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Sushi and yoga are also victims of this troubling phenomenon.

In the last five years, Americans have opened up a necessary dialogue into the many ways we appropriate other cultures for our own benefit. When Miley Cyrus twerked at the 2013 VMAs, she performed a dance style that originated in Africa and came to maturity in New Orleans’ bounce music dance scene—with no acknowledgment of its history or best-known practitioners (hint: not Miley).

At the MTV Movie Awards that same year, Selena Gomez donned a bindi while failing to acknowledge its religious significance.

The performances launched a firestorm of controversy over when, exactly, cultural influence crosses a line and becomes exploitation. What devil’s advocates frequently fail to recognize is that there is a distinct difference between appropriation and influence: Namely, that it is possible to be inspired by a culture without diminishing or erasing the group of people that originated it.

Appropriation is not the only way cultures spread?—?anthropologists believe that in some cases, customs can become looped. In these instances, one nation’s tradition finds appreciation in another country before being re-imported back into its country of origin. Back in 1970, Agehananda Bharati, a Hindu monk and anthropology professor at Syracuse University, gave this cycle a name. He called the process “the pizza effect.” To understand it fully, we first need to revisit the history of pizza.

Pizza: a slice of history

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The first piece of pizza was likely consumed in the late 1700s in Naples, Italy, but it wasn’t pizza as we know it today. At the time, Naples was a poor, overpopulated waterfront city and many of the residents lived far below the poverty line. To accommodate their small budgets and busy schedules, street vendors sold slices of flatbread topped with tomatoes, cheese, garlic and oil.

In the early 1900s, immigrants began flooding the United States, in search of better opportunities in the form of factory jobs. And as cultures began to co-mingle, Neapolitan pizza caught on in a big way. In 1905, Lombardi’s?—?the first licensed pizzeria?—?opened for business in New York City. From there, pizza took over the country; the conclusion of World War II led to pizza’s global domination.

When Italian-Americans traveled back to visit their family and friends in Italy, they brought with them the Americanized form of pizza. Pizza?—?which in Italy had always been looked down on as a low-class, working-man’s food?—?was suddenly embraced as it had never been before. Italians loved the Americanized version of pizza, elevating it to be served alongside authentic Italian cuisine.

The pizza effect strikes again

Pizza is the default culinary example of the pizza effect, but the phenomenon has affected other foods as well. Chicken tikka masala was allegedly invented in the United Kingdom by?—?depending whom you ask?—?Pakistani, Bangladeshi or Indian chefs. Despite being inspired by Indian cuisine, the dish is native to the UK and was never an authentically Indian food?—?which comes as a bit of a shock to the tourists who attempt to order it while visiting India.

Sushi is another such example: The California roll was invented in the States, but is so in-demand amongst American tourists that you can now order the dish in Japan (albeit under a different name).

The pizza effect isn’t restricted to food?—?Indians have lauded the meditative and spiritual benefits of yoga for thousands of years, but it wasn’t until yoga became a popular form of exercise in the 1980s that it received global recognition.

All forms of culture are subject to the pizza effect, from religion to philosophy to music. And the world is a brighter, more textured place when cultures riff off each other. The problem emerges when cultural influence becomes cultural appropriation?—?after all, if you invented pizza, wouldn’t you want a little credit for it?