Cultural appropriation is never a good look. It happens when a person adopts part of the culture from a less-privileged group in ways that ignores or exploits the less-privileged group. It happens when a Kardashian gets credit for starting a "new" hair trend that's long been popular with women of colour. Or when a white pop star like Miley Cyrus borrows the fashion, slang, or dance moves from a specific corner of black culture to gain "edgy" credibility, and then easily discards it when she's ready to change her image again.

"Black women are often demonized, caricatured, and body-shamed for their hair, styles of clothing, and cultural production, like dance or vernacular," explains Dr. Akil Houston a cultural and media studies scholar in Ohio University's African American Studies Department. "However, when a white woman adopts similar styles or the same, they are celebrated by mainstream culture in ways that black women are not." Dreadlocks are considered dirty, until they show up on white models on Marc Jacobs's runway. Or, cornrows are associated with criminals, until Kylie Jenner posts hers on Instagram.

"Marginalized cultures serve as the repository for mainstream culture," Houston explains. Often people in positions of privilege feel free to take as they please, without giving credit or thought to the culture they take from. It's not just black culture. LGBTQ, Native American, Latino, Asian, and other communities are also treated as a spice that can season an otherwise bland mainstream culture, a metaphor popularized by feminist theorist and cultural critic bell hooks. Need to add a "cool" hipster factor to your boring festival outfit? Throw in a Native American headdress — without any awareness that many native people consider them sacred.

Beauty traditions are an especially popular source of "inspiration" for mainstream pop culture. Just like claims of colour blindness, the idea that any culture should be able to borrow looks from another ignores important historical context. After coming under fire for featuring dreadlocks on an almost all-white runway cast in 2016, Marc Jacobs created a false equivalency and said it was "funny how you don't criticize women of colour for straightening their hair." But actually it's not funny at all that women of colour are quietly expected to conform to typically white standards. Houston says that any discussion of cultural appropriation must consider our country's past and current relationship with race.

Thanks in part to the vocal presence of Black Twitter, along with the work of more traditional advocacy groups, problematic instances of cultural appropriation get more attention today. As Houston recognises, some people might see this as an overreaction by the "PC police." But while each case of cultural borrowing should be judged on its own, he says common-sense guidelines exist. "When one engages in the use of another's culture it should include respectful citational celebration," Houston explains. "Just like you would credit the original author of a written piece or music composition, one should credit a culture whose work serves as an inspiration or canvas from which one draws on." In addition to giving credit, one should also avoid perpetuating blatant stereotypes, which can do harm to members of a marginalized group.

When a public figure does cause a controversy, Houston suggests they take time to understand a culture and themselves. "Once caught up, own and acknowledge," Houston advises. "At the same time, I recognise that some celebrity figures, particularly those famous for doing nothing but product advertising, create these media spectacles to generate and sustain the longevity of their brand." Whatever their intentions — ignorant or cynical — public instances of cultural appropriation offer us all a chance to better understand different cultures and ourselves. Here are 15 recent examples from the beauty world to get us started.