Author: Shelby Wickert

One of the cornerstones of modern science is the criterion of replicability. Replicability is the idea that if a phenomenon is real, it should be possible to demonstrate it repeatedly and on demand. If a team of researchers conducts an experiment to test a hypothesis and finds a positive result, then other researchers should get similar results if they conduct experiments on the same topic. This is the basis of almost any scientific field that uses experiments to test hypotheses. For instance, we can be reasonably sure that gravity exists because many studies on the orbits of planets, gravity’s relationship to weight, and other aspects of the phenomenon have generally produced consistent observations and data.

Replication is essential to the process of science because it allows scientists to separate good hypotheses from bad ones. Individual studies may yield inaccurate results for a number of reasons. Sometimes a study is biased, skewing the results and making them appear more or less significant than they actually are. Sometimes the participants don’t reflect the overall population, leading to results that can’t easily be applied to all people. Sometimes the study simply finds an illusory correlation that doesn’t exist in the real world. Replication of original studies helps researchers confirm that an effect is real and further examine how it works. If an idea is accurate, many replications will produce consistent evidence of its existence. If not, replications will show weak or conflicting information, leading researchers to drop the original idea and explore other ones.

However, within roughly the last decade and a half, the concept of replication has caused quite a bit of turmoil in the field of psychology. Researchers have looked back on the history of psychology research and realized that many psychology studies, including some for concepts that define major ideas in the field, have not been successfully replicated or failed to replicate as often as expected (Shrout and Rodgers 2018). In some cases, replication studies were performed but produced results that conflicted with the original findings. Other phenomena have been given replication studies, but the replications didn’t use the methods of the original study, leaving open the possibility that the original results may have been effects of experimental design. Finally, for a few concepts, there have been no attempts to replicate at all! How did this situation come to be?

History

Lack of replication has been noted for decades in psychological research (and in some other fields as well). However, several events in the early 2010s put psychology in the spotlight and made the problem impossible to ignore.

The first event to make headlines was the academic response to a 2011 study on precognition, the idea that some people have the ability to predict the future (Wiggins and Christopherson 2019). The study’s author claimed that he had produced clear evidence in favor of precognition’s existence, which other researchers found questionable due to the claim’s outlandish nature and apparent errors in how the experiment was conducted. A few replication studies were done and found no evidence for precognition. However, the replications were rejected by several scientific journals because they weren’t perceived as being important, despite providing clarification on the likelihood of a controversial idea. Had a person looked through the psychology literature on precognition at that time, they would have seen only the poorly conducted initial study in favor of precognition and not the more numerous replications that rejected its findings.

Later that year, Diedrik Stapel, a scientist who had authored many psychology studies, was proven to have committed fraud in most of them (including faking data). Although not directly related to replication, this event shocked the psychology community and demonstrated how easy it was for bad data to become a part of the overall scientific literature (Wiggins and Christopherson 2019). How had Stapel been able to lie for so long? Where had research and publication protocols had failed? Perhaps if someone had checked his research more thoroughly, such as by trying to replicate it, the fraud would have been discovered as soon as it started.

Finally, several researchers realized that many psychology studies had issues with problematic research practices, including the manipulation of negative results to appear significant. They took it upon themselves to expose these problems by publishing an article appropriately titled “False Positive Psychology: Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything as Significant in Psychological Science.” In the article, they used studies and statistics to “prove” the idea that a person can de-age themselves by listening to a Beatles song (Wiggins and Christopherson 2019). Despite the ridiculous conclusion, the studies had been conducted according to the norms of research at the time and their statistical methods were all common and accepted practices. The article demonstrated how easily ordinary research practices could be misused.

These events opened the floodgates to a wave of doubt about the validity of psychology research, and the more people looked at the problem, the more issues they found. One report estimated that the field has a replication rate as low as 36% (and only as high as 47%) (Wiggins and Christopherson 2019).

One area of psychology that was hit particularly hard was the concept of priming. Priming is the idea that exposure to certain sights or events make people more likely to respond in ways that relate to what they just experienced. For instance, if a person saw a picture of a couch and was asked to fill in the blank letters in the word “S_ _ a,” they would likely say “sofa” instead of “soda,” “saga,” or other words that would also fit the letters given. Basic effects like this are relatively uncontroversial, but many proponents of priming have claimed to find much more extensive influences. One study published in the 1990s claimed that participants who were exposed to words associated with old age walked more slowly afterwards, as if affected by the stereotype that old people are slow (Lunbeck 2025). Academics were quick to conclude that this meant that people are so heavily influenced by the environment that even simple actions like walking are predetermined and not under our control! However, follow-up experiments found nothing of the sort.

One more thing: It’s worth noting that although the most famous examples of failed replication involve hypotheses that are particularly extreme or unlikely, more ordinary research can also fall afoul of reproducibility norms. In fact, one of the most worrying implications of the replication crisis is that other, more mundane inaccuracies are flying under the scientific method’s radar, and researchers don’t realize the need to weed them out. It’s easy to doubt that humans are mindless robots programmed by the words they read but harder to reconsider ideas that seem intuitive and logical.

Potential Solutions

So how can this issue be fixed? There is no one solution, but a number of measures can greatly improve the reliability of psychological research and end the replication crisis.

• Preregistration of studies: Some academic journals now require researchers to “register” their experiments before actually conducting them. The researchers have to share their topic, methods (the protocols they will use for the study), and hypotheses and stick to them during the testing period. If they change any of the details, especially in their methods, the study may be rejected and not published by the journal. This measure encourages transparency in how data is collected and discourages unscrupulous authors from changing the methods partway through the experiment to manipulate results. Because it means that studies are published before the results are known, it also cuts back on the practice of choosing studies for publication because they support ideas that are popular.
• Better measurement and statistical hygiene: This reform is only related to replication indirectly, but it is nonetheless extremely important. Using more precise measurements when collecting data and analyzing that data more honestly will cut down on errors and yield more realistic conclusions. These measures can create more honest and accurate results, which go hand in hand with replicability.
• Sharing of specific methods: A major critique of psychological research papers is that they don’t always include enough details about their methods to allow for replication. As a result, follow-up studies may not be close enough to the original to accurately test the phenomenon under study. A simple fix for this issue is to require more specific reporting of data collection procedures, allowing any lab to perform exact replications.
• Publishing more replications and rewarding researchers for replicating significant studies: At the institutional level, there needs to be a significant change in what scientific journals consider to be worth publishing. Currently, many journals are much more willing to accept studies that show new and interesting findings than replications of those findings, and research that disproves or fails to find evidence for particular hypotheses is often rejected even if the methods are sound (a phenomenon called the “file drawer effect”). This issue is severe enough that the replication crisis probably cannot be solved without a new commitment to publishing replication studies, including ones with negative results. Proposed fixes include rewarding researchers for transparency in their methods (allowing for replication), relaxing publication standards to include more replications and negative studies, and even requiring journals to publish replications of studies that they previously accepted.

