Small Wars Journal

Hostile Information Operations and Mass Hysteria

Share this Post

Hostile Information Operations and Mass Hysteria

Karl Umbrasas

Introduction

Mass hysteria may occur within cohesive groups that share information.  The nature of twenty-first century media, coupled with frank information manipulation, may create conditions favorable for mass hysterical reactions.  The strategic aims of this information operation go beyond the fanciful symptoms often seen in mass hysteria and instead capitalize on the fixed false belief that motivates behavior in this state.  The source of anxiety manipulated to induce mass hysteria is social, cultural, and political issues, which have pre-existing high levels of emotional valence.  A goal of mass hysteria is to create societal disequilibrium, which creates conditions favorable to revolution.

Russian Information Operations

Twenty-first century technology provides an effective means of delivering information warfare.  Media of various forms inundates society.  Media saturation is particularly prominent in the West, where higher standards of living and a greater orientation towards information has given way to creative methods of staying informed and staying connected.  Social media provides instantaneous information flows and connection to others, which allows news outlets and people to have instant access to millions of individuals.  In addition to the access being instant, it is also continuous.  People are constantly flooded with headlines, tabloids, and gossip.  The open nature of Western society places a premium on non-censorship, so the filtering of information is minimal.  It is therefore not uncommon to have opinion presented as authentic news or to read poorly substantiated news claims that are nonetheless presented as credible.  The constant information saturation and lack of filtering makes Western society highly vulnerable to information tailored for certain effects.  This permissive environment is further exploited by hacking, leaks, bots, trolls, directed advertising, and downright falsities to manipulate perceptions.[1]

Russia is accused of increased information operations across the West.  Information operations are a common part of the Russian armamentarium and have been for generations.  Russian information warfare attracted renewed attention, however, with its role in the Gerasimov doctrine, which focuses on non-conventional modes of hostility to achieve military and political objectives.  Weakened social cohesion and weakened political systems are two commonly sought-after effects with this approach.[2]  These effects are important because they disrupt societal equilibrium, which is a prerequisite for fomenting revolution.  Russia weakened social cohesion in Ukraine during its assault on the country’s east during the 2014 Ukrainian revolution by, among other things, coopting social media and tapping into sociocultural vulnerabilities.[3]  This allowed Russia to subvert a portion of Ukrainian society for its military-political objectives.

The Russian information attacks in the United States are also aimed at shaping perceptions as a means to larger effects.  One way this is accomplished is by controlling social media trends to delegitimize American institutions.[4]  Project Latkha, for example, sought to manipulate Americans’ attitudes towards the election process, in addition to its frank election meddling.[5]  Delegitimizing the electoral process is a way of undermining societal equilibrium, which is to desynchronize it, to foment a cancerous attack of the nation from within.  Longstanding social relationships between groups are invalidated in a desynchronized society, the type of society that has pervasive doubt about its institutions and social contracts.[6] 

In the United States, many divergent interest groups are held together by shared American values and supported by American institutions.  Fundamental American values are embodied in legal canons, such as Due Process and Equal Protection, which are then reflected in the privileges and institutions particular to American society.  Undermining American values and institutions may bring about larger effects in the US that override American society’s robust tension management ability.

Societies that do not have effective tension management capabilities can be overcome by social instability.  Again, this is exemplified in Ukraine, where the sociopolitical order was undermined by using information operations, which set the stage for a severe fracturing of society.  The weaponization of information was evident in Russia’s reference to parts of southeastern Ukraine as Novorussiya, which attacked the integrity of the state by inflaming division.[7]  Russia employed other tactics, such as non-attributed comments on websites, fake hashtag campaigns, and troll and bot social media accounts to further manipulate perception.[8]

Russia actively promulgates fake news stories as part of its methodology.  The Russian fake-news disinformation campaign is likely to be more difficult to discern from reality as deep fake technology is used to create audio and visual falsities that are applied to shape perception.[9]  Russia’s pattern of attack on the West, particularly the US, raises questions about its motivations.  Does Russia perceive greater opportunity to dis-equilibrate Western societies in the twenty-first century?

