The generation entering maturity in the 1950s and 1960s were known as the "civil rights generation," since their social activism resulted in President Lyndon B. Johnson eventually signing the Civil Rights Act of 1964. Segregation and institutional prejudice were now outlawed. Their children, the "hip hop generation," experienced a different set of problems, including inner-city crime and the crack epidemic.
From the early 1970s, the DJ Clive Campbell (1955-present) began organizing hip hop music parties in New York City's Bronx borough. Also known as DJ Kool Herc, Campbell was responsible for a number of innovations, including sampling the drum beat of hard funk labels. Another Bronx resident, Grandmater Flash, refined a technique for "scratching" records, or shifting the record on the turntable to create a distinct phrasing. In addition to innovations in live music, distinctive elements of hip hop were graffiti art and breakdancing.
Between the late 1970s and 1980s, cities such as New York City and Detroit experienced a crime wave, with gang violence especially on the rise. By 1980, the the crack epidemic, which mostly affected the same African-American communities, was underway on the East Coast. Historians like Bakari Kitwani write that hip hop was an opportunity for youths to avoid becoming involved with gang violence or heavy drug use.
Hip hop has found a global audience, with artists like MIA emerging from Sri Lanka. Counties as diverse as Nigeria and Albania have distinct hip hop sub-cultures. Harvard University professor Orlando Patterson has studied rap as a "cultural response to historic oppression and racism, a system for communication among black communities throughout the United States." Patterson also describes how rap has taken advantage of globalized systems of mass communication.
The hip hop generation has been criticized for what is perceived as commercialism at the expense of artistry, and the encouragement of violence. According to an article in the Seattle Post Intelligencer, the criticism of over-commercialized music was particularly pointed when the hip hop niche went from underground to being "found everywhere from a Burger King commercial to episodes of Blue's Clues." After two prominent rappers, Tupac and Notorious B.I.G., were killed in a span of seven months in 1996 and 1997, hip hop music was the subject of a strong backlash, especially since gangsta rap is a subgenre of hip hop.