Street bands playing Rock’n’Roll in Berlin, Marvin Gaye on the jukebox in a Thailand bar, Nas blaring on the streets of Johannesburg, house music in the mega-clubs of Shanghai — wherever one goes in the world today, no effort is needed to find African-American music and its derivatives.
The embellishment of African-derived rhythm and melody with European harmonics gave birth to Jazz, arguably the most significant musical explosion of the last millennium. In the 100 years since, African-American music — which became largely synonymous with American music — has been wielding a tremendous amount of global influence. The spread of this influence accelerated after World War 2, as the US became a global economic and military super power, aggressively pursuing a program of cultural imperialism and which increasingly saturated the world with its ideas, stories, images and sounds.
But there is one peculiar thing which nearly all American music has in common — and the more one considers it, the more peculiar it becomes: an extensive emphasis on a rhythm very different from that found almost anywhere else in the world. It goes like this: Boom – Bap – Boom – Bap, with a kick drum on the 1st and 3rd beat, or all 4, a snare drum precisely on the 2 and 4, with nearly nothing between except maybe a high hat, and no major hits ever landing off the grid. This rhythm is called the “Duple” in music theory, and you can find variations of it driving all modern popular American music styles: Blues, Motown, Soul, Funk, Rock, Disco, Hip Hop, House, Pop, and more.
The pervasive dominance of this simplified, rigid, and mechanical mono-rhythm, minimizing poly-rhythmic elements in the music to the role of embellishment, sometimes to the point of non-existence, is very different from the focus on complex polyrhythms in various forms of modern South American and Caribbean music. Cuban Son and Rumba, Brazillian Bossa Nova, Haitian Gwo Ka and Compas, Trinidadian Calypso … none of them rely so extensively on the Duple (besides sub-genres which were directly influenced by US exports, such as Ska Reggae, which heavily borrows from the Rhythm ‘n Blues of the 50s).
And if we zoom out to look at great traditions of music of the world — Asia, the Middle East, Africa — with zero exceptions, the Duple beat is never a central element, and hardly even exists at all in the major bodies of music produced by these ancient cultures. All of them are based on intricately interlocking polyrhythms arranged in hypnotic, complex mathematical patterns.
(The much younger European classical tradition, which developed as entertainment for royalty and the rich, has always regarded rhythm as an element of the underclasses and ‘primitives’, and according to Piero Scaruffi has “long discarded African music as an oddity of the animal kingdom” . With very few exceptions, these attitudes and a refusal to accept African music and its offspring continued all the way through the 20th century until today, which explains the increasing gap between it and the rest of the world.)
Slavery and duple roots
So how did North American modern music become so different? Why did the evolution of American rhythm take this unique path? The answer is very complex, and includes elements such as Native American tribal influence and the folk music of the European colonists, most of which used relatively simple rhythms. But there is another, perhaps even more important factor which might explain this phenomenon, a single historical process which began in the early days of America. Historians and scholars have written much about it, but the story remains relatively untold in the public sphere. The following is a condensed, brief and generalized version.
When first brought to North America during the 1600s and 1700s, slaves from the west coast of Africa used drums to communicate with each other in much the same way as they did at home, sending coded rhythmic messages Europeans could not understand over long distances. In this way slaves held in different encampments could stay in contact, and rebellions could be planned. But after some time the masters realised that the drums could talk.
“It is absolutely necessary to the safety of this Province, that all due care be taken to restrain Negroes from using or keeping of drums, which may call together or give sign or notice to one another of their wicked designs and purposes.”
— Slave Code of South Carolina, Article 36 (1740).
Starting on the plantations of the Carolinas and Georgia, this ban soon spread across the United States. Without drums, slaves used whatever was around to make beats: spoons, washboards, furniture, and their own bodies with hand-clapping, drumming on various surfaces of the body (Patting Juba), and foot-stomping and shuffling (Ring Shout).
“It always rouses my imagination,” wrote Lydia Parrish of the Georgia Sea Islands in 1942, “to see the way in which the McIntosh County ‘shouters’ tap their heels on the resonant floor to imitate the beat of the drum their forebears were not allowed to have.” 
These earlier practices are also the origin of modern art forms like tap dancing.
The most widely used substitute for drums, partly because of its ready availability, was the human voice. Field hollers, call and response, work songs, prison songs, and all kinds of vocality were developed, with the voice often replicating drum patterns and creating counterpoints, using standard singing, chanting, as well as extended techniques such as guttural effects, interpolated vocality and melisma. Sounds of the work itself, such as chopping wood or marching, as well as foot stomping or hand clapping during off hours, provided a basic time signature over which the polyrhythmic vocal sounds could improvise (the roots of scat singing). Sometimes imitating the beats of many drums in one line, these vocal elements filled the incremental spaces between each clap of the hand or fall of the hammer, and played an important role in the preservation of African rhythmic heritage.