It’s also worth noting that some observers argue that the replication crisis was never very serious in the first place, or point to the positive changes that are being made. This is why the replication crisis is sometimes referred to as a “credibility revolution” instead (Korbmacher et al. 2023). Although the situation may look bleak, researchers have begun implementing reforms. Various actors are encouraging open access research, incentivizing high-quality studies while deemphasizing the study quantity, creating new guidelines for journal editors who make the decision to accept or reject research, creating better reviews that summarize many studies, and more. There is still a long way to go, but these measures can ameliorate many of the problems that plague psychology and other fields and create a better future for science.

Ultimately, the replication crisis in psychology demonstrates many of the challenges that science is facing today and points toward ways that it can be improved. There are serious issues in academia’s publication practices and ability to prevent fraud, but these problems are not unfixable. Better research practices and a unified effort by scientific journals can end the replication crisis and work towards ensuring a psychological science that is more replicable, accurate, and open for all.

Sources:

Korbmacher, Max, et al. “The replication crisis has led to positive structural, procedural, and community changes.” Communications Psychology, 25 July 2023, https://doi.org/10.1038/s44271-023-00003-2.

Lunbeck, Elizabeth. Failure to replicate: A historian confronts the complicated origins and uncertain future of priming research, Review of Anatomy of a Train Wreck: The Rise and Fall of Priming Research Science, vol. 387, no. 6730, 9 Jan. 2025, pp. 145–145, https://www.science.org/doi/10.1126/science.adu0370.

Shrout, Patrick E., and Joseph L. Rodgers. “Psychology, Science, and Knowledge Construction: Broadening Perspectives from the Replication Crisis.” Annual Review of Psychology, vol. 69, no. 1, 4 Jan. 2018, pp. 487–510, https://doi.org/10.1146/annurev-psych-122216-011845.

Wiggins, Bradford J., and Cody D. Chrisopherson. “The Replication Crisis in Psychology: An Overview for Theoretical and Philosophical Psychology.” Journal of Theoretical and Philosophical Psychology, vol. 39, no. 4, Nov. 2019, pp. 202–217, https://doi.org/10.1037/teo0000137.

What’s the weirdest psychiatric condition you’ve ever heard of? Odds are, this one is infinitely stranger. Delusional Infestation (DI) is a condition in which a person falsely believes that their skin is infested with parasites, insects, bacteria, fungi, or other harmful items (Campbell et al. 2019). They often experience symptoms such as itchy or tingling sensations, or even feel something crawling on or under their skin, which further convinces them that the infestation is real. They may bring “specimens” of the parasites to show their doctors and remain unconvinced when told that the specimens are harmless objects or that medical tests have found nothing physically wrong with their skin.

The condition is also known as Delusional Parasitosis (DP), given that many people who have the condition attribute it to parasites. However, the terminology is changing in response to the fact that a wide variety of both living organisms and inanimate objects are blamed for symptoms (Bewley 2010).

Once it has been established that the person is not actually infested, they may be diagnosed with Delusional Infestation if:

• They have had the delusion for at least a month
• Aside from the delusion, their lives are mostly unimpaired
• Any mood episodes (mania or depression) that have occurred are brief compared to the duration of the delusion
• Their symptoms are not better explained by another physical or mental illness, including schizophrenia, or by substance use* (Campbell et al. 2019)

*If the case is primary DI; more on this in the next section

Causes

The cause of Delusional Infestation depends on the type of DI. Cases where DI is the only condition present are called primary DI. However, a person may also experience DI as a symptom of a different illness or due to the effects of certain drugs. In these situations, they are diagnosed with secondary DI because it is not the primary condition (Wikipedia Contributors 2019).

The cause of primary DI is currently unknown, though it may have something to do with the neurotransmitter dopamine. The presence of unusually high amounts of dopamine in certain brain regions can create formication, the skin-crawling sensation experienced by many people with DI, and faulty dopamine activity has also been implicated in other psychotic disorders like schizophrenia. However, research on this topic is still developing, making it impossible to draw conclusions at this time (Wikipedia Contributors 2019).

Secondary DI has quite a few potential causes. A vast range of physical medical conditions, from AIDS and hepatitis to traumatic brain injury and vitamin B12 deficiency, may cause delusions or crawling sensations (Reich et al. 2019, Wikipedia Contributors 2019). Consuming certain drugs, both legal and illegal, can also create similar effects. The side effects of some prescription drugs include DI, along with alcohol, cocaine, amphetamines, and cannabis (Campbell et al. 2019, Reich et al. 2019). Finally, other, more common mental conditions such as schizophrenia and depression may have symptoms that include DI.

Treatment

Thankfully, we know far more about treating DI than we do about its causes. Symptoms often respond well to antipsychotic medications, and in the case of secondary DI, they may vanish entirely when the person receives treatment for their primary condition (Campbell et al. 2019).

Unfortunately, treatment of Delusional Infestation is often difficult, as by definition, people with DI believe that they have a physical illness, not a mental one. DI cases most often begin in the offices of dermatologists, parasitologists, and entomologists instead of psychiatrists. Upon being shown evidence that their condition is not physical (such as negative test results or proof that a specimen is ordinary detritus), a person may simply leave and go to a different doctor in an attempt to get the diagnosis they want. Recent discussions of DI among researchers and health care professionals have emphasized the importance of collaboration between a person’s doctors and maintaining a positive relationship with patients (Reich et al. 2019, Campbell et al. 2019). These measures can persuade some people with DI to agree to psychiatric treatment, but others may refuse to accept it no matter what.

Potential Harms

Many friends, relatives, and doctors who have seen the effects of Delusional Infestation become frustrated by their inability to persuade the affected person of the reality of their illness. At the same time, it is important to encourage DI patients to accept treatment, as the condition is not harmless. The most obvious problem caused by DI is the stress and mental suffering caused by the symptoms themselves – no one enjoys feeling like they have bugs inside their body! People with DI sometimes scratch or pick at their skin, potentially causing more issues. The symptoms and delusions may also cause problems at work and in social relationships. In rare cases, people with DI may harm themselves, other people, or pets in the course of attempts to get rid of the “infestation” (Shelomi 2026).

A further danger exists in the form of people and organizations who, despite the seriousness of this condition, take advantage of vulnerable people with DI in order to gain money from them. There are multiple pseudoscientific diagnoses promoted in low-quality research and on the Internet that emphasize DI symptoms but cruelly encourage the delusion that the condition has a physical cause. Scary-sounding terms like “Morgellons Disease” and “Neurocutaneous Syndrome” are marketed to the public in order to promote the services of a sketchy doctor or sell a miracle cure (Shelomi 2026). Belief in these false diseases can prevent a person from getting real treatment or unnecessarily prolong their suffering by prompting them to chase after false cures for lengthy periods of time when they could have received help right away.

Overall, Delusional Infestation is an interesting condition that exposes a number of phenomena related to the current state of science and medicine in our society. The need for more effective communication regarding rare conditions, the importance of trust between patients and doctors, and the prevalence of scammers that prey on vulnerable demographics are all important issues that deserve greater examination. DI demonstrates a complicated and strange relationship between our brains and bodies and exposes gaps in our knowledge of medicine and psychiatry. Hopefully in the future, it will get the attention it deserves in the form of more research into its causes and more effective treatments for those who suffer from its symptoms.

