that I should do. And I could see the vision as he spoke. I could see it, and Jim described what he saw, what we both saw in vision.” (http://www.thisamericanlife.org/radio-archives/episode/21/transcript)

  6. Avatar
    godspell  February 9, 2016

    Happens without any religious basis to it, of course.

    The Great Fear of 1789, in revolutionary-era France. With the breakdown of the social order, paranoia reigned–rumors spread through the countryside that bands of brigands or foreign soldiers were burning, looting, raping–people would swear that they heard the brigands approaching, could even see them, and they reacted by running away, or sometimes attacking the local manor house to get weapons, food, etc.

    Just before WWI began, there were rumors that the Germans were sending zeppelins to attack Britain, and people kept reporting them overhead, even though there clearly were no zeppelins.

    UFO’s, reports of aliens, Bigfoot. And of course, Slender Man.


    And that began with the originator of the myth admitting upfront that he was just making it up as an experiment.

    Human minds can be highly suggestible, and this seems to be equally true when no conventional religious idea is behind it.

  7. Avatar
    WimV  February 9, 2016

    All sorts of things are going on in such mass hallucination situations: people are often being primed by another person (like a leader), by each other and/or by their surroundings, witness contamination occurs during and after the event, people passionately want to be part of the group that sees something and don’t want to look less “chosen” than people who claim to see something, etc. A couple of years ago I had a look at the alleged “Marian apparition” at a Coptic church in Warraq, Egypt, because there is a fair amount of footage that exists of it.I did a video on it showing the most likely explanation (http://youtu.be/rFZfWWeAGiM): church lights being turned on in the middle of the night captured with (back then) low-resolution cell phone cameras. The low-res, overexposed footage was sent around to people because the church lights in the tower kind of looked like a figure (i.e. pareidolia), and that seems to have gotten the ball rolling.

  8. Avatar
    fishician  February 9, 2016

    I’m sure some of this is the “Emperor’s New Clothes” phenomenon. “I saw it, didn’t you?!” “Well sure, I saw it too!” No true believer wants to admit they didn’t see the miracle, lest they lose face with their fellow believers.

  9. Avatar
    Stephen  February 9, 2016

    Actually the more you examine these incidents the more ephemeral they become. Of the three children at Fatima only one claimed to have actually seen Mary. At the “cosmic miracle of the sun” incident witnesses reported seeing different things and many reported seeing nothing at all. And it’s interesting how in the retelling the size of the crowd kept getting bigger and bigger.

    Allow me to recommend the late great Oliver Sack’s wonderful book HALLUCINATIONS from 2013. From the blurb:

    “To many people, hallucinations imply madness, but in fact they are a common part of the human experience. These sensory distortions range from the shimmering zigzags of a visual migraine to powerful visions brought on by fever, injuries, drugs, sensory deprivation, exhaustion, or even grief. Hallucinations doubtless lie behind many mythological traditions, literary inventions, and religious epiphanies. Drawing on his own experiences, a wealth of clinical cases from among his patients, and famous historical examples ranging from Dostoevsky to Lewis Carroll, the legendary neurologist Oliver Sacks investigates the mystery of these sensory deceptions: what they say about the working of our brains, how they have influenced our folklore and culture, and why the potential for hallucination is present in us all.”

    • Bart
      Bart  February 10, 2016

      Yup, great book!

    • Avatar
      Pattycake1974  February 10, 2016

      Interesting. I may read it.

    • Avatar
      clipper9422@yahoo.com  August 19, 2016

      Does the Sacks book deal with the apparitions of Mary in Venezuela? My starting point for claims like that is skepticism. To be able to reasonably conclude that Mary did in fact appear, the standard of evidence to be met would have to be extremely high. But am I being being reasonable if I deny a priori that something like that is possible? Or, to put it more precisely, that there couldn’t be more evidence for the apparitions actually happening than for some other explanation. Why not rely on empiricism? A group vision/hallucination perceived by large numbers of people, including well-educated people, on multiple occasions seems to at least begin to approximate the kind of occurrence that can be investigated objectively by impartial observers. I don’t know if journalists and scientists and atheists descended upon the site to investigate it. If they had it seems plausible that, depending on the evidence, they could have reached the conclusion that Mary did appear. As I think someone else asked, did any atheists see Mary, or see substantially the same phenomenon/sense data that the believers in Mary saw? We know a lot of people at least thought they saw Mary. How many did not see Mary?

