When we say a meme goes “viral,” we don’t mean it’s making people sick. Instead, we’re talking about how quickly and widely it spreads, similar to how a virus spreads. Hi, I’m Cameron, and this is MinuteEarth.
When someone catches a contagious germ, they can pass it on to others. After a while, they stop spreading it, and the people they infected also stop passing it on. This creates a curve on a graph, like the one showing flu cases in Mexico in 2009. Memes, catchy songs, or viral videos spread in a similar way. Someone shares it, others catch on, and eventually, interest fades, leading to less sharing.
Because memes and infectious diseases spread in similar ways—usually a quick rise followed by a decline—we can use the same math to describe both. Two main factors determine how something spreads: how many people an infected person can reach each day and how quickly they stop being contagious. By multiplying these factors, we get the “basic reproduction number,” which tells us how contagious something is. If this number is greater than 1, it means more people are getting infected than recovering, suggesting a potential outbreak.
During the 2009 flu outbreak in Mexico, the basic reproduction number was between 1.5 and 3. In contrast, the Grumpy Cat meme had a reproduction number of 7.3, making it quite viral. Some memes spread even faster; the Overly Attached Girlfriend meme had a reproduction rate of around 11 in 2012, almost as contagious as measles, which has a reproduction number between 12 and 18.
Most diseases aren’t as contagious as super-viral memes. The reproduction number measures how fast something spreads, not how dangerous it is. Even COVID-19, despite its seriousness, has reproduction numbers between 2 and 5. Memes spread more easily because many people can see a meme online at once, unlike a virus that spreads through direct contact. Plus, we take steps to stop diseases from spreading, but we don’t do the same for memes.
While memes and viruses don’t spread in exactly the same way, understanding how they spread can help us prevent future pandemics. That’s why we’ve teamed up with scientists studying diseases to create videos on this topic. Researchers funded by the US Department of Agriculture are looking into how viruses jump between species, including humans, and how different COVID variants might spread among animals. Their work shows that differences among animal species—like their habitats and immune systems—affect whether a virus will continue to spread in animals and potentially jump to humans.
Design a meme that you think could go viral. Consider what makes memes catchy and relatable. Share your creation with the class and explain why you think it has the potential to spread widely.
Using graph paper or a digital tool, plot a graph showing the spread of a meme over time. Compare it to the spread of a disease, using the basic reproduction number. Discuss the similarities and differences in the patterns you observe.
Calculate the basic reproduction number for a hypothetical meme. Assume each person shares it with a certain number of people per day, and interest fades after a set number of days. Present your findings and discuss how changing variables affect the spread.
Participate in a role-playing game where you simulate the spread of a meme and a virus. Assign roles such as “meme creator,” “infected person,” and “public health official.” Discuss strategies for spreading or containing each.
Research a real-life example of a viral meme or disease. Present your findings to the class, focusing on how it spread and the factors that influenced its reproduction number. Highlight any measures taken to control its spread.
When we say a meme goes “viral,” we aren’t actually implying it’s making people sick. However, the math behind a meme’s spread suggests it’s a fitting analogy. Hi, I’m Cameron, and this is MinuteEarth.
When a person gets infected with a contagious germ, they start spreading it to others; after a certain amount of time, they stop infecting others, and the people they’ve infected also stop spreading it. This type of “viral” spread creates a curve, similar to the graph of reported cases of pandemic flu in Mexico in 2009. The same pattern occurs with a meme, or something meme-like, such as a catchy song or a video; someone gets “infected,” starts sharing it with others, and eventually, interest wanes, leading to a decline in sharing.
Because infectious diseases and memes follow such a similar pattern—typically a steep rise followed by a decline—we can use the same math to describe that pattern in either case or even to model whether something will “go viral” in the first place. The two main factors that determine the curve’s trajectory are how many people an infected person can reach per day and how quickly a person stops being contagious. By multiplying these two factors, we get what epidemiologists call the “basic reproduction number,” which estimates how contagious the infection is. If this number is greater than 1, then the number of new cases is higher than the number of recoveries, indicating potential for an outbreak.
For example, during the 2009 outbreak of pandemic flu in Mexico, the basic reproduction number was estimated to be between 1.5 and 3. In comparison, the Grumpy Cat meme had an estimated reproduction number of 7.3, indicating it was quite viral. Some memes are even more contagious; for instance, the Overly Attached Girlfriend meme likely had a basic reproduction rate of around 11 in 2012, which is only slightly less than measles, one of the most contagious viruses, with a reproduction number between 12 and 18.
Most diseases, however, aren’t as infectious as super-viral memes. It’s important to note that the reproduction number measures how quickly a virus spreads, not necessarily how deadly it is. Even COVID-19, despite its severity, has reproduction numbers between 2 and 5. One reason memes might spread more effectively than viruses is that many people can be exposed to a single instance of a meme shared online, compared to the limited exposure from a person with a contagious disease. Additionally, we often take measures to prevent the spread of diseases, which lowers their reproduction numbers, while we don’t implement similar precautions for memes.
While the spread of a meme is not identical to the spread of a virus, understanding the dynamics of viral spread can help us prevent future pandemics. This is why we’ve collaborated with a group of scientists studying diseases to create a series of videos on the topic, including this one! Researchers from various institutions, funded by the US Department of Agriculture, are studying how viruses jump between species, including humans, and how different COVID variants may spread among various animal species. Their research highlights that the differences among animal species—such as their habitats, immune system strengths, and interactions with other animals—significantly impact whether a particular variant will persist in animals and spill over into humans.
Memes – In biology, a meme is an idea, behavior, or style that spreads from person to person within a culture. – The concept of natural selection can be considered a meme that has spread widely in the scientific community.
Viral – In biology, viral refers to something related to or caused by a virus. – The viral infection spread rapidly through the population, affecting many individuals.
Spread – In mathematics, spread can refer to the distribution of data points in a graph or chart. – The spread of the data points on the graph showed a clear trend over time.
Reproduction – In biology, reproduction is the process by which organisms produce offspring. – The reproduction of cells is essential for growth and repair in living organisms.
Contagious – In biology, contagious describes a disease that can be transmitted from one individual to another. – The flu is a contagious disease that can easily spread in crowded places.
Diseases – In biology, diseases are disorders or malfunctions in living organisms that can affect normal functioning. – Scientists study diseases to understand their causes and develop treatments.
Graph – In mathematics, a graph is a diagram that represents data, showing the relationship between different variables. – The graph displayed the increase in temperature over the past decade.
Factors – In mathematics, factors are numbers that divide another number exactly without leaving a remainder. – The factors of 12 are 1, 2, 3, 4, 6, and 12.
Outbreaks – In biology, outbreaks refer to the sudden occurrence of a disease in a specific area. – Health officials worked quickly to contain the outbreaks of the disease in the region.
Animals – In biology, animals are multicellular organisms that can move and consume organic material for energy. – Animals play a crucial role in ecosystems by maintaining balance and supporting biodiversity.
