Contagion Effect: Definition and Examples

contagion effect examples and definition, explained below

Contagion Effect refers to the phenomenon where an attitude, behavior, or emotion spreads from person to person within a group, much like a viral infection.

This concept is common in various disciplines, including psychology, sociology, and economics.

We can observe the contagion effect as a social phenomenon when individuals repeat or mimic actions that they witness within their social network. This copying can manifest in numerous ways, from adopting behavioral trends to mirroring emotional reactions.

Contagion Effect Examples

1. in Psychology

In psychology, the Contagion Effect refers to the tendency for particular behavior or emotional states to spread from individual to individual, much like a contagious virus (Herrando & Constantinides, 2021).

It’s a key component of Social Learning Theory, which suggests that we learn from observing and mimicking others around us. Outcomes can be positive, such as when optimism or perseverance spreads within a team, or negative, such as the proliferation of anxiety or panic within a group.

Examples include:

  • Emotional Contagion: Emotional contagion is when emotions spread reciprocally among individuals within a group. These emotions can range from joy to anxiety and may deeply influence group dynamics (Herrando & Constantinides, 2021). For instance, if a member of a work team is visibly upset (perhaps due to personal issues), it could negatively affect the overall mood of the team and lower productivity.
  • Psychological Contagion in Crowds: These happen during live events, such as concerts or sporting events, where the energy and emotion of those in the crowd can quickly spread to others, causing people to feel a sense of deindividuation. For instance, if a select few start cheering louder at a football game, it often leads others around them to engage similarly, resulting in a deafening roar throughout the entire stadium.
  • Informational Contagion: When a person spreads information or an idea, and it quickly disseminates among others, we call this informational contagion (Lerman & Ghosh, 2010). Consider the propagation of a popular fashion trend; it begins with fashion icons or influencers showcasing a certain style (say, wearing bucket hats), and their followers soon replicate this, leading to a sweeping fashion trend.
  • Health Behavior Contagion: This refers to the spread of health-related behaviors within a social network. An example is a rise in physical fitness activities among friends when one person begins a new workout routine or diet, subsequently inspiring others to make similar lifestyle changes.

2. in Sociology

In sociology, the Contagion Effect describes collective behavior where emotions, attitudes, or behaviors spread rapidly within a group or society (Das, 2004).

This cascade effect can be observed in various social contexts–from the spread of cultural norms or practices to the dissemination of ideas, innovations, or trends through globalized social networks or media platforms.

The Contagion Effect is instrumental in understanding cultural diffusion, mass hysteria, and even the widespread adoption of new technologies or practices.

Examples include:

  • Collective Behavior Contagion: This occurs when group (or collective) behaviors or emotions spread among individuals. Take the example of a protest; if a select few start shouting slogans or becoming disruptive, it can cause the broader group of protestors to follow suit—amplifying the intensity and possibly escalating the situation. This is related to the bandwagon effect.
  • Normative Contagion: This happens when social norms from one group spread to other groups or individuals. For instance, a community may adopt recycling as a social norm due to its influence on neighboring communities who’ve championed for environmental responsibility. This community then establishes recycling behavior as a requirement, integrating it into their everyday lives.
  • Social Media Contagion: The widespread use of social media enables rapid spread of ideas, trends, behaviors, causing what could be considered social media contagion (Hodas & Lerman, 2014; Vishwanath, 2015). For instance, when a dance trend such as the “Harlem Shake” or the “floss” goes viral on platforms like TikTok, people around the globe recreate these dances, demonstrating contagious behavior in the digital realm.
  • Cultural Contagion: Aspects of culture, such as language, rituals, or norms can rapidly spread within a group or across societies, revealing an example of cultural contagion (Morris, 2022). A clear illustration of this is the global adoption of Western fast-food chains like McDonald’s, with countries around the world adopting the fast-food culture, originally typical of American society (this phenomenon is called McDonaldization).

Case Study: Moral Panic
Moral panic serves as a compelling example of the contagion effect, particularly within the realm of sociology. It refers to a widespread fear that emerges in society over an issue perceived as threatening the social order. This fear is often exaggerated or unproportional to the actual threat posed. For example, consider the public uproar caused by the perceived phenomenon of “stranger danger” irrationally portraying every unfamiliar adult as a potential child abductor. The heightened emotions and anxiety rapidly spread within the society, inspiring people to take action, often misguidedly, against the apparent threat.

See Also: Social Contagion Theory

in Economics and Markets

The Contagion Effect in economics is the concept that economic events in one country or sector can rapidly spread to others, especially during periods of crisis or uncertainty.

It embodies the interconnectedness and interdependency of global markets and is often used to explain global financial crises.

For instance, if a major economic power experiences a recession or financial instability, investor confidence can plummet globally, leading to widespread economic downturns. It underscores the need for coordinated international fiscal and monetary policymaking.