      Of course even if there is evidence for some kind of weird and extremely unusual phenomenon, there is probably a very large amount of interpretation that goes into the process of concluding that it’s Mary. Someone else asked how the people knew it was Mary or knew what Mary looked like. And what if there should be an equally well-attested apparition by a god (Kali?) that Catholicism denies exists. My point here is that the conclusion has to somehow fit, even if only very roughly but without formal contradiction, with other (background) knowledge that is even more strongly attested. It’s not simply a question of evidence for the isolated case. But the isolated case nevertheless is some kind of evidence.

  10. Avatar
    christophe  February 9, 2016

    Dr Ehrman, do you know some examples of “group hallucinations” in non-christian religions ? For some reason I have never heard of this kind of things outside Christianity.

    • Bart
      Bart  February 10, 2016

      I”m afraid I’ve never looked into it!

    • talmoore
      talmoore  February 10, 2016

      Devotees of the late Hindu Guru Sathya Sai Baba claim to see mass manifestations of him regularly.

    • Avatar
      flshrP  February 11, 2016

      Sam Harris frequently mentions the contemporary India mystic, faith healer and miracle worker Sathya Sai Baba who performs “miracles” similar to the ones attributed to Jesus in the NT. See this video for more info


  11. Avatar
    Lawyerskeptic  February 9, 2016

    If you search “our lady of zeitoun” on YouTube, you’ll see several videos showing pictures of the alleged Virgin Mary appearances. They are nothing but an oblong blob of light. If the same thing appeared at a UFO convention, people would see aliens.
    “Hallucination” does not seem to be the right name for this phenomenon. Michael Shermer uses the term “patternicity” for our tendency to see patterns that are not really there.

  12. Avatar
    dragonfly  February 10, 2016

    What does Mary look like? How do they know it’s her?

  13. Avatar
    RonaldTaska  February 10, 2016

    Before I retired, I practiced psychiatry for 4 decades. During that time, I worked primarily with psychotic patients and saw hundreds of patients who were having hallucinations, mostly auditory hallucinations. Visual hallucinations are usually associated with drug abuse. During that time, I never saw a group having the same hallucination. Hence, I was skeptical about such reports, but the examples I read in your book are fairly convincing that people actually report such group hallucinations, especially about Mary. I have no clue about how to understand these phenomena except people see what they want to see. I have certainly seen groups of people believe all sorts of weird stuff as part of their subculture. I guess I would call it “indoctrination.”

    This reminds me of a past article in National Geographic about a group in Indonesia who used monkeys in their worship and refused to stop doing this even when the scientific evidence was clear that the monkeys were spreading a possibly fatal disease among the members of the congregation.

    I also once saw a psychotic patient who plucked out his eye as the Bible directs. It was pretty gross and upsetting. .

    • Bart
      Bart  February 10, 2016

      Ugh. Sounds gruesome…

    • Avatar
      Pattycake1974  February 10, 2016

      I teach in a residential facility where hallucinations are common. Most are auditory as you stated, and I’ve never seen a shared hallucination.
      Speaking of taking the bible literally, my husband who is a paramedic was called to the scene of a similar situation. He cheated on his wife, so you can guess what he cut off. Unfortunately, he died.

  14. Avatar
    Pattycake1974  February 10, 2016

    I’d like to know if any atheists shared in these mass visions. I just haven’t found a satisfactory answer to these types of experiences. I don’t see how it’s possible that people could see the same thing at the same time if something wasn’t actually there.
    Anthony Sukto was 8 years old when he was stabbed by his father. His mother was attacked as well but didn’t survive. After his father left the house, Anthony said he saw three angels that helped him survive the ordeal. They lifted him to the phone and helped him call 911. The angels told him to play dead when his father returned to the house. He was a guest on Oprah several years back. He’s 18 now and maintains that he did see angels but hasn’t seen any since that time.

    You could say that his brain was helping him cope with the situation, but how do we know that for sure?

    • Bart
      Bart  February 10, 2016

      Yup — no way to know!