Sources:

Bewley, A.P., et al. “Delusional Parasitosis: Time to Call It Delusional Infestation.” British Journal of Dermatology, vol. 163, no. 1, 22 Feb. 2010, pp. 1–2, https://doi.org/10.1111/j.1365-2133.2010.09841.x

Campbell, Elliott H., et al. “Diagnosis and Management of Delusional Parasitosis.” Journal of the American Academy of Dermatology, vol. 80, no. 5, May 2019, pp. 1428–1434, www.sciencedirect.com/science/article/pii/S0190962218330548, https://doi.org/10.1016/j.jaad.2018.12.012

Reich, Adam, et al. “Delusions of Parasitosis: An Update.” Dermatology and Therapy, vol. 9, no. 4, 13 Sept. 2019, pp. 631–638, www.ncbi.nlm.nih.gov/pmc/articles/PMC6828902/, https://doi.org/10.1007/s13555-019-00324-3

Shelomi, Matan. “Delusion or Dentistry: The Pseudoscientific Diagnosis of Neurocutaneous Syndrome | Skeptical Inquirer.” Skepticalinquirer.org, 4 Mar. 2026, skepticalinquirer.org/exclusive/delusion-or-dentistry-the-pseudoscientific-diagnosis-of-neurocutaneous-syndrome/

Wikipedia Contributors. “Delusional Parasitosis.” Wikipedia, Wikimedia Foundation, 16 July 2019, en.wikipedia.org/wiki/Delusional_parasitosis

How often have you heard a mention of a machine called a “lie detector?” According to pop culture, members of law enforcement organizations, and even the U.S. government, a polygraph or lie detector is a machine that records certain vital functions of a person suspected of lying. The person is asked a series of questions while the polygraph reads their physiological responses, and the resulting readings are supposedly highly accurate evidence as to whether that person was lying or telling the truth.

Over the decades, many people have protested the use of the polygraph in the justice system, as a tool for detecting disloyalty in intelligence agencies, or as a condition of employment. Some arguments have been based mainly on philosophical objections to the concept of a lie detector: Preemptive polygraph tests contradict the principle that people are innocent until proven guilty in a fair justice system, or they violate a person’s constitutional right to be protected from self-incrimination, or they prevent them from “remaining silent” regarding criminal charges. These arguments have merit, and they are undoubtedly made out of genuine concern for human rights. However, there is a much more practical, relevant, and immediate reason to protest the use of polygraphs as lie detectors: They don’t work.

The basic premise that is used to promote the accuracy of polygraphs is that all humans – regardless of age, sex, ethnicity, health, personality, and all other factors – display some uniform,  measurable physiological reaction when saying something they know to be false which is clearly different from their response to stating something that is true. This reaction is usually said to be increases in pulse, blood pressure, and breathing rate and sometimes changes in skin conductance and/or resistance. The only problem? There is no evidence to support the existence of such a universal reaction. No study has ever shown that a person’s reaction to lying is measurable, and people don’t always react to lying, stress, or the feeling of being nervous in the same way.

The accuracy of polygraphs has been disputed and many studies on the topic are heavily flawed. Researchers who already believe in the polygraph’s accuracy unsurprisingly tend to find the highest estimates, claiming guilty accuracy rates above 80% or 90%, and an innocent accuracy rate of a perfect 100%. That is, they claim that people who are truthful will always be found innocent, and liars will be caught often enough that if the polygraph was a student, it would average an A or a B. However, skeptical research teams have found more modest guilty accuracy rates of around 74-76% (Tavel 2016, Synnott 2015). Even worse, the innocent accuracy rate plummets when questioned; only about 52% of innocent people will be judged truthful (Tavel 2016).

False Negatives

The first type of invalid result from a polygraph involves people who lied during the test but are judged truthful, a result called a false negative. This may stem from a number of factors, including a number of “countermeasures” that can influence a person’s physiological state, but the basic idea behind the polygraph may create errors as well. If a guilty person doesn’t feel nervous, the test may not indicate abnormal vital signs.

There are a number of well-known cases of liars passing polygraph tests, especially in the area of national defense and intelligence. Despite the extensive use of polygraphs by the CIA during the Cold War to screen its agents for dishonesty and disloyalty, there are six known people who have been judged innocent while actively delivering U.S. secrets to foreign governments. One of the most high-profile cases was that of Aldrich Ames. Ames had a long career in the CIA, starting with summer jobs as a high school student. He applied to his first full-time position in 1962, and was also given his first polygraph at this time. During the test, he admitted to the petty crime of stealing a bicycle while drunk, and was deemed honest.

In 1985, Ames began passing information the Soviet Union regarding the activities of CIA agents and assets. Initially, he planned it as a one-time payoff to satisfy his debts, including the money he owed his first wife per their divorce settlement, but the arrangement quickly became extensive and permanent. The information he disclosed included the identities of CIA assets, endangering their safety and freedom, and in some cases costing them their lives. During this period, he was given three more polygraph tests, one in 1986 and two in 1991. During the initial 1991 polygraph, the results showed a seemingly deceptive response from Ames in reaction to a question of whether he was “concealing contacts with foreign nationals,” but not when he was asked if he was “working for a foreign intelligence service” (Senate Select Committee on Intelligence 1994). The response to the “foreign nationals” question was concerning enough to the polygraph examiner that Ames was asked to come in for a follow-up polygraph a few days later. That test showed no indication of deception at all. Ames was declared honest.

Ames was arrested in 1994 after his connections to the leaks were noticed, and an investigation was immediately begun into how one man had been able to do so much damage to American intelligence interests and avoid suspicion for so long. An assessment was commissioned for the Senate Select Committee on Intelligence, and it briefly discussed the possibility that Ames had been specially “trained” to beat the polygraph by his Soviet handlers. In truth, Ames received no training; his contacts merely told him to get a good night’s sleep and avoid stress on the day of the test. One might think that the US government would be quite concerned about this fact, but the report waves it off and instead faults other factors for the CIA’s failure to prevent or immediately stop Ames’ actions. No recommendations were made regarding the use of the polygraph in internal investigations, even though the report contains ample evidence of the fallibility of polygraph testing and nonchalantly mentions a number of incidents that imply CIA overconfidence in the inability of employees to conceal information. One quote says that Ames became so rich from selling state secrets that he was able to “purchase a new Jaguar automobile and a $540,000 home, with cash, in Arlington. Apparently, these seemingly large expenditures by an employee making less than $70,000 a year had not raised questions at the CIA” (Senate Select Committee on Intelligence 1994).

False Positives

The other type of inaccurate result happens when polygraphs “prove” that truthful people are lying. This scenario is everyone’s worst nightmare. Picture it: you are accused of a terrible crime and agree to take a lie detector test to clear your name. Despite being truthful and telling the police everything you know, you are told that the polygraph readings show that you were lying. Instead of being released, you are taken to an interrogation room, where officers press you for more information. You must have been lying, they tell you, because you were tested by a scientific instrument that measures specific human reactions to withholding the truth. What do you do then?

