A lot of the research in this area has looked at what makes people share, since it's assumed something goes viral because it's shareable. But exactly what motivates a person to tell others about a video?
Viral videos have four things in common that inspire us to share and drive up those YouTube views.
YOU ARE WHAT YOU SHARE
The first is self-intensification. This is an instinctive tendency people have to build and maintain their self-esteem.
One way we build self-esteem is by earning respect from others. Information that has value to others is shareable because it reflects well on the sender, since people signal gratification and "like" the person who shared it. Movies that have gone viral are almost always viewed as aiding self-intensification.
Self-intensification can be earned in several ways. One way is by legitimising membership of a social group, such as when a goth shares a particularly goth-looking shirt.
Another way is by sharing something you think is important about your character, such as a surfer sharing information about ocean pollution. But perhaps the most common form of self-intensification is sharing information that's judged to be practically useful to others.
Life-hacks that solve an everyday problem are one example of this category, such as how to successfully peel a bucketful of potatoes in the shortest period of time. When people pass useful and relevant information on, they earn respect, which makes the sharer feel good about themselves.
The second aspect of a viral video is the way it sparks emotions. When people experience strong emotions the mind naturally attempts to make sense of what happened. This motivates their desire to relive the experience by telling others.
In the same way, the more emotion a video packs in, the more likely it'll be shared. For a video to motivate people to share, the emotions need to be intense.
One way to do this is to shift people rapidly from a negative emotion to a positive one, or vice versa. The not-for-profit organisation Save the Children produced the viral advertisement Most Shocking Second a Day using this technique.
The video has had more than 52 million views. It features a series of one second scenes of memorable moments in a young girl's life. She has a flat screen TV, music lessons, and an abundance of food choices. The emotions are playful, happy, and joyful.
About 20 seconds into the ad, the scenes begin to flash a change in mood as it becomes clear the country the girl lives in is on the verge of war. The scenes switch from times of happiness to times of terror and sadness as the conflict reaches her neighbourhood.
The fighting forces the girl and her family to flee. After time spent on the run, struggling to find food and escape the chaos, she eventually winds up in a makeshift hospital. The scenes are heart-wrenching and full of sadness. The movie shifts emotions from positive to negative, in under two minutes.
INTENSELY RELEVANT TO YOU
The third quality is affinity – best described as intense relevance. It manifests as a feeling of warmth, respect, and deep appreciation for an activity, idea, or object. Think about a time you heard a song that you used to like but haven't heard in a long while. That feeling is affinity.
Sometimes, affinity is evoked by the hobbies people are intensely interested in. For example, car club members are often so passionate that they might name their car, talk to their car, and even look forward to seeing it again after a period away.
Affinity is not easy to create though, when so many people have such diverse interests. So one technique that is often used is to activate certain memories, since some features of a person's life are commonly shared.
The World's Toughest Job video successfully activates memories to create affinity. It has over 25 million views. The video features a prank, where a fictional company interviews potential employees for the position of Director of Operations.
When describing the requirements of the job, the interviewer tells the candidates that they must be willing to stand up most of the day, and be on call 24 hours. The candidates are perturbed, but remain interested and continue to present themselves in the best light.
The interviewer then tells them that they should expect no scheduled breaks, and be prepared to work extra hard on public holidays including Christmas. The candidates start to look worried, but persevere. Finally, the interviewer tells the candidates that they must be willing to do the job for free.
By this stage of the interview the candidates are shocked, telling the interviewer the job sounds cruel, inhumane, unfair, and potentially illegal.
The video concludes with the interviewer letting them in on the prank. He explains that there are already many billions of people throughout the world who are doing the exact job – mothers. Most people have strong memories of their mother, and these memories have special meaning, creating the feeling of affinity.
GET YOUR HEART RACING
The fourth mechanism is frisson, which is a biological response to media, in this case information. It manifests as an increase in heart-rate, the release of endorphins and adrenalin, and in some cases a feeling of chills running up the spine. Why frisson makes people share is not fully understood, but interestingly it activates primitive parts of the brain usually associated with survival (eating, sleeping, and procreating).
Frisson can be activated using music, but is also created using certain moods, such as awe and thrills. In viral advertising, attempts to make something thrilling are common. Red Bull and Go Pro are two brands that frequently use thrills in extreme sports advertisements.
One of the more effective examples is the GoPro Backflip Over 72ft Canyon video. The super-viral clip features point-of-view footage of freeride mountain biker Kelly McGarry riding his bike across a narrow rocky ridge.
At the end he pulls a harrowing backflip. Shot from a point-of-view perspective, the ride is truly thrilling, giving the viewer a sense of what it feels like to be there.
The facial expression observed when a person watches something thrilling is the same one observed when we are faced with a fight or flight survival encounter.
The jaw drops (to enable more oxygen in to feed the muscles), the eyes open wider to enable faster reactions, and the face may even become pale as blood is transferred to the muscles in preparation for energy expenditure.
Viral movies don't have to contain all four elements. Popular life-hack movies such as how to peel 20 potatoes in two minutes aren't high on emotion and don't get our heart racing.
But in video ads that have gone viral, affinity and self-intensification are almost always present.