The sustained general, but also targeted, exposure to socio-politically charged issues, some of which are manipulated to inflame sensibilities, finds natural affinity in those who share similar beliefs and natural aversion in those who disagree with those beliefs.  Indeed, political beliefs color how individuals perceive events, and concomitant political partisanship motivates behavior.[10]  Political behavior is likely activated by the continuous exposure to partisan information, which at this time is unprecedented in history.  Americans, for example, consume approximately fifteen hours of media per day.[11]  The cumulative effects of false or emotionally charged information, particularly at the current rate of information saturation, is not known.  However, Americans’ exposure to unfiltered information and a predisposition to accept politically charged claims remains an opportunistic target for enemies of the United States who seek to create turmoil within the homeland.

Since human cognition is the terrain upon which this unprecedented Russian information operation takes place, it is important to understand the impact this can have on the mind, and, by extension, behavior.  This paper examines a possible psychological effect associated with the contemporary information operations against the West, particularly the United States.  It is hypothesized that information operations are designed to affect the mind and behavior through saturation of emotionally arousing information.  The emotionally arousing information taps into pre-existing social, cultural, and political issues that possess particular emotional valences.  One possible outcome of this form of information saturation is hysterical reactions.

Strategic Implications for Russian Information Operations

Information operations against the US is a logical choice for Russia.  A force-on-force competition between the two countries is untenable because of the role of nuclear weapons.[12]  Russian information operations that attack the American societal equilibrium is a non-kinetic but highly pernicious alternative.  This form of attack is nonetheless a difficult task considering that American society remains in a dynamic flux with social change often incorporated into the societal mainstream.  Information saturation in the twenty-first century, however, enhanced by manipulation of the information, may yield strategic effects not attainable until now.

Sustained information saturation, targeted to individuals based on sociopolitical characteristics, may create conditions favorable to mass hysteria.  There are numerous documented cases throughout history of people in cohesive groups who shared some form of debilitating symptom through transfer of information.[13]  In 1944, for example, ninety-three people in a small town fell victim to hysterical symptoms after a report that a neighborhood prowler sprayed a gaseous substance on an individual in her home at night that caused paralysis in her leg.[14]  Those displaying symptoms reported a range of problems from coughing to paralysis.  Perhaps more important than the symptoms, however, is the actual belief that some phantom intruder existed who caused atypical symptoms throughout the town.  Equally important is that the hysterical belief resulted in a substantial community response, including citizens arming themselves and lying in wait for the purported intruder, while the police employed a concerted effort to catch the alleged perpetrator.  The hysterical suggestion was propagated in this case by direct contact with a victim but also by indirect conversation within the community and reading the evening newspaper.

People are quite vulnerable to social contagion.  One experiment showed that mass hysterical symptoms can be induced purposefully in susceptible groups through the social contagion associated with an “affected” index case.  This experiment suggested that the psychogenic symptoms induced in others were not merely reflections of the index case’s symptoms, however, as each new case’s symptoms changed in complexity from the index case.[15]  As such, an index case may affect another person, whose symptoms are then prone to take their own course.  These groups exhibited physical signs and psychological symptoms of illness despite no evidence for a physical cause of their affliction.[16]

Hypothesizes about the origins of mass hysteria suggest it is associated with longstanding anxiety related to culturally relevant issues that lead to increasing suggestibility and the loosening of normally integrated functions of consciousness, such as identity and perception.[17]  People who cannot discern the true nature of their anxiety or persistently avoid it may also be susceptible to mass hysteria.[18]  Though actual events tend to precipitate mass hysteria, rumors are sufficient to create it.[19]  Dominant sociocultural concerns pervade the content of mass hysteria.[20]  Scholars suggest that threats related to Weapons of Mass Destruction (WMD) has posed a risk for mass hysteria in the American psyche since the end of World War I (WWI), but environmental hazards also predispose people to mass hysterical symptoms in the US.[21]  On the whole, people with a disposition to believe something, whether it is rational or not, may actually begin to believe it in an emotionally laden information milieu.