Just as with false negatives, there are known examples of polygraphs giving false positive results, and they have had terrible consequences on some lives. Here are a few examples:

• A man who was a suspect in the Green River Killer cases was deemed a liar after a polygraph test. Later, DNA evidence proved that the culprit was actually Gary Ridgway, who had escaped suspicion after passing a polygraph.
• For almost two decades, the main suspect in the death of Vicki Wegerle was her husband Bill, who failed not one but two polygraphs during the course of the investigation. The real murderer was Dennis Rader, another serial killer known as BTK, who was also caught with DNA evidence.
• Numerous people have applied for jobs at the FBI, CIA, and other government agencies that are allowed to require polygraph testing as a condition of employment and have been rejected despite telling the truth. The website AntiPolygraph.org maintains a list of statements made by these people, who describe abusive treatment, “guilty until proven innocent” attitudes, extreme suspicion, leading questions, and (ironically) lying on the part of their examiners. This process has also been used as a pretext for firing employees, with the failed polygraph results, or even just the examiner’s intuition, as the only evidence whatsoever.

Going beyond individual cases, there is evidence that polygraphs and other attempts at detecting a person’s level of honesty are actually biased against truth tellers. Questions may lead to an increased response in an examinee because they are unusually guilt-prone and feel nervous and guilty in response to hearing details of a crime even if they did not commit it. Such people are sometimes called “guilt grabbers” (Lilienfeld 1993).

In addition, test questions may be phrased in a way that makes them likely to provoke a response in anyone, guilty or not. The behavior of the examiner likely has an influence on the results as well. One of the statements from Antipolygraph.org, made by an applicant to the Arizona Department of Public Safety, is a great example of these effects. In his statement, “Derek” notes that he was pressured by the examiner to answer in certain ways and was repeatedly asked about his sex life, including the question, “Have you ever fondled a girl while she was sleeping?” (Antipolygraph.org, 2022) Since any person with a conscience would react to this statement with feelings of shock and disgust, a polygraph would no doubt almost always record a “lie” response to this question, picking up the heightened blood pressure and heartbeat caused by such feelings. This treatment seems egregious, especially since (if the polygraph truly detected lies) a simple “Have you ever committed a sex crime?” should be sufficient to catch sexual predators and prevent them from working in public service. As it was asked, though, the only type of person who would consistently be judged truthful would be someone who felt calm and unconcerned about child molestation!

Conclusions

The myth of the polygraph as a lie detector has persisted for decades. Why? Aldrich Ames can offer an educated guess. In a letter written in 2000 to the Federation of American Scientists, he notes a number of factors that may be at play – polygraph examiners profit from their work, the polygraph is easily abused to force confessions, etc. (Ames 2000) The ideas that he focuses on, however, are the systematic suspicion of US intelligence services and the tremendous risk of their putting trust in the wrong person. With the polygraph, politicians and bureaucrats can claim that they are doing their due diligence for national security by using a “scientific” technique to root out liars, and if someone slips through the cracks, they can avoid blame by faulting a “rare” machine-made mistake rather than human error. This practice has enabled what Ames calls “bureaucratically-driven flights from accountability,” and it will likely continue into the foreseeable future unless our government decides to follow the science and face the polygraph’s long history of false positives and false negatives (Ames 2000).

In sum, the idea that the polygraph can accurately detect lies is a complete myth. It has no established scientific basis, and has failed repeatedly when applied in the real world. Thanks to its continuing use in our society, innocent people have been accused of serious crimes, and spies have been declared honest while actively working against US government and intelligence interests. It’s time for the polygraph to be seen for what it truly is: wishful thinking and willful ignorance masquerading as science.

References:

Ames, Aldrich. “A Letter from Aldrich Ames on Polygraph Testing.” Sgp.fas.org, 28 Nov.      2000, sgp.fas.org/othergov/polygraph/ames.html.

Lilienfeld, Scott. “Do “Honesty” Tests Really Measure Honesty?” Skeptical Inquirer, 1993,    cdn.centerforinquiry.org/wp-content/uploads/sites/29/1993/10/22165136/p34.pdf.

“Personal Statements of Polygraph Victims | AntiPolygraph.org.” AntiPolygraph.org, 2025,     antipolygraph.org/statements.shtml. Accessed 19 Apr. 2025.

“Polygraph Statement of Derek (Arizona Department of Public Safety).” AntiPolygraph.org,  2022, antipolygraph.org/statements/statement-046.shtml. Accessed 19 Apr. 2025.

Senate Select Committee on Intelligence. “An Assessment of the Aldrich H. Ames      Espionage Case and Its Implications for U.S. Intelligence – Senate Select Committee on Intelligence – 01 November 1994 – Part One.” Irp.fas.org, 1 Nov. 1994,             irp.fas.org/congress/1994_rpt/ssci_ames.htm.

Synnott, John, et al. “A Review of the Polygraph: History, Methodology and Current            Status.” Crime Psychology Review, vol. 1, no. 1, Jan. 2015, pp. 59–83,                  www.tandfonline.com/doi/full/10.1080/23744006.2015.1060080,                        https://doi.org/10.1080/23744006.2015.1060080.

Tavel, Morton. The “Lie Detector” Test Revisited: A Great Example of Junk Science |            Skeptical Inquirer. 30 Mar. 2016, skepticalinquirer.org/2016/03/the-lie-detector-    test-revisited-a-great-example-of-junk-science/.

Wikipedia Contributors. “Polygraph.” Wikipedia, Wikimedia Foundation, 21 May 2019,         en.wikipedia.org/wiki/Polygraph.

Medical marijuana is an issue that has drawn significant debate. As of 2025, it has been legalized for medical use in 39 states (and also for recreational use in 24). Cannabis is becoming more present in the medical landscape and corporations have begun developing and selling a wide variety of products incorporating it. A few cannabinoids have received FDA approval. This relaxation of previous bans has benefitted many, but it has also opened up cannabis to for-profit industries and unethical marketing.

Marijuana is routinely marketed to the public for a wide variety of purposes. It is sold as medicine, but also food, drinks, soap, makeup, and a huge number of other products. Companies that sell medical and recreational marijuana often make sensational claims about how much it can improve one’s health, downplay or ignore any risks that come with their products, then slip in a fine-print statement that they “cannot guarantee the accuracy” of any of the information that they themselves promote.

So what conditions does cannabis actually treat, and what are its risks and benefits?

Chronic Pain

A number of studies have supported the theory that cannabis is effective at treating chronic pain in adults. An important limitation to this statement is that most studies on the topic were conducted with nabiximol, a marijuana extract that is only available as a medication outside the United States. The studies that came from the US investigated marijuana that was instead vaporized or smoked. Nonetheless, the NIH recommended in 2017 that more research be done to investigate the effects of medical marijuana on chronic pain, especially with regard to different forms of cannabis and methods of administration.

