Understanding the Psychology of Rumours: Characteristics and Spread

In times of crisis, uncertainty, and rapid change, rumours emerge as powerful forces that can shape public perception, influence behaviour, and sometimes cause significant harm. Understanding what drives rumours-why they start, how they evolve, and why people believe and share them-is essential for anyone involved in disaster management or crisis communication. Rumours are not random; they follow predictable psychological patterns that can be studied, understood, and ultimately managed.

What is a rumour? 🔗

A rumour can be defined as an unverified piece of information circulating among people, typically without solid evidence to support it. Unlike verified news, rumours lack concrete authentication and emerge when formal information channels fail to satisfy the public’s demand for knowledge. They represent collective efforts to interpret unclear situations and provide meaning during uncertainty.

According to the foundational work of psychologists Gordon W. Allport and Leo Postman, a rumour is a specific proposition passed from person to person, usually by word of mouth, without secure standards of evidence being present. The critical element here is that rumours exist in the absence of reliable evidence but are nevertheless accepted by recipients as potentially true.

Key characteristics of rumours 🔗

Rumours possess several distinctive features that separate them from other forms of communication. First, they are typically grounded in partial truth-most rumours aren’t entirely fabricated but begin with a kernel of truth that becomes distorted through transmission. Second, they are evolutionary in nature, meaning details are added, removed, or altered as the rumour passes from person to person. Third, they are emotionally influenced-the emotional state of both sender and receiver significantly affects interpretation and transmission. Fourth, they lack formal verification yet persist by filling information gaps with speculation. Finally, in today’s digital age, rumours demonstrate rapid transmission, spreading exponentially faster than verified information.

The psychological mechanisms behind rumour spread 🔗

Understanding why rumours spread requires examining the psychological mechanisms that drive their creation and transmission. Two primary factors contribute to a rumour’s lifecycle: importance and ambiguity. This understanding is fundamental to both predicting rumour behaviour and developing effective countermeasures.

The Allport-Postman rumour formula 🔗

Allport and Postman formalized the relationship between these factors in their seminal 1947 work, The Psychology of Rumor. They proposed a mathematical formula that describes rumour dynamics:

R ≈ i × a

In this formula, R represents the reach, intensity, duration, and reliance on a rumour; i represents the importance of the rumour to the hearer if true; and a represents the level of ambiguity or uncertainty surrounding the rumour.

The relationship between importance and ambiguity is multiplicative, not additive. This means that if either factor approaches zero, the rumour diminishes. If people don’t care about the topic (low importance) or if clear, verified information is readily available (low ambiguity), rumour activity declines significantly. Conversely, when both factors are high-when information is critically important to people’s wellbeing and highly ambiguous-rumour activity reaches its peak.

Why disasters are breeding grounds for rumours 🔗

Disaster situations create perfect conditions for rumour propagation because they maximize both importance and ambiguity. People urgently need information about threats to their safety at precisely the time when communication systems may be compromised and situations are evolving rapidly. Official channels often cannot keep pace with the public’s demand for information, creating vacuums that rumours quickly fill.

How rumours transform: leveling, sharpening, and assimilation 🔗

As rumours spread, they undergo predictable transformations through three interrelated processes. Leveling involves the simplification of information, where complex or nuanced details are omitted for easier transmission. Research shows that about 70% of details in a message are typically lost in the first five to six mouth-to-mouth transmissions.

Sharpening refers to the selective emphasis of specific elements that resonate with the communicator or audience. Certain details become exaggerated or more intensely recalled because they fit the overall narrative or emotional tone. Assimilation involves distortion of information to fit pre-existing beliefs, prejudices, and stereotypes. Through these processes, rumours become more streamlined and impactful-but often less accurate-as they spread.

For instance, a complex announcement about temporary water supply interruptions might be leveled to “there’s no water” and sharpened to “authorities are hiding water shortages,” creating a more alarming and shareable rumour than the original information warranted.

Case study: the Karunanidhi health rumour 🔗

A compelling illustration of rumour dynamics in action occurred in September 2017, when false rumours about the death of DMK President M. Karunanidhi spread rapidly across India. Karunanidhi, a prominent political figure and five-time Chief Minister of Tamil Nadu, was 93 years old and had been experiencing health issues, making him a subject of public concern.