Hysterical symptoms proliferate within cohesive groups, so they have historically manifested in schools, social groups, and workplaces.[22]  Susceptible people in close proximity to index cases accelerate the proliferation of mass hysteria.[23]  Some symptoms reported in mass hysteria include pervasive anxiety, hyperventilation, chest pain, shared perception, and motor tics.[24]

However, mass hysteria is not merely an anxiety or hyperarousal response.  Anxiety and arousal may indeed be within normal limits among afflicted groups, but the perception shared by those afflicted is still significantly distorted.[25]  This tendency for people to share a fixed false perception based on information exchange appears most important because it is the shared misperception that motivates behavior.  Scores of people shared a fixed, yet highly distorted belief, in seventeenth century Salem communities that resulted in twenty executions and a number of other victims who conformed to the stereotype of what was believed to be witchcraft.[26]

The nature of communication in twenty-first century American society may create a vulnerability to direct or indirect induction of mass hysterical beliefs, which were historically infrequent in less information-rich environments.  A counterintuitive aspect of contemporary media is that, despite its pervasive presence, it can be compartmentalized so that people receive certain information, such as the news or gossip they prefer.  This may be enhanced with actual manipulation of the information domain by trolls and bots and reinforced by communication with likeminded individuals.  Political blog readers provide a prime example of information compartmentalization.  Political blog readers tend to only read blogs that support their political beliefs, and across the aggregate, hold more extreme political beliefs and have higher political participation rates when compared to non-blog readers.[27]  A preference for political information such as this could be enhanced purposefully or through the natural dissemination of information to further determine the political blog reader’s reality.  The outcome of this type of information dissemination is that people may exist on virtual islands of information disconnected from other viewpoints.  This may, in effect, create the conditions found on the island of Tristan da Cunha in the 1930’s or Matoon, Illinois, circa 1944.

If the aim of a hostile nation is to manipulate information to bring about societal discord, then the human ability to form alternate realities when in the throes of hysterical contagion may suit their agenda.  Though people affected by mass hysteria display fanciful symptoms, this is less important than the seriously distorted nature of their perception.  Hysterical people, en masse, believe things that do not conform to clear patterns of fact or to physical reality.  People believe they are sick when no pathogen exists, and they are often convinced some source caused their illness, whether human or environmental, when it did not.

A hostile information operation would likely benefit from exploiting peoples’ tendency towards hysterical beliefs.  Exposure to sustained information related to inflammatory sociopolitical issues can tap into a wellspring of anxiety about these matters.  This anxiety can be made worse with fake and manipulated information, or information that is targeted so that people receive only provocative information.  The net effect of this information operation may be actual belief, in those susceptible, that certain social, cultural, or political issues are in jeopardy.  This may generate increased emotion and corresponding motivation to remedy the perceived source of concern.

Based on this, people may embrace persecutions that conform to their fears and anger, which result in the violation of peoples’ rights and the exacerbation of sociopolitical tensions.  Persecutions in the extreme would likely be more overt and brazen in their harm, but a subtle persecution mentality is also damaging as it may foster discriminatory behavior that can be expressed individually or institutionally to harm one’s perceived opponent.  In this manner, people who hold certain political or cultural beliefs, or who have certain ethnic or cultural backgrounds, are targeted for mistreatment based on reinforced distorted beliefs.  This hostile action works against the stability in the US because it attacks the values and social contracts expected in American society.  Victims of hysterical persecutions may experience an arbitrariness to their accusations that offends notions of Due Process or other American values.

At the least, sociocultural hysteria can enhance divisions by pushing like-minded people together through animus.  The compartmentalizing of US society along fault-line issues works as a shaping objective for adversaries.  Once various groups are firmly in their respective corners, it is easier to exploit the partisanship that can be inflamed, which can have greater effects depending on the issue and its support.

Mass hysterical behavior is filled with so much uncertainty because it is an irrational expression grounded in anxiety.  Hysteria invites the chaos, uncertainty, friction, and change associated with fog of war that can be exploited by an adversary.[28]  The uncertainty plus chaos in hysterical states also has potential to yield a range of synergistic effects.  For example, it is uncertain how political leaders would respond to the influences of hysterical constituents, or how unaffected social milieus would respond to hysterical clarion calls.  Furthermore, how do those who essentially live in an alternate information reality interact with a society that does not conform to their perception of reality?

Though hysterical effects can be an unintended side effect of the rate, quality, and quantity of twenty-first century information-interface, some evidence suggests that Russia specifically wants to tap into hysterical anxiety.  It is known that the American psyche has a latent fear of WMD.  This fear is being stoked by Russia, which has been open about its nuclear arsenal.  Russia has portrayed its missiles as able to maneuver around traditional missile defenses and it has boasted about a water-borne nuclear delivery system.  Russia also stoked cultural flames in the US during the 2016 Presidential election by circulating stories on social media that tapped into sociocultural sensitivities, such as stories that questioned social justice or that magnified welfare fraud.[29]  This suggests a purposeful effort to contact and even direct the emotions of the American population.