    • Avatar
      Kent  February 14, 2016

      I think that there is a large difference between a multitude ‘experiencing ‘ a thing simultaneously and a multitude ‘recalling or reporting’ a given event.
      We have lots of reports of evidence but very little actual evidence.

  15. Avatar
    flshrP  February 11, 2016

    Coincidentally, the PBS “NOVA” program last night (10 Feb 2016) aired an episode entitled “Memory Hackers” (season 43, episode 6).
    An hour of up-to-date info on memory research by neuroscientists in the U.S. and Europe.
    I was really interested in the second half hour wherein research on memory reconsolidation and on implanting false memories is discussed. Appeared to me to be very relevant to the topics discussed in this thread.

  16. Avatar
    TubaMike  February 12, 2016

    I would imagine, if we were able to record such things, that we would have more than 50,000 people that could attest to not seeing anything (using the “cosmic miracle of the sun” as en example). In fact, I would guess that the number of those seeing nothing would far outweigh the number of those who do see these “miracles” in all of these instances.

  17. Rick
    Rick  February 12, 2016

    Professor, rereading from How Jesus became God I again triggered a question that has nagged. In discussing apostle’s visions of Jesus you said ” Paul too explicitly states that he had a vision of Jesus, and I think we can take him at his word that he believes Jesus appeared to him.” And my question is why take him at his word? And I say that because I’ve often wondered if Paul was not seeking respect as a leader in a group and switched groups to advance quickly. Paul to himself:
    “Here I am dragging my tired backside down this hot dirty road to Damascus to whip Christians for old Gamliel’s henchmen and for what – so I can wait 30 years for them to die off to take their place? You know this Christian thing…. might work a lot sooner – and all I have to do is say I saw him! Old Cephas he can’t say I didn’t or the others will say he didn’t either!

    • Bart
      Bart  February 13, 2016

      I suppose historians think he is not fabricating the story because it did not provide any real gain to him — other than beatings, floggings, being stoned, imprisoned, and eventually executed; so it’s not like an evangelist who propounds a view because he makes millions out of it. And in Paul’s case there doesn’t seem to be anything in his writings to make you doubt his deep sincerity. He may have been mistaken but he probalby wasn’t lying.

      • Avatar
        VirtualAlex  February 17, 2016

        But he didn’t really have a vision of Jesus. He saw a light and heard a voice (sometimes attributed to epilepsy?). He concluded afterwards that it was a divine experience perhaps to get in good with the apostles, whose experiences appear to have been quite different (seeing a man, talking/eating with him).

  18. Avatar
    Monty  February 20, 2016

    I have sometimes thought that had Paul not had that vision, Christianity would not exist as we know it. There is a good chance, I think, that it would have continued to exist, mainly because ideas die hard, but I can’t imagine how it wouldn’t be very different, possibly considered an obscure sect of Judaism. There wouldn’t have been the Galatians argument with the Jerusalem apostles about circumcision, and perhaps gentile Christians would simply be circumcised converts to this Jewish sect. And finally, had Christianity not spread like it did thanks to Paul, what impact would that have had upon Islam? When you think about it from a historical perspective, the world as we know it would not exist were it not for that vision, hallucination or not.

  19. Avatar
    Jana  February 24, 2016

    In Tibetan Buddhism as well as Kundalini Yoga which are both my long time practices (over 35 years) a range of phenomena including visions is part of the territory for advanced practitioners. Having said that, I’ve recently started investigating what’s called “swarm mentality” which occurs in the natural world frankly prompted by watching a lot of Sir David Attenborough nature videos. I’m wondering without coming to any conclusion if a similar pattern if not phenomena … “swarm mentality” exists among groups of people (dare I use the word cults?). Definitely need to study more about this including mass hypnosis.

  20. Avatar
    Jana  February 24, 2016

    Playing Daniel’s Websters Advocate playfully 🙂 you wrote above “My point is not that Mary really is appearing in these times and places. But people deeply believe she is.” Why couldn’t the event have been fact?

    • Bart
      Bart  February 25, 2016

      I’m neither confirming nor denying it; I’m simply saying that conservative evangelical Christians who claim that group hallucinations are impossible do NOT think that Mary really appears — and so by definition they DO think that group hallucinations are possible.

      • Avatar
        Jana  February 25, 2016

        Thank you for the clarification. I understand better the dual thinking.

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