  • Financial Market Contagion: It is often noticed that when a crisis hits a particular market, it tends to spread to other markets. For instance, in the 2008 financial crisis, the collapse of Lehman Brothers in the U.S triggered a massive sell-off in stock markets worldwide, demonstrating the contagion effect on a global economic scale (Bucci et al., 2019).
  • Currency Contagion: When a country devalues its currency, it may cause investors to fear that other countries may follow suit. A classic example is the 1997 Asian financial crisis when the devaluation of the Thai Baht provoked financial instability and currency devaluations in other Asian economies, including South Korea and Indonesia.
  • Interest Rate Contagion: Negative changes in interest rates in a major economy can spread to other economies. For example, suppose the U.S. Federal Reserve raises interest rates. In that case, it might lead to capital outflows from emerging markets as investors move their assets to benefit from higher rates in the United States, leading to potential economic instability in those countries.
  • Real Estate Contagion: Shocks in the housing market can influence other industries or economies. The housing bubble in the U.S during the mid-2000s serves as an example, where the surge and ensuing collapse in housing prices not only struck other sectors within the U.S. economy but also had serious implications for financial markets worldwide (Hui & Chan, 2012).

How the Contagion Effect Affects People and Societies

The contagion effect has a profound impact on decision-making processes, both positive and negative. However, it’s generally believed that awareness of this phenomenon can help us to resist falling into groupthink.

If you are aware of the contagion effect and its potential consequences, you can take steps to lessen its negative impact. For instance, realizing that fear can spread in financial markets, you may resist the urge to sell your stocks too quickly, potentially preventing a market crash.

However, the Contagion Effect is not inherently negative. Numerous positive behaviors and attitudes can spread within a group, leading to improved group dynamics and overall wellbeing. For example, a team member’s dedication and hard work may inspire others to increase their efforts, enhancing the team’s productivity and success.

Positive Effects (Pros)Negative Effects (Cons)
Economic interconnectivity: Economic contagion promotes global economic interconnectivity and integration, as it reflects how economies are tied together.Spread of economic crises: Economic contagion can cause economic downturns or crises to spread rapidly from one country to another, potentially leading to global economic crises (Hui & Chan, 2012).
Market correction: In some cases, contagion effects can lead to market corrections, where overvalued assets or economic bubbles are deflated.Financial instability: The contagion effect can undermine the stability of financial institutions and systems, particularly in countries with weaker economies or less robust financial systems (Bucci et al., 2019).
Potential for global cooperation: The risk of contagion effects may stimulate international cooperation, prompting countries to work together to avert economic crises.Risk of widespread panic: The contagion effect causes irrational panic which (economically) can cause devastation to financial markets, and (sociology) can cause people to discriminate and harm others.
Spread of good ideas: The mechanisms of the contagion effect allows good ideas to spread, such as when democracy spread around the world in the 18th and 19th Centuries.Cultural Damage: Global cultural diffusion occurs through the contagion effect, but also leads to the loss of local cultures and increased homogenization of culture.


In conclusion, the Contagion Effect is a potent social phenomenon that impacts many aspects of our lives, from our social interactions to our financial decisions. By being aware of this concept, we can better manage its effects and ensure it contributes towards productive and positive outcomes.


Bucci, A., La Torre, D., Liuzzi, D., & Marsiglio, S. (2019). Financial contagion and economic development: An epidemiological approach. Journal of Economic Behavior & Organization162, 211-228.

Das, D. K. (2004). Globalization: Introducing the Concept. In The Economic Dimensions of Globalization (pp. 1-37). London: Palgrave Macmillan UK.

Herrando, C., & Constantinides, E. (2021). Emotional contagion: a brief overview and future directions. Frontiers in psychology12, 2881. doi:

Hodas, N. O., & Lerman, K. (2014). The simple rules of social contagionScientific reports4(1), 4343. doi:

Hui, E. C., & Chan, K. K. K. (2012). Are the global real estate markets contagious?. International Journal of Strategic Property Management16(3), 219-235.

Lerman, K., & Ghosh, R. (2010, May). Information contagion: An empirical study of the spread of news on digg and twitter social networks. In Proceedings of the International AAAI Conference on Web and Social Media (Vol. 4, No. 1, pp. 90-97). doi:

Morris, R. L. (2022). Modeling cultural contagion using Social Impact Theory (Doctoral dissertation, Cardiff University).

Vishwanath, A. (2015). Diffusion of deception in social media: Social contagion effects and its antecedents. Information Systems Frontiers17, 1353-1367. doi:

Website | + posts

Dr. Chris Drew is the founder of the Helpful Professor. He holds a PhD in education and has published over 20 articles in scholarly journals. He is the former editor of the Journal of Learning Development in Higher Education. [Image Descriptor: Photo of Chris]

Leave a Comment

Your email address will not be published. Required fields are marked *