Nausea and Vomiting Caused by Chemotherapy

When cancer patients go through chemotherapy, they often experience the unpleasant side effects of nausea and vomiting. To counteract this, they are often prescribed antiemetic drugs, which prevent those symptoms. So far, two THC-based medications have been approved by the FDA: nabilone and dronabinol. They were both found in clinical trials to have greater effects than placebos, and are considered to be as effective as medications that do not include cannabis products. Nabilone and dronabinol are sometimes given to patients who do not experience improvement after trying other antiemetics.

Spasticity?

There have been many studies that have examined the possibility that medical marijuana can alleviate spasticity, a symptom of some neurological conditions. Spasticity involves muscle stiffness and a loss of control over one’s movements. Cannabis extracts, nabiximols, and THC have all been tested as potential treatments. However, the results of these studies are often divided in a curious way. When people with Multiple Sclerosis (MS) are treated with cannabis, they report moderate but significant improvements in their symptoms. At the same time, when spasticity is measured by a doctor, there is no consistent effect reported. As with chronic pain, more research is needed on the link between medical marijuana and spasticity symptoms.

Sleep Disorders?

Cannabis has also been studied for a potential effect on a number of sleep issues with a wide variety of causes. The NIH stated in 2017 that there was “moderate evidence” that nabiximols could reduce sleep disturbances that were symptoms of sleep apnea, fibromyalgia, chronic pain, and Multiple Sclerosis. However, these effects were only observed in the short term. Again, more research is necessary before we can fully conclude that medical marijuana can treat sleep problems.

Risks

• Side effects: As with most medications, medical marijuana can have side effects, which most often are minor, such as drowsiness. Use of marijuana as medicine can also occasionally cause symptoms similar to those of recreational use (the “high”) when taken at higher doses.
• Addiction: It is possible to develop an addiction to marijuana. Among people who use marijuana, the proportion who become dependent on it is roughly 9-10%; this figure is considerably lower than addiction rates for many other drugs, both legal (15% for alcohol, 23% for opioids, and 32% for nicotine) and illegal (17% for cocaine and 23% for heroin). In addition, marijuana addiction tends to develop gradually, and the risk decreases as the user ages. After age 25, a person’s risk of becoming dependent on marijuana is roughly 0%.
• Effects on physical, cognitive, and mental health: A number of other concerns have been raised about marijuana/cannabis use. Some users of medical marijuana consume it via smoking, which may increase their risk for lung cancer. It is known that recreational consumption of marijuana can cause detrimental cognitive effects such as learning loss, and it is unclear whether medical use has the same effects or not. Finally, some studies have found associations between marijuana use and the development of mental illnesses, especially schizophrenia and psychotic symptoms. However, an association is different from a causal effect, and the most dramatic links tend to be in people who already displayed symptoms or who were considered to have a higher risk of mental illness than the average person. All of these effects require more research to determine the likelihood of these risks to medical marijuana users, who generally use smaller doses and different methods of consumption than recreational marijuana users.

A Marijuana Myth – The “Gateway Drug”

One idea that historically has been brought up frequently in discussions of the risks of marijuana is the statement that marijuana is a “gateway drug.” The Marijuana Gateway Hypothesis holds that marijuana use increases a person’s risk for using more dangerous drugs later on. If true, this would be a significant risk for recreational users and likely for medical users as well. However, research on this topic is often performed without control groups and does not always find statistically significant results. Even studies that do produce significant results have found support only for correlations and temporal connections (one event happening after another) between marijuana use and later hard drug use. This leaves open the possibility that there are other variables, called third variables, that influence both a person’s marijuana use and hard drug use. Third variables can be characteristics of the people themselves, or aspects of the environment they live in. A list of possible third variables includes: peer groups and social encouragement/pressure to use particular substances, level of engagement with school, deviant behaviors, thrill seeking, problems with behavioral and emotional regulation, level of self-control, genetics, and age at first use. Given that there are so many alternate explanations for hard drug use other than marijuana use, it is unlikely that the Marijuana Gateway Hypothesis is accurate.

Conclusions

The subject of medical marijuana has been heavily distorted and clouded by misinformation and marketing. To clear the confusion, accurate information needs to be provided to consumers regarding what conditions can be treated with cannabis and the potential risks and benefits of using cannabis-related products. In addition, people should be aware of the limits of our current knowledge. Many aspects of medical marijuana have not been studied closely, and we are acting on limited information that may change as marijuana is researched more widely in a clinical setting. There may come a day when we will know everything there is to know about cannabis treatments and understand exactly how useful they are for every imaginable human condition, and these facts will be common knowledge available to all. Until then, it’s best to do some fact-checking when faced with exaggerated claims or a decision about your health.

Resources:

Ayers, John W., et al. “The Need for Federal Regulation of Marijuana Marketing.” JAMA, vol.         321, no. 22, 11 June 2019, pp. 2163–2164, jamanetwork.com/journals/jama/article-         abstract/2734209, https://doi.org/10.1001/jama.2019.4432. Accessed 26 June 2020.

Bostwick, J. Michael. “Blurred Boundaries: The Therapeutics and Politics of Medical      Marijuana.” Mayo Clinic Proceedings, vol. 87, no. 2, Feb. 2012, pp. 172–186,             www.mayoclinicproceedings.org/article/S0025-6196(11)00021-8/fulltext,             https://doi.org/10.1016/j.mayocp.2011.10.003.

Cohen, Peter J. “Medical Marijuana: The Conflict between Scientific Evidence and Political            Ideology. Part One of Two.” Journal of Pain & Palliative Care Pharmacotherapy, vol.         23, no. 1, Jan. 2009, pp. 4–25, https://doi.org/10.1080/15360280902727973.

Jorgensen, Cody, and Jessica Wells. “Is Marijuana Really a Gateway Drug? A Nationally     Representative Test of the Marijuana Gateway Hypothesis Using a Propensity Score             Matching Design.” Journal of Experimental Criminology, vol. 18, 6 Apr. 2021,             https://doi.org/10.1007/s11292-021-09464-z.

National Library of Medicine. “Therapeutic Effects of Cannabis and Cannabinoids.” Nih.gov,         National Academies Press (US), 12 Jan. 2017,   www.ncbi.nlm.nih.gov/books/NBK425767/.

Pratt, Misty, et al. “Benefits and Harms of Medical Cannabis: A Scoping Review of Systematic           Reviews.” Systematic Reviews, vol. 8, no. 1, Dec. 2019, pp. 1–35,      https://doi.org/10.1186/s13643-019-1243-x.

Wikipedia Contributors. “Legality of Cannabis by U.S. Jurisdiction.” Wikipedia, Wikimedia Foundation, 19 March 2025,      en.wikipedia.org/wiki/Legality_of_cannabis_by_U.S._jurisdiction.

For decades, science and pseudoscience have been compared to each other using a wide variety of criteria. The question of what distinguishes the two is especially relevant today, but scientists and philosophers have historically struggled with this division and how to use it to defend the public from bogus discoveries and scams based on scientific-sounding gibberish. In general, pseudoscience is defined as a non-scientific doctrine whose supporters claim that it is scientific, but there are many other definitions, including those below.

Science . . .