Haitian Compas music:https://www.youtube.com/watch?v=mYsGw3W_qdU
Black slave music / mainstream white culture
Thus African rhythmic traditions survived through mutation and adaptation, and formed the drum-less foundation of American music. The descendants of these earlier styles later became wildly popular, beginning in the 19th Century: Ragtime, Minstrelsy, Spirituals, Salon Music, Jubilee, Blues, and Gospel. The appropriation of black slave music by white mainstream society started at this time with the phenomenon of Blackface minstrelsy. One of the first and most enduring artists / thieves was Stephen Foster, who took African derived rhythms played on the African-derived instrument the Banjo, and incorporated them into songs such as Oh Susana (which became one of the most popular American songs of all time). This, and the mixing of African slave traditions with European folk music, formed the basis of Country music.
“One of the reasons country music was created by African-Americans, as well as European-Americans, is because blacks and whites in rural communities in the south often worked and played together” — DeFord Bailey 
And because the drums were taken away, the forms of West African music which were either purely vocal or featured the voice prominently, traditionally played without drums, using simple instruments, such as many kinds of narrative song cycles in the Griot traditions of Mali and Senegal, took root in a big way and gained wide popularity in the deep South. No specific African musical form can be identified as the single direct ancestor of the Blues, but many elements of the Blues, such as the call-and-response format and the use of blue notes, can be traced back to the music of Africa. 
Historians have also speculated that the Spanish slavers, who first set up colonies in the Americas in South America, and had at that time not long expelled the North African Moors after 800 years of Islamic rule back home, preferred not to import Afro-Muslims. Thus a higher concentration of people from the Sahel / Mali / Senegal region, many of whom were Muslim, ended up in North America, bringing with them their more vocal and string-based musical traditions. Conversely, more people from the Congo / Ghana / Nigeria region arrived in South America and the Caribbean, with their more extensive drumming traditions.
Here’s a classic sound collage by Alan Lomax, comparing traditional vocal music from Africa and vocal music from the Delta, alternating, line by line, between American and Senegalese singing:https://www.youtube.com/watch?v=Cnx47gpSVLc
The direct ancestor of the banjo was the Malian/Senegalese instrument Xalam or Ngoni, widely used by Griots:https://www.youtube.com/watch?v=kOaLjU1CyTE
Exceptions to the rules
There was one exception to drum-lessness: due to the Catholic laws in Louisiana being different from the protestant ones in Georgia and the Carolinas, drums were not banned in New Orleans, the centre of the American slave trade, until much later, in the second half of the 19th Century. This and other crucial social conditions were the ingredients of a series of cultural / musical explosions that would change the course of music forever.
Prior to the waves of repression that would follow later, this port city (which was directly connected to Cuba and the Caribbean) included a substantial Creole land-owning middle class, so that “black” was not automatically equated with slavery — an anomaly in the South at the time, to say the least. Before the 1890s, when this mixed race group suddenly lost their privilege and equality, they participated in every level of society, including politics, making a huge difference in terms of racial tolerance, inclusiveness, cultural exchange with Cuba, and the development of both local music as well as music in Cuba.
“Untouched by the industrial revolution and less socially stressed than other plantation-oriented economies, New Orleans was able to retain the traditions of the various ethnic groups while they were rapidly being annihilated in the rest of the USA.” — Piero Scaruffi 
An economy based on trade meant less regimented attitudes and more respect for difference. Also, Southern Europeans, due to their countries of origin being closer to Africa, and already heavily influenced by African culture, had somewhat different ideas from the Northern Europeans in their treatment of slaves. New Orleans brothels allowed sex across the colour line (not just unheard of but completely mind-boggling in the 1800s) all the way until 1918 when the US government forced the mayor of New Orleans to segregate.
In an atmosphere of relative tolerance and less repressive laws, for much of the 19th century this opulent melting pot city was host to vibrant nightlife, exotic rituals, tribal dances, pagan festivals, funeral marches and all kinds of parties that never seemed to stop. Further, there was one place, indeed the only place on the entire continent, the “Congo Square” in the Tremé neighborhood, where slaves had for a long time been allowed to make music.