Preventing Attacks in the US

Russian effectiveness applying information operations across the West and particularly in the United States suggests that it will continue.  The United States must therefore be prepared to defend against ongoing information attacks.  An offensive response to hostile information operations should occur after any information attack.  Smaller and more aggressively contested Russian possessions, for example, would be more appropriate for an attack, such as Russian assets in Ukraine, rather than Russia-proper.  Strictly from a defense perspective, however, protection against hostile information operations that seek to manipulate American emotion and perception can be facilitated in a number of ways.  Early identification and public disclosure of the attack should be made to alert the public about the potential manipulation of perception through existing information channels.  The threat of information manipulation has been highlighted in the public domain since the 2016 election, which helps prepare the population.

Social, cultural, and political leaders must take a leading role in protecting their constituencies from manipulation.  This may entail clear delimitations of what is acceptable behavior within their communities.  In essence, this calls for a return to good sportsmanship.  Competition within the social, cultural, and political domains appear to have a pseudo-existential quality, where proponents of a position seek a “win” at all costs no matter how uncouth their methods or outcomes.  Leaders of various positions must reorient their communities to virtues, such as respect, which instills discipline and protects their zealousness from unwitting cooptation for nefarious purposes.

Defense against hostile information should also begin during the school years.  School curriculum that emphasizes the liberal arts helps develop the critical faculties needed to critique information.  Schooling in the liberal arts cultivates understanding and the pursuit of wisdom as opposed to merely receiving what purports to be fact.[30]  The deep and active thinking associated with subjects, such as history, philosophy, and the humanities, develops analytical faculties that could defeat attempts at manipulation.  Even if the rational faculties developed in the liberal arts is overborne by bias, lessons learned from the content of these disciplines works against manipulation by elucidating the perils associated with division and the rewards associated with social harmony.

Information as a Public Health Matter

As the information age continues to take shape, it is reasonable to consider information as having the potential to not only adversely affect security but also health, which in itself has security implications.  As noted above, information can be the medium through which bad actors conduct hostile actions against the US.  Aside from bad actors, however, the level of twenty-first century information saturation may have unintended health consequences.  Not only can hysterical beliefs be induced by information saturation but a range of other cognitive and emotional effects, such as panic, sadness, and even suicidal thinking, are possible.

If information can carry security and health consequences, it is reasonable to provide some public protection against harmful consequences of information.  This, however, does not mean that regulation of information is needed; rather, the answer is more information.  Just as every item of food and drink carries a label with nutrition facts, information can be made safer with facts about the veracity of its contents.  In this way, the information rating on a blog carries much less weight than the information rating of a news organization.  Even news organizations, however, may be subject to varying ratings depending on their reporting.  News organizations tend to be major for-profit industries, so the quality of their information dissemination varies depending on their business model.  Explicitly identifying information-credibility based on a rating scheme may help differentiate the type of information being received.  Though critical thinking seems like an automatic activity, it often is not, and it is further blinded by individual motives that may or may not be recognized.

What About Habituation?

Habituation describes a process whereby a response is gradually diminished with continuous exposure.[31]  Habituation is often present with anxiety in that continual exposure to an anxiety producing stimulus results in the gradual diminution of anxiety response.  An example of habituation to anxiety is seen in public speaking.  Public speaking often elicits anxiety that may increase up to the point where the person is actually speaking.  Once at the podium, however, the person may actually notice a decrease in anxiety shortly after beginning to speak.  The person’s anxiety is said to have habituated.  Based on this, a reasonable postulate is that hysterical reactions will not occur in an information saturated environment because the anxiety will just habituate.  That is, constant exposure to anxiety producing information will gradually lose strength and therefore not induce hysterical reactions.  This may not necessarily occur in an information-saturated environment, however.  Continuous information exposure is akin to rumination, which is self-perpetuating rather than habituating.  Rather than simply being exposed to an anxiety provoking stimulus, which gradually loses its strength, information saturation offers new twists in stories and renewed causes for alarm.  Habituation of a stimulus, therefore, does not occur.