• . . . is based on sound research and and changes over time as new research causes the revision or discarding of older ideas. This feature is apparent across all fields, since every scientific discipline, from physics to psychology, has undergone dramatic changes throughout its existence.
• . . . fulfills or endorses all or most of the following philosophical criteria:
  • Logic
  • Semantical (a realist view of meaning)
  • Ontological (all real things are material and follow scientific laws)
  • Epistemological (theories reflect facts about the real world)
  • Reasonable ethics, including an aim to serve the greater good
  • Sociological (created and regulated by a community of experts)
• . . . must be falsifiable. That is, it must be able to be proven wrong under some circumstances. Basically, this means that ideas must hold up against fair efforts to test them.
  • Some researchers include the criteria that an idea must actually be tested in addition to being falsifiable, and that supporters of the idea accept any negative results.
• . . . investigates questions, including its own failures. If a researcher performs an experiment and their hypothesis not supported by the results, they must investigate why this would be and revise their ideas.
• . . . tests new ideas and leads to progressively greater knowledge of the world

Pseudoscience . . .

• . . . is not based on reliable research and does not change in response to new research or at all. Homeopathy demonstrates this feature well. The practice originated in the 1800s and is based on the idea that extremely tiny quantities of certain substances have medicinal purposes. The original experiments on homeopathy were poorly designed, and the field remained the same even as new discoveries in chemistry contradicted its claims. Homeopathy now defies most of the principles of chemistry.
• . . . fails to satisfy most or all scientific philosophical criteria, and may include idealism, such as:
  • Idealist epistemology (there are things that do not have to conform to scientific laws). For instance, the belief that some people have special powers, such as telekinesis, that defy the laws of physics uses idealist epistemology.
  • Dubious or flexible ethics, especially regarding experimentation. A psychic may say that their powers “do not appear on command” to avoid participation in a lab experiment, while at the same time offering frequent readings on the street that they claim are 100% accurate.
  • In addition, supporters of an ideology-based pseudoscience may claim that “science is just one more opinion.” This tactic can be a part of any pseudoscience, but it is most notably used by groups who use pseudoscience for religious purposes, such as proponents of creationism or intelligent design.
• . . . includes ideas that are impossible or unreasonably difficult to disprove, and may be attached to “ad hoc” hypotheses that function as excuses in the event that evidence is produced against the idea. A great example is the statement “Bigfoot exists.” It is unlikely that Bigfoot is actually real, but no evidence against the existence of Bigfoot would ever convince believers. A skeptical question such as, “If Bigfoot exists, why have no Bigfoot corpses or skeletons been found?” will prompt the production of even more unfalsifiable (and often ridiculous) assertions, including: “Bigfeet decay unusually quickly.” “When a Bigfoot dies, it is always buried by another Bigfoot.” “No animal bodies are ever found unless they were killed by humans, and no Bigfoot has ever been killed by a human.” When a pseudoscientific idea is found to be inaccurate, supporters usually refuse to admit that they were wrong, rather than rejecting or revising the idea and moving on to further investigation.
• . . . does not investigate much and doesn’t question its failures. Astrology is one pseudoscience that ignores many potential investigations. For instance, astrologers claim that an individual’s personality is determined by the position of the sun, moon, planets, and stars at the moment of their birth. This idea prompts a number of questions, including how stars and planets would affect a person’s brain or why birth is the determining event as opposed to conception. However, astrology contains no answers to these questions, and most astrologers seem uninterested in looking into the glaring issues they pose for the field.
• . . . is unwelcoming to new ideas, and theories mostly conform to what is already believed. There are a number of reasons why Sigmund Freud’s ideas of psychoanalysis are pseudoscientific, but one of the most immediate is that the field rejects ideas that Freud himself did not invent. In one case, Karen Horney, a fellow psychoanalyst, tried to introduce the concept of “womb envy” to the field as a response to Freud’s theory of “penis envy.” Freud had declared that penis envy was a woman’s desire for male anatomy that led to a sense of inferiority and that all women experienced these feelings their entire lives. Horney, taking the idea further, theorized that men were also jealous of women and wished for the ability to give birth and participate in motherhood. However, Horney believed that both penis envy and womb envy were rare and that they involved desires for certain social and cultural roles held by the opposite gender, rather than a literal wish for different reproductive organs. Freud rejected the idea of womb envy and essentially told Horney that she’d only come up with the concept due to her own problems with penis envy!

The differences between science and pseudoscience is a topic that many have studied and worked on for a long time, and will without a doubt continue to be debated far into the future. Is it more important to define pseudoscience as a lack of investigation or as idealism? Is science more reliable than pseudoscience because it is based on better research or because it is more testable? As we encounter scientific-sounding claims in advertising and health care, and on social media, it’s important to keep these questions in mind. They may save us from the consequences of falling for a pseudoscientific claim.

References:

“Astrology – the Skeptic’s Dictionary – Skepdic.com.” Skepdic.com, skepdic.com/astrology.html.

Bunge, Mario. The Philosophy behind Pseudoscience. Skeptical Inquirer, 2006.

Hansson, Sven Ove. “Science and Pseudo-Science.” Plato.stanford.edu, 3 Sept. 2008,          plato.stanford.edu/entries/pseudo-science/ utm_campaign=OImrt19&utm_medium=organic&utm_source=instantmagazine

“Homeopathy – the Skeptic’s Dictionary – Skepdic.com.” Skepdic.com, 2015,    skepdic.com/homeo.html.

Hu, Zhe, and Haofeng Sun. A Contrast Analysis of Sigmund Freud and Karen Horney’s Theory of Psychology. 2017.

Loxton, Daniel, and Donald R Prothero. Abominable Science! : Origins of the Yeti, Nessie, and Other Famous Cryptids. New York, Columbia University Press, 2015.

Yadav, Riya. “Sigmund Freud and Penis Envy – a Failure of Courage?” BPS, 8 May 2018,    www.bps.org.uk/psychologist/sigmund-freud-and-penis-envy-failure-courage.

Bigfoot. Alien abduction. Backwards masking. Haunted houses. If you have access to the Internet, social media, television, or any other pop culture outlet, odds are you’ve been exposed to ideas about the paranormal, and these ideas may or may not have been accompanied by a set of tropes about people who believe in the paranormal. Conspiracy beliefs, wacky behavior, and tinfoil hats are frequent clichés. Despite these stereotypes, both paranormal beliefs and anomalous experiences are surprisingly common in various Western countries (Hoogeveen et al. 2024; Halligan and Pechey 2011; Loxton and Prothero 2013, 310-311). For instance, when given a list of ten paranormal topics and asked whether they believed, 73% of American adults responded “yes” to at least one topic (Loxton and Prothero 2013, 311).

“Paranormal” is roughly defined as any topic that cannot be explained by or is not supported by science, and some researchers add the additional criterion that the subject must also not be promoted by any mainstream religion (Loxton and Prothero 2013, 310). This definition begs an interesting question: if neither science nor religion are a source of such ideas, why do people believe in the paranormal and report paranormal experiences? (At least, it begs the question if we assume that reports of being probed by aliens, hearing Satanic propaganda in Led Zeppelin songs, or sighting 600-foot long sea serpents are not based in reality.)

