The bass guitar, electric bass, or simply bass, is the lowest-pitched member of the guitar family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck and scale length, and typically four to six strings or courses. Since the mid-1950s, the bass guitar has largely replaced the double bass in popular music. The four-string bass is usually tuned the same as the double bass, which corresponds to pitches one octave lower than the four lowest-pitched strings of a guitar (E, A, D, and G). It is played primarily with the fingers or thumb, or by striking with a pick. The electric bass guitar has pickups and must be connected to an amplifier and speaker.