Conclusion

Media saturation in the United States presents a significant vulnerability to hostile information operations.  This vulnerability can be used to manipulate emotions within the population and cause hysterical responses.  More important than any physical symptom associated with hysteria is hysteria’s shared false belief.  People who succumb to hysterical beliefs may behave irrationally or according to their false perception.  When tied to sociocultural or political issues, hysterical reactions can create or enhance divisions within the larger population.  The strategic goal of widespread emotional manipulation and hysteria is to create societal discord, which undermines the American societal equilibrium, and can be used to an adversary’s advantage.

The views expressed in this article are those of the author and do not reflect the official policy of the Department of the Army, Department of Defense, or U.S. Government.

End Notes

[1]Keir Giles, “Countering Russian Information Operations in the Age of Social Media.” Council on Foreign Relations.  Retrieved from https://www.cfr.org/report/countering-russian-information-operations-age-social-media

[2]Keir Giles

[3] Michael Kofman, Katya Migacheva, Brian Nichiporuk, Andrew Radin, Olesya Tkacheva, Jenny Oberholtzer, “Lessons from Russia’s Operations in Crimea and Eastern Ukraine.” Santa Monica, CA: RAND.

[4] Jarred Prier, “Commanding the Trend: Social Media as Information Warfare.” Strategic Studies Quarterly, vol 11, no 4 (2017).

[5] Julian Sanchez, “Russia wanted Trump to Win.  And it wanted to get Caught.”  CATO Institute.  Retrieved from https://www.cato.org/publications/commentary/russia-wanted-trump-win-it-wanted-get-caught

[6] Chalmers Johnson, “Revolutionary Change” (2nd Edition), Stanford, CA: Stanford University Press, 180.

[7] Margarita Jaitner, “Russian Information Warfare: Lessons Learned from Ukraine.” NATO Cyber Defense Center O Excellence, 2015.

[8] Todd Helmus, “Russian Social Media Influence: Understanding Russian Propaganda in Eastern Europe.” (Santa Monica, CA: RAND, 2018), ix.

[9] Kyle Rempfer, “Ever heard of ‘deep fake’ technology? The phony audio and video tech could be used to blackmail US troops. Military Times, July 19, 2018.  Retrieved from https://www.militarytimes.com/news/your-air-force/2018/07/19/ever-heard-of-deep-fake-technology-the-phony-audio-and-video-tech-could-be-used-to-blackmail-us-troops/

[10] See Larry Bartels, “Beyond the Running Tally: Partisan Bias in Political Perceptions.” Political Behavior, Vol 24 no 2, 133; Alan Gerber, Gregory Huber, and Ebonya Washington, “Party Affiliation, Partisanship, and Political Beliefs: A Field Experiment.” American Political Science Review, Vol 104, no 4, 722.

[11]Jan Zverina, US Media Consumption to Rise to 15.5 Hours a Day—Per Person—by 2015.  UC San Diego, Retrieved from https://ucsdnews.ucsd.edu/pressrelease/u.s._media_consumption_to_rise_to_15.5_hours_a_day_per_person_by_2015

[12]Hannah Arendt, “On Violence” (New York: Harcourt, 1970), 3.

[13]See Small and Borus; Haque; Cohen; Sittert; Johnson

[14] Johnson

[15] Broderick et al

[16]Bartholomew and Wessely;

[17]Bartholomew and Wessely

[18] Wessely

[19] Balaratnasingam and Janca

[20] Balaratnasingam and Janca

[21] See Bartholomew and Wessely; Balaratnasingam and Janca;

[22] Broderick et al

[23] Small and Borus

[24] Wessely

[25] Broderick et al

[26] Latner 2008

[27] Lawrence, Eric, John Sides, and Henry Farrell. "Self-segregation or deliberation? Blog readership, participation, and polarization in American politics." Perspectives on Politics 8, no. 1 (2010): 141-157.

[28]Sean Elward, “The Fog of War: A Necessary Component of Modern Warfare.” Unpublished Paper, Naval War College, Newport, Rhode Island.

[29]Nicholas Confessore and Daisuke Wakabayashi, “How Russia Harvested American Rage to Reshape US Politics.”  New York Times, Retrieved from https://www.nytimes.com/2017/10/09/technology/russia-election-facebook-ads-rage.html

[30]Mortimer Adler, “The Great Conversation.” (New York: Encyclopedia Britannica, 2006), 24.