There are a few immediate explanations for paranormal events. Overactive imaginations and pop culture’s frequent reinforcement of the idea that the known laws of physics need not apply to every situation could easily be factors in many reports of strange phenomena. A significant percentage of paranormal reports can be proven to be intentional frauds or hoaxes. Additionally, some people who report anomalous events have severe neurological or psychiatric disorders that cause them to experience and believe in events or ideas that do not exist.

The above explanations account for situations in which the “paranormal” event can easily be proven to be false. What about the remaining cases, then? One tempting idea is that people who claim to have experienced the paranormal are simply stupid, ignorant, or uneducated. Those people might believe in ghosts, but you know better. You always look at the evidence before forming an opinion; you apply your knowledge and common sense to every situation! However, this hypothesis isn’t clearly supported by scientific evidence. A review of 71 studies by Charlotte Dean et al. examined the effects of six different cognitive variables (perception and cognitive biases; reasoning; intelligence, critical thinking, and academic performance; thinking style; executive function; and other cognitive functions) on paranormal belief and found weak and inconsistent evidence for all variables (Dean et al. 2022). The analysis seemed to find some evidence of a direct relationship between paranormal belief and an intuitive thinking style (which is faster and guided by emotion). However, it failed to find a consistent inverse relationship between paranormal belief and an analytical thinking style (slower and more logic-based). The authors ultimately came to the conclusion that a number of factors were likely at play and that no one influence determined whether or not an individual would claim belief in one or more paranormal topics (Dean et al. 2022). Furthermore, a quick look at a number of famous scientists provides additional evidence against the “true believers are dumb” explanation. Isaac Newton, Marie Curie, and Alan Turing, for example, were all believers in some aspect of the paranormal, despite clearly being intelligent and educated and despite the fact that they all made valuable contributions to science (Hoogeveen et al. 2024). (Fun fact: Turing apparently cited ESP as evidence in service of his opinion that computers were incapable of human thought [Hoogeveen et al. 2024].) In light of these evaluations, it seems that the idea that paranormal belief is the result of subpar thinking is overly simplistic at best and pejorative at worst.

So what prompts an otherwise reasonable, intelligent, and mentally functional individual to believe in something that is strange, illogical, and contrary to what we know about how the world works? One obvious factor stands out: having a paranormal experience could easily influence paranormal belief. Some studies have found moderate correlations between anomalous experiences and anomalous beliefs, though it has been noted that many people who believe in some aspect of the paranormal do not claim any anomalous experience (Halligan and Pechey 2011). Given this information, it seems that there is some relationship between experiencing and believing in the paranormal, though researchers don’t yet know much about it. It could be that having a strange paranormal experience leads directly to paranormal belief. On the other hand, paranormal belief may cause paranormal experiences by influencing a person’s interpretation of strange events. In addition, some other variable or variables, such as time spent consuming media that promotes pseudoscience, affects both experiences and beliefs. With this limitation in mind, this article will explore unusual sensory experiences as a potential cause of belief in the paranormal.

One might think that human sensations and perceptions are very accurate most of the time, but our brains can make surprisingly large errors, and our senses can fail us even under the best circumstances. The following sensory phenomena can happen to anyone, regardless of their intelligence, education, or mental health. They range from ordinary mistakes made by our brains to cases where a scary malfunction occurs.

Pareidolia

What do you see in these pictures?

Photos from Science.org, Behance.net, and Skepdic.org

If your answer for any of them was “a face,” then you’ve experienced a phenomenon known as pareidolia, in which a person sees a clear, meaningful visual pattern in random or vague stimuli (French 2001). This happens when our brains take our ability to remember and recognize objects a step too far.

Pareidolia’s effects are not limited to faces (have you ever seen a cloud that looks like an animal?), but seeing a face where there isn’t one is a famous illusion for a reason. A great deal of the supposed evidence of alien visitation to Earth involves photos of the surface of Mars that proponents claim are sculptures created by a Martian civilization (above right) (The Skeptic’s Dictionary 2013). Such claims would be amazing if true, but unfortunately, these “faces on Mars” are simply unusual rock formations. We only see meaning in them because our brains have applied our ability to recognize human faces to nonhuman objects. Although there is some evidence that religious people and believers in the paranormal are more likely than nonbelievers to see faces in random stimuli, anyone can be fooled by this illusion (Riekki et al. 2012, French 2001). Despite the fact that the faces on Mars and similar phenomena have been revealed as pareidolia, the images still fool many people and create or confirm their belief in intelligent extraterrestrial life.

(Since the initial commotion about Martian monuments in 1976, the features have been further investigated by NASA and confirmed to be a natural ridge [NASA 2001]. See a higher-resolution image below.)

Photo from Nasa

Top-Down Processing

Photo from Pinterest

Top-down processing is a phenomenon in which a person has knowledge or expectations about an event or sensation prior to the actual experience which influence what they sense. As with pareidolia, it’s a normal function of the human nervous system. Top-down processing can organize visual information and help someone figure out what to focus on (Gilbert and Li, 2013). This feature can lead us to sense inaccurately, however, if we are misled about what to expect, and it is particularly influential when bottom-up processing (using one’s senses without relying on previous ideas) is impeded (French 2001).

One intersection between top-down processing and paranormal belief is experiencing the presence of a ghost or spirit. In many cases, a person will see a ghost in dim lighting or darkness, while they are unable to rely much on bottom-up processing. Spirit encounters also frequently occur during visits to a “haunted” house or a historical site where someone has died or experienced great suffering. Advance knowledge of ghost lore has an obvious top-down influence on any unusual visual stimuli.

Other ghost-related sensory experiences can be found in electronic voice phenomena, or EVP. According to many believers in ghosts, tape recorders can capture messages from spirits, and their voices can be heard by listening to static-filled recordings. Interestingly, the same idea is applied to the belief that certain rock songs contain backwards Satanic messages. Supposedly, if one plays a song backward, one can hear the singers’ voices reciting statements praising the devil. (Note that this phenomenon is distinct from cases in which rock groups are known to have intentionally added backwards dialogue into their songs.) Both of these phenomena can be confirmed as the result of top-down processing with a very simple experiment: when an EVP or backwards recording is played for a person who doesn’t know what they are “supposed” to hear, they rarely report hearing a message, and sometimes not even a voice (French 2001). Since these recordings are almost always presented with a transcript, however, the listener is provided with cues suggesting what they should hear. The recordings reinforce themselves with the power of top-down processing, providing “conclusive proof” of ghosts or Satanism.

Misidentification Errors

Photos from Shutterstock

In addition to the sensory quirks described above, the human brain is capable of a large number of garden-variety errors when trying to identify a person or object. As stated above, we often assume that any person, when presented with an image, can immediately understand what they are looking at and identify it with almost 100% accuracy. However, our perception is much more fallible than we would like to think, especially when an event happens quickly or viewing conditions are imperfect. A number of situational factors, including but not limited to sleepiness, poor eyesight, distractions, emotions, and stress can also interfere with a person’s perception, causing them to confidently misidentify objects that they have seen or completely miss objects that they should have noticed (Loxton and Prothero 2013, 14 and 59).