“In Louisiana during the 18th century, slaves were commonly allowed Sundays off from their work. They were allowed to gather in the “Place de Negres”, informally “Place Congo”, where the slaves would set up a market, sing, dance, and play music.” — Peter Kolchin 
Jazz and the birth of Rock ‘n Roll
The dominant rhythmic figure popular in New Orleans and performed on Congo Square during this time, with origins in many different slave musics of the Caribbean, is the three-stroke pattern known in Cuban music as tresillo (06). Louis Armstrong must have heard it plenty as a boy growing up mere blocks from Congo Square. In the post-Civil War period, African-Americans in New Orleans were able to obtain surplus military bass drums, snare drums, fifes, trumpets and saxophones. As a result, an original African-American fife and drum music arose, featuring tresillo and related syncopated rhythmic figures.
“Tresillo is the most basic and by far, the most prevalent duple-pulse rhythmic cell in sub-Saharan African music traditions, and the music of the African Diaspora.” — David Peñalosa 
And so it was in the brothels and bars of the red-light district of New Orleans where a potent combination of Blues, Ragtime, Quadrilles, Salon Music, Afro-Latin music, Native American music, European folk music and Marching Bands, played by multi-racial musicians who shared a passion for syncopation and improvisation, with discarded military brass and reed instruments, first came together to form what we know as Jazz.
“It is probably safe to say that by and large the simpler African rhythmic patterns survived in jazz … because they could be adapted more readily to European rhythmic conceptions. Some survived, others were discarded as the Europeanization progressed. It may also account for the fact that patterns such as tresillo have remained one of the most useful and common syncopated patterns in jazz.” — Gunther Schuller 
A few decades later a new hybrid style with even more reduced, simplistic, and obvious drum beats was born in the same city, in fact the exact same neighborhood: the first Rock ‘n’ Roll records were made in the Tremé district.
“Without New Orleans’ rich musical contribution there would have been no Elvis Presley or The Beatles. Both acts were heavily influenced by the songs recorded by Fats Domino and Little Richards at Cosimo Matassa’s Studios (close to Congo Square).” — Fabian Jolivet.
So there you have it: Jazz and Rock’n’Roll, probably the two most significant American cultural exports ever, both born in the only place in America where for a few decades slaves were allowed to play drums and dance.
Global music, afro roots
Though New Orleans Jazz did sometimes use rhythm patterns more subtle and complex than the Duple (but still much less intricate and nuanced than its Afro-Latin and African influences), the much wider and older history of drum-lessness had a deeply profound effect on American music in general, and the Duple fundamentally shaped all popular music to come in the 20th Century.
There were of course other sources and reasons, both historical and modern: Native American music and Irish, Italian, German folk music such as the Oompah or Polka all used simple mono-rhythms; as well as modern environmental factors such as the rigid and repetitive sound of machines, factories, automobiles and trains in the industrialized landscape.
All of these cultures contributed to the complex hybrid that is American music, but from where I’m standing, as a person from East Asia, an outsider to American music, European music and African music alike, the origins of Jazz, Rock and Hip Hop are clearly located much more in the blues and slave music from both at home and Latin America than traditions mentioned above. If one accepts the seminal, foundational influence exerted by transplanted African culture, this legacy of drum-less evolution might just be the most important piece of the puzzle, the main answer to the question of how the Duple came to dominate American modern music.
But unlike African-Americans who re-invented their African musical heritage through memory and forgetfulness in a completely new context, Africans in Latin America and the Caribbean large preserved their historic drumming traditions, which survive nearly intact today.
The Caribbean influence
Drums were also banned in the Caribbean, in places like Trinidad — but only much later in the 19th Century. Slaves thus had a stronger connection to African rhythm culture, which was apparent when they started using frying pans, dustbin lids and oil drums after the ban (oil was an important national product), forming the Trinidadian tradition of Steel Pan and Steel Drum music . Similarly, drums were taken away from slaves in Cuba, and the roots of Rumba lie in Afro-Cubans playing African music with household items: “the side of a cabinet functioned in the role of the present-day tumba or salidor (the primary supportive drum), while an overturned drawer served as the quinto (the lead drum) and a pair of spoons played the cáscara part on whatever was available.” — David Peñalosa 
The handmade percussion instrument Claves, which came from hitting wooden pegs together in shipyards to accompany slave work songs, is now ubiquitous in all Cuban music and its derivatives from Son to Mambo to Salsa to Timba, playing the Clavé rhythm pattern of African origin.