[31]John Cooper, Timothy Heron, and William Heward, “Applied Behavior Analysis” Second Edition (Upper Saddle River, NJ: 2007), 30

 

About the Author(s)

Dr. Karl Umbrasas, Psy.D., is a clinical psychologist and forensic psychology fellow on active duty in the Army.  In addition to psychology, Karl has studied intelligence, counterterrorism studies, and criminology.  Karl has written on topics related to social movements and national security.

Comments

Bill C.

Fri, 11/09/2018 - 12:40pm

Russian information operations today, much like U.S./Western information operations during the Old Cold War; these would both appear to be/to have been organized, ordered and employed to achieve a certain, common, strategic goal.

This such common goal being, in both such cases, to (a) prevent an "expansionist" great power from (b) successfully prosecuting a "world revolution;" this, (c) more along the "expansionist" great power's own political, economic, social and value lines.

Thus, while:

a.  The U.S./the West of late (much like the Soviets/the communists in the recent past)  has been pursuing -- throughout the world -- an expansionist "revolutionary warfare" grand strategy.

From "Mao's Tse-tung on Guerrilla Warfare:"  

"Conventional war rarely challenges the political system; even "unconventional" partisan war usually seeks the preservation of that system or restoration of the status quo ante--revolutionary war aims at the liquidation of the existing power structure and at a transformation in the structure of society."

https://www.marines.mil/Portals/59/Publications/FMFRP%2012-18%20%20Mao%20Tse-tung%20on%20Guerrilla%20Warfare.pdf  (See Page 7.)

b.  The Russians, et. al, of late (much like the U.S./the West did during the Old Cold War?) has been pursuing -- in response to same -- a defensive "containment" and/or "roll back" grand strategy.

From MG Linder's "The Battlefield Tomorrow Fought Today: Winning in the Human Domain:"

""Differing from the previous Tsarist regional empire and the Soviet globalist one, the new Russian foreign policy has a more pragmatic goal. It aims to build different types of buffer zones against NATO encroachment to the West and U.S. counter-terrorism efforts in Central Asia." 

http://smallwarsjournal.com/jrnl/art/the-battlefield-of-tomorrow-fought-today-winning-in-the-human-domain

With regard to the Russians (et. al's) such current defensive (and, in truth, "anti-revolutionary warfare"?) grand strategy (see "containment" and "roll back" above), does not the undermining of the social cohesiveness of one's "expansionist" opponent -- does this not make perfect sense?  

Why?  Because it can cause (or should cause?) the "expansionist" great power to:

a.  Abandon its "world revolution" grand strategy and to focus its attention, instead, on

b.  Achieving (re-achieving?) internal stability?

(Thus, "containment" achieved?)

kumbrasas

Fri, 11/09/2018 - 9:50am

Fuller references for the identified endnotes:

13. Gary Small and Jonathan Borus, “Outbreak of Illness in a School Chorus: Toxic Poisoning or Mass Hysteria?” The New England Journal of Medicine, Vol 308, no 11 (1983); Farhana Haque, “Outbreak of Mass Sociogenic Illness in a School Feeding Program in Northwest Bangladesh, 2010” PLOS ONE, Vol 8 no 11 (2013); Patricia Cohen, “Current Affairs and the Public Psyche: American Anxiety in the post-9/11 World” Social Psychiatry and Psychiatric Epidemiology, Vol 41, (2006); Lance van Sittert, “Fighting Spells: The Politics of Hysteria and the Hysteria of Politics on Tristan da Cunha, 1937-1938” Journal of Social History, Vol 49 no 1 (2015); Donald Johnson, “The ‘Phantom Anesthetist’ of Mattoon: A Field Study of Mass Hysteria” The Journal of Abnormal and Social Psychology, Vol 40 no 2 (1945).

15. Joan Broderick, Evonne Kaplan-Liss, and Elizabeth Bass, “Experimental Induction of Psychogenic Illness in the Context of a Medical Event and Media Exposure” American Journal of Disaster Medicine, Vol 6 no 3 (2011).

16. Robert Bartholomew and Simon Wessely, “Protean Nature of Mass Sociogenic Illness: From Possessed Nuns to Chemical and Biological Terrorism Fears” British Journal of Psychiatry, Vol 180, (2002)

19. Sivasankaran Balaratnasingam and Aleksandar Janca, “Mass Hysteria Revisited” Current Opinion in Psychiatry, Vol 19 (2006)

26. Richard Latner, “The Long and Short of Salem Witchcraft: Chronology and Collective Violence in 1692” Journal of Social History (2008).