Last month I wrote about Havana Syndrome, the claim that a number of American and Canadian diplomats and military personnel were the targets of some sort of directed energy weapon attack causing symptoms of headache, disorientation, nausea, and sometimes associated with an auditory sensation. The point of the article was to do a plausibility analysis, based on what information I could find. I concluded:

“So far it seems that the objective evidence favors the “mass delusion” hypothesis. This is similar to “sick building syndrome” and other health incidents where a chance cluster of symptoms leads to widespread reporting which is followed by confirmation bias and the background noise of stress and symptoms focusing on the alleged syndrome. This explanation, at least, cannot be ruled out by current evidence.”

But I also thought we could not rule out (“rule out” is a strong position) that some of the initial cases may have been a genuine external attack. Part of my point was to caution skeptics about landing prematurely on a skeptical narrative and then biasing any further analysis toward that narrative. Sometimes information is messy, and there are legitimate points on more than one side. Don’t use bad arguments even to defend legitimate skeptical positions.

Specifically, I wondered if Havana Syndrome were more like some prior mass delusions, where there was a core of genuine cases. The Pokemon seizure panic of the 1990s is a good example –  most of the cases were some form of mass delusion, but about 10% were actually photosensitive seizures in susceptible individuals. So, how do we distinguish between 100% mass delusion and just mostly mass delusion? Arguments and evidence that some of the cases were not compatible with external attack or were clearly some form of hypervigilance, anxiety, or delusion do not make the distinction.

The strongest case against the external attack hypothesis that I could find was the fact that the American intelligence agencies investigated reports of Havana Syndrome and found no evidence to suggest external attack. I reject any notion of a coverup, which makes no sense, and is just being dismissive of the evidence. But could they have missed evidence of a covert foreign operation? I don’t know – but as I said, the more time that goes by, the less likely this becomes.

Another line of argument focuses on the alleged weapons themselves, either some form of sonic device or a directed microwave weapon. I don’t think it’s fair to entirely dismiss this technology as implausible. Directed microwave weapons in particular are feasible. We had working prototypes 20 years ago and stopped development mainly due to ethical reasons, but there is no reason to think that Russia and China also stopped. But do they fit the details of Havana Syndrome?

The reason I am writing again about this topic is because I just did an extensive interview with Robert Bartholomew, who has spent years investigating Havana Syndrome. He filled in some important gaps for me. Part of this interview will be on this week’s SGU episode and the entire hour-long interview will be available for SGU members. He provided a lot of information, but there are two pieces of information in particular that seem most devastating to the external attack hypothesis.

The first involves so-called “patient zero” of Havana Syndrome, a CIA officer who was the first to report the sudden onset of symptoms like headache, nausea, and disorientation. The first case is critical – if it is potentially a legitimate external attack, then that could explain triggering a mass delusion. But if the first case is likely not external attack, then it is far more likely that the entire syndrome is mass delusion. It would be a strange coincidence if the first false case triggered belief in a syndrome that later turned out to be real.

According to Bartholomew, who has direct information from interviews, the first case is extremely questionable. It occurred on the background of frequent harassment of US diplomats by the Cuban government, so there was already high anxiety that they were being targeted. When patient zero developed symptoms, he became convinced it was an external attack because they were accompanied by a sound – a sound that he recorded. Analysis of that sound concluded that he was just hearing the mating call of a local cricket species.

Patient zero, however, was convinced he was the victim of an attack, and then aggressively began promoting this idea, and warning all of his colleagues to be on the lookout for similar symptoms. This, predictably, led to a cluster of reports of symptoms. This, in turn, lead to the US state department putting out a notice to all US personnel stationed abroad to also be on the lookout for similar symptoms – a notice that would have gone to literally millions of people. This is a great way to generate a mass delusion.

Therefore, what we have is not just mass delusion as a diagnosis of exclusion, a plausible explanation in the absence of evidence for another cause. Bartholomew lays out a convincing affirmative case for a mass delusion, linking it back to patient zero and everything that flowed from them.

The second piece of information I found compelling was part of the intelligence investigation. The main argument against a directed microwave attack is not that such technology is impossible, but rather that use of such a device would have necessarily produced certain effects that were absent. A microwave beam would heat up any electronic or metal objects in the path, and would have likely caused noticeable heating of any tissue that was targeted. It would also likely have interfered with WiFi. None of this was reported, and is not part of the syndrome.

If we combine the results of the intelligence agency investigations with the strong case for a mass delusion leading back to patient zero, that really is left as the only plausible explanation. Of course, negative conclusions – that there were no external attacks – are always difficult. We cannot rule out, for example, that an alien spacecraft has ever visited the Earth, only that there is no definitive evidence that they have, and there is a strong positive case to make for the conclusion that the UFO phenomenon is a psychocultural one.

My original point, however, stands. When dealing with claims that are not paranormal, do not break the laws of physics, and are not literally impossible, we have to be careful not to overstate the skeptical case, or to endorse arguments that are weak just because they support the skeptical narrative. Also, having plausible alternate explanations, like mass delusion, is useful but not definitive in itself. The “explanation of exclusion” may be correct, and may be the most likely answer, but always comes with a question mark. Far better is when there is positive evidence for an alternate explanation.

In the case of Havana Syndrome, it is satisfying to conclude that the skeptical answer, that it is almost certainly entirely a mass delusion, is the best current answer.