Other reasons for the stronger ties with African culture in the Caribbean and South America include the much greater number of slaves — North America had 0.5 million; the Caribbean and South America had 5 million each) — as well as slavery lasting much longer. Also important were certain practices in slavery: in places like Cuba, unlike in North America, slaves were literally worked to death to increase the profit of the sugar trade. Since they were not bred to be sold (as they were in North America), fresh supplies had to be imported directly from Africa, a practice that continued in Havana until 1873. Thus Africans continued to arrive in South America constantly and much more frequently during the later period of the slave trade, maintaining their folkloric traditions through secret societies (particularly Yoruba and Kikongo) , producing amazing cultural hybrids such as Capoeira.https://www.youtube.com/watch?v=6H0D8VaIli0
Rhythm and resistance
As we have seen, rhythm in America took on a drastically different character as result of a particular historical process, a specific evolutionary path. This can be acutely felt today. Consider Hip Hop: the simple, skeletal ‘boom – bap’ beat is the modern version of foot-stomping and hand-clapping, performing the same function of time-keeping, and just as 500 years ago, complex vocal delivery (rap) fills in all the fractions of time between, imitating and substituting for drum patterns — a mutated continuation of African musical heritage.
Americans tend to react with defensiveness when this story is told. But while it is indisputable that American rhythm is in general relatively more simplified and rigid compared to most of the rest of the world, it’s not necessarily a bad thing. The raw physical force of simplicity, that punch-you-in-the-gut-and-make-you-see-stars brute power of American modern music cannot be denied. As a result of its development through the legacy of oppression and misery, American music is still without a doubt the best for expressions of anger, frustration and resentment in a modern world filled with injustice. On another level, perhaps rigid, mechanical rhythms just suit our rigid and mechanical urban lifestyles better than organic polyrhythms; and the information saturated and sound-polluted environments in which we live might explain the modern taste for stripped down and minimalistic beats. Besides, the understatement of subtle, implicit or suggested polyrhythms in a lot of African-American music gives it beautiful new qualities and possibilities not found in African music.
But in many ways explicit use of African polyrhythms is returning to African-American music, from the self-conscious attempts to reconnect with Motherland culture made by musicians in the 1960s and 70s to the Chicago Juke / Footwork of today. It seems unlikely that only one type of rhythm can sustain all these different kinds of music for long, and I think we are currently in the process of a global polyrhythmic revival.
Now we come to the grand finale, rainbow-in-the-sky, lighters-in-the-air, closing message of this long and dense story spanning half a millennium: African rhythm heritage not only survives but thrives in any hostile environment, despite every hardship, against every repressive measure, in defiance of all forces that tries to destroy it.
Thanks to Keith Jones, Wayne Marshall and Darius James.
(01) Scaruffi, Piero. A History of Popular Music before Rock Music
(02) Palmer, Robert. Deep Blues
(03) Kingsbury Paul. The encyclopedia of country music: the ultimate guide to the music
(04) David Evans. The Curious Listener’s Guide to the Blues
(05) Kolchin, Peter. American Slavery: 1619-1877
(06) Sublette, Ned. The World that made New Orleans: from Spanish silver to Congo Square
(07) Peñalosa, David. The Clave Matrix; Afro-Cuban Rhythm: Its Principles and African Origins
(08) Schuller, Gunther. Early Jazz; Its Roots and Musical Development
(09) Palmer, Robert. Deep Blues
(10) Saldenha, Robert. Another Look At The History Of The Steel Band
(11) Peñalosa, David. Rumba Quinto
(12) Sublette, Ned. A History of Cuba and its Music
Over the years I’ve heard people say things like “at least slavery gave us good music”, or “without slavery music would be boring”.
To this I respond:
1. Cultures mix via trade and other means all the time, such as the cultures all along the “Silk Road” trade routes. For example Turkish ideas inspired Chinese music and vice versa, without war or violence, and the resulting Uyghur music is anything but boring. Similarly, Africa could have met Europe in a number of different ways, without subjugation or slavery.
2. Given that much of American music was born in the only place where slaves were allowed to make music, what kinds of creativity would have blossomed from the meeting of African and European musical ideas if the slaves had been allowed to make music anywhere in America? What if there was no slavery at all and musicians could collaborate and inspire each other on equal footing? And what if Europeans were never blinded by ignorance and racism, and had combined their developed harmony with sophisticated African rhythm starting from a much earlier time?
3. Slavery created a particular need to express anger, sadness and resentment through music, and we have come to prize and “enjoy” these qualities in music. But we should not get confused and believe these qualities to be inherently, naturally good. Because without that legacy of abuse, it is possible we would not enjoy angry and sad music at all, and would have come to appreciate other qualities instead.
4. Yes, something good can come out of any catastrophic and violent injustice, but this is because of the strength of the human spirit and the endurance of culture, not because of the injustice.
5. Any argument that any part of slavery, however small, was good in any way, is an attempt to justify racist violence.