How the rumour began 🔗

The rumour allegedly started when a routine circular from the Director-General of Police directing all Tamil Nadu Special Police battalions to report to their respective headquarters was misinterpreted. This routine administrative action, combined with Karunanidhi’s known health vulnerabilities, triggered speculation that something serious had occurred. The ambiguity of the police circular-its timing coinciding with public anxiety about the leader’s health-created fertile ground for rumour formation.

Rapid spread and public impact 🔗

The rumours spread like wildfire across social media platforms. Online search volumes for news on Karunanidhi spiked dramatically, particularly in the hours after lunch on the day the rumour began circulating. The situation became so intense that senior party leaders, including DMK working president MK Stalin and former ministers, rushed to Karunanidhi’s residence to verify his condition.

The rumour’s impact extended beyond mere concern. Reports indicated that people began hoarding ration and milk, with some shops reportedly selling milk at inflated prices due to fears that all shops would close. Programmes were cancelled or postponed, and a general sense of panic gripped certain areas.

Countering the rumour 🔗

To counter the false information, party leaders took multiple steps. Karunanidhi’s daughter Kanimozhi publicly stated that her father was doing well. The DMK released photographs of party leaders meeting with Karunanidhi, providing visual evidence contradicting the death rumours. By reducing ambiguity through clear communication and visual proof, the party successfully diminished the rumour’s intensity.

Lessons from the case 🔗

This case demonstrates several critical aspects of rumour dynamics. First, it shows how the Allport-Postman formula works in practice-the combination of high importance (a beloved political figure’s health) and initial ambiguity (a misinterpreted police circular) created perfect conditions for rapid rumour propagation. Second, it reveals how modern communication technologies can accelerate rumour spread beyond what was possible in earlier eras. Third, it illustrates that definitive, visible proof (photographs and public statements) was ultimately more effective at dispelling the rumour than verbal denials alone.

Types of rumours in disaster contexts 🔗

During disasters, rumours typically fall into three categories. Dread rumours spread fears about worst-case scenarios, such as rumours about dam failures during floods or aftershocks during earthquakes. Wish rumours express desired outcomes, such as imminent rescue operations or quick restoration of services. Wedge-driving rumours attempt to divide communities by assigning blame or creating suspicion between groups.

Each type serves a different psychological function. Dread rumours help people prepare for potential threats. Wish rumours provide hope and emotional comfort. Wedge-driving rumours often emerge from pre-existing tensions and can be particularly damaging to community cohesion during recovery efforts.

Managing rumours effectively 🔗

Understanding rumour psychology provides practical tools for management. To reduce rumour spread, authorities must address both importance and ambiguity. While the importance of certain topics cannot be artificially reduced during genuine crises, ambiguity can be actively managed through clear, timely, and consistent communication.

Effective rumour management involves providing factual information as quickly as possible, addressing information gaps before rumours fill them, using multiple channels to ensure widespread reach, and presenting evidence rather than simply denying rumours. Simply denying a rumour without providing context may actually increase ambiguity and make matters worse.

Pre-crisis preparation is equally important. Organizations and communities that have established credibility before crises occur are better positioned to have their communications believed when emergencies happen. As Allport and Postman noted, when people distrust the news they receive, rumours race unchecked.

What do you think? Consider a time when you encountered or perhaps even shared a rumour during an uncertain situation. What made it seem believable at the time? How might understanding the importance-ambiguity formula help you evaluate information more critically during future crises?

References

1. https://en.wikipedia.org/wiki/Rumor
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC9244448/
3. https://www.crisisnavigator.com/Killing-Rumors-A-50-Year-Old-Mathematical-Formula-Is-Key-Tool-in-Managing.491.0.html
4. https://thedecisionlab.com/biases/leveling-and-sharpening
5. https://www.india.com/news/karunanidhis-death-rumors-news-about-his-deteriorating-health-are-false-daughter-kanimozhi-says-dmk-president-is-perfectly-fine-2499416/
6. https://newsable.asianetnews.com/tamil-nadu/stalin-rubishes-rumours-on-karunanidhis-health
7. https://zeenews.india.com/tamil-nadu/karunanidhi-is-well-rumours-of-death-are-completely-false-say-dmk-leaders-2045712.html
8. https://psychology.iresearchnet.com/social-psychology/group/rumors/