This article is about call and response as a musical pattern. For other meanings see: Call and response (disambiguation).
In music, a call and response is a succession of two distinct phrases usually played by different musicians, where the second phrase is heard as a direct commentary on or response to the first. It corresponds to the call-and-response pattern in human communication and is found in many traditions.
In Sub-Saharan African cultures, call and response is a pervasive pattern of democratic participation -- in public gatherings in the discussion of civic affairs, in religious rituals, as well as in vocal and instrumental musical expression. It is this tradition that African bondsmen and women brought with them to the New World and which has been transmitted over the centuries in various forms of cultural expression -- in religious observance; public gatherings; sporting events; even in children's rhymes; and, most notably, in African-American music in its myriad forms and descendants including: gospel, blues, rhythm and blues, jazz and jazz extensions.
These forms also possibly influenced the evolution of call and response in the ancient Indian Classical Music technique of Jugalbandi.
Call and response is likewise widely present in other parts of the Americas touched by the trans-Atlantic slave trade. Known under the Spanish term coro-pregon, it can be found in Afro-Latin music based on religious chants.

Classical music
The phenomenon of call and response is pervasive in modern Western popular music, as well, largely because Western music has been so heavily shaped by African contributions. Cross-over rhythm and blues, rock 'n' roll, and rock music exhibit call-and-response characteristics, as well. One example is The Who's song, My Generation:

Where call and response is most apparent in the secular music arena is in traditional and electric blues, where the most common 12-bar form is an AA'B pattern where the AA' is the call (repeated once with slight variation), and B is the response. But, each A and B part may itself consist of a short call and a short response, and those 2-bar calls and response may also be divided into 1-bar-each call-response pairs.
To make an attempt at diagraming it:
Note that each turnaround can be considered a call which the next A section is the response to.

A: 4-bar CALL

• (2-bar vocal CALL
  
  
  
  • [1-bar CALL, 1-bar RESPONSE]
    2-bar instrumental RESPONSE
    
    
    
    • [1-bar CALL, 1-bar RESPONSE])
      A': 4-bar CALL (repeated with slight variation)
      
      
      
      • (2-bar vocal CALL
        
        
        
        • [1-bar CALL, 1-bar RESPONSE]
          2-bar instrumental RESPONSE
          
          
          
          • [1-bar CALL, 1-bar RESPONSE])
            B: 4-bar RESPONSE (repeated)
            
            
            
            • (2-bar vocal CALL
              
              
              
              • [1-bar CALL, 1-bar RESPONSE]
                2-bar instrumental RESPONSE/turnaround
                
                
                
                • [1-bar CALL, 1-bar RESPONSE]) Popular music
                  A single leader makes a musical statement, and then the chorus responds together. American bluesman Bo Diddley utilizes call and response in one of his signature songs, "I'm a Man," which is almost entirely Leader/Chorus call and response.
                  
                  CALL: Diddley's vocal: "Now when I was a little boy"
                  RESPONSE: (Harmonica/rhythm section riff)
                  CALL: Diddley: "At the age of 5"
                  RESPONSE: (Harmonica/rhythm section riff) Question/Answer call and response
                  A distinct section in North Indian Classical Music is known as sawaal-javaab (question-answer). Primarily an instrumental technique, the sawaal-javaab occurs between two artists. One artist will present a melodically and rhythmically challenging riff which will be either replicated or improved upon by the other artist.