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Is Smiling Contagious?

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Areas of Science
Time Required
Average (6-10 days)
Material Availability
Readily available
Very Low (under $20)
Adult supervision is recommended when collecting your data.
*Note: For this science project you will need to develop your own experimental procedure. Use the information in the summary tab as a starting place. If you would like to discuss your ideas or need help troubleshooting, use the Ask An Expert forum. Our Experts won't do the work for you, but they will make suggestions and offer guidance if you come to them with specific questions.

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You've probably observed from your own personal experiences that some actions are contagious. Yawning is a great example. When one person in a room yawns, several other people usually do, too. Coughing, clearing your throat, these are other actions that often seem contagious. But what about smiling? Have you ever walked down the street and had a random stranger smile at you? Did it make you happy? Did you smile back? In this science fair project, you'll investigate whether smiling is contagious. You'll need to think of a way to design your experiment. One option would be to take a walk around a park and keep track of how many people smile at you, and whether those numbers change based on whether you smile at them or not. Or maybe you want to see if smiling has a chain reaction by having a friend walk a little ways behind you and see if the number of smiles he or she receives changes depending on whether you smile at the passersby first. However you design your experiment, make sure you're observing many people so that you can draw accurate conclusions. The Science Buddies guide Sample Size: How Many Survey Participants Do I Need? will help you determine how many observations you need to make. So put on a smile, because science is fun!
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If you like this project, you might enjoy exploring these related careers:

Career Profile
Why people take certain actions can often feel like a mystery. Psychologists help solve these mysteries by investigating the physical, cognitive, emotional, or social aspects of human behavior and the human mind. Some psychologists also apply these findings in order to design better products or to help people change their behaviors. Read more

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General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "Is Smiling Contagious?" Science Buddies, 20 Nov. 2020, https://www.sciencebuddies.org/science-fair-projects/project-ideas/HumBeh_p042/human-behavior/is-smiling-contagious. Accessed 24 Feb. 2024.

APA Style

Science Buddies Staff. (2020, November 20). Is Smiling Contagious? Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/HumBeh_p042/human-behavior/is-smiling-contagious

Last edit date: 2020-11-20
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