In many anomalous encounters, especially those involving paranormal animals (aka “cryptids”) such as Bigfoot, sightings are frequently the result of the misidentification of normal animals and objects. In the book Abominable Science! Origins of the Yeti, Nessie, and Other Famous Cryptids, one of the authors recalls an amusing anecdote about a personal experience with misidentification errors (Loxton and Prothero 2013, 56-57). Two coworkers had told him about spotting a Sasquatch while they were out on the job in a rural area. They claimed that they had seen something that looked very similar to the legendary animal and that it had turned its head to watch them. When the group had the chance to go back to the scene of the sighting, they discovered that their Bigfoot was in fact an unusually shaped tree stump!

Inanimate objects are unlikely to be the sole source of Bigfoot sightings, but there are plenty of other Bigfoot-like objects that people can misidentify. For example, bears are similar in description to the pop-culture image of Bigfoot, being large, bulky mammals with brown or black fur and having thick, short necks. Additionally, bears are able to stand and walk on their hind legs for short periods of time, furthering the similarity (Loxton and Prothero 2013, 57-58). Add that to the fact that in many Bigfoot sightings, the mystery animal is seen from far away, in dim lighting or darkness, with other objects such as rocks, trees, and leaves obscuring the view of the observer, and the probability of Bigfoot actually being a series of bear sightings seems very high. With this is mind, it may not be surprising that one study has found that the supposed range of Bigfoot habitat (based on sighting reports) corresponds almost exactly to black bear habitat (Loxton and Prothero 2013, 57).

Sleep Paralysis

Photo from SoundCloud

Sleep paralysis is a strange, confusing, and often terrifying experience. Normally, a person’s muscles are paralyzed while they are in REM sleep, which is a normal function of the brain. However, in some cases, a person becomes paralyzed when falling asleep or waking up, and they realize that they cannot move (French 2001). Sleep paralysis episodes are frequently accompanied by hallucinations, including but not limited to sensations of levitating, pressure on one’s chest, sensing evil intruders, being attacked, and auditory hallucinations (French 2001, Sharpless and Barber 2011). Although no actual harm is done, many people who have suffered through this phenomenon feel extremely afraid and confused about their experience.

The symptoms of sleep paralysis are remarkable in their own right, but it has also been noted that they match closely with accounts of alien abductions. People who claim to have been kidnapped by extraterrestrial visitors generally describe being paralyzed, sensing nonhuman figures in their room, and flying. All of these features are associated with sleep paralysis, and abductions are also frequently said to happen at night (Holden and French 2010). The similarities are prominent enough that a large percentage of alien abduction cases could actually be instances of sleep paralysis. Self-described alien abductees may simply not be sufficiently informed about sleep problems to correctly identify their experience.

Sleep paralysis is relatively common in the general population. Though it usually occurs as a symptom of narcolepsy, anyone can experience it (Sharpless and Barber 2011, Holden and French 2010). It is difficult to determine how many people experience sleep paralysis due to the inconsistent findings of studies on the subject, but some research has found that as many as 40% of all people have had a sleep paralysis experience (Holden and French 2010). In other cases, researchers have settled on more modest estimates, such as a review that concluded that less than 8% of the general population had experienced it (Sharpless and Barber 2011). Still, sleep paralysis seems common, especially given that the human population is over 8 billion. Even if the lower 8% finding is accurate, almost 27 million people in the US alone will have an episode at least once in their lifetime!

In short, there are many aspects of the paranormal that have perfectly mundane explanations. Sensory quirks and altered states of consciousness have greater influences on us than we know, and they can produce convincing and powerful anomalous experiences. The general public is not well informed about phenomena such as pareidolia, top-down processing, misidentification errors, and sleep paralysis. At the same time, everyone is susceptible to them, because everyone occasionally faces situations that are confusing and ambiguous. Everyone can misinterpret a strange situation that feeds a belief in a paranormal topic. When taking these facts into account, it is not so surprising that so many people believe, even without evidence that any of it is real.

References:

Dean, Charlotte E., et al. “Paranormal Beliefs and Cognitive Function: A Systematic Review and   Assessment of Study Quality across Four Decades of Research.” PLOS ONE, vol. 17, no. 5, 4 May 2022, p. e0267360, https://doi.org/10.1371/journal.pone.0267360.

“Face on Mars – the Skeptic’s Dictionary – Skepdic.com.” Skepdic.com, 2016,    skepdic.com/faceonmars.html. Accessed 8 Nov. 2024.

French, Christopher. “Paranormal Perception? A Critical Evaluation.” Monograph Series No. 42, The Institute for Cultural Research, 2001.

Gilbert, Charles D., and Wu Li. “Top-down Influences on Visual Processing.” Nature Reviews Neuroscience, vol. 14, no. 5, 18 Apr. 2013, pp. 350–363,             www.ncbi.nlm.nih.gov/pmc/articles/PMC3864796/, https://doi.org/10.1038/nrn3476.

“Highest-Resolution View of “Face on Mars.”” NASA Jet Propulsion Laboratory (JPL), 24 May     2001, www.jpl.nasa.gov/images/pia03225-highest-resolution-view-of-face-on-mars/.   Accessed 8 Nov. 2024.

Holden, Katharine J., and Christopher C. French. “Alien Abduction Experiences: Some Clues from Neuropsychology and Neuropsychiatry.” Cognitive Neuropsychiatry, vol. 7, no. 3,     Aug. 2010, pp. 163–178, https://doi.org/10.1080/13546800244000058.

Hoogeveen, S, et al. “Prevalence, Patterns and Predictors of Paranormal Beliefs in the       Netherlands: A Several-Analysts Approach.” Royal Society Open Science, vol. 11, no. 9,     1 Sept. 2024, https://doi.org/10.1098/rsos.240049. Accessed 30 Oct. 2024.

Loxton, Daniel, and Donald R Prothero. Abominable Science! : Origins of the Yeti, Nessie, and Other Famous Cryptids. New York, Columbia University Press, 2015.

Pechey, Rachel, and Peter Halligan. “Prevalence and Correlates of Anomalous Experiences in a Large Non-Clinical Sample.” Psychology and Psychotherapy: Theory, Research and       Practice, vol. 85, no. 2, 16 June 2011, pp. 150–162, https://doi.org/10.1111/j.2044-         8341.2011.02024.x.

Riekki, Tapani, et al. “Paranormal and Religious Believers Are More Prone to Illusory Face   Perception than Skeptics and Non-Believers.” Applied Cognitive Psychology, vol. 27, no.       2, 2 Oct. 2012, pp. 150–155, https://doi.org/10.1002/acp.2874.

Sharpless, Brian A., and Jacques P. Barber. “Lifetime Prevalence Rates of Sleep Paralysis: A Systematic Review.” Sleep Medicine Reviews, vol. 15, no. 5, Oct. 2011, pp. 311–315,         www.ncbi.nlm.nih.gov/pmc/articles/PMC3156892/,             https://doi.org/10.1016/j.smrv.